eaogorg.files.wordpress.com€¦ · Web viewGEOCHEMISTRY ARTICLES – November 2018. Analytical...

GEOCHEMISTRY ARTICLES – November 2018

Analytical Chemistry

Afshar Mogaddam, M.R., Mohebbi, A., Pazhohan, A., Khodadadeian, F., Farajzadeh, M.A., 2019. Headspace mode of liquid phase microextraction: A review. TrAC Trends in Analytical Chemistry 110, 8-14.

Anger, P.M., von der Esch, E., Baumann, T., Elsner, M., Niessner, R., Ivleva, N.P., 2018. Raman microspectroscopy as a tool for microplastic particle analysis. TrAC Trends in Analytical Chemistry 109, 214-226.

Bäuchle, M., Lüdecke, T., Rabieh, S., Calnek, K., Bromage, T.G., 2018. Quantification of 71 detected elements from Li to U for aqueous samples by simultaneous-inductively coupled plasma-mass spectrometry. RSC Advances 8, 37008-37020.

Cabernard, L., Roscher, L., Lorenz, C., Gerdts, G., Primpke, S., 2018. Comparison of Raman and Fourier transform infrared spectroscopy for the quantification of microplastics in the aquatic environment. Environmental Science & Technology 52, 13279-13288.

Dal Poggetto, G., Castañar, L., Foroozandeh, M., Kiraly, P., Adams, R.W., Morris, G.A., Nilsson, M., 2018. Unexploited dimension: New software for mixture analysis by 3D diffusion-ordered NMR spectroscopy. Analytical Chemistry 90, 13695-13701.

Háková, M., Chocholoušová Havlíková, L., Solich, P., Švec, F., Šatínský, D., 2019. Electrospun nanofiber polymers as extraction phases in analytical chemistry – The advances of the last decade. TrAC Trends in Analytical Chemistry 110, 81-96.

Hang, L., Xu, Z., Yin, Z., Hang, W., 2018. Approaching standardless quantitative elemental analysis of solids: Microsecond pulsed glow discharge and buffer-gas-assisted laser ionization time-of-flight mass spectrometry. Analytical Chemistry 90, 13222-13228.

López-López, J.A., Mendiguchía, C., Pinto, J.J., Moreno, C., 2019. Application of solvent-bar micro-extraction for the determination of organic and inorganic compounds. TrAC Trends in Analytical Chemistry 110, 57-65.

Perminova, I.V., Shirshin, E.A., Konstantinov, A.I., Zherebker, A., Lebedev, V.A., Dubinenkov, I.V., Kulikova, N.A., Nikolaev, E.N., Bulygina, E., Holmes, R.M., 2018. The structural arrangement and relative abundance of aliphatic units may effect long-wave absorbance of natural organic matter as revealed by 1H NMR spectroscopy. Environmental Science & Technology 52, 12526-12537.

GAS CHROMATOGRAPHY/GC×GC/GC-MS

Bai, L., Carlton, D.D., Schug, K.A., 2018. Complex mixture quantification without calibration using gas chromatography and a comprehensive carbon reactor in conjunction with flame ionization detection. Journal of Separation Science 41, 4031-4037.

Giardina, M., McCurry, J.D., Cardinael, P., Semard-Jousset, G., Cordero, C., Bicchi, C., 2018. Development and validation of a pneumatic model for the reversed-flow differential flow modulator for comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1577, 72-81.

Han, X., Liu, J., Wang, B., Du, A., Xu, L., Wu, B., 2018. Synthesis and chromatographic applications of polysiloxane-based stationary phase containing nitrogen heterocyclic system. Journal of Chromatography A 1578, 76-82.

Idowu, I., Johnson, W., Francisco, O., Obal, T., Marvin, C., Thomas, P.J., Sandau, C.D., Stetefeld, J., Tomy, G.T., 2018. Comprehensive two-dimensional gas chromatography high-resolution mass spectrometry for the analysis of substituted and unsubstituted polycyclic aromatic compounds in environmental samples. Journal of Chromatography A 1579, 106-114.

Olarte, M.V., Albrecht, K.O., Bays, J.T., Polikarpov, E., Maddi, B., Linehan, J.C., O'Hagan, M.J., Gaspar, D.J., 2019. Autoignition and select properties of low sample volume thermochemical mixtures from renewable sources. Fuel 238, 493-506.

Patil, R.A., Talebi, M., Sidisky, L.M., Berthod, A., Armstrong, D.W., 2018. Gas chromatography selectivity of new phosphonium-based dicationic ionic liquid stationary phases. Journal of Separation Science 41, 4142-4148.

Patrushev, Y.V., Sidelnikov, V.N., 2018. Selection of the porous layer open tubular columns for separation of light components in comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1579, 83-88.

Piotrowski, P.K., Tasker, T.L., Burgos, W.D., Dorman, F.L., 2018. Applications of thermal desorption coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for hydrocarbon fingerprinting of hydraulically fractured shale rocks. Journal of Chromatography A 1579, 99-105.

Regmi, B.P., Agah, M., 2018. Micro gas chromatography: An overview of critical components and their integration. Analytical Chemistry 90, 13133-13150.

Romanczyk, M., Ramirez Velasco, J.H., Xu, L., Vozka, P., Dissanayake, P., Wehde, K.E., Roe, N., Keating, E., Kilaz, G., Trice, R.W., Luning Prak, D.J., Kenttӓmaa, H., 2019. The capability of organic compounds to swell acrylonitrile butadiene O-rings and their effects on O-ring mechanical properties. Fuel 238, 483-492.

Samokhin, A., 2018. Spectral skewing in gas chromatography–mass spectrometry: Misconceptions and realities. Journal of Chromatography A 1576, 113-119.

Scarlett, A.G., Despaigne-Diaz, A.I., Wilde, S.A., Grice, K., 2019. An examination by GC×GC-TOFMS of organic molecules present in highly degraded oils emerging from Caribbean terrestrial seeps of Cretaceous age. Geoscience Frontiers 10, 5-15.

Shafer, W.D., Davis, B.H., 2018. Exchange interference for a range of partially deuterated hydrocarbons using a GC-EI-MSD. Journal of Mass Spectrometry 53, 1169-1177.

Šuklje, K., Carlin, S., Stanstrup, J., Antalick, G., Blackman, J.W., Meeks, C., Deloire, A., Schmidtke, L.M., Vrhovsek, U., 2019. Unravelling wine volatile evolution during Shiraz

grape ripening by untargeted HS-SPME-GC×GC-TOFMS. Food Chemistry 277, 753-765.

Veenaas, C., Linusson, A., Haglund, P., 2018. Retention-time prediction in comprehensive two-dimensional gas chromatography to aid identification of unknown contaminants. Analytical and Bioanalytical Chemistry 410, 7931-7941.

Wang, G., Simoneit, B.R.T., Shi, S., Wang, T., Zhong, N., Wang, P., 2018. A GC×GC-ToFMS investigation of the unresolved complex mixture and associated biomarkers in biodegraded petroleum. Acta Geologica Sinica - English Edition 92, 1959-1972.

Wang, X., Nie, J., Yu, G., Wang, P., Li, Z., Lee, M., 2018. Microwave-assisted-demulsification–dispersive liquid–liquid microextraction coupled with gas chromatography–mass spectrometry for the determination of PAHs in water. Analytical Methods 10, 5105-5111.

Yang, Y., Qi, M., Wang, J., 2018. Separation performance of a star-shaped truxene-based stationary phase functionalized with peripheral 3,4-ethylenedioxythiophene moieties for capillary gas chromatography. Journal of Chromatography A 1578, 67-75.

Zhang, G., Yang, C., Serhan, M., Koivu, G., Yang, Z., Hollebone, B., Lambert, P., Brown, C.E., 2018. Characterization of nitrogen-containing polycyclic aromatic heterocycles in crude oils and refined petroleum products. Advances in Marine Biology 81, 59-96.

IMAGING: SEM, TEM, HIM, AFM

Afsharpoor, A., Javadpour, F., 2018. Pore connectivity between organic and inorganic matter in shale: Network modeling of mercury capillary pressure. Transport in Porous Media 125, 503-519.

Almeida, G.M.F., Leppänen, M., Maasilta, I.J., Sundberg, L.-R., 2018. Bacteriophage imaging: past, present and future. Research in Microbiology 169, 488-494.

Al-Shabib, N.A., Husain, F.M., Ahmed, F., Khan, R.A., Khan, M.S., Ansari, F.A., Alam, M.Z., Ahmed, M.A., Khan, M.S., Baig, M.H., Khan, J.M., Shahzad, S.A., Arshad, M., Alyousef, A., Ahmad, I., 2018. Low temperature synthesis of superparamagnetic iron oxide (Fe3O4) nanoparticles and their ROS mediated inhibition of biofilm formed by food-associated bacteria. Frontiers in Microbiology 9, 2567. doi: 2510.3389/fmicb.2018.02567.

Bankole, S.A., Buckman, J., Stow, D., Lever, H., 2019. Grain-size analysis of mudrocks: A new semi-automated method from SEM images. Journal of Petroleum Science and Engineering 174, 244-256.

Borrelli, M., Campilongo, G., Critelli, S., Perrotta Ida, D., Perri, E., 2019. 3D nanopores modeling using TEM-tomography (dolostones - Upper Triassic). Marine and Petroleum Geology 99, 443-452.

Cao, T., Deng, M., Song, Z., Luo, H., Hursthouse, A.S., 2018. Characteristics and controlling factors of pore structure of the Permian shale in southern Anhui province, East China. Journal of Natural Gas Science and Engineering 60, 228-245.

Chen, D., Zhang, J., Wang, X., Lan, B., Li, Z., Liu, T., 2018. Characteristics of lacustrine shale reservoir and its effect on methane adsorption capacity in Fuxin Basin. Energy & Fuels 32, 11105-11117.

Fang, T., Zhang, L., Liu, N., Zhang, L., Wang, W., Yu, L., Li, C., Lei, Y., 2018. Quantitative characterization of pore structure of the Carboniferous–Permian tight sandstone gas reservoirs in eastern Linqing depression by using NMR technique. Petroleum Research 3, 110-123.

Fisenko, A.V., Verchovsky, A.B., Shiryaev, A.A., Semjonova, L.F., Averin, A.A., Vasiliev, A.L., Nickolsky, M.S., 2018. On the carrier phase of the “planetary” noble gases: TEM, Raman, and stepped combustion data for acid-resistant residues from the Saratov (L4) meteorite. Meteoritics & Planetary Science 53, 2343-2356.

Gao, P., Liu, G., Lash, G.G., Li, B., Yan, D., Chen, C., 2018. Occurrences and origin of reservoir solid bitumen in Sinian Dengying Formation dolomites of the Sichuan Basin, SW China. International Journal of Coal Geology 200, 135-152.

Gholami, F., Mosmeri, H., Shavandi, M., Dastgheib, S.M.M., Amoozegar, M.A., 2019. Application of encapsulated magnesium peroxide (MgO2) nanoparticles in permeable reactive barrier (PRB) for naphthalene and toluene bioremediation from groundwater. Science of The Total Environment 655, 633-640.

Gómez Dacal, A.R., Richiano, S.M., Gómez Peral, L.E., Spalletti, L.A., Sial, A.N., Poiré, D.G., 2019. Evidence of warm seas in high latitudes of southern South America during the Early Cretaceous. Cretaceous Research 95, 8-20.

Gong, Y., Qiao, C., Yu, X., Wang, J., Gong, D., 2019. Study on the ancient putty from the site of the Ming Dynasty (1368–1644 CE) Baochuanchang Shipyard, Nanjing, China. Journal of Archaeological Science: Reports 23, 189-195.

Hao, B., Zhao, W., Hu, S., Shi, S., Gao, P., Wang, T., Huang, S., Jiang, H., 2018. Bitumen formation of Cambrian Longwangmiao Formation in the central Sichuan and its implication for hydrocarbon accumulation. Petroleum Research 3, 44-56.

Hao, X.-L., Li, Y.-L., 2018. Experimental approach to the direct interaction between the H2O-CO2 atmosphere and the crust on the earliest Earth: Implications for the early evolution of minerals and the proto-atmosphere. Frontiers in Earth Science 6, 180. doi: 110.3389/feart.2018.00180.

Jones, C.G., Martynowycz, M.W., Hattne, J., Fulton, T.J., Stoltz, B.M., Rodriguez, J.A., Nelson, H.M., Gonen, T., 2018. The CryoEM method MicroED as a powerful tool for small molecule structure determination. ACS Central Science 4, 1587-1592.

Kazak, A., Chugunov, S., Chashkov, A., 2018. Integration of large-area scanning-electron-microscopy imaging and automated mineralogy/petrography data for selection of nanoscale pore-space characterization sites. SPE-191369-PA 21, 821-836.

Li, K., Zhao, L.-S., Sun, H.-M., Tang, R.-C., Chen, Z.-H., Su, H.-N., Chen, X.-L., Zhang, Y.-Z., 2018. Capsular polysaccharide production from Zunongwangia profunda SM-A87 monitored at single cell level by atomic force microscopy. Deep Sea Research Part II: Topical Studies in Oceanography 155, 44-49.

Li, N., Zhong, T., Liu, J.-l., Zheng, J., Deng, H.-c., Zhou, W., Li, M., Feng, M.-s., Liu, Q.-j., Li, C.-y., 2018. Precise identification and analysis of micro/nano-sized pore structure in shale with Fe3O4/Au hybrid nanocomposite. Analytical Chemistry 90, 12706-12713.

Liu, K., Ostadhassan, M., Gentzis, T., Fowler, H., 2019. Image analysis of the pore structures: An intensive study for Middle Bakken. Journal of Natural Gas Science and Engineering 61, 32-45.

Liu, Z., Gao, B., Hu, Z., Du, W., Nie, H., Jiang, T., 2018. Pore characteristics and formation mechanism of high-maturity organic-rich shale in Lower Cambrian Jiumenchong Formation, southern Guizhou. Petroleum Research 3, 57-65.

Misch, D., Klaver, J., Gross, D., Mayer-Kiener, V., Mendez-Martin, F., Schmatz, J., Sachsenhofer, R.F., 2018. Factors controlling shale microstructure and porosity: A case study on upper Visean Rudov beds from the Ukrainian Dneiper–Donets Basin. American Association of Petroleum Geologists Bulletin 102, 2629-2654.

Mitchell, A.C., Espinosa-Ortiz, E.J., Parks, S.L., Phillips, A., Cunningham, A.B., Gerlach, R., 2018. Kinetics of calcite precipitation by ureolytic bacteria under aerobic and anaerobic conditions. Biogeosciences Discussions 2018, 1-26.

Nagai, Y., Uematsu, K., Chen, C., Wani, R., Tyszka, J., Toyofuku, T., 2018. Weaving of biomineralization framework in rotaliid foraminifera: implications for paleoceanographic proxies. Biogeosciences 15, 6773-6789.

Pan, J., Lv, M., Hou, Q., Han, Y., Wang, K., 2019. Coal microcrystalline structural changes related to methane adsorption/desorption. Fuel 239, 13-23.

Philben, M., Butler, S., Billings, S.A., Benner, R., Edwards, K.A., Ziegler, S.E., 2018. Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues. Biogeosciences 15, 6731-6746.

Rajasekar, A., Wilkinson, S., Sekar, R., Bridge, J., Medina-Roldán, E., Moy, C.K.S., 2018. Biomineralisation performance of bacteria isolated from a landfill in China. Canadian Journal of Microbiology 64, 945-953.

Rosestolato, J.C.S., Pérez-Gramatges, A., Lachter, E.R., Nascimento, R.S.V., 2019. Lipid nanostructures as surfactant carriers for enhanced oil recovery. Fuel 239, 403-412.

Saxena, N., Kumar, A., Mandal, A., 2019. Adsorption analysis of natural anionic surfactant for enhanced oil recovery: The role of mineralogy, salinity, alkalinity and nanoparticles. Journal of Petroleum Science and Engineering 173, 1264-1283.

Shaldybin, M.V., Wilson, M.J., Wilson, L., Lopushnyak, Y.M., Brydson, R., Krupskaya, V.V., Kondrashova, E.S., Glotov, A.V., Goncharov, I.V., Samoilenko, V.V., Arbuzov, S.I., Bether, O.V., Fraser, A.R., Bowen, L., White, D., Dorofeeva, N.V., 2019. The nature, origin and significance of luminescent layers in the Bazhenov Shale Formation of West Siberia, Russia. Marine and Petroleum Geology 100, 358-375.

Sokol, J., 2018. Cracking the Cambrian. Science 362, 880-884.

Song, C., Elsworth, D., 2018. Strengthening mylonitized soft-coal reservoirs by microbial mineralization. International Journal of Coal Geology 200, 166-172.

Sun, L., Chin, W.-C., Chiu, M.-H., Xu, C., Lin, P., Schwehr, K.A., Quigg, A., Santschi, P.H., 2019. Sunlight induced aggregation of dissolved organic matter: Role of proteins in linking organic carbon and nitrogen cycling in seawater. Science of The Total Environment 654, 872-877.

Sun, W., Zuo, Y., Wu, Z., Liu, H., Xi, S., Shui, Y., Wang, J., Liu, R., Lin, J., 2019. Fractal analysis of pores and the pore structure of the Lower Cambrian Niutitang shale in northern Guizhou province: Investigations using NMR, SEM and image analyses. Marine and Petroleum Geology 99, 416-428.

Sun, X., Zhang, Y., Chen, G., Liu, T., Ren, D., Ma, J., Sheng, Y., Karwani, S., 2018. Wettability of hybrid nanofluid-treated sandstone/heavy oil/brine systems: Implications for enhanced heavy oil recovery potential. Energy & Fuels 32, 11118-11135.

Wang, D., Tian, B., Cao, M., Sun, Y., Li, S., Lu, T., Wang, J., 2018. Mechanism discussion of nanofluid for enhanced oil recovery: Adhesion work evaluation and direct force measurements between nanoparticles and surfaces. Energy & Fuels 32, 11390-11397.

Wang, P., Jiang, Z., Han, B., Lv, P., Jin, C., Zhang, K., Li, X., Li, T., 2018. Reservoir characteristics and controlling factor of shale gas in Lower Cambrian Niutitang Formation, South China. Petroleum Research 3, 210-220.

Wang, X., O’Connor, J.K., Maina, J.N., Pan, Y., Wang, M., Wang, Y., Zheng, X., Zhou, Z., 2018. Archaeorhynchus preserving significant soft tissue including probable fossilized lungs. Proceedings of the National Academy of Sciences 115, 11555-11560;.

Wei, Q., Li, X., Zhang, J., Hu, B., Zhu, W., Liang, W., Sun, K., 2019. Full-size pore structure characterization of deep-buried coals and its impact on methane adsorption capacity: A case study of the Shihezi Formation coals from the Panji Deep Area in Huainan Coalfield, Southern North China. Journal of Petroleum Science and Engineering 173, 975-989.

Wood, J.M., Sanei, H., Haeri-Ardakani, O., Curtis, M.E., Akai, T., 2018. Organic petrography and scanning electron microscopy imaging of a thermal maturity series from the Montney tight-gas and hydrocarbon liquids fairway. Bulletin of Canadian Petroleum Geology 66, 499-515.

Wüst, R.A.J., Tu, S., Nassichuk, B., Bozarth, T., Tucker, J., Cui, A., 2018. Chemostratigraphy, petrography, and SEM investigations of the Lower Triassic Montney Formation in Alberta: Implications for a new and revised diagenetic and depositional model. Bulletin of Canadian Petroleum Geology 66, 436-471.

Zhang, N., Thompson, C.E.L., Townend, I.H., Rankin, K.E., Paterson, D.M., Manning, A.J., 2018. Nondestructive 3D imaging and quantification of hydrated biofilm-sediment aggregates using X-ray microcomputed tomography. Environmental Science & Technology 52, 13306-13313.

Zhang, S., Yan, J., Hu, Q., Wang, J., Tian, T., Chao, J., Wang, M., 2019. Integrated NMR and FE-SEM methods for pore structure characterization of Shahejie shale from the Dongying Depression, Bohai Bay Basin. Marine and Petroleum Geology 100, 85-94.

Zhang, T., Wang, Q., Li, G., Zhao, Y., Lv, X., Luo, Y., Zhang, Y., 2019. Formation of carbon nanotubes from potassium catalyzed pyrolysis of bituminous coal. Fuel 239, 230-238.

IMAGING: XRAY CT

Alvarez, J.O., Tovar, F.D., Schechter, D.S., 2018. Improving oil recovery in the Wolfcamp reservoir by soaking/flowback production schedule with surfactant additives. SPE-191369-PA 21, 1083-1096.


Georgieva, M.N., Little, C.T.S., Bailey, R.J., Ball, A.D., Glover, A.G., 2018. Microbial-tubeworm associations in a 440 million year old hydrothermal vent community. Proceedings of the Royal Society B: Biological Sciences 285, Article 20182004.

Mehta, A.P., Supekova, L., Chen, J.-H., Pestonjamasp, K., Webster, P., Ko, Y., Henderson, S.C., McDermott, G., Supek, F., Schultz, P.G., 2018. Engineering yeast endosymbionts as a step toward the evolution of mitochondria. Proceedings of the National Academy of Sciences 115, 11796-11801.

Mendoza, A.M., Babak, P., Kantzas, A., 2018. Estimation of diffusion coefficients in liquid solvent–bitumen systems. Energy & Fuels 32, 11143-11152.

Qi, C., Wang, X., Wang, W., Liu, J., Tuo, J., Liu, K., 2018. Three-dimensional characterization of micro-fractures in shale reservoir rocks. Petroleum Research 3, 259-268.

Qi , C., Wang, X., Wang, W., Liu, J., Tuo, J., Liu, K., 2018. Three-dimensional fine characterization method of micro-fractures in shale reservoirs. Acta Petrolei Sinica 39, 1175-1185

Sampath, K.H.S.M., Perera, M.S.A., Li, D.-y., Ranjith, P.G., Matthai, S.K., 2019. Characterization of dynamic mechanical alterations of supercritical CO2-interacted coal through gamma-ray attenuation, ultrasonic and X-ray computed tomography techniques. Journal of Petroleum Science and Engineering 174, 268-280.


Zhang, P., Lu, S., Li, J., 2019. Characterization of pore size distributions of shale oil reservoirs: A case study from Dongying sag, Bohai Bay basin, China. Marine and Petroleum Geology 100, 297-308.


LIQUID CHROMATOGRAPHY/LC-MS/SFC

Adamopoulou, T., Deridder, S., Desmet, G., Schoenmakers, P.J., 2018. Two-dimensional insertable separation tool (TWIST) for flow confinement in spatial separations. Journal of Chromatography A 1577, 120-123.

Becker, C., Jochmann, M.A., Schmidt, T.C., 2019. An overview of approaches in liquid chromatography flame ionization detection. TrAC Trends in Analytical Chemistry 110, 143-149.

Brezinski, K., Gorczyca, B., 2019. An overview of the uses of high performance size exclusion chromatography (HPSEC) in the characterization of natural organic matter (NOM) in potable water, and ion-exchange applications. Chemosphere 217, 122-139.

Fichou, D., Morlock, G.E., 2018. Office chromatography: Miniaturized all-in-one open-source system for planar chromatography. Analytical Chemistry 90, 12647-12654.

Gimenes de Souza, C., Torres de Araújo, M., Cavalcante dos Santos, R., França de Andrade, D., Vasconcello da Silva, B., d′Avila, L.A., 2018. Analysis and quantitation of fatty acid methyl esters in biodiesel by high-performance liquid chromatography. Energy & Fuels 32, 11547-11554.

Higgins Keppler, E.A., Jenkins, C.L., Davis, T.J., Bean, H.D., 2018. Advances in the application of comprehensive two-dimensional gas chromatography in metabolomics. TrAC Trends in Analytical Chemistry 109, 275-286.

Marlot, L., Batteau, M., De Beer, D., Faure, K., 2018. In silico screening of comprehensive two-dimensional centrifugal partition chromatography × liquid chromatography for multiple compound isolation. Analytical Chemistry.

Zhou, W., Wang, J., Zhao, Y., Yu, L., Fang, Y., Jin, H., Zhou, H., Zhang, P., Liu, Y., Zhang, X., Liang, X., 2018. Discovery of β2- adrenoceptor agonists in Curcuma zedoaria Rosc using label-free cell phenotypic assay combined with two-dimensional liquid chromatography. Journal of Chromatography A 1577, 59-65.

MASS SPECTROSCOPY/ICR-FTMS/ORBITRAP

Antony, R., Willoughby, A.S., Grannas, A.M., Catanzano, V., Sleighter, R.L., Thamban, M., Hatcher, P.G., 2018. Photo-biochemical transformation of dissolved organic matter on the surface of the coastal East Antarctic ice sheet. Biogeochemistry 141, 229-247.

Bercovici, S.K., Koch, B.P., Lechtenfeld, O.J., McCallister, S.L., Schmitt-Kopplin, P., Hansell, D.A., 2018. Aging and molecular changes of dissolved organic matter between two deep oceanic end-members. Global Biogeochemical Cycles 32, 1449-1456.

Geng, C.-X., Cao, N., Xu, W., He, C., Yuan, Z.-W., Liu, J.-W., Shi, Q., Xu, C.-M., Liu, S.-T., Zhao, H.-Z., 2018. Molecular characterization of organics removed by a covalently bound inorganic–organic hybrid coagulant for advanced treatment of municipal sewage. Environmental Science & Technology 52, 12642-12648.

He, Z., Guo, M., Sleighter, R.L., Zhang, H., Chanel, F., Hatcher, P.G., 2018. Characterization of defatted cottonseed meal-derived pyrolysis bio-oil by ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Journal of Analytical and Applied Pyrolysis 136, 96-106.

Szykuła, K.M., Wicking, C., Whitmarsh, S., Creaser, C.S., Reynolds, J.C., 2018. Characterization of crude oil and its saturate, aromatic, and resin fractions by high-field asymmetric waveform ion mobility spectrometry–high-resolution mass spectrometry. Energy & Fuels 32, 11310-11316.

Wang, P., Zhang, Y., Xu, C., Zhang, W., Zhu, G., Li, Z., Ji, H., Shi, Q., 2018. Molecular characterization of ketones in a petroleum source rock. Energy & Fuels 32, 11136-11142.

GCXiao, L., Hu, S., Song, Y., Zhang, L., Han, H., Liu, C., Jiang, L., Xu, K., Su, S., Wang, Y., Xiang, J., 2019. The formation mechanism for OPAHs during the cellulose thermal conversion in inert atmosphere at different temperatures based on ESI(−) FT-ICR MS measurement and density functional theory (DFT). Fuel 239, 320-329.

Xiong, Z., Han, H., Azis, M.M., Hu, X., Wang, Y., Su, S., Hu, S., Xiang, J., 2019. Formation of the heavy tar during bio-oil pyrolysis: A study based on Fourier transform ion cyclotron resonance mass spectrometry. Fuel 239, 108-116.

Zuber, J., Rathsack, P., Otto, M., 2018. Structural characterization of acidic compounds in pyrolysis liquids using collision-induced dissociation and Fourier transform ion cyclotron resonance mass spectrometry. Analytical Chemistry 90, 12655-12662.

MASS SPECTROSCOPY/OTHER

Neubauer, C., Sweredoski, M.J., Moradian, A., Newman, D.K., Robins, R.J., Eiler, J.M., 2018. Scanning the isotopic structure of molecules by tandem mass spectrometry. International Journal of Mass Spectrometry 434, 276-286.

Omari, I., Zhu, H., McGarvey, G.B., McIndoe, J.S., 2019. Acid-selective mass spectrometric analysis of petroleum fractions. International Journal of Mass Spectrometry 435, 315-320.

Patterson, N.H., Tuck, M., Lewis, A., Kaushansky, A., Norris, J.L., Van de Plas, R., Caprioli, R.M., 2018. Next generation histology-directed imaging mass spectrometry driven by autofluorescence microscopy. Analytical Chemistry 90, 12404-12413.

Patterson, N.H., Tuck, M., Van de Plas, R., Caprioli, R.M., 2018. Advanced registration and analysis of MALDI imaging mass spectrometry measurements through autofluorescence microscopy. Analytical Chemistry 90, 12395-12403.

Race, A.M., Römpp, A., 2018. Error-free data visualization and processing through imzML and mzML validation. Analytical Chemistry 90, 13378-13384.

Ryan, D.J., Spraggins, J.M., Caprioli, R.M., 2019. Protein identification strategies in MALDI imaging mass spectrometry: a brief review. Current Opinion in Chemical Biology 48, 64-72.

Snyder, D.T., Szalwinski, L.J., Wells, J.M., Cooks, R.G., 2018. Logical MS/MS scans: a new set of operations for tandem mass spectrometry. Analyst 143, 5438-5452.

Trindade, G.F., Abel, M.-L., Watts, J.F., 2018. simsMVA: A tool for multivariate analysis of ToF-SIMS datasets. Chemometrics and Intelligent Laboratory Systems 182, 180-187.

METABOLOMICS/LIPIDOMICS

Baumann, L.M.F., Taubner, R.-S., Bauersachs, T., Steiner, M., Schleper, C., Peckmann, J., Rittmann, S.K.M.R., Birgel, D., 2018. Intact polar lipid and core lipid inventory of the hydrothermal vent methanogens Methanocaldococcus villosus and Methanothermococcus okinawensis. Organic Geochemistry 126, 33-42.

Beale, D.J., Pinu, F.R., Kouremenos, K.A., Poojary, M.M., Narayana, V.K., Boughton, B.A., Kanojia, K., Dayalan, S., Jones, O.A.H., Dias, D.A., 2018. Review of recent developments in GC–MS approaches to metabolomics-based research. Metabolomics 14, 152.

Beccaria, M., Franchina, F.A., Nasir, M., Mellors, T., Hill, J.E., Purcaro, G., 2018. Investigation of mycobacteria fatty acid profile using different ionization energies in GC–MS. Analytical and Bioanalytical Chemistry 410, 7987-7996.

Ding, S., Kohlhepp, B., Trumbore, S., Küsel, K., Totsche, K.-U., Pohnert, G., Gleixner, G., Schwab, V.F., 2018. In situ production of core and intact bacterial and archaeal tetraether lipids in groundwater. Organic Geochemistry 126, 1-12.

Gao, Y., Wu, S., Feng, L., 2019. Rapid and direct determination of fatty acids and glycerides profiles in Schisandra chinensis oil by using UPLC-Q/TOF-MSE. Journal of Chromatography B 1104, 157-167.

Gathungu, R.M., Larrea, P., Sniatynski, M.J., Marur, V.R., Bowden, J.A., Koelmel, J.P., Starke-Reed, P., Hubbard, V.S., Kristal, B.S., 2018. Optimization of electrospray ionization source parameters for lipidomics to reduce misannotation of in-source fragments as precursor ions. Analytical Chemistry 90, 13523-13532.

Goetsch, C., Conners, M.G., Budge, S.M., Mitani, Y., Walker, W.A., Bromaghin, J.F., Simmons, S.E., Reichmuth, C., Costa, D.P., 2018. Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis. Frontiers in Marine Science 5, 430. doi: 410.3389/fmars.2018.00430.

Guijas, C., Siuzdak, G., 2018. Reply to Comment on METLIN: A technology platform for identifying knowns and unknowns. Analytical Chemistry 90, 13128-13129.

Han, W., He, P., Shao, L., Lü, F., 2018. Metabolic interactions of a chain elongation microbiome. Applied and Environmental Microbiology 84, Article e01614-18.


Kite, G.C., 2018. Comment on METLIN: A technology platform for identifying knowns and unknowns. Analytical Chemistry 90, 13126-13127.

Leonavicius, K., Nainys, J., Kuciauskas, D., Mazutis, L., 2019. Multi-omics at single-cell resolution: comparison of experimental and data fusion approaches. Current Opinion in Biotechnology 55, 159-166.

Samaraweera, M.A., Hall, L.M., Hill, D.W., Grant, D.F., 2018. Evaluation of an artificial neural network retention index model for chemical structure identification in nontargeted metabolomics. Analytical Chemistry 90, 12752-12760.

Schubotz, F., Xie, S., Lipp, J.S., Hinrichs, K.-U., Wakeham, S.G., 2018. Intact polar lipids in the water column of the eastern tropical North Pacific: abundance and structural variety of non-phosphorus lipids. Biogeosciences 15, 6481-6501.

Verhoeven, A., Giera, M., Mayboroda, O.A., 2018. KIMBLE: A versatile visual NMR metabolomics workbench in KNIME. Analytica Chimica Acta 1044, 66-76.

PUPPYOMICS

Hoffman, C.L., Stutz, K., Vasilopoulos, T., 2018. An examination of adult women’s sleep quality and sleep routines in relation to pet ownership and bedsharing. Anthrozoös 31, 711-725.

McGuire, B., Olsen, B., Bemis, K.E., Orantes, D., 2018. Urine marking in male domestic dogs: honest or dishonest? Journal of Zoology 306, 163-170.

Archaeological/Art Organic Chemistry

Carlson, K., Bement, L.C., Carter, B.J., Culleton, B.J., Kennett, D.J., 2018. A Younger Dryas signature in bison bone stable isotopes from the southern Plains of North America. Journal of Archaeological Science: Reports 21, 1259-1265.

Carmody, S., Davis, J., Tadi, S., Sharp, J.S., Hunt, R.K., Russ, J., 2018. Evidence of tobacco from a Late Archaic smoking tube recovered from the Flint River site in southeastern North America. Journal of Archaeological Science: Reports 21, 904-910.

Cersoy, S., Zirah, S., Marie, A., Zazzo, A., 2019. Toward a versatile protocol for radiocarbon and proteomics analysis of ancient collagen. Journal of Archaeological Science 101, 1-10.

Curry, A., 2018. Early Mongolians ate dairy, but lacked the gene to digest it. Science 362, 626-627.

Fors, Y., Isaksson, S., 2019. GCMS analyses of direct methylated lipids in binders used in 18th–19th century folk painted interiors in Hälsingland, Sweden. Journal of Archaeological Science: Reports 23, 127-136.


Hennius, A., 2018. Viking Age tar production and outland exploitation. Antiquity 92, 1349-1361.

Jones, J., Higham, T.F.G., Chivall, D., Bianucci, R., Kay, G.L., Pallen, M.J., Oldfield, R., Ugliano, F., Buckley, S.A., 2018. A prehistoric Egyptian mummy: Evidence for an ‘embalming recipe’ and the evolution of early formative funerary treatments. Journal of Archaeological Science 100, 191-200.

Lawler, A., 2018. Migrants and trade spiced up Canaanite metropolis. Science 362, 980-981.

Niemeyer, H.M., de Souza, P., Camilo, C., Echeverría, J., 2018. Chemical evidence of prehistoric passive tobacco consumption by a human perinate (early Formative Period, South-Central Andes). Journal of Archaeological Science 100, 130-138.

Orlando, L., 2018. Late Bronze Age cultural origins of dairy pastoralism in Mongolia. Proceedings of the National Academy of Sciences 115, 12083-12085.

Park, J., Schilling, M.R., Khanjian, H., Lee, J., 2018. Stratigraphic examination of a Korean lacquered wooden coffin sample by pyrolysis/GC/MS. Chromatographia 81, 1685-1694.

Pederzani, S., Britton, K., 2019. Oxygen isotopes in bioarchaeology: Principles and applications, challenges and opportunities. Earth-Science Reviews 188, 77-107.

Perruchini, E., Glatz, C., Hald, M.M., Casana, J., Toney, J.L., 2018. Revealing invisible brews: A new approach to the chemical identification of ancient beer. Journal of Archaeological Science 100, 176-190.

Tushingham, S., Snyder, C.M., Brownstein, K.J., Damitio, W.J., Gang, D.R., 2018. Biomolecular archaeology reveals ancient origins of indigenous tobacco smoking in North American Plateau. Proceedings of the National Academy of Sciences 115, 11742-11747.

Vandenabeele, P., Edwards, H., 2019. Raman Spectroscopy in Archaeology and Art History, Volume 2. The Royal Society of Chemistry, p. 349.

Yang, X., Chen, Q., Ma, Y., Li, Z., Hung, H.-c., Zhang, Q., Jin, Z., Liu, S., Zhou, Z., Fu, X., 2018. New radiocarbon and archaeobotanical evidence reveal the timing and route of southward dispersal of rice farming in south China. Science Bulletin 63, 1495-1501.

Zarrillo, S., Gaikwad, N., Lanaud, C., Powis, T., Viot, C., Lesur, I., Fouet, O., Argout, X., Guichoux, E., Salin, F., Solorzano, R.L., Bouchez, O., Vignes, H., Severts, P., Hurtado, J., Yepez, A., Grivetti, L., Blake, M., Valdez, F., 2018. The use and domestication of Theobroma cacao during the mid-Holocene in the upper Amazon. Nature Ecology & Evolution 2, 1879-1888.

Biochemistry

Christensen, L.F.B., Hansen, L.M., Finster, K., Christiansen, G., Nielsen, P.H., Otzen, D.E., Dueholm, M.S., 2018. The sheaths of Methanospirillum are made of a new type of amyloid protein. Frontiers in Microbiology 9, 1099. doi: 1010.3389/fmicb.2015.01099.

Huang, L., Tang, J., Chen, M., Liu, X., Zhou, S., 2018. Two modes of riboflavin-mediated extracellular electron transfer in Geobacter uraniireducens. Frontiers in Microbiology 9, 2886. doi: 2810.3389/fmicb.2018.02886.



Martínez-Sosa, P., Tierney, J.E., 2019. Lacustrine brGDGT response to microcosm and mesocosm incubations. Organic Geochemistry 127, 12-22.

Rodrigues, M.L., 2018. The multifunctional fungal ergosterol. mBio 9, Article e01755-01718.

Tanaka, K., Yokoe, S., Igarashi, K., Takashino, M., Ishikawa, M., Hori, K., Nakanishi, S., Kato, S., 2018. Extracellular electron transfer via outer membrane cytochromes in a methanotrophic bacterium Methylococcus capsulatus (Bath). Frontiers in Microbiology 9, 2905. doi: 2910.3389/fmicb.2018.02905.

Yu, T., Chen, Y., 2019. Effects of elevated carbon dioxide on environmental microbes and its mechanisms: A review. Science of The Total Environment 655, 865-879.

Biodegradation

Cai, Q., Zhu, Z., Chen, B., Zhang, B., 2019. Oil-in-water emulsion breaking marine bacteria for demulsifying oily wastewater. Water Research 149, 292-301.

Huang, X., Wang, J., Ma, C., Ma, L., Qiao, C., 2019. Diversity analysis of microbial communities and biodegradation performance of two halotolerant and thermotolerant Bacillus licheniformis strains in oilfield-produced wastewater. International Biodeterioration & Biodegradation 137, 30-41.

Littlefair, C.A., Tank, S.E., 2018. Biodegradability of thermokarst carbon in a till-associated, glacial margin landscape: The case of the Peel Plateau, NWT, Canada. Journal of Geophysical Research: Biogeosciences 123, 3293-3307.

Ma, Q., Zhang, X., Qu, Y., 2018. Biodegradation and biotransformation of indole: Advances and perspectives. Frontiers in Microbiology 9, 2625. doi: 2610.3389/fmicb.2018.02625.

Ma, S.-j., Ma, H.-j., Hu, H.-d., Ren, H.-q., 2019. Effect of mixing intensity on hydrolysis and acidification of sewage sludge in two-stage anaerobic digestion: Characteristics of dissolved organic matter and the key microorganisms. Water Research 148, 359-367.

Qiao, W., Luo, F., Lomheim, L., Mack, E.E., Ye, S., Wu, J., Edwards, E.A., 2018. A Dehalogenimonas population respires 1,2,4-trichlorobenzene and dichlorobenzenes. Environmental Science & Technology 52, 13391-13398.

Šafarič, L., Shakeri Yekta, S., Liu, T., Svensson, H.B., Schnürer, A., Bastviken, D., Björn, A., 2018. Dynamics of a perturbed microbial community during thermophilic anaerobic digestion of chemically defined soluble organic compounds. Microorganisms 6, Article 105.

Vergeynst, L., Christensen, J.H., Kjeldsen, K.U., Meire, L., Boone, W., Malmquist, L.M.V., Rysgaard, S., 2019. In situ biodegradation, photooxidation and dissolution of petroleum compounds in Arctic seawater and sea ice. Water Research 148, 459-468.

Xu, S., Wang, W., Zhu, L., 2019. Enhanced microbial degradation of benzo[a]pyrene by chemical oxidation. Science of The Total Environment 653, 1293-1300.

BIODEGRADATION PATHWAYS/GENOMICS

Cecil, J.H., Garcia, D.C., Giannone, R.J., Michener, J.K., 2018. Rapid, parallel identification of catabolism pathways of lignin-derived aromatic compounds in Novosphingobium aromaticivorans. Applied and Environmental Microbiology 84, Article e01185-18.

Horinouchi, M., Koshino, H., Malon, M., Hirota, H., Hayashi, T., 2018. Steroid degradation in Comamonas testosteroni TA441: Identification oF metabolites and the genes involved in the reactions necessary before D-ring cleavage. Applied and Environmental Microbiology 84, Article e01324-18.

Sperfeld, M., Diekert, G., Studenik, S., 2019. Anaerobic aromatic compound degradation in Sulfuritalea hydrogenivorans sk43H. FEMS Microbiology Ecology 95, Article fiy199.

Zhao, S., He, J., 2019. Reductive dechlorination of high concentrations of chloroethenes by a Dehalococcoides mccartyi strain 11G. FEMS Microbiology Ecology 95, fiy209-fiy209.

Biofuels/Biomass

Chen, H., Zhao, L., Hu, S., Yuan, Z., Guo, J., 2018. High-rate production of short-chain fatty acids from methane in a mixed-culture membrane biofilm reactor. Environmental Science & Technology Letters 5, 662-667.


Grossman, A., Wilfred, V., 2019. Lignin-based polymers and nanomaterials. Current Opinion in Biotechnology 56, 112-120.


Henard, C.A., Franklin, T.G., Youhenna, B., But, S., Alexander, D., Kalyuzhnaya, M.G., Guarnieri, M.T., 2018. Biogas biocatalysis: Methanotrophic bacterial cultivation, metabolite profiling, and bioconversion to lactic acid. Frontiers in Microbiology 9, 2610. doi: 2610.3389/fmicb.2018.02610.

Jiang, Y., Chekuri, S., Fang, R.H., Zhang, L., 2019. Engineering biological interactions on the nanoscale. Current Opinion in Biotechnology 58, 1-8.

Kim, T.-Y., Kim, M.G., Lee, J.-H., Hur, H.-G., 2018. Biosynthesis of nanomaterials by Shewanella species for application in lithium ion batteries. Frontiers in Microbiology 9, 2817. doi: 2810.3389/fmicb.2018.02817.

Kumar, L.R., Yellapu, S.K., Zhang, X., Tyagi, R.D., 2019. Energy balance for biodiesel production processes using microbial oil and scum. Bioresource Technology 272, 379-388.

Mishra, S., Mohanty, K., 2019. Comprehensive characterization of microalgal isolates and lipid-extracted biomass as zero-waste bioenergy feedstock: An integrated bioremediation and biorefinery approach. Bioresource Technology 273, 177-184.

Ponnusamy, V.K., Nguyen, D.D., Dharmaraja, J., Shobana, S., Banu, J.R., Saratale, R.G., Chang, S.W., Kumar, G., 2019. A review on lignin structure, pretreatments, fermentation reactions and biorefinery potential. Bioresource Technology 271, 462-472.

Prabhu, A.A., Gadela, R., Bharali, B., Deshavath, N.N., Dasu, V.V., 2019. Development of high biomass and lipid yielding medium for newly isolated Rhodotorula mucilaginosa. Fuel 239, 874-885.

Qiao, W., Tao, J., Luo, Y., Tang, T., Miao, J., Yang, Q., 2018. Microbial oil production from solid-state fermentation by a newly isolated oleaginous fungus, Mucor circinelloides Q531 from mulberry branches. Royal Society Open Science 5, Article 180551.

Renault, H., Werck-Reichhart, D., Weng, J.-K., 2019. Harnessing lignin evolution for biotechnological applications. Current Opinion in Biotechnology 56, 105-111.

Sakarika, M., Kornaros, M., 2019. Chlorella vulgaris as a green biofuel factory: Comparison between biodiesel, biogas and combustible biomass production. Bioresource Technology 273, 237-243.

Sharifzadeh, M., Sadeqzadeh, M., Guo, M., Borhani, T.N., Murthy Konda, N.V.S.N., Garcia, M.C., Wang, L., Hallett, J., Shah, N., 2019. The multi-scale challenges of biomass fast pyrolysis and bio-oil upgrading: Review of the state of art and future research directions. Progress in Energy and Combustion Science 71, 1-80.

Terrett, O.M., Dupree, P., 2019. Covalent interactions between lignin and hemicelluloses in plant secondary cell walls. Current Opinion in Biotechnology 56, 97-104.

Wang, H., Pu, Y., Ragauskas, A., Yang, B., 2019. From lignin to valuable products–strategies, challenges, and prospects. Bioresource Technology 271, 449-461.

Xiao, L., Hu, S., Song, Y., Zhang, L., Han, H., Liu, C., Jiang, L., Xu, K., Su, S., Wang, Y., Xiang, J., 2019. The formation mechanism for OPAHs during the cellulose thermal conversion in inert atmosphere at different temperatures based on ESI(−) FT-ICR MS measurement and density functional theory (DFT). Fuel 239, 320-329.


Yu, J., Maliutina, K., Tahmasebi, A., 2018. A review on the production of nitrogen-containing compounds from microalgal biomass via pyrolysis. Bioresource Technology 270, 689-701.

Biogeochemistry

Adam, N., Perner, M., 2018. Microbially mediated hydrogen cycling in deep-sea hydrothermal vents. Frontiers in Microbiology 9, 2873. doi: 2810.3389/fmicb.2018.02873.

Akberdin, I.R., Collins, D.A., Hamilton, R., Oshchepkov, D.Y., Shukla, A.K., Nicora, C.D., Nakayasu, E.S., Adkins, J.N., Kalyuzhnaya, M.G., 2018. Rare earth elements alter redox balance in Methylomicrobium alcaliphilum 20ZR. Frontiers in Microbiology 9, 2735. doi: 2710.3389/fmicb.2018.02735.

Bartl, I., Hellemann, D., Rabouille, C., Schulz, K., Tallberg, P., Hietanen, S., Voss, M., 2018. Particulate organic matter controls benthic microbial N retention and N removal in contrasting estuaries of the Baltic Sea. Biogeosciences Discussions 2018, 1-27.

Ekau, W., Auel, H., Hagen, W., Koppelmann, R., Wasmund, N., Bohata, K., Buchholz, F., Geist, S., Martin, B., Schukat, A., Verheye, H.M., Werner, T., 2018. Pelagic key species and mechanisms driving energy flows in the northern Benguela upwelling ecosystem and their feedback into biogeochemical cycles. Journal of Marine Systems 188, 49-62.

Emeis, K., Eggert, A., Flohr, A., Lahajnar, N., Nausch, G., Neumann, A., Rixen, T., Schmidt, M., Van der Plas, A., Wasmund, N., 2018. Biogeochemical processes and turnover rates in the Northern Benguela Upwelling System. Journal of Marine Systems 188, 63-80.

Fuentes-Lema, A., Sanleón-Bartolomé, H., Lubián, L.M., Sobrino, C., 2018. Effects of elevated CO2 and phytoplankton-derived organic matter on the metabolism of bacterial communities from coastal waters. Biogeosciences 15, 6927-6940.

Hermoso, M., Lecasble, M., 2018. The effect of salinity on the biogeochemistry of the coccolithophores with implications for coccolith-based isotopic proxies. Biogeosciences 15, 6761-6772.

Kimble, J.C., Winter, A.S., Spilde, M.N., Sinsabaugh, R.L., Northup, D.E., 2018. A potential central role of Thaumarchaeota in N-Cycling in a semi-arid environment, Fort Stanton Cave, Snowy River passage, New Mexico, USA. FEMS Microbiology Ecology 94, Article fiy173.

Li, Y., Tang, K., Zhang, L., Zhao, Z., Xie, X., Chen, C.-T.A., Wang, D., Jiao, N., Zhang, Y., 2018. Coupled carbon, sulfur, and nitrogen cycles mediated by microorganisms in the water column of a shallow-water hydrothermal ecosystem. Frontiers in Microbiology 9, 2718. doi: 2710.3389/fmicb.2018.02718.

Lin, Y.-T., Tu, T.-H., Wei, C.-L., Rumble, D., Lin, L.-H., Wang, P.-L., 2018. Steep redox gradient and biogeochemical cycling driven by deeply sourced fluids and gases in a terrestrial mud volcano. FEMS Microbiology Ecology 94, Article fiy171.

Macdonald, M.L., Wadham, J.L., Telling, J., Skidmore, M.L., 2018. Glacial erosion liberates lithologic energy sources for microbes and acidity for chemical weathering beneath glaciers and ice sheets. Frontiers in Earth Science 6, 212. doi: 210.3389/feart.2018.00212.

Monteverde, D.R., Sylvan, J.B., Suffridge, C., Baronas, J.J., Fichot, E., Fuhrman, J., Berelson, W., Sañudo-Wilhelmy, S.A., 2018. Distribution of extracellular flavins in a coastal marine basin and their relationship to redox gradients and microbial community members. Environmental Science & Technology 52, 12265-12274.


von Gunten, K., Hamilton, S.M., Zhong, C., Nesbø, C., Li, J., Muehlenbachs, K., Konhauser, K.O., Alessi, D.S., 2018. Electron donor-driven bacterial and archaeal community patterns along forest ring edges in Ontario, Canada. Environmental Microbiology Reports 10, 663-672.

Wen, X., Unger, V., Jurasinski, G., Koebsch, F., Horn, F., Rehder, G., Sachs, T., Zak, D., Lischeid, G., Knorr, K.-H., Böttcher, M.E., Winkel, M., Bodelier, P.L.E., Liebner, S., 2018. Predominance of methanogens over methanotrophs in rewetted fens characterized by high methane emissions. Biogeosciences 15, 6519-6536.

Wieler, N., Ginat, H., Gillor, O., Angel, R., 2018. The origin and role of biological rock crusts in rocky desert weathering. Biogeosciences Discussions 2018, 1-19.

Xu, Y., Ge, H., Fang, J., 2018. Biogeochemistry of hadal trenches: Recent developments and future perspectives. Deep Sea Research Part II: Topical Studies in Oceanography 155, 19-26.

Yang, Y., Chen, J., Li, B., Liu, Y., Xie, S., 2018. Anaerobic methane oxidation potential and bacteria in freshwater lakes: Seasonal changes and the influence of trophic status. Systematic and Applied Microbiology 41, 650-657.

Zheng, J., RoyChowdhury, T., Yang, Z., Gu, B., Wullschleger, S.D., Graham, D.E., 2018. Impacts of temperature and soil characteristics on methane production and oxidation in Arctic tundra. Biogeosciences 15, 6621-6635.

Zwicker, J., Smrzka, D., Himmler, T., Monien, P., Gier, S., Goedert, J.L., Peckmann, J., 2018. Rare earth elements as tracers for microbial activity and early diagenesis: A new perspective from carbonate cements of ancient methane-seep deposits. Chemical Geology 501, 77-85.

BIOFILM/MICROBIAL INDUCED CORROSION


Haynes, H.M., Pearce, C.I., Boothman, C., Lloyd, J.R., 2018. Response of bentonite microbial communities to stresses relevant to geodisposal of radioactive waste. Chemical Geology 501, 58-67.

Jia, R., Unsal, T., Xu, D., Lekbach, Y., Gu, T., 2019. Microbiologically influenced corrosion and current mitigation strategies: A state of the art review. International Biodeterioration & Biodegradation 137, 42-58.

Suma, M.S., Basheer, R., Sreelekshmy, B.R., Vipinlal, V., Sha, M.A., Jineesh, P., Krishnan, A., Archana, S.R., Saji, V.S., Shibli, S.M.A., 2019. Pseudomonas putida RSS biopassivation of mild steel for long term corrosion inhibition. International Biodeterioration & Biodegradation 137, 59-67.

Wan, N., Wang, H., Ng, C.K., Mukherjee, M., Ren, D., Cao, B., Tang, Y.J., 2018. Bacterial metabolism during biofilm growth investigated by 13C tracing. Frontiers in Microbiology 9, 2657. doi: 2610.3389/fmicb.2018.02657.


MICROBIAL MEDIATION OF MINERAL FORMATION/DEGRADATION

Aromokeye, D.A., Richter-Heitmann, T., Oni, O.E., Kulkarni, A., Yin, X., Kasten, S., Friedrich, M.W., 2018. Temperature controls crystalline iron oxide utilization by microbial communities in methanic ferruginous marine sediment incubations. Frontiers in Microbiology 9, 2574. doi: 2510.3389/fmicb.2018.02574.




Seifan, M., Berenjian, A., 2018. Application of microbially induced calcium carbonate precipitation in designing bio self-healing concrete. World Journal of Microbiology and Biotechnology 34, 168.


Sun, Q., Lian, B., 2019. The different roles of Aspergillus nidulans carbonic anhydrases in wollastonite weathering accompanied by carbonation. Geochimica et Cosmochimica Acta 244, 437-450.


Carbon Cycle

Amann, T., Hartmann, J., Struyf, E., Garcia, W.d.O., Fischer, E.K., Janssens, I., Meire, P., Schoelynck, J., 2018. Constraints on enhanced weathering and related carbon sequestration – a cropland mesocosm approach. Biogeosciences Discussions 2018, 1-21.

Beck, J., Bock, M., Schmitt, J., Seth, B., Blunier, T., Fischer, H., 2018. Bipolar carbon and hydrogen isotope constraints on the Holocene methane budget. Biogeosciences 15, 7155-7175.

Blattmann, T.M., Letsch, D., Eglinton, T.I., 2018. On the geological and scientific legacy of petrogenic organic carbon. American Journal of Science 318, 861-881.

Cartapanis, O., Galbraith, E.D., Bianchi, D., Jaccard, S.L., 2018. Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle. Climate of the Past 14, 1819-1850.

Fawcett, S.E., Johnson, K.S., Riser, S.C., Van Oostende, N., Sigman, D.M., 2018. Low-nutrient organic matter in the Sargasso Sea thermocline: A hypothesis for its role, identity, and carbon cycle implications. Marine Chemistry 207, 108-123.

Gasser, T., Kechiar, M., Ciais, P., Burke, E.J., Kleinen, T., Zhu, D., Huang, Y., Ekici, A., Obersteiner, M., 2018. Path-dependent reductions in CO2 emission budgets caused by permafrost carbon release. Nature Geoscience 11, 830-835.

Ilyinskaya, E., Mobbs, S., Burton, R., Burton, M., Pardini, F., Pfeffer, M.A., Purvis, R., Lee, J., Bauguitte, S., Brooks, B., Colfescu, I., Petersen, G.N., Wellpott, A., Bergsson, B., 2018. Globally significant CO2 emissions from Katla, a subglacial volcano in Iceland. Geophysical Research Letters 45, 10,332-310,341.

Jiao, N., Liang, Y., Zhang, Y., Liu, J., Zhang, Y., Zhang, R., Zhao, M., Dai, M., Zhai, W., Gao, K., Song, J., Yuan, D., Li, C., Lin, G., Huang, X., Yan, H., Hu, L., Zhang, Z., Wang, L., Cao, C., Luo, Y., Luo, T., Wang, N., Dang, H., Wang, D., Zhang, S., 2018. Carbon pools and fluxes in the China Seas and adjacent oceans. Science China Earth Sciences 61, 1535-1563.

Kirschbaum, M.U.F., Zeng, G., Ximenes, F., Giltrap, D.L., Zeldis, J.R., 2018. Towards a more complete quantification of the global carbon cycle. Biogeosciences Discussions 2018, 1-31.

Liu, Q., Guo, X., Yin, Z., Zhou, K., Roberts, E.G., Dai, M., 2018. Carbon fluxes in the China Seas: An overview and perspective. Science China Earth Sciences 61, 1564-1582.

Lu, W., Luo, Y., Yan, X., Jiang, Y., 2018. Modeling the contribution of the microbial carbon pump to carbon sequestration in the South China Sea. Science China Earth Sciences 61, 1594-1604.

Martin, P., Cherukuru, N., Tan, A.S.Y., Sanwlani, N., Mujahid, A., Müller, M., 2018. Distribution and cycling of terrigenous dissolved organic carbon in peatland-draining rivers and coastal waters of Sarawak, Borneo. Biogeosciences 15, 6847-6865.

Shingubara, R., Sugimoto, A., Murase, J., Iwahana, G., Tei, S., Liang, M., Takano, S., Morozumi, T., Maximov, T., 2018. Multi-year effect of wetting on CH4 flux at taiga-tundra boundary in northeastern Siberia deduced from stable isotope ratios of CH4. Biogeosciences Discussions 2018, 1-25.

Smith, K.L., Ruhl, H.A., Huffard, C.L., Messié, M., Kahru, M., 2018. Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific. Proceedings of the National Academy of Sciences 115, 12235-12240.

Song, J., Qu, B., Li, X., Yuan, H., Li, N., Duan, L., 2018. Carbon sinks/sources in the Yellow and East China Seas—Air-sea interface exchange, dissolution in seawater, and burial in sediments. Science China Earth Sciences 61, 1583-1593.

Carbon Sequestration


Amshoff, P., Weger, T., Ostertag-Henning, C., 2018. Dissolution kinetics of CO2 and CO2-SO2 mixtures in water and brine at geological storage conditions of 16 MPa and 333 K. International Journal of Greenhouse Gas Control 79, 173-180.

Deng, K., Lin, Y., Ning, H., Liu, W., Singh, A., Zhang, G., 2018. Influences of temperature and pressure on CO2 solubility in saline solutions in simulated oil and gas well environments. Applied Geochemistry 99, 22-30.


Zhang, F., Zhang, Q., Gardner, R.P., Liu, J., Zhang, X., Qiu, F., Chen, Q., Tian, L., Wang, Y., 2018. Quantitative monitoring of CO2 sequestration using thermal neutron detection technique in heavy oil reservoirs. International Journal of Greenhouse Gas Control 79, 154-164.

Climate Change

Broecker, W., 2018. CO2: Earth’s climate driver. Geochemical Perspectives 7, 117-196.


Jordan, T.A., Martin, C., Ferraccioli, F., Matsuoka, K., Corr, H., Forsberg, R., Olesen, A., Siegert, M., 2018. Anomalously high geothermal flux near the South Pole. Scientific Reports 8, Article 16785.

Serikova, S., Pokrovsky, O.S., Ala-Aho, P., Kazantsev, V., Kirpotin, S.N., Kopysov, S.G., Krickov, I.V., Laudon, H., Manasypov, R.M., Shirokova, L.S., Soulsby, C., Tetzlaff, D., Karlsson, J., 2018. High riverine CO2 emissions at the permafrost boundary of Western Siberia. Nature Geoscience 11, 825-829.

Sulpis, O., Boudreau, B.P., Mucci, A., Jenkins, C., Trossman, D.S., Arbic, B.K., Key, R.M., 2018. Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2. Proceedings of the National Academy of Sciences 115, 11700-11705.

Venturi, S., Tassi, F., Magi, F., Cabassi, J., Ricci, A., Capecchiacci, F., Caponi, C., Nisi, B., Vaselli, O., 2019. Carbon isotopic signature of interstitial soil gases reveals the potential role of ecosystems in mitigating geogenic greenhouse gas emissions: Case studies from hydrothermal systems in Italy. Science of The Total Environment 655, 887-898.

Coal/Lignite/Peat Geochemistry

Guo, W., Dai, S., Nechaev, V.P., Nechaeva, E.V., Wei, G., Finkelman, R.B., Spiro, B.F., 2019. Geochemistry of Palaeogene coals from the Fuqiang Mine, Hunchun Coalfield, northeastern China: Composition, provenance, and relation to the adjacent polymetallic deposits. Journal of Geochemical Exploration 196, 192-207.

Jiang, J., Yang, W., Cheng, Y., Liu, Z., Zhang, Q., Zhao, K., 2019. Molecular structure characterization of middle-high rank coal via XRD, Raman and FTIR spectroscopy: Implications for coalification. Fuel 239, 559-572.

Jing, Z., Rodrigues, S., Strounina, E., Li, M., Wood, B., Underschultz, J.R., Esterle, J.S., Steel, K.M., 2019. Use of FTIR, XPS, NMR to characterize oxidative effects of NaClO on coal molecular structures. International Journal of Coal Geology 201, 1-13.

Li, Y., Shao, L., Yan, Z., Hou, H., Tang, Y., Large, D.J., 2018. Net primary productivity and its control of the Middle Jurassic peatlands: An example from the southern Junggar coalfield. Science China Earth Sciences 61, 1633-1643.

Liu, S., Sang, S., Wang, T., Du, Y., Jia, J., Fang, H., 2018. The effects of CO2 on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy. Energy Exploration & Exploitation 36, 1566-1592.

Liu, Y., Tang, D., Xu, H., Tao, S., Li, S., 2019. Quantitative characterization of middle-high ranked coal reservoirs in the Hancheng Block, eastern margin, Ordos Basin, China: implications for permeability evolution with the coal macrolithotypes. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 201-215.

Moore, T.R., Large, D., Talbot, J., Wang, M., Riley, J.L., 2018. The stoichiometry of carbon, hydrogen, and oxygen in peat. Journal of Geophysical Research: Biogeosciences 123, 3101-3110.

Moroeng, O.M., Wagner, N.J., Hall, G., Roberts, R.J., 2018. Using δ15N and δ13C and nitrogen functionalities to support a fire origin for certain inertinite macerals in a No. 4 Seam Upper Witbank coal, South Africa. Organic Geochemistry 126, 23-32.



Zhang, J., Wei, C., Ju, W., Yan, G., Lu, G., Hou, X., Kai, Z., 2019. Stress sensitivity characterization and heterogeneous variation of the pore-fracture system in middle-high rank coals reservoir based on NMR experiments. Fuel 238, 331-344.

COAL BED METHANE

Chen, Y., Qin, Y., Li, Z., Shi, Q., Wei, C., Wu, C., Cao, C., Qu, Z., 2019. Differences in desorption rate and composition of desorbed gases between undeformed and mylonitic coals in the Zhina Coalfield, Southwest China. Fuel 239, 905-916.

Jian, K., Chen, G., Guo, C., Ma, G., Ru, Z., 2019. Biogenic gas simulation of low-rank coal and its structure evolution. Journal of Petroleum Science and Engineering 173, 1284-1288.

Jiang, W., Zhang, Q., Zeng, F., 2019. Metamorphic degree of coal dependence of content and genesis of coal-bed methane in China. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 378-388.

Kiani, A., Sakurovs, R., Grigore, M., Sokolova, A., 2018. Gas sorption capacity, gas sorption rates and nanoporosity in coals. International Journal of Coal Geology 200, 77-86.

Ni, X.M., Jia, Q.F., Wang, Y.B., 2018. Characterization of permeability changes in coal of high rank during the CH4-CO2 replacement process. Geofluids 2018, 8.


Wang, L., Jiang, B., Chen, R., Li, Y., 2018. Evolutions of nanoscale pore and chemical structures of tectonically deformed coals after supercritical CO2 treatment. International Journal of Oil, Gas and Coal Technology 19, 477-500.


Zhang, K., Meng, Z., Wang, X., 2019. Distribution of methane carbon isotope and its significance on CBM accumulation of No.2 coal seam in Yanchuannan CBM block, Ordos Basin, China. Journal of Petroleum Science and Engineering 174, 92-105.

Zhi, S., Elsworth, D., Wang, J., Gan, Q., Liu, S., 2018. Hydraulic fracturing for improved nutrient delivery in microbially-enhanced coalbed-methane (MECBM) production. Journal of Natural Gas Science and Engineering 60, 294-311.

Cosmochemistry/Planetary Geochemistry

Bialy, S., Loeb, A., 2018. Could solar radiation pressure explain 'Oumuamua's peculiar acceleration? arXiv:1810.11490v2 [astro-ph.EP]


Hargitai, H.I., Gulick, V.C., Glines, N.H., 2018. Paleolakes of northeast Hellas: Precipitation, groundwater-fed, and fluvial lakes in the Navua–Hadriacus–Ausonia Region, Mars. Astrobiology 18, 1435-1459.

Kiddell, C.B., Cloutis, E.A., Dagdick, B.R., Stromberg, J.M., Applin, D.M., Mann, J.P., 2018. Spectral reflectance of powder coatings on carbonaceous chondrite slabs: Implications for asteroid regolith observations. Journal of Geophysical Research: Planets 123, 2803-2840.

Lai, J.C.Y., Pearce, B.K.D., Pudritz, R.E., Lee, D., 2019. Meteoritic abundances of fatty acids and potential reaction pathways in planetesimals. Icarus 319, 685-700.

Mann, A., 2018. Large galaxy found lurking on the Milky Way's far side. Science 362, 737.

Royle, S.H., Tan, J., Kounaves, S.P., Sephton, M.A., 2018. Survivability of 1-chloronapthalene during simulated early diagenesis: Implications for chlorinated hydrocarbon detection on Mars. Journal of Geophysical Research: Planets 123, 2790-2802.

Rubin, A.E., 2018. Carbonaceous and noncarbonaceous iron meteorites: Differences in chemical, physical, and collective properties. Meteoritics & Planetary Science 53, 2357-2371.

Steele, A., Benning, L.G., Wirth, R., Siljeström, S., Fries, M.D., Hauri, E., Conrad, P.G., Rogers, K., Eigenbrode, J., Schreiber, A., Needham, A., Wang, J.H., McCubbin, F.M., Kilcoyne, D., Rodriguez Blanco, J.D., 2018. Organic synthesis on Mars by electrochemical reduction of CO2. Science Advances 4, Article eaat5118.

ASTROBIOLOGY

Estrela, R., Valio, A., 2018. Superflare ultraviolet impact on Kepler-96 system: A glimpse of habitability when the ozone layer first formed on Earth. Astrobiology 18, 1414-1424.

Georgiou, C.D., 2018. Functional properties of amino acid side chains as biomarkers of extraterrestrial life. Astrobiology 18, 1479-1496.

Jagadeesh, M.K., Roszkowska, M., Kaczmarek, Ł., 2018. Tardigrade indexing approach on exoplanets. Life Sciences in Space Research 19, 13-16.

Mann, A., 2018. Inner workings: Hunting for microbial life throughout the solar system. Proceedings of the National Academy of Sciences 115, 11348.

Neveu, M., Hays, L.E., Voytek, M.A., New, M.H., Schulte, M.D., 2018. The ladder of life detection. Astrobiology 18, 1375-1402.

Olsson-Francis, K., Billi, D., Teske, A., de Vera, J.-P.P., 2018. Editorial: Habitability beyond Earth. Frontiers in Microbiology 9, 2645. doi: 2610.3389/fmicb.2018.02645.

Pulschen, A.A., de Araujo, G.G., de Carvalho, A.C.S.R., Cerini, M.F., Fonseca, L.d.M., Galante, D., Rodrigues, F., 2018. Survival of extremophilic yeasts in the stratospheric environment during balloon flights and in laboratory simulations. Applied and Environmental Microbiology 84, Article e01942-18.

Romsdahl, J., Blachowicz, A., Chiang, A.J., Singh, N., Stajich, J.E., Kalkum, M., Venkateswaran, K., Wang, C.C.C., 2018. Characterization of Aspergillus niger isolated from the International Space Station. mSystems 3, Article e00112-00118.

Shkolyar, S., Farmer, J.D., 2018. Biosignature preservation potential in playa evaporites: Impacts of diagenesis and implications for Mars exploration. Astrobiology 18, 1460-1478.

Yamagishi, A., Kawaguchi, Y., Hashimoto, H., Yano, H., Imai, E., Kodaira, S., Uchihori, Y., Nakagawa, K., 2018. Environmental data and survival data of Deinococcus aetherius from the exposure facility of the Japan Experimental Module of the International Space Station obtained by the Tanpopo Mission. Astrobiology 18, 1369-1374.

Zammuto, V., Fuchs, F.M., Fiebrandt, M., Stapelmann, K., Ulrich, N.J., Maugeri, T.L., Pukall, R., Gugliandolo, C., Moeller, R., 2018. Comparing spore resistance of Bacillus strains isolated from hydrothermal vents and spacecraft assembly facilities to environmental stressors and decontamination treatments. Astrobiology 18, 1425-1434.

Environmental Geochemistry



Cabral, A.C., Wilhelm, M.M., Figueira, R.C.L., Martins, C.C., 2019. Tracking the historical sewage input in South American subtropical estuarine systems based on faecal sterols and bulk organic matter stable isotopes (δ13C and δ15N). Science of The Total Environment 655, 855-864.

Caniani, D., Calace, S., Mazzone, G., Caivano, M., Mancini, I.M., Greco, M., Masi, S., 2018. Removal of hydrocarbons from contaminated soils by using a thermally expanded graphite sorbent. Bulletin of Environmental Contamination and Toxicology 101, 698-704.

Cao, S., Na, G., Li, R., Ge, L., Gao, H., Jin, S., Hou, C., Gao, Y., Zhang, Z., 2018. Fate and deposition of polycyclic aromatic hydrocarbons in the Bransfield Strait, Antarctica. Marine Pollution Bulletin 137, 533-541.

Casal, P., Cabrerizo, A., Vila-Costa, M., Pizarro, M., Jiménez, B., Dachs, J., 2018. Pivotal role of snow deposition and melting driving fluxes of polycyclic aromatic hydrocarbons at coastal Livingston Island (Antarctica). Environmental Science & Technology 52, 12327-12337.


Idowu, I., Johnson, W., Francisco, O., Obal, T., Marvin, C., Thomas, P.J., Sandau, C.D., Stetefeld, J., Tomy, G.T., 2018. Comprehensive two-dimensional gas chromatography high-resolution mass spectrometry for the analysis of substituted and unsubstituted polycyclic aromatic compounds in environmental samples. Journal of Chromatography A 1579, 106-114.

Kaiser, D., Schulz-Bull, D.E., Waniek, J.J., 2018. Polycyclic and organochlorine hydrocarbons in sediments of the northern South China Sea. Marine Pollution Bulletin 137, 668-676.

Kopprio, G.A., Dutto, M.S., Garzón Cardona, J.E., Gärdes, A., Lara, R.J., Graeve, M., 2018. Biogeochemical markers across a pollution gradient in a Patagonian estuary: A multidimensional approach of fatty acids and stable isotopes. Marine Pollution Bulletin 137, 617-626.

Maaten, B., Järvik, O., Loo, L., Konist, A., Siirde, A., 2018. Characterization of the pyrolytic water from shale oil industry. Oil Shale 35, 365–374.

McGuire, J.T., Cozzarelli, I.M., Bekins, B.A., Link, H., Martinović-Weigelt, D., 2018. Toxicity assessment of groundwater contaminated by petroleum hydrocarbons at a well-characterized, aged, crude oil release site. Environmental Science & Technology 52, 12172-12178.

Omara, M., Zimmerman, N., Sullivan, M.R., Li, X., Ellis, A., Cesa, R., Subramanian, R., Presto, A.A., Robinson, A.L., 2018. Methane emissions from natural gas production sites in the United States: Data synthesis and national estimate. Environmental Science & Technology 52, 12915-12925.

Park, J.J., Kim, H.J., 2018. Use of a forensic geochemical technique and a hydrogeological assessment to determine the source of petroleum hydrocarbon contamination at a foreshore site in Korea. Environmental Earth Sciences 77, 742.

Tyner, D.R., Johnson, M.R., 2018. A techno-economic analysis of methane mitigation potential from reported venting at oil production sites in Alberta. Environmental Science & Technology 52, 12877-12885.

Umeh, A.C., Duan, L., Naidu, R., Semple, K.T., 2018. Time-dependent remobilization of nonextractable benzo[a]pyrene residues in contrasting soils: Effects of aging, spiked concentration, and soil properties. Environmental Science & Technology 52, 12295-12305.

Vaughn, T.L., Bell, C.S., Pickering, C.K., Schwietzke, S., Heath, G.A., Pétron, G., Zimmerle, D.J., Schnell, R.C., Nummedal, D., 2018. Temporal variability largely explains top-down/bottom-up difference in methane emission estimates from a natural gas production region. Proceedings of the National Academy of Sciences 115, 11712-11717.

Yuan, H.-Y., Ding, L.-J., Zama, E.F., Liu, P.-P., Hozzein, W.N., Zhu, Y.-G., 2018. Biochar modulates methanogenesis through electron syntrophy of microorganisms with ethanol as a substrate. Environmental Science & Technology 52, 12198-12207.

BIOREMEDIATION


Duggan, S.B., Kotalik, C.J., Clements, W.H., 2018. Integrating results of field biomonitoring and mesocosm experiments to validate postspill impacts of petroleum hydrocarbons on stream benthic communities. Environmental Science & Technology 52, 13584-13590.


Hou, N., Xia, Y., Wang, X., Liu, H., Liu, H., Xun, L., 2018. H2S biotreatment with sulfide-oxidizing heterotrophic bacteria. Biodegradation 29, 511-524.

Lee, Y., Jeong, S.E., Hur, M., Ko, S., Jeon, C.O., 2018. Construction and evaluation of a Korean native microbial consortium for the bioremediation of diesel fuel-contaminated soil in Korea. Frontiers in Microbiology 9, 2594. doi: 2510.3389/fmicb.2018.02594.

Lu, H., Wang, W., Li, F., Zhu, L., 2019. Mixed-surfactant-enhanced phytoremediation of PAHs in soil: Bioavailability of PAHs and responses of microbial community structure. Science of The Total Environment 653, 658-666.


Orellana, R., Macaya, C., Bravo, G., Dorochesi, F., Cumsille, A., Valencia, R., Rojas, C., Seeger, M., 2018. Living at the frontiers of life: Extremophiles in Chile and their potential for bioremediation. Frontiers in Microbiology 9, 2309. doi: 2310.3389/fmicb.2018.02309.

Rehman, K., Imran, A., Amin, I., Afzal, M., 2019. Enhancement of oil field-produced wastewater remediation by bacterially-augmented floating treatment wetlands. Chemosphere 217, 576-583.


Zhao, Y., Bai, Y., Guo, Q., Li, Z., Qi, M., Ma, X., Wang, H., Kong, D., Wang, A., Liang, B., 2019. Bioremediation of contaminated urban river sediment with methanol stimulation: Metabolic processes accompanied with microbial community changes. Science of The Total Environment 653, 649-657.

DEEPWATER HORIZON/MACONDO – OIL SPILLS BIANCHINI, K., MORRISSE

Bera, G., Parkerton, T., Redman, A., Turner, N.R., Renegar, D.A., Sericano, J.L., Knap, A.H., 2018. Passive dosing yields dissolved aqueous exposures of crude oil comparable to the CROSERF (Chemical Response to Oil Spill: Ecological Effects Research Forum) water accommodated fraction method. Environmental Toxicology and Chemistry 37, 2810-2819.

Bianchini, K., Morrissey, C.A., 2018. Assessment of shorebird migratory fueling physiology and departure timing in relation to polycyclic aromatic hydrocarbon contamination in the Gulf of Mexico. Environmental Science & Technology 52, 13562-13573.

Boccadoro, C., Krolicka, A., Receveur, J., Aeppli, C., Le Floch, S., 2018. Microbial community response and migration of petroleum compounds during a sea-ice oil spill experiment in Svalbard. Marine Environmental Research 142, 214-233.

Chiu, C.-M., Huang, C.-J., Wu, L.-C., Zhang, Y.J., Chuang, L.Z.-H., Fan, Y., Yu, H.-C., 2018. Forecasting of oil-spill trajectories by using SCHISM and X-band radar. Marine Pollution Bulletin 137, 566-581.

Gros, J., Dissanayake, A.L., Daniels, M.M., Barker, C.H., Lehr, W., Socolofsky, S.A., 2018. Oil spill modeling in deep waters: Estimation of pseudo-component properties for cubic equations of state from distillation data. Marine Pollution Bulletin 137, 627-637.

Li, N., Liu, Y., Liu, Y., Lou, Y., Zhao, X., 2019. Effect of oil spill on compound-specific stable carbon isotope composition of amino acid in Nitzschia closterium and Heterosigma akashiwo. Science of The Total Environment 653, 1095-1104.

Morrison, A.E., Dhoonmoon, C., White, H.K., 2018. Chemical characterization of natural and anthropogenic-derived oil residues on Gulf of Mexico beaches. Marine Pollution Bulletin 137, 501-508.

Paris, C.B., Berenshtein, I., Trillo, M.L., Faillettaz, R., Olascoaga, M.J., Aman, Z.M., Schlüter, M., Joye, S.B., 2018. BP Gulf Science Data reveals ineffectual subsea dispersant injection for the Macondo blowout. Frontiers in Marine Science 5, 389. doi: 310.3389/fmars.2018.00389.



OIL SAND PROCESS WATERS/TAILING PONDS

Cheng, I., Wen, D., Zhang, L., Wu, Z., Qiu, X., Yang, F., Harner, T., 2018. Deposition mapping of polycyclic aromatic compounds in the oil sands region of Alberta, Canada and linkages to ecosystem impacts. Environmental Science & Technology 52, 12456-12464.

Landis, M.S., Studabaker, W.B., Pancras, J.P., Graney, J.R., Puckett, K., White, E.M., Edgerton, E.S., 2019. Source apportionment of an epiphytic lichen biomonitor to elucidate the sources and spatial distribution of polycyclic aromatic hydrocarbons in the Athabasca Oil Sands Region, Alberta, Canada. Science of The Total Environment 654, 1241-1257.

Robertson, J.M., Nesbitt, J.A., Lindsay, M.B.J., 2019. Aqueous- and solid-phase molybdenum geochemistry of oil sands fluid petroleum coke deposits, Alberta, Canada. Chemosphere 217, 715-723.


Samanipour, S., Hooshyari, M., Baz-Lomba, J.A., Reid, M.J., Casale, M., Thomas, K.V., 2019. The effect of extraction methodology on the recovery and distribution of naphthenic acids of oilfield produced water. Science of The Total Environment 652, 1416-1423.

UNCONVENTIONALSHALE GAS-CBM RESOURCES

Liden, T., Carlton, D.D., Miyazaki, S., Otoyo, T., Schug, K.A., 2019. Forward osmosis remediation of high salinity Permian Basin produced water from unconventional oil and gas development. Science of The Total Environment 653, 82-90.

Tang, H.L., Tang, L., Xie, Y.F., 2018. Aerated electrolysis for reducing impacts of shale gas production wastewater on water sources regarding disinfection byproduct formation. Environmental Science & Technology Letters 5, 681-686.

Wu, C., Yang, Z., Qin, Y., Chen, J., Zhang, Z., Li, Y., 2018. Characteristics of hydrogen and oxygen isotopes in produced water and productivity response of coalbed methane wells in western Guizhou. Energy & Fuels 32, 11203-11211.

Evolution/Paleontology/Palynology

Benton, M.J., Bernardi, M., Kinsella, C., 2018. The Carnian Pluvial Episode and the origin of dinosaurs. Journal of the Geological Society 175, 1019.

Coiro, M., Chomicki, G., Doyle, J.A., 2018. Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of the relationship of angiosperms and Gnetales. Paleobiology 44, 490-510.

Dececchi, T.A., Narbonne, G.M., Greentree, C., Laflamme, M., 2018. Phylogenetic relationships among the Rangeomorpha: the importance of outgroup selection and implications for their diversification. Canadian Journal of Earth Sciences 55, 1223-1239.

Feng, Z., Wei, H., Guo, Y., Bomfleur, B., 2018. A conifer-dominated Early Triassic flora from Southwest China. Science Bulletin 63, 1462-1463.


Jeffery, J.E., Storrs, G.W., Holland, T., Tabin, C.J., Ahlberg, P.E., 2018. Unique pelvic fin in a tetrapod-like fossil fish, and the evolution of limb patterning. Proceedings of the National Academy of Sciences 115, 12005-12010.

Karp, A.T., Behrensmeyer, A.K., Freeman, K.H., 2018. Grassland fire ecology has roots in the late Miocene. Proceedings of the National Academy of Sciences 115, 12130-12135.

Li, F., Gong, Q., Burne, R.V., Tang, H., Su, C., Zeng, K., Zhang, Y., Tan, X., 2019. Ooid factories operating under hothouse conditions in the earliest Triassic of South China. Global and Planetary Change 172, 336-354.

Mitchell, E.G., Kenchington, C.G., Harris, S., Wilby, P.R., 2018. Revealing rangeomorph species characters using spatial analyses. Canadian Journal of Earth Sciences 55, 1262-1270.

Naimark, E., Kalinina, M., Shokurov, A., Markov, A., Zaytseva, L., Boeva, N., 2018. Mineral composition of host sediments influences the fossilization of soft tissues. Canadian Journal of Earth Sciences 55, 1271-1283.

Siveter, D.J., Briggs, D.E.G., Siveter, D.J., Sutton, M.D., 2018. A well-preserved respiratory system in a Silurian ostracod. Biology Letters 14, Article 20180464.


Vogel, G., 2018. Giant mammal cousin rivaled early dinosaurs. Science 362, 879.


Wiemann, J., Yang, T.-R., Norell, M.A., 2018. Dinosaur egg colour had a single evolutionary origin. Nature 563, 555-558.

Zhang, M., Dai, S., Du, B., Ji, L., Hu, S., 2018. Mid-Cretaceous hothouse climate and the expansion of early angiosperms. Acta Geologica Sinica - English Edition 92, 2004-2025.

ORIGINS OF LIFE/MICROBIAL GENOMICS

Ahrendt, S.R., Quandt, C.A., Ciobanu, D., Clum, A., Salamov, A., Andreopoulos, B., Cheng, J.-F., Woyke, T., Pelin, A., Henrissat, B., Reynolds, N.K., Benny, G.L., Smith, M.E., James, T.Y., Grigoriev, I.V., 2018. Leveraging single-cell genomics to expand the fungal tree of life. Nature Microbiology 3, 1417-1428.

Bray, M.S., Lenz, T.K., Haynes, J.W., Bowman, J.C., Petrov, A.S., Reddi, A.R., Hud, N.V., Williams, L.D., Glass, J.B., 2018. Multiple prebiotic metals mediate translation. Proceedings of the National Academy of Sciences 115, 12164-12169.

Colson, P., Levasseur, A., La Scola, B., Sharma, V., Nasir, A., Pontarotti, P., Caetano-Anollés, G., Raoult, D., 2018. Ancestrality and mosaicism of giant viruses supporting the

definition of the fourth TRUC of microbes. Frontiers in Microbiology 9, 2668. doi: 2610.3389/fmicb.2018.02668.

Gumulya, Y., Baek, J.-M., Wun, S.-J., Thomson, R.E.S., Harris, K.L., Hunter, D.J.B., Behrendorff, J.B.Y.H., Kulig, J., Zheng, S., Wu, X., Wu, B., Stok, J.E., De Voss, J.J., Schenk, G., Jurva, U., Andersson, S., Isin, E.M., Bodén, M., Guddat, L., Gillam, E.M.J., 2018. Engineering highly functional thermostable proteins using ancestral sequence reconstruction. Nature Catalysis 1, 878-888.

Hirose, H., Tsiamantas, C., Katoh, T., Suga, H., 2019. In vitro expression of genetically encoded non-standard peptides consisting of exotic amino acid building blocks. Current Opinion in Biotechnology 58, 28-36.

Juntunen, H.L., Leinen, L.J., Pitts, B.K., O’Hanlon, S.M., Theiling, B.P., Barge, L.M., Videau, P., Gaylor, M.O., 2018. Investigating the kinetics of montmorillonite clay-catalyzed conversion of anthracene to 9,10-anthraquinone in the context of prebiotic chemistry. Origins of Life and Evolution of Biospheres 48, 321-330.

Kawamura, K., Konagaya, N., Maruoka, Y., 2018. Enhancement and inhibitory activities of minerals for alanine oligopeptide elongation under hydrothermal conditions. Astrobiology 18, 1403-1413.

Khadka, R., Clothier, L., Wang, L., Lim, C.K., Klotz, M.G., Dunfield, P.F., 2018. Evolutionary history of copper membrane monooxygenases. Frontiers in Microbiology 9, 2493. doi: 2410.3389/fmicb.2018.02493.

Kivisaar, M., 2018. The effect of cellular redox status on the evolvability of new catabolic pathways. mBio 9, Article e01981-18.

Lan, P., Tan, M., Zhang, Y., Niu, S., Chen, J., Shi, S., Qiu, S., Wang, X., Peng, X., Cai, G., Cheng, H., Wu, J., Li, G., Lei, M., 2018. Structural insight into precursor tRNA processing by yeast ribonuclease P. Science 362, eaat6678 DOI: 6610.1126/science.aat6678

Li, Z., Lyu, R., Tower, J., 2018. Models of replicator proliferation involving differential replicator subunit stability. Origins of Life and Evolution of Biospheres 48, 331-342.

Mazel, F., Davis, K.M., Loudon, A., Kwong, W.K., Groussin, M., Parfrey, L.W., 2018. Is host filtering the main driver of phylosymbiosis across the tree of Life? mSystems 3, Article e00097-00018.


Payne, S., McCarthy, S., Johnson, T., North, E., Blum, P., 2018. Nonmutational mechanism of inheritance in the Archaeon Sulfolobus solfataricus. Proceedings of the National Academy of Sciences 115, 12271-12276.

Scott, W.G., Nagai, K., 2018. Recruiting more proteins to the RNA world. Science 362, 644-645.

Sibilska, I., Feng, Y., Li, L., Yin, J., 2018. Trimetaphosphate activates prebiotic peptide synthesis across a wide range of temperature and pH. Origins of Life and Evolution of Biospheres 48, 277-287.

HOMINID EVOLUTION

Beier, J., Anthes, N., Wahl, J., Harvati, K., 2018. Similar cranial trauma prevalence among Neanderthals and Upper Palaeolithic modern humans. Nature 563, 686-690.

Bobe, R., Carvalho, S., 2018. The decline of Africa's largest mammals. Science 362, 892-893.

Faith, J.T., Rowan, J., Du, A., Koch, P.L., 2018. Plio-Pleistocene decline of African megaherbivores: No evidence for ancient hominin impacts. Science 362, 938-941.

Owen, R.B., Muiruri, V.M., Lowenstein, T.K., Renaut, R.W., Rabideaux, N., Luo, S., Deino, A.L., Sier, M.J., Dupont-Nivet, G., McNulty, E.P., Leet, K., Cohen, A., Campisano, C., Deocampo, D., Shen, C.-C., Billingsley, A., Mbuthia, A., 2018. Progressive aridification in East Africa over the last half million years and implications for human evolution. Proceedings of the National Academy of Sciences 115, 11174-11179.

Roberts, P., Stewart, M., Alagaili, A.N., Breeze, P., Candy, I., Drake, N., Groucutt, H.S., Scerri, E.M.L., Lee-Thorp, J., Louys, J., Zalmout, I.S., Al-Mufarreh, Y.S.A., Zech, J., Alsharekh, A.M., al Omari, A., Boivin, N., Petraglia, M., 2018. Fossil herbivore stable isotopes reveal middle Pleistocene hominin palaeoenvironment in ‘Green Arabia’. Nature Ecology & Evolution 2, 1871-1878.

Trinkaus, E., 2018. An abundance of developmental anomalies and abnormalities in Pleistocene people. Proceedings of the National Academy of Sciences 115, 11941-11946.

Zhang, J.-F., Dennell, R., 2018. The last of Asia conquered by Homo sapiens. Science 362, 992-993.

Zhang, X.L., Ha, B.B., Wang, S.J., Chen, Z.J., Ge, J.Y., Long, H., He, W., Da, W., Nian, X.M., Yi, M.J., Zhou, X.Y., Zhang, P.Q., Jin, Y.S., Bar-Yosef, O., Olsen, J.W., Gao, X., 2018. The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago. Science 362, 1049-1051.

Fluid Inclusions

Bassez, M.-P., 2018. Water near its supercritical point and at alkaline pH for the production of ferric oxides and silicates in anoxic conditions. A new hypothesis for the synthesis of minerals observed in banded iron formations and for the related geobiotropic chemistry inside fluid inclusions. Origins of Life and Evolution of Biospheres 48, 289-320.


Lajoinie, M.F., Ballivián Justiniano, C.A., Salvioli, M.A., Ruiz, R., Recio, C., Sial, A.N., Etcheverry, R.O., Curci, M.V., de la Cal, H.G., Lanfranchini, M.E., 2019. Significance of graphite inclusion occurrence in the minerals of the San Miguel skarn for the Palaeoproterozoic basement of Tandilia Belt (Argentina) and for the Río de la Plata Craton. Journal of South American Earth Sciences 89, 118-139.


Pestilho, A.L.S., Monteiro, L.V.S., Carbonezi, C.A., Jorge, S.B., Santos Neto, E.V., 2018. Corrigendum to “Linking the geochemistry of crude oils and petroleum inclusions in the Ubarana and Lorena oilfields, Potiguar Basin, Brazilian Equatorial Margin” [Org. Geochem. 124 (2018) 133–150]. Organic Geochemistry 125, 300-301.

Ping, H., Chen, H., George, S.C., Li, C., Hu, S., 2019. Relationship between the fluorescence color of oil inclusions and thermal maturity in the Dongying Depression, Bohai Bay Basin, China: Part 1. Fluorescence evolution of oil in the context of hydrous pyrolysis experiments with increasing maturity. Marine and Petroleum Geology 100, 1-19.

Zhao, S., Chen, W., Zhou, L., Zhou, P., Zhang, J., 2019. Characteristics of fluid inclusions and implications for the timing of hydrocarbon accumulation in the Cretaceous reservoirs, Kelasu Thrust Belt, Tarim Basin, China. Marine and Petroleum Geology 99, 473-487.

General Interest

Gibbons, A., 2018. Eruption made 536 ‘the worst year to be alive’. Science 362, 733-734.

Lee, S., Suh, J., Choi, Y., 2018. Review of smartphone applications for geoscience: current status, limitations, and future perspectives. Earth Science Informatics 11, 463-486.

Geology

Cawood, P.A., Zhao, G., Yao, J., Wang, W., Xu, Y., Wang, Y., 2018. Reconstructing South China in Phanerozoic and Precambrian supercontinents. Earth-Science Reviews 186, 173-194.

Crede, L.-S., Liu, W., Evans, K.A., Rempel, K.U., Testemale, D., Brugger, J., 2019. Crude oils as ore fluids: An experimental in-situ XAS study of gold partitioning between brine and organic fluid from 25 to 250 °C. Geochimica et Cosmochimica Acta 244, 352-365.

Crede, L.-S., Rempel, K.U., Hu, S.-Y., Evans, K.A., 2018. An experimental method for gold partitioning between two immiscible fluids: Brine and n-dodecane. Chemical Geology 501, 35-50.

Hu, W., Wang, X., Zhu, D., You, D., Wu, H., 2018. An overview of types and characterization of hot fluids associated with reservoir formation in petroliferous basins. Energy Exploration & Exploitation 36, 1359-1375.

Kars, M., Musgrave, R.J., Hoshino, T., Jonas, A.-S., Bauersachs, T., Inagaki, F., Kodama, K., 2018. Magnetic mineral diagenesis in a high temperature and deep methanic zone in Izu Rear Arc marine sediments, Northwest Pacific Ocean. Journal of Geophysical Research: Solid Earth 123, 8331-8348.

Kershaw, S., Munnecke, A., Jarochowska, E., 2018. Understanding Palaeozoic stromatoporoid growth. Earth-Science Reviews 187, 53-76.

Li, S., Zhao, S., Liu, X., Cao, H., Yu, S., Li, X., Somerville, I., Yu, S., Suo, Y., 2018. Closure of the Proto-Tethys Ocean and Early Paleozoic amalgamation of microcontinental blocks in East Asia. Earth-Science Reviews 186, 37-75.

Seyfullah, L.J., Roghi, G., Corso, J.D., Schmidt, A.R., 2018. The Carnian Pluvial Episode and the first global appearance of amber. Journal of the Geological Society 175, 1012.

Wang, Y., Qian, X., Cawood, P.A., Liu, H., Feng, Q., Zhao, G., Zhang, Y., He, H., Zhang, P., 2018. Closure of the East Paleotethyan Ocean and amalgamation of the Eastern Cimmerian and Southeast Asia continental fragments. Earth-Science Reviews 186, 195-230.

Zhao, G., Wang, Y., Huang, B., Dong, Y., Li, S., Zhang, G., Yu, S., 2018. Geological reconstructions of the East Asian blocks: From the breakup of Rodinia to the assembly of Pangea. Earth-Science Reviews 186, 262-286.

Zhao, J., Li, J., Xu, Z., 2018. Advances in the origin of overpressures in sedimentary basins. Petroleum Research 3, 1-24.

BOLIDE IMPACTS/CRATER GEOCHEMISTRY

Briggs, D.E.G., Liu, H.P., McKay, R.M., Witzke, B.J., 2018. The Winneshiek biota: exceptionally well-preserved fossils in a Middle Ordovician impact crater. Journal of the Geological Society 175, 865.

French, B.M., McKay, R.M., Liu, H.P., Briggs, D.E.G., Witzke, B.J., 2018. The Decorah structure, northeastern Iowa: Geology and evidence for formation by meteorite impact. GSA Bulletin 130, 2062-2086.

Kjær, K.H., Larsen, N.K., Binder, T., Bjørk, A.A., Eisen, O., Fahnestock, M.A., Funder, S., Garde, A.A., Haack, H., Helm, V., Houmark-Nielsen, M., Kjeldsen, K.K., Khan, S.A., Machguth, H., McDonald, I., Morlighem, M., Mouginot, J., Paden, J.D., Waight, T.E., Weikusat, C., Willerslev, E., MacGregor, J.A., 2018. A large impact crater beneath Hiawatha Glacier in northwest Greenland. Science Advances 4, Article eaar8173.

MacLagan, E.A., Walton, E.L., Herd, C.D.K., Dence, M., 2018. Investigation of impact melt in allochthonous crater-fill deposits of the Steen River impact structure, Alberta, Canada. Meteoritics & Planetary Science 53, 2285-2305.

Plado, J., Hietala, S., Kreitsmann, T., Lerssi, J., Nenonen, J., Pesonen, L.J., 2018. Summanen, a new meteorite impact structure in Central Finland. Meteoritics & Planetary Science 53, 2413-2426.

Voosen, P., 2018. Ice age impact. Science 362, 738-742.

Wulf, G., Hergarten, S., Kenkmann, T., 2019. Combined remote sensing analyses and landform evolution modeling reveal the terrestrial Bosumtwi impact structure as a Mars-like rampart crater. Earth and Planetary Science Letters 506, 209-220.

Hydrates

Betlem, P., Senger, K., Hodson, A., 2019. 3D thermobaric modelling of the gas hydrate stability zone onshore central Spitsbergen, Arctic Norway. Marine and Petroleum Geology 100, 246-262.

Chen, W., Hartman, R.L., 2018. Methane hydrate intrinsic dissociation kinetics measured in a microfluidic system by means of in situ Raman spectroscopy. Energy & Fuels 32, 11761-11771.

Chen, Y., Wu, N., Liang, D., Hu, R., 2018. Numerical simulation on the resistivity of hydrate-bearing sediment based on fractal pore model. Natural Gas Industry 38, 128-134.

Du, Z., Zhang, X., Xi, S., Li, L., Luan, Z., Lian, C., Wang, B., Yan, J., 2018. In situ Raman spectroscopy study of synthetic gas hydrate formed by cold seep flow in the South China Sea. Journal of Asian Earth Sciences 168, 197-206.

Feng, D., Luo, M., Sun, X., Wang, J., 2018. South China Sea seeps. Journal of Asian Earth Sciences 168, 1-2.

Feng, D., Qiu, J.-W., Hu, Y., Peckmann, J., Guan, H., Tong, H., Chen, C., Chen, J., Gong, S., Li, N., Chen, D., 2018. Cold seep systems in the South China Sea: An overview. Journal of Asian Earth Sciences 168, 3-16.

Feng, J., Yang, S., Liang, J., Fang, Y., He, Y., Luo, M., Chen, D., 2018. Methane seepage inferred from the porewater geochemistry of shallow sediments in the Beikang Basin of the southern South China Sea. Journal of Asian Earth Sciences 168, 77-86.

Hu, Y., Luo, M., Chen, L., Liang, Q., Feng, D., Tao, J., Yang, S., Chen, D., 2018. Methane source linked to gas hydrate system at hydrate drilling areas of the South China Sea: Porewater geochemistry and numerical model constraints. Journal of Asian Earth Sciences 168, 87-95.

Lin, Z., Sun, X., Lu, Y., Strauss, H., Xu, L., Chen, T., Lu, H., Peckmann, J., 2018. Iron isotope constraints on diagenetic iron cycling in the Taixinan seepage area, South China Sea. Journal of Asian Earth Sciences 168, 112-124.

Mohamadi-Baghmolaei, M., Hajizadeh, A., Azin, R., Izadpanah, A.A., 2018. Assessing thermodynamic models and introducing novel method for prediction of methane hydrate formation. Journal of Petroleum Exploration and Production Technology 8, 1401-1412.

Pan, Z., Wang, Z., Zhang, Z., Ma, G., Zhang, L., Huang, Y., 2018. Natural gas hydrate formation dynamics in a diesel water-in-oil emulsion system. Petroleum Science and Technology 36, 1649-1656.

Stoporev, A.S., Sizikov, A.A., Cheshkova, T.V., Loskutova, A.O., Grinko, A.A., Yarkova, E.A., Semenov, A.P., Manakov, A.Y., Vinokurov, V.A., 2018. Influence of fractions isolated from

crude oils and refined petroleum product on decomposition process of methane hydrate. Energy & Fuels 32, 11279-11288.

Su, P., Liang, J., Peng, J., Zhang, W., Xu, J., 2018. Petroleum systems modeling on gas hydrate of the first experimental exploitation region in the Shenhu area, northern South China sea. Journal of Asian Earth Sciences 168, 57-76.

Wan, S., Feng, D., Chen, F., Zhuang, C., Chen, D., 2018. Foraminifera from gas hydrate-bearing sediments of the northeastern South China Sea: Proxy evaluation and application for methane release activity. Journal of Asian Earth Sciences 168, 125-136.

Wang, J., Wu, S., Kong, X., Ma, B., Li, W., Wang, D., Gao, J., Chen, W., 2018. Subsurface fluid flow at an active cold seep area in the Qiongdongnan Basin, northern South China Sea. Journal of Asian Earth Sciences 168, 17-26.

Wang, X., Liu, B., Qian, J., Zhang, X., Guo, Y., Su, P., Liang, J., Jin, J., Luan, Z., Chen, D., Xi, S., Li, C., 2018. Geophysical evidence for gas hydrate accumulation related to methane seepage in the Taixinan Basin, South China Sea. Journal of Asian Earth Sciences 168, 27-37.

Yang, K., Chu, F., Zhu, Z., Dong, Y., Yu, X., Zhang, W., Ma, W., 2018. Formation of methane-derived carbonates during the last glacial period on the northern slope of the South China Sea. Journal of Asian Earth Sciences 168, 173-185.

Isotope Geochemistry

Badger, M.P.S., Chalk, T.B., Foster, G.L., Bown, P.R., Gibbs, S.J., Sexton, P.F., Schmidt, D.N., Pälike, H., Mackensen, A., Pancost, R.D., 2018. Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels. Climate of the Past Discussions 2018, 1-30.


Berke, M.A., Cartagena Sierra, A., Bush, R., Cheah, D., O'Connor, K., 2019. Controls on leaf wax fractionation and δ2H values in tundra vascular plants from western Greenland. Geochimica et Cosmochimica Acta 244, 565-583.


Cassarino, L., Coath, C.D., Xavier, J.R., Hendry, K.R., 2018. Silicon isotopes of deep sea sponges: new insights into biomineralisation and skeletal structure. Biogeosciences 15, 6959-6977.

Enge, A.J., Wanek, W., Heinz, P., 2018. Preservation effects on isotopic signatures in benthic foraminiferal biomass. Marine Micropaleontology 144, 50-59.

Hain, M.P., Foster, G.L., Chalk, T., 2018. Robust constraints on past CO2 climate forcing from the boron isotope proxy. Paleoceanography and Paleoclimatology 33, 1099-1115.



King, E.K., Pett-Ridge, J.C., 2018. Reassessing the dissolved molybdenum isotopic composition of ocean inputs: The effect of chemical weathering and groundwater. Geology 46, 955-958.

Kueter, N., Schmidt, M.W., Lilley, M.D., Bernasconi, S.M., 2019. Experimental determination of equilibrium CH4–CO2–CO carbon isotope fractionation factors (300–1200°C). Earth and Planetary Science Letters 506, 64-75.

Liu, J., An, Z., 2018. A hierarchical framework for disentangling different controls on leaf wax δDn-alkane values in terrestrial higher plants. Quaternary Science Reviews 201, 409-417.

Ratié, G., Quantin, C., Maia De Freitas, A., Echevarria, G., Ponzevera, E., Garnier, J., 2019. The behavior of nickel isotopes at the biogeochemical interface between ultramafic soils and Ni accumulator species. Journal of Geochemical Exploration 196, 182-191.

Schulte, M., Jochmann, M.A., Gehrke, T., Denecke, M., Schmidt, T.C., 2018. Carbon isotopic fractionation via diffusion in a coarse material. Geochemistry, Geophysics, Geosystems 19, 3246-3253.


Tripti, M., Gurumurthy, G.P., Lambs, L., Riotte, J., Balakrishna, K., 2018. Water and organic carbon cycles in monsoon-driven humid tropics of the western Ghats Mountain Belt, India: Insights from stable isotope approach. Journal of the Geological Society of India 92, 579-587.

Wang, H., Hu, X., Rabalais, N.N., Brandes, J., 2018. Drivers of oxygen consumption in the Northern Gulf of Mexico hypoxic waters—a stable carbon isotope perspective. Geophysical Research Letters 45, 10,528-510,538.

Wang, J., Xu, Y., Zhou, L., Shi, M., Axia, E., Jia, Y., Chen, Z., Li, J., Wang, G., 2018. Disentangling temperature effects on leaf wax n-alkane traits and carbon isotopic composition from phylogeny and precipitation. Organic Geochemistry 126, 13-22.

Wu, F., Owens, J.D., Huang, T., Sarafian, A., Huang, K.-F., Sen, I.S., Horner, T.J., Blusztajn, J., Morton, P., Nielsen, S.G., 2019. Vanadium isotope composition of seawater. Geochimica et Cosmochimica Acta 244, 403-415.

CLUMPED ISOTOPES

Bernasconi, S.M., Müller, I.A., Bergmann, K.D., Breitenbach, S.F.M., Fernandez, A., Hodell, D.A., Jaggi, M., Meckler, A.N., Millan, I., Ziegler, M., 2018. Reducing

uncertainties in carbonate clumped isotope analysis through consistent carbonate-based standardization. Geochemistry, Geophysics, Geosystems 19, 2895-2914.

Davies, A.J., John, C.M., 2019. The clumped (13C–18O) isotope composition of echinoid calcite: Further evidence for “vital effects” in the clumped isotope proxy. Geochimica et Cosmochimica Acta 245, 172-189.

Kato, H., Amekawa, S., Kano, A., Mori, T., Kuwahara, Y., Quade, J., 2019. Seasonal temperature changes obtained from carbonate clumped isotopes of annually laminated tufas from Japan: Discrepancy between natural and synthetic calcites. Geochimica et Cosmochimica Acta 244, 548-564.

Van Plantinga, A.A., Grossman, E.L., 2018. Stable and clumped isotope sclerochronologies of mussels from the Brazos River, Texas (USA): Environmental and ecologic proxy. Chemical Geology 502, 55-65.

METHODS/INSTRUMENTATION

Mathematical Geochemistry/Phase Behavior

Abutaqiya, M.I.L., Sisco, C.J., Vargas, F.M., 2019. A Linear Extrapolation of Normalized Cohesive Energy (LENCE) for fast and accurate prediction of the asphaltene onset pressure. Fluid Phase Equilibria 483, 52-69.

Barbosa, N.S.V., Lima, E.R.A., Tavares, F.W., 2019. Wettability of rock, oil and brine system based on density functional theory. Fluid Phase Equilibria 479, 99-105.

Chen, M., Sasanipour, J., Kiaian Mousavy, S.A., Khajeh, E., Kamyab, M., 2018. Estimating phase behavior of the asphaltene precipitation by GA-ANFIS approach. Petroleum Science and Technology 36, 1582-1588.

Luo, S., Lutkenhaus, J.L., Nasrabadi, H., 2018. Multiscale fluid-phase-behavior simulation in shale reservoirs using a pore-size-dependent equation of state. SPE-191369-PA 21, 806-820.

Zeng, Y., Khodadadi, J.M., 2018. Molecular dynamics simulations of the crystallization process of n-alkane mixtures and the resulting thermal conductivity. Energy & Fuels 32, 11253-11260.

Zhao, J., Yao, G., Ramisetti, S.B., Hammond, R.B., Wen, D., 2018. Molecular dynamics simulation of the salinity effect on the n-decane/water/vapor interfacial equilibrium. Energy & Fuels 32, 11080-11092.

Zhao, J., Yao, G., Ramisetti, S.B., Hammond, R.B., Wen, D., 2019. Molecular dynamics investigation of substrate wettability alteration and oil transport in a calcite nanopore. Fuel 239, 1149-1161.

Microbiology/Extremophiles

Belahbib, H., Summers, Z.M., Fardeau, M.-L., Joseph, M., Tamburini, C., Dolla, A., Ollivier, B., Armougom, F., 2018. Towards a congruent reclassification and nomenclature of the thermophilic species of the genus Pseudothermotoga within the order Thermotogales. Systematic and Applied Microbiology 41, 555-563.

Garanina, I.A., Fisunov, G.Y., Govorun, V.M., 2018. BAC-BROWSER: The tool for visualization and analysis of prokaryotic genomes. Frontiers in Microbiology 9, 2827. doi: 2810.3389/fmicb.2018.02827.

Hug, L.A., 2018. Sizing up the uncultured microbial majority. mSystems 3, Article e00185-00118.

Lloyd, K.G., Steen, A.D., Ladau, J., Yin, J., Crosby, L., 2018. Phylogenetically novel uncultured microbial cells dominate Earth microbiomes. mSystems 3, Article e00055-00018.

Schulz, F., Alteio, L., Goudeau, D., Ryan, E.M., Yu, F.B., Malmstrom, R.R., Blanchard, J., Woyke, T., 2018. Hidden diversity of soil giant viruses. Nature Communications 9, Article 4881.

MICROBIAL ECOSYSTEMS

Abia, A.L.K., Alisoltani, A., Ubomba-Jaswa, E., Dippenaar, M.A., 2019. Microbial life beyond the grave: 16S rRNA gene-based metagenomic analysis of bacteria diversity and their functional profiles in cemetery environments. Science of The Total Environment 655, 831-841.

Bravo, A.G., Peura, S., Buck, M., Ahmed, O., Mateos-Rivera, A., Herrero Ortega, S., Schaefer, J.K., Bouchet, S., Tolu, J., Björn, E., Bertilsson, S., 2018. Methanogens and iron-reducing bacteria: The overlooked members of mercury-methylating microbial communities in boreal lakes. Applied and Environmental Microbiology 84, Article e01774-18.

Carraro, L., Hartikainen, H., Jokela, J., Bertuzzo, E., Rinaldo, A., 2018. Estimating species distribution and abundance in river networks using environmental DNA. Proceedings of the National Academy of Sciences 115, 11724-11729.

Dombrowski, N., Teske, A.P., Baker, B.J., 2018. Expansive microbial metabolic versatility and biodiversity in dynamic Guaymas Basin hydrothermal sediments. Nature Communications 9, Article 4999.


Fadeev, E., Salter, I., Schourup-Kristensen, V., Nöthig, E.-M., Metfies, K., Engel, A., Piontek, J., Boetius, A., Bienhold, C., 2018. Microbial communities in the East and West Fram Strait during sea ice melting season. Frontiers in Marine Science 5, 429. doi: 410.3389/fmars.2018.00429.


Hershey, O.S., Kallmeyer, J., Wallace, A., Barton, M.D., Barton, H.A., 2018. High microbial diversity despite extremely low biomass in a deep karst aquifer. Frontiers in Microbiology 9, 2823. doi: 2810.3389/fmicb.2018.02823.

Ivančić, I., Paliaga, P., Pfannkuchen, M., Djakovac, T., Najdek, M., Steiner, P., Korlević, M., Markovski, M., Baričević, A., Tanković, M.S., Herndl, G.J., 2018. Seasonal variations in extracellular enzymatic activity in marine snow-associated microbial communities and their impact on the surrounding water. FEMS Microbiology Ecology 94, fiy198-fiy198.

Jing, H., Zhu, W., Liu, H., Zheng, L., Zhang, Y., 2018. Particle-attached and free-living archaeal communities in the benthic boundary layer of the Mariana Trench. Frontiers in Microbiology 9, 2821. doi: 2810.3389/fmicb.2018.02821.


Liu, Q., Kämpf, H., Bussert, R., Krauze, P., Horn, F., Nickschick, T., Plessen, B., Wagner, D., Alawi, M., 2018. Influence of CO2 degassing on the microbial community in a dry mofette field in Hartoušov, Czech Republic (Western Eger Rift). Frontiers in Microbiology 9, 2787. doi: 2710.3389/fmicb.2018.02787.

Liu, Y., Liu, J., Yao, P., Ge, T., Qiao, Y., Zhao, M., Zhang, X.-H., 2018. Distribution patterns of ammonia-oxidizing archaea and bacteria in sediments of the eastern China marginal seas. Systematic and Applied Microbiology 41, 658-668.

Lopez-Fernandez, M., Åström, M., Bertilsson, S., Dopson, M., 2018. Depth and dissolved organic carbon shape microbial communities in surface influenced but not ancient saline terrestrial aquifers. Frontiers in Microbiology 9, 2880. doi: 2810.3389/fmicb.2018.02880.

Malard, L.A., Pearce, D.A., 2018. Microbial diversity and biogeography in Arctic soils. Environmental Microbiology Reports 10, 611-625.

Nguyen, T.M., Seo, C., Ji, M., Paik, M.-J., Myung, S.-W., Kim, J., 2018. Effective soil extraction method for cultivating previously uncultured soil bacteria. Applied and Environmental Microbiology 84, Article e01145-01118.


Santini, T.C., Raudsepp, M., Hamilton, J., Nunn, J., 2018. Extreme geochemical conditions and dispersal limitation retard primary succession of microbial communities in gold tailings. Frontiers in Microbiology 9, 2785. doi: 2710.3389/fmicb.2018.02785.

Storey, S., Ashaari, M.M., Clipson, N., Doyle, E., de Menezes, A.B., 2018. Opportunistic bacteria dominate the soil microbiome response to phenanthrene in a microcosm-based study. Frontiers in Microbiology 9, 2815. doi: 2810.3389/fmicb.2018.02815.

Sun, W., Xiao, E., Häggblom, M., Krumins, V., Dong, Y., Sun, X., Li, F., Wang, Q., Li, B., Yan, B., 2018. Bacterial survival strategies in an alkaline tailing site and the physiological mechanisms of dominant phylotypes as revealed by metagenomic analyses. Environmental Science & Technology 52, 13370-13380.

Trubl, G., Jang, H.B., Roux, S., Emerson, J.B., Solonenko, N., Vik, D.R., Solden, L., Ellenbogen, J., Runyon, A.T., Bolduc, B., Woodcroft, B.J., Saleska, S.R., Tyson, G.W., Wrighton, K.C., Sullivan, M.B., Rich, V.I., 2018. Soil viruses are underexplored players in ecosystem carbon processing. mSystems 3, Article e00076-00018.

Wei, N., Nakajima, F., Tobino, T., 2018. A microcosm study of surface sediment environmental DNA: Decay observation, abundance estimation, and fragment length comparison. Environmental Science & Technology 52, 12428-12435.

Zhang, Z., Wu, Y., Zhang, X.-H., 2018. Cultivation of microbes from the deep-sea environments. Deep Sea Research Part II: Topical Studies in Oceanography 155, 34-43.

PETROLEUM DEGRADERS

Borah, D., Yadav, R.N.S., 2018. Molecular characterization of biosurfactant producing Bacillus cereus strain DRDU1 for its potential application in bioremediation and further EOR studies. Petroleum Science and Technology 36, 1605-1612.







Sperfeld, M., Diekert, G., Studenik, S., 2019. Community dynamics in a nitrate-reducing microbial consortium cultivated with p-alkylated vs. non-p-alkylated aromatic compounds. FEMS Microbiology Ecology 95, fiy200-fiy200.

Spini, G., Spina, F., Poli, A., Blieux, A.-L., Regnier, T., Gramellini, C., Varese, G.C., Puglisi, E., 2018. Molecular and microbiological insights on the enrichment procedures for the isolation of petroleum degrading bacteria and fungi. Frontiers in Microbiology 9, 2543. doi: 2510.3389/fmicb.2018.02543.

Sugai, Y., Owaki, Y., Sasaki, K., Kaneko, F., Sakai, T., 2018. Numerical modelling of the growth of sulfate-reducing bacteria indigenous to an oilfield in Japan. Petroleum Science and Technology 36, 1597-1604.

Wang, X., Li, X., Yu, L., Huang, L., Xiu, J., Lin, W., Zhang, Y., 2019. Characterizing the microbiome in petroleum reservoir flooded by different water sources. Science of The Total Environment 653, 872-885.

Oil & Gas Exploration

Abd-Allah, Z.M., Maky, A.F., Ramadan, M.A.M., 2018. Organic source of crude oils and 1D basin modeling of upper Cretaceous rocks, Badr Concession, Abu Gharadig Basin, Western Desert, Egypt. Arabian Journal of Geosciences 11, 704.

Ahmed, M.A., Afife, M.M., 2018. Hydrocarbon-generating potential of the Eocene Thebes Formation, Gulf of Suez: 1D basin modeling as a supplementary tool for source rock evaluation. Arabian Journal of Geosciences 11, 713.

Craig, J., Hakhoo, N., Bhat, G.M., Hafiz, M., Khan, M.R., Misra, R., Pandita, S.K., Raina, B.K., Thurow, J., Thusu, B., Ahmed, W., Khullar, S., 2018. Petroleum systems and hydrocarbon potential of the North-West Himalaya of India and Pakistan. Earth-Science Reviews 187, 109-185.

Deng, H., Fu, M., Huang, T., Gluyas, J.G., Tong, M., Wang, X., Zhou, W., Liu, F., 2018. Ahdeb oil field, Mesopotamian Basin, Iraq: Reservoir architecture and oil charge history. American Association of Petroleum Geologists Bulletin 102, 2447-2480.

Ezeldin, F.M., Xie, X., 2018. Source rock evaluation and thermal maturity modeling of Jake oil fields, Fula sub-basin, Muglad Basin, Sudan. Arabian Journal of Geosciences 11, 664.

Hanafy, S., Farhood, K., Mahmoud, S.E., Nimmagadda, S., Mabrouk, W.M., 2018. Geological and geophysical analyses of the different reasons for DHI failure case in the Nile Delta Pliocene section. Journal of Petroleum Exploration and Production Technology 8, 969-981.

Nader, F.H., Inati, L., Ghalayini, R., Hawie, N., Bou Daher, S., 2018. Key geological characteristics of the Saida-Tyr Platform along the eastern margin of the Levant Basin, offshore Lebanon: implications for hydrocarbon exploration. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 50.

Qin, M., Huang, S., He, Z., Xu, Q., Song, J., Liu, Z., Guo, Q., 2018. Evolution of tectonic uplift, hydrocarbon migration, and uranium mineralization in the NW Junggar Basin: An apatite

fission-track thermochronology study. Acta Geologica Sinica - English Edition 92, 1901-1916.

Ren, R., Guan, S., Wu, L., Zhu, G., 2018. Evolution of the Neoproterozoic rift basins and its implication for oil and gas exploration in the Tarim Basin. Petroleum Research 3, 66-76.

Wang, Z., 2018. Reservoir forming conditions and key exploration and development technologies for marine shale gas fields in Fuling area, South China. Petroleum Research 3, 197-209.

Zhang, X., Xia, Y., Zhang, Y., Chen, Y., Zhang, G., Gao, W., 2018. Volcanic reservoir characteristics and hydrocarbon genesis of Jiamuhe formation in Jinlong 2 wellblock, Junggar Basin. Petroleum Science and Technology 36, 1516-1523.


Zhu, G., Du, D., Chen, W., Sun, Q., Li, T., Zhang, Z., Chen, Z., 2018. Discovery of Precambrian thick black mudstones and its implication for hydrocarbon exploration in the southwest Tarim Basin. Petroleum Research 3, 124-131.

Oil & Gas Generation/Expulsion



Sciarra, A., Saroni, A., Etiope, G., Coltorti, M., Mazzarini, F., Lott, C., Grassa, F., Italiano, F., 2019. Shallow submarine seep of abiotic methane from serpentinized peridotite off the Island of Elba, Italy. Applied Geochemistry 100, 1-7.

Xie, X., Krooss, B.M., Littke, R., Amann-Hildenbrand, A., Li, M., Li, Z., Snowdon, L.R., Mohnhoff, D., 2019. Accessibility and mobility of hydrocarbons in lacustrine shale: Solvent flow-through extraction experiments on Eocene oil shales from Bohai Bay Basin, eastern China. Organic Geochemistry 127, 23-36.

Zheng, T., Ma, X., Pang, X., Wang, W., Zheng, D., Huang, Y., Wang, X., Wang, K., 2019. Organic geochemistry of the Upper Triassic T3x5 source rocks and the hydrocarbon generation and expulsion characteristics in Sichuan Basin, central China. Journal of Petroleum Science and Engineering 173, 1340-1354.

Oil & Gas Geochemistry


Adepoju, A., Adekola, S.A., Omotoye, S., Akinlua, A., 2018. Light hydrocarbon geochemistry of crude oils from Eastern Niger Delta. Petroleum Science and Technology 36, 1573-1581.

Al-Hajeri, M.M., Bowden, S.A., 2018. Origin of oil geochemical compositional heterogeneity in the Radhuma and Tayarat formations heavy oil carbonate reservoirs of Burgan Field, south Kuwait. Arabian Journal of Geosciences 11, 649.

Delgado, L., Batezelli, A., Luna, J., 2018. Petroleum geochemical characterization of Albian-Oligocene sequences in the Campos Basin: “Case study: Eastern Marlim oilfield, offshore, Brazil”. Journal of South American Earth Sciences 88, 715-735.

Demirbas, A., Cek, N., Acar, S., 2018. Chemical analyses of shale gas and conventional natural gas. Petroleum Science and Technology 36, 1690-1695.



Hu, F., Liu, Z., Meng, Q., Wang, J., Song, Q., Xie, W., 2018. Biomarker characterization of various oil shale grades in the Upper Cretaceous Qingshankou Formation, southeastern Songliao Basin, NE China. Oil Shale 35, 304–326.

Jin, X., Zhang, Z., Wu, J., Zhang, C., He, Y., Cao, L., Zheng, R., Meng, W., Xia, H., 2019. Origin and geochemical implication of relatively high abundance of 17α (H)-diahopane in Yabulai basin, northwest China. Marine and Petroleum Geology 99, 429-442.

Liu, Y.-M., Dong, Y., Rui, Z.-H., Lu, X.-S., Zhou, X.-M., Wei, L.-C., 2018. Origin, migration, and accumulation of carbon dioxide in the East Changde Gas Field, Songliao Basin, northeastern China. Petroleum Science 15, 695-708.

Norrman, K., Sølling, T.I., Ceccato, M., Stamate, E., Bovet, N., Stipp, S.L.S., 2018. Chemical composition and structure of adsorbed material on pore surfaces in Middle East reservoir rocks. Energy & Fuels 32, 11234-11242.

Ogala, J.E., Kalaitzidis, S., Christanis, K., Omo-Irabor, O.O., Akinmosin, A., Yusuf, C.U., Pasadakis, N., Constantinopoulos, M., Papaefthymiou, H., 2019. Geochemical and organic petrological study of bituminous sediments from Dahomey Basin, SW Nigeria. Marine and Petroleum Geology 99, 577-595.


Qian, K., Fredriksen, T.R., Mennito, A.S., Zhang, Y., Harper, M.R., Merchant, S., Kushnerick, J.D., Rytting, B.M., Kilpatrick, P.K., 2019. Evidence of naturally-occurring vanadyl porphyrins containing multiple S and O atoms. Fuel 239, 1258-1264.

Qin, S., Zhou, G., Zhou, Z., Yang, Y., 2018. Geochemical characteristics of natural gases from different petroleum systems in the Longgang gas field, Sichuan Basin, China. Energy Exploration & Exploitation 36, 1376-1394.




Xie, Z., Zhang, B., Yang, C., Dong, C., Pei, S., Zhao, J., Guo, J., Zhang, L., 2018. Geochemical characteristics and source trace of the Devonian natural gas and bitumen in Northwest Sichuan Basin. Acta Petrolei Sinica 39, 1103-1113.

Xu, Y., Chang, X., Shi, B., Wang, Y., Li, Y., 2018. Geochemistry of severely biodegraded oils in the Carboniferous volcanic reservoir of the Chepaizi Uplift, Junggar Basin, NW China. Energy Exploration & Exploitation 36, 1461-1481.

Yalcin Erik, N., 2018. Hydrocarbon generation potential of Late Cretaceous shales and carbonates in Hekimhan Basin and genetic relationships with Karadere oil seep (eastern Anatolia Region, Turkey). Journal of Petroleum Exploration and Production Technology 8, 1139-1158.

Yang, Z., Li, M., Cheng, D., Xiao, H., Lai, H., Chen, Q., 2019. Geochemistry and possible origins of biodegraded oils in the Cretaceous reservoir of the Muglad Basin and their application in hydrocarbon exploration. Journal of Petroleum Science and Engineering 173, 889-898.

Zhan, Z.-W., Lin, X.-H., Zou, Y.-R., Li, Z., Wang, D., Liu, C., Peng, P.a., 2019. Chemometric differentiation of crude oil families in the southern Dongying Depression, Bohai Bay Basin, China. Organic Geochemistry 127, 37-49.

Zhao, J., Li, J., Cao, Q., Bai, Y., Wu, W., Ma, Y., 2019. Quasi-continuous hydrocarbon accumulation: An alternative model for the formation of large tight oil and gas accumulations. Journal of Petroleum Science and Engineering 174, 25-39.

Zhu, G., Zhang, Z., Zhou, X., Yan, L., Sun, C., Zhao, B., 2018. Preservation of ultradeep liquid oil and its exploration limit. Energy & Fuels 32, 11165-11176.

Paleoclimatology/Palaeocenography

Aichner, B., Ott, F., Słowiński, M., Noryśkiewicz, A.M., Brauer, A., Sachse, D., 2018. Leaf wax n-alkane distributions record ecological changes during the Younger Dryas at Trzechowskie paleolake (northern Poland) without temporal delay. Climate of the Past 14, 1607-1624.


Barili, R., Neilson, J.E., Brasier, A.T., Goldberg, K., Pastro Bardola, T., De Ros, L.F., Leng, M., 2018. Carbon isotopes, stratigraphy, and environmental change: the Middle–Upper Cambrian Positive Excursion (SPICE) in Port au Port Group, western Newfoundland, Canada. Canadian Journal of Earth Sciences 55, 1209-1222.

Belt, S.T., 2018. Source-specific biomarkers as proxies for Arctic and Antarctic sea ice. Organic Geochemistry 125, 277-298.

Buchanan, P.J., Matear, R.J., Chase, Z., Phipps, S.J., Bindoff, N.L., 2018. Ocean carbon and nitrogen isotopes in CSIRO Mk3L-COAL version 1.0: A tool for palaeoceanographic research. Geoscientific Model Development Discussions 2018, 1-44.


Caruthers, A.H., Gröcke, D.R., Kaczmarek, S.E., Rine, M.J., Kuglitsch, J., Harrison III, W.B., 2018. Utility of organic carbon isotope data from the Salina Group halite (Michigan Basin): A new tool for stratigraphic correlation and paleoclimate proxy resource. GSA Bulletin 130, 1782-1790.

Ceccopieri, M., Carreira, R.S., Wagener, A.L.R., Hefter, J.H., Mollenhauer, G., 2018. On the application of alkenone- and GDGT-based temperature proxies in the south-eastern Brazilian continental margin. Organic Geochemistry 126, 43-56.

Cheng, C., Li, S., Xie, X., Cao, T., Manger, W.L., Busbey, A.B., 2019. Permian carbon isotope and clay mineral records from the Xikou section, Zhen'an, Shaanxi Province, central China: Climatological implications for the easternmost Paleo-Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 407-422.

de Bar, M.W., Stolwijk, D.J., McManus, J.F., Sinninghe Damsté, J.S., Schouten, S., 2018. A Late Quaternary climate record based on long-chain diol proxies from the Chilean margin. Climate of the Past 14, 1783-1803.

Eriksson, K.A., McClung, W.S., Simpson, E.L., 2019. Sequence stratigraphic expression of greenhouse, transitional and icehouse conditions in siliciclastic successions: Paleozoic examples from the Central Appalachian Basin, USA. Earth-Science Reviews 188, 176-189.

Fantasia, A., Föllmi, K.B., Adatte, T., Bernárdez, E., Spangenberg, J.E., Mattioli, E., 2018. The Toarcian Oceanic Anoxic Event in southwestern Gondwana: an example from the Andean Basin, northern Chile. Journal of the Geological Society 175, 883.



Jensen, S., Högström, A.E.S., Høyberget, M., Meinhold, G., McIlroy, D., Ebbestad, J.O.R., Taylor, W.L., Agić, H., Palacios, T., 2018. New occurrences of Palaeopascichnus from the Stáhpogieddi Formation, Arctic Norway, and their bearing on the age of the Varanger Ice Age. Canadian Journal of Earth Sciences 55, 1253-1261.

Lauretano, V., Zachos, J.C., Lourens, L.J., 2018. Orbitally paced carbon and deep-sea temperature changes at the peak of the Early Eocene climatic optimum. Paleoceanography and Paleoclimatology 33, 1050-1065.

Liang, J., Russell, J.M., Xie, H., Lupien, R.L., Si, G., Wang, J., Hou, J., Zhang, G., 2019. Vegetation effects on temperature calibrations of branched glycerol dialkyl glycerol tetraether (brGDGTs) in soils. Organic Geochemistry 127, 1-11.

Liu, M., Chen, D., Zhou, X., Yuan, W., Jiang, M., Liu, L., 2019. Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin, NW China and implications for the Great Ordovician Biodiversification Event. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 522-535.

Loydell, D.K., Large, R.R., 2019. Biotic, geochemical and environmental changes through the early Sheinwoodian (Wenlock, Silurian) carbon isotope excursion (ESCIE), Buttington Quarry, Wales. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 305-325.

Luo, M., Algeo, T.J., Tong, H., Gieskes, J., Chen, L., Shi, X., Chen, D., 2018. More reducing bottom-water redox conditions during the Last Glacial Maximum in the southern Challenger Deep (Mariana Trench, western Pacific) driven by enhanced productivity. Deep Sea Research Part II: Topical Studies in Oceanography 155, 70-82.

Lupien, R.L., Russell, J.M., Feibel, C., Beck, C., Castãneda, I., Deino, A., Cohen, A.S., 2018. Reply to comments by Nutz and Schuster (2018) on “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya”. Quaternary Science Reviews 201, 508-510.

Miller, D.R., Habicht, M.H., Keisling, B.A., Castañeda, I.S., Bradley, R.S., 2018. A 900-year New England temperature reconstruction from in situ seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs). Climate of the Past 14, 1653-1667.


Nutz, A., Schuster, M., 2018. Comments on: “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya” by Lupien et al. [Quat. Sci. Rev. 186 (2018), 225–235]. Quaternary Science Reviews 201, 505-507.

Owen, R.B., Muiruri, V.M., Lowenstein, T.K., Renaut, R.W., Rabideaux, N., Luo, S., Deino, A.L., Sier, M.J., Dupont-Nivet, G., McNulty, E.P., Leet, K., Cohen, A., Campisano, C.,

Deocampo, D., Shen, C.-C., Billingsley, A., Mbuthia, A., 2018. Progressive aridification in East Africa over the last half million years and implications for human evolution. Proceedings of the National Academy of Sciences 115, 11174-11179.

Roberts, P., Stewart, M., Alagaili, A.N., Breeze, P., Candy, I., Drake, N., Groucutt, H.S., Scerri, E.M.L., Lee-Thorp, J., Louys, J., Zalmout, I.S., Al-Mufarreh, Y.S.A., Zech, J., Alsharekh, A.M., al Omari, A., Boivin, N., Petraglia, M., 2018. Fossil herbivore stable isotopes reveal middle Pleistocene hominin palaeoenvironment in ‘Green Arabia’. Nature Ecology & Evolution 2, 1871-1878.

Royer, D.L., Moynihan, K.M., McKee, M.L., Londoño, L., Franks, P.J., 2018. Sensitivity of a leaf gas-exchange model for estimating paleoatmospheric CO2 concentration. Climate of the Past Discussions 2018, 1-23.

Ruebsam, W., Mayer, B., Schwark, L., 2019. Cryosphere carbon dynamics control early Toarcian global warming and sea level evolution. Global and Planetary Change 172, 440-453.

Sreenivasan, S.P., Bera, M.K., Samanta, A., Vadlamani, R., 2018. Palaeocene–Eocene carbon isotopic excursion from the shallow-marine-carbonate sequence of northeast India: Implications on the CIE magnitude and geometry. Journal of Earth System Science 127, 105.

Todd, S.E., Pufahl, P.K., Murphy, J.B., Taylor, K.G., 2019. Sedimentology and oceanography of Early Ordovician ironstone, Bell Island, Newfoundland: Ferruginous seawater and upwelling in the Rheic Ocean. Sedimentary Geology 379, 1-15.

Tostevin, R., Clarkson, M.O., Gangl, S., Shields, G.A., Wood, R.A., Bowyer, F., Penny, A.M., Stirling, C.H., 2019. Uranium isotope evidence for an expansion of anoxia in terminal Ediacaran oceans. Earth and Planetary Science Letters 506, 104-112.

Wu, M., Zhuang, G., Hou, M., Miao, Y., 2019. Ecologic shift and aridification in the northern Tibetan Plateau revealed by leaf wax n-alkane δ2H and δ13C records. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 464-473.

Yi, F., Yi, H., Xia, G., Cai, Z., 2018. Atmospheric carbon dioxide reconstruction and ocean acidification deduced from carbon isotope variations across the Triassic–Jurassic boundary in the Qiangtang area, Tibetan Plateau. Acta Geologica Sinica - English Edition 92, 2055-2057.

Yuan, T., Yi, H., Zhang, S., Cai, Z., Li, G., 2018. Carbon isotope excursions and paleo-oceanography of the Ordovician–Silurian boundary carbonate rocks from the Xainza Area, Tibet. Acta Geologica Sinica - English Edition 92, 2052-2054.

EXTINCTION EVENTS

Arenillas, I., Arz, J.A., Gilabert, V., 2018. Blooms of aberrant planktic foraminifera across the K/Pg boundary in the Western Tethys: causes and evolutionary implications. Paleobiology 44, 460-489.

Dai, X., Song, H., Wignall, P.B., Jia, E., Bai, R., Wang, F., Chen, J., Tian, L., 2018. Rapid biotic rebound during the late Griesbachian indicates heterogeneous recovery patterns after the Permian-Triassic mass extinction. GSA Bulletin 130, 2015-2030.

Kletetschka, G., Vondrák, D., Hruba, J., Prochazka, V., Nabelek, L., Svitavská-Svobodová, H., Bobek, P., Horicka, Z., Kadlec, J., Takac, M., Stuchlik, E., 2018. Cosmic-impact event in lake sediments from Central Europe postdates the Laacher See eruption and marks onset of the Younger Dryas. The Journal of Geology 126, 561-575.

Percival, L.M.E., Jenkyns, H.C., Mather, T.A., Dickson, A.J., Batenburg, S.J., Ruhl, M., Hesselbo, S.P., Barclay, R., Jarvis, I., Robinson, S.A., Woelders, L., 2018. Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-Cretaceous to other Mesozoic events. American Journal of Science 318, 799-860.

Smith, S.M., Sprain, C.J., Clemens, W.A., Lofgren, D.L., Renne, P.R., Wilson, G.P., 2018. Early mammalian recovery after the end-Cretaceous mass extinction: A high-resolution view from McGuire Creek area, Montana, USA. GSA Bulletin 130, 2000-2014.


Precambrian Geochemistry

Cheng, M., Li, C., Chen, X., Zhou, L., Algeo, T.J., Ling, H.-F., Feng, L.-J., Jin, C.-S., 2018. Delayed Neoproterozoic oceanic oxygenation: Evidence from Mo isotopes of the Cryogenian Datangpo Formation. Precambrian Research 319, 187-197.

Gebauer, S., Grenfell, J.L., Lehmann, R., Rauer, H., 2018. Effect of geologically constrained environmental parameters on the atmosphere and biosphere of Early Earth. ACS Earth and Space Chemistry 2, 1112-1136.

Hantsoo, K.G., Kaufman, A.J., Cui, H., Plummer, R.E., Narbonne, G.M., 2018. Effects of bioturbation on carbon and sulfur cycling across the Ediacaran–Cambrian transition at the GSSP in Newfoundland, Canada. Canadian Journal of Earth Sciences 55, 1240-1252.


Koehler, M.C., Buick, R., Barley, M.E., 2019. Nitrogen isotope evidence for anoxic deep marine environments from the Mesoarchean Mosquito Creek Formation, Australia. Precambrian Research 320, 281-290.

Lan, Z., Sano, Y., Yahagi, T., Tanaka, K., Shirai, K., Papineau, D., Sawaki, Y., Ohno, T., Abe, M., Yang, H., Liu, H., Jiang, T., Wang, T., 2019. An integrated chemostratigraphic (δ13C-δ18O-87Sr/86Sr-δ15N) study of the Doushantuo Formation in western Hubei Province, South China. Precambrian Research 320, 232-252.

Long, D.G.F., 2019. Archean fluvial deposits: A review. Earth-Science Reviews 188, 148-175.

Soares, G.G., Van Kranendonk, M.J., Belousova, E., Thomson, S., 2019. Phosphogenesis in the immediate aftermath of the Great Oxidation Event: Evidence from the Turee Creek Group, Western Australia. Precambrian Research 320, 193-212.

Sui, Y., Huang, C., Zhang, R., Wang, Z., Ogg, J., Kemp, D.B., 2018. Astronomical time scale for the lower Doushantuo Formation of early Ediacaran, South China. Science Bulletin 63, 1485-1494.

Vaziri, S.H., Laflamme, M., 2018. Lithostratigraphy and sedimentary environment of the Precambrian Kushk Series of central Iran. Canadian Journal of Earth Sciences 55, 1284-1296.

Wei, W., Frei, R., Klaebe, R., Li, D., Wei, G.-Y., Ling, H.-F., 2018. Redox condition in the Nanhua Basin during the waning of the Sturtian glaciation: A chromium-isotope perspective. Precambrian Research 319, 198-210.

Zhang, S.-H., Ernst, R.E., Pei, J.-L., Zhao, Y., Zhou, M.-F., Hu, G.-H., 2018. A temporal and causal link between ca. 1380 Ma large igneous provinces and black shales: Implications for the Mesoproterozoic time scale and paleoenvironment. Geology 46, 963-966.

ORGANICS/MICROFOSSILS/MICROBIAL EVOLUTION

Allwood, A.C., Rosing, M.T., Flannery, D.T., Hurowitz, J.A., Heirwegh, C.M., 2018. Reassessing evidence of life in 3,700-million-year-old rocks of Greenland. Nature 563, 241-244.

Kolosov, P.N., Sofroneeva, L.S., 2018. New Vendian saarinid microorganisms from the Siberian Platform. Paleontological Journal 52, 589-592.

Lepot, K., Williford, K.H., Philippot, P., Thomazo, C., Ushikubo, T., Kitajima, K., Mostefaoui, S., Valley, J.W., 2019. Extreme 13C-depletions and organic sulfur content argue for S-fueled anaerobic methane oxidation in 2.72 Ga old stromatolites. Geochimica et Cosmochimica Acta 244, 522-547.

Qing, O., Zhou, C., Xiao, S., Chen, Z., Shao, Y., 2019. Acanthomorphic acritarchs from the Ediacaran Doushantuo Formation at Zhangcunping in South China, with implications for the evolution of early Ediacaran eukaryotes. Precambrian Research 320, 171-192.


Riedman, L.A., Porter, S.M., Calver, C.R., 2018. Vase-shaped microfossil biostratigraphy with new data from Tasmania, Svalbard, Greenland, Sweden and the Yukon. Precambrian Research 319, 19-36.

Riedman, L.A., Sadler, P.M., 2018. Global species richness record and biostratigraphic potential of early to middle Neoproterozoic eukaryote fossils. Precambrian Research 319, 6-18.

van Zuilen, M.A., 2018. Proposed early signs of life not set in stone. Nature 563, 190-191.


PALEOCLIMATOLOGY/PALEOCENOGRAPHY

Bindeman, I.N., Lee, J.E., 2018. The possibility of obtaining ultra-low-δ18O signature of precipitation near equatorial latitudes during the Snowball Earth glaciation episodes. Precambrian Research 319, 211-219.

Klaebe, R.M., Smith, M.P., Fairchild, I.J., Fleming, E.J., Kennedy, M.J., 2018. Facies-dependent δ13C variation and diagenetic overprinting at the onset of the Sturtian glaciation in North-East Greenland. Precambrian Research 319, 96-113.

Scheller, E.L., Dickson, A.J., Canfield, D.E., Korte, C., Kristiansen, K.K., Dahl, T.W., 2018. Ocean redox conditions between the snowballs – Geochemical constraints from Arena Formation, East Greenland. Precambrian Research 319, 173-186.

Shields, G.A., Halverson, G.P., Porter, S.M., 2018. Descent into the Cryogenian. Precambrian Research 319, 1-5.

Skelton, A., Löwhagen, L., Fairchild, I.J., Boyce, A., Mörth, C.-M., Siegmund, H., Webster, D., Spencer, A.M., 2019. Stable isotopes of oxygen and hydrogen in meteoric water during the Cryogenian Period. Precambrian Research 320, 253-260.

Wilmeth, D.T., Corsetti, F.A., Beukes, N.J., Awramik, S.M., Petryshyn, V., Spear, J.R., Celestian, A.J., 2019. Neoarchean (2.7 Ga) lacustrine stromatolite deposits in the Hartbeesfontein Basin, Ventersdorp Supergroup, South Africa: Implications for oxygen oases. Precambrian Research 320, 291-302.

Zhou, M., Luo, T., Huff, W.D., Yang, Z., Zhou, G., Gan, T., Yang, H., Zhang, D., 2018. Timing the termination of the Doushantuo negative carbon isotope excursion: evidence from U-Pb ages from the Dengying and Liuchapo formations, South China. Science Bulletin 63, 1431-1438.

CRUSTAL EVOLUTION

Byerly, B.L., Lowe, D.R., Drabon, N., Coble, M.A., Burns, D.H., Byerly, G.R., 2018. Hadean zircon from a 3.3 Ga sandstone, Barberton greenstone belt, South Africa. Geology 46, 967-970.

Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zakharov, V.S., Gerya, T.V., 2018. Precambrian ultra-hot orogenic factory: Making and reworking of continental crust. Tectonophysics 746, 572-586.

Sizova, E., Gerya, T., Brown, M., Stüwe, K., 2018. What drives metamorphism in early Archean greenstone belts? Insights from numerical modeling. Tectonophysics 746, 587-601.

Wang, H., van Hunen, J., Pearson, D.G., 2018. Making Archean cratonic roots by lateral compression: A two-stage thickening and stabilization model. Tectonophysics 746, 562-571.

Production/Engineering Geochemistry

Gizatullin, B., Gafurov, M., Rodionov, A., Mamin, G., Mattea, C., Stapf, S., Orlinskii, S., 2018. Proton–radical interaction in crude oil—a combined NMR and EPR study. Energy & Fuels 32, 11261-11268.

Ji, Y., Hou, Y., Ren, S., Yao, C., Wu, W., 2019. Separation of phenolic compounds from oil mixtures using environmentally benign biological reagents based on Brønsted acid-Lewis base interaction. Fuel 239, 926-934.

Kamel, A., Alomair, O., Elsharkawy, A., 2019. Measurements and predictions of Middle Eastern heavy crude oil viscosity using compositional data. Journal of Petroleum Science and Engineering 173, 990-1004.

Li, J., He, Y., Tan, L., Zhang, P., Peng, X., Oruganti, A., Yang, G., Abe, H., Wang, Y., Tsubaki, N., 2018. Integrated tuneable synthesis of liquid fuels via Fischer–Tropsch technology. Nature Catalysis 1, 787-793.

Malkin, A.Y., Zuev, K.V., Arinina, M.P., Kulichikhin, V.G., 2018. Modifying the viscosity of heavy crude oil using surfactants and polymer additives. Energy & Fuels 32, 11991-11999.


Montes, L.F., Oliveira, E.C.S., Neto, Á.C., Menezes, S.M.C., Castro, E.R.V., Barbosa, L.L., 2019. fLow-field NMR: A new alternative to determine the aromatic content of petroleum distillates. Fuel 239, 413-420.

Sad, C.M.S., da Silva, M., dos Santos, F.D., Pereira, L.B., Corona, R.R.B., Silva, S.R.C., Portela, N.A., Castro, E.V.R., Filgueiras, P.R., Lacerda, V., 2019. Multivariate data analysis applied in the evaluation of crude oil blends. Fuel 239, 421-428.

Sallam, M.A., El-Banbi, A.H., 2018. Analysis of multi-layered commingled and compartmentalized gas reservoirs. Journal of Petroleum Exploration and Production Technology 8, 1573-1586.



ASPHALTENES


Ahmadi, Y., Aminshahidy, B., 2018. Effects of hydrophobic CaO and SiO2 nanoparticles on Asphaltene Precipitation Envelope (APE): an experimental and modeling approach. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 56.


Hasanvand, M.Z., Feyzi, F., Behbahani, R.M., Dehghani, S.A.M., 2018. Detection of solid asphaltene phase separation via viscosity monitoring at high pressure high temperature conditions. International Journal of Oil, Gas and Coal Technology 19, 458-476.

Keshmiri, K., Huang, H., Nazemifard, N., 2019. Microfluidic platform to evaluate asphaltene deposition during solvent-based extraction of bitumen. Fuel 239, 841-851.

Khalaf, M.H., Mansoori, G.A., 2019. Asphaltenes aggregation during petroleum reservoir air and nitrogen flooding. Journal of Petroleum Science and Engineering 173, 1121-1129.

Khamehchi, E., Shakiba, M., Ardakani, M.S., 2018. A novel approach to oil production optimization considering asphaltene precipitation: a case study on one of the Iranian south oil wells. Journal of Petroleum Exploration and Production Technology 8, 1303-1317.

Morimoto, M., Fukatsu, N., Tanaka, R., Takanohashi, T., Kumagai, H., Morita, T., Tykwinski, R.R., Scott, D.E., Stryker, J.M., Gray, M.R., Sato, T., Yamamoto, H., 2018. Determination of Hansen solubility parameters of asphaltene model compounds. Energy & Fuels 32, 11296-11303.

Santos Silva, H., Alfarra, A., Vallverdu, G., Bégué, D., Bouyssiere, B., Baraille, I., 2018. Impact of H-bonds and porphyrins on asphaltene aggregation as revealed by molecular dynamics simulations. Energy & Fuels 32, 11153-11164.

Shao, R., Shen, Z., Li, D., Sun, Z., Pei, L., Liu, X., Li, W., Dan, Y., 2018. Investigation on composition and structure of asphaltenes during low-temperature coal tar hydrotreatment under various reaction pressures. Journal of Analytical and Applied Pyrolysis 136, 44-52.

Sinha, U., Dindoruk, B., Soliman, M.Y., 2019. Development of a new correlation to determine relative viscosity of heavy oils with varying asphaltene content and temperature. Journal of Petroleum Science and Engineering 173, 1020-1030.

Tabzar, A., Fathinasab, M., Salehi, A., Bahrami, B., Mohammadi, A.H., 2018. Multiphase flow modeling of asphaltene precipitation and deposition. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 51.

Yakubova, S.G., Tazeeva, E.G., Abilova, G.R., Milordov, D.V., Yakubov, M.R., 2018. Relationship of light absorption and vanadium content in asphaltenes and resins of heavy oils. Petroleum Science and Technology 36, 1657-1662.

Zuo, P., Qu, S., Shen, W., 2019. Asphaltenes: Separations, structural analysis and applications. Journal of Energy Chemistry 34, 186-207.

INTERFACES/EOR

Agi, A., Junin, R., Gbonhinbor, J., Onyekonwu, M., 2018. Natural polymer flow behaviour in porous media for enhanced oil recovery applications: a review. Journal of Petroleum Exploration and Production Technology 8, 1349-1362.


Amirmoshiri, M., Zeng, Y., Chen, Z., Singer, P.M., Puerto, M.C., Grier, H., Bahrim, R.Z.K., Vincent-Bonnieu, S., Farajzadeh, R., Biswal, S.L., Hirasaki, G.J., 2018. Probing the effect of oil type and saturation on foam flow in porous media: Core-flooding and nuclear magnetic resonance (NMR) imaging. Energy & Fuels 32, 11177-11189.



Chen, J., Li, T., Wu, S., 2018. Changes in the properties of conventional crude oil before and after CO2 flooding. Petroleum Science and Technology 36, 1642-1648.

Chen, L., Zhu, X., Wang, L., Yang, H., Wang, D., Fu, M., 2018. Experimental study of effective amphiphilic graphene oxide flooding for an ultralow-permeability reservoir. Energy & Fuels 32, 11269-11278.


Gbadamosi, A.O., Kiwalabye, J., Junin, R., Augustine, A., 2018. A review of gas enhanced oil recovery schemes used in the North Sea. Journal of Petroleum Exploration and Production Technology 8, 1373-1387.

Ghalamizade Elyaderani, S.M., Jafari, A., 2019. Microfluidics experimental study in porous media applied for nanosilica/alkaline flooding. Journal of Petroleum Science and Engineering 173, 1289-1303.

He, H., Fu, J., Zhao, H., Yuan, F., Guo, L., Li, Z., Wang, X., Peng, H., 2018. Synergistic mechanism of hydrolyzed polyacrylamide enhanced branched-preformed particle gel for enhanced oil recovery in mature oilfields. Energy & Fuels 32, 11093-11104.


Li, Q., Wang, Y., Wang, X., Yu, H., Li, Q., Wang, F., Bai, H., Kobina, F., 2019. An application of thickener to increase viscosity of liquid CO2 and the assessment of the reservoir geological damage and CO2 utilization. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 368-377.

Liu, H., Guo, P., Du, J., Ou, H., Wang, Z., Yang, L., Jiang, X., Wang, C., 2019. Investigating the influence of CO2 injection and reservoir cores on the phase behavior of two low-permeability crude oils: Experimental verification and thermodynamic model development. Fuel 239, 701-708.

Liu, Y., Kaszuba, J., Oakey, J., 2019. Microfluidic investigations of crude oil-brine interface elasticity modifications via brine chemistry to enhance oil recovery. Fuel 239, 338-346.

Madani, M., Zargar, G., Takassi, M.A., Daryasafar, A., Wood, D.A., Zhang, Z., 2019. Fundamental investigation of an environmentally-friendly surfactant agent for chemical enhanced oil recovery. Fuel 238, 186-197.

Nandwani, S.K., Chakraborty, M., Gupta, S., 2019. Chemical flooding with ionic liquid and nonionic surfactant mixture in artificially prepared carbonate cores: A diffusion controlled CFD simulation. Journal of Petroleum Science and Engineering 173, 835-843.

Pal, N., Kumar, N., Verma, A., Ojha, K., Mandal, A., 2018. Performance evaluation of novel sunflower oil-based gemini surfactant(s) with different spacer lengths: Application in enhanced oil recovery. Energy & Fuels 32, 11344-11361.

Patel, K., Shah, M., Sircar, A., 2018. Plasma pulse technology: An uprising EOR technique. Petroleum Research 3, 180-188.

Pourkhalil, H., Nakhaee, A., 2019. Effect of Nano ZnO on wellbore stability in shale: An experimental investigation. Journal of Petroleum Science and Engineering 173, 880-888.

Rellegadla, S., Bairwa, H.K., Kumari, M.R., Prajapat, G., Nimesh, S., Pareek, N., Jain, S., Agrawal, A., 2018. An effective approach for enhanced oil recovery using nickel nanoparticles assisted polymer flooding. Energy & Fuels 32, 11212-11221.

Rezaei Dehshibi, R., Mohebbi, A., Riazi, M., Danafar, F., 2019. Visualization study of the effects of oil type and model geometry on oil recovery under ultrasonic irradiation in a glass micro-model. Fuel 239, 709-716.



Sayed, A.M., Olesen, K.B., Alkahala, A.S., Sølling, T.I., Alyafei, N., 2019. The effect of organic acids and salinity on the interfacial tension of n-decane/ water systems. Journal of Petroleum Science and Engineering 173, 1047-1052.

Souayeh, M., Al-Maamari, R.S., Aoudia, M., Karimi, M., Hadji, M., 2018. Experimental investigation of wettability alteration of oil-wet carbonates by a non-ionic surfactant. Energy & Fuels 32, 11222-11233.

Souraki, Y., Hosseini, E., Yaghodous, A., 2019. Wettability alteration of carbonate reservoir rock using amphoteric and cationic surfactants: Experimental investigation. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 349-359.


Sun, X., Zhang, Y., Gai, Z., Zhao, H., Chen, G., Song, Z., 2019. Comprehensive experimental study of the interfacial stability of foamy oil and identification of the characteristic responsible for foamy oil formation. Fuel 238, 514-525.

Sun, Y.-Y., Zhang, S.-Y., Yang, Z.-P., Sang, G.-Q., Li, T., Li, Y.-C., 2018. Laboratory simulation and CO2 flooding efficiency of oil-water transition zones in a low permeability reservoir in the Jilin Oilfield. Petroleum Research 3, 283-287.


Wang, L., Yu, W., 2019. Mechanistic simulation study of gas Puff and Huff process for Bakken tight oil fractured reservoir. Fuel 239, 1179-1193.

Xu, K., Agrawal, D., Darugar, Q., 2018. Hydrophilic, nanoparticle-based enhanced oil recovery: Microfluidic investigations on mechanisms. Energy & Fuels 32, 11243-11252.

Zhao, G., Li, J., Gu, C., Li, L., Sun, Y., Dai, C., 2018. Dispersed particle gel-strengthened polymer/surfactant as a novel combination flooding system for enhanced oil recovery. Energy & Fuels 32, 11317-11327.



HEAVY OIL PRODUCTION

Ado, M.R., Greaves, M., Rigby, S.P., 2019. Numerical simulation of the impact of geological heterogeneity on performance and safety of THAI heavy oil production process. Journal of Petroleum Science and Engineering 173, 1130-1148.

Al-Mudhafar, W.J., 2018. From coreflooding and scaled physical model experiments to field-scale enhanced oil recovery evaluations: Comprehensive review of the gas-assisted gravity drainage process. Energy & Fuels 32, 11067-11079.

Gharibshahi, R., Jafari, A., Ahmadi, H., 2019. CFD investigation of enhanced extra-heavy oil recovery using metallic nanoparticles/steam injection in a micromodel with random pore distribution. Journal of Petroleum Science and Engineering 174, 374-383.

Guan, W., Zhang, X., Xi, C., Wang, X., Yang, F., Shi, X., Li, Q., 2018. Displacement and development characteristics of fire flooding of vertical wells in old heavy oil areas. Petroleum Research 3, 165-179.

Mohammadzadeh, O., Sedaghat, M.H., Kord, S., Zendehboudi, S., Giesy, J.P., 2019. Pore-level visual analysis of heavy oil recovery using chemical-assisted waterflooding process – Use of a new chemical agent. Fuel 239, 202-218.

Shi, L., Liu, P., Shen, D., Liu, P., Xi, C., Zhang, Y., 2019. Improving heavy oil recovery using a top-driving, CO2-assisted hot-water flooding method in deep and pressure-depleted reservoirs. Journal of Petroleum Science and Engineering 173, 922-931.

Xu, X., Huang, H., Zhang, S., Hu, S., 2019. Gas generation potential and processes of Athabasca oil sand bitumen from gold tube pyrolysis experiments. Fuel 239, 804-813.

Zare, A., Hamouda, A.A., 2019. Coinjection of C6, C7, and CO2 with steam to improve low-pressure SAGD process. Fuel 238, 394-401.

CARBON MATERIALS

Kinloch, I.A., Suhr, J., Lou, J., Young, R.J., Ajayan, P.M., 2018. Composites with carbon nanotubes and graphene: An outlook. Science 362, 547-553.

Kueh, B., Kapsi, M., Veziri, C.M., Athanasekou, C., Pilatos, G., Reddy, K.S.K., Raj, A., Karanikolos, G.N., 2018. Asphaltene-derived activated carbon and carbon nanotube membranes for CO2 separation. Energy & Fuels 32, 11718-11730.

Morken, J.P., 2018. Practically simple reactions convert hydrocarbons to precious chemicals. Nature 563, 336-337.

Wang, Z., Yin, H., Fu, G.C., 2018. Catalytic enantioconvergent coupling of secondary and tertiary electrophiles with olefins. Nature 563, 379-383.

Xie, J., Zhang, X., Xie, J., Xu, J., Pan, L., Zou, J.-J., 2019. Acid-catalyzed rearrangement of tetrahydrotricyclopentadiene for synthesis of high density alkyl-diamondoid fuel. Fuel 239, 652-658.


Recent Sediments

Arias-Ortiz, A., Masqué, P., Garcia-Orellana, J., Serrano, O., Mazarrasa, I., Marbà, N., Lovelock, C.E., Lavery, P.S., Duarte, C.M., 2018. Reviews and syntheses: 210Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems – setting the record straight. Biogeosciences 15, 6791-6818.

Bakrač, K., Ilijanić, N., Miko, S., Hasan, O., 2018. Evidence of sapropel S1 formation from Holocene lacustrine sequences in Lake Vrana in Dalmatia (Croatia). Quaternary International 494, 5-18.

Bao, R., Blattmann, T.M., McIntyre, C., Zhao, M., Eglinton, T.I., 2019. Relationships between grain size and organic carbon 14C heterogeneity in continental margin sediments. Earth and Planetary Science Letters 505, 76-85.


Blattmann, T.M., Wessels, M., McIntyre, C.P., Eglinton, T.I., 2019. Petrogenic organic carbon retention in terrestrial basins: A case study from perialpine Lake Constance. Chemical Geology 503, 52-60.


Dong, L., Jia, G., Li, Q., Li, L., Shi, J., Zhang, C.L., 2018. Intact polar glycosidic GDGTs in sediments settle from water column as evidenced from downcore sediment records. Chemical Geology 501, 12-18.

Guan, H., Chen, L., Luo, M., Liu, L., Mao, S., Ge, H., Zhang, M., Fang, J., Chen, D., 2019. Composition and origin of lipid biomarkers in the surface sediments from the southern Challenger Deep, Mariana Trench. Geoscience Frontiers 10, 351-360.

Jamieson, A.J., 2018. A contemporary perspective on hadal science. Deep Sea Research Part II: Topical Studies in Oceanography 155, 4-10.

Kandasamy, S., Lin, B., Lou, J.-Y., Kao, S.-J., Chen, C.-T.A., Mayer, L.M., 2018. Estimation of marine versus terrigenous organic carbon in sediments off southwestern Taiwan using the bromine to total organic carbon ratio as a proxy. Journal of Geophysical Research: Biogeosciences 123, 3387-3402.

Liu, J., Izon, G., Wang, J., Antler, G., Wang, Z., Zhao, J., Egger, M., 2018. Vivianite formation in methane-rich deep-sea sediments from the South China Sea. Biogeosciences 15, 6329-6348.



Regier, P., He, D., Saunders, C.J., Jara, B., Hansen, C., Newman, S., Tate-Boldt, E., Coronado-Molina, C., Jaffé, R., 2018. Sheet flow effects on sediment transport in a degraded ridge-and-slough wetland: Insights using molecular markers. Journal of Geophysical Research: Biogeosciences 123, 3124-3139.

Russell, J.M., Hopmans, E.C., Loomis, S.E., Liang, J., Sinninghe Damsté, J.S., 2018. Corrigendum to “Distributions of 5- and 6-methyl branched glycerol dialkyl glycerol tetraethers (brGDGTs) in East African lake sediment: Effects of temperature, pH, and new

lacustrine paleotemperature calibrations” [Org. Geochem. 117 (2018) 56–69]. Organic Geochemistry 125, 299.


Shulga, N.A., 2018. Characteristics of alkanes in ferromanganese nodules of the Clarion–Clipperton Fracture Zone. Oceanology 58, 672-678.

ThomasArrigo, L.K., Byrne, J.M., Kappler, A., Kretzschmar, R., 2018. Impact of organic matter on iron(II)-catalyzed mineral transformations in ferrihydrite–organic matter coprecipitates. Environmental Science & Technology 52, 12316-12326.

Thorhaug, A.L., Poulos, H.M., López-Portillo, J., Barr, J., Lara-Domínguez, A.L., Ku, T.C., Berlyn, G.P., 2019. Gulf of Mexico estuarine blue carbon stock, extent and flux: Mangroves, marshes, and seagrasses: A North American hotspot. Science of The Total Environment 653, 1253-1261.

Ulyantsev, A.S., Belyaev, N.A., Bratskaya, S.Y., Romankevich, E.A., 2018. The molecular composition of lignin as an indicator of subaqueous permafrost thawing. Doklady Earth Sciences 482, 1357-1361.

Wang, Q., Song, J., Yuan, H., Li, X., Li, N., Wang, Y., 2018. Sources and burial of particulate organic matter in the Kuroshio mainstream and its response to climate change over the past millennium. Geo-Marine Letters 38, 497-511.

Wang, S., Liu, G., Zhang, J., Zhou, L., Lam, P.K.S., 2019. An effective method for reconstructing the historical change in anthropogenic contribution to sedimentary organic matters in rivers. Science of The Total Environment 655, 968-976.


ATMOSPHERIC GEOCHEMISTRY

Knackstedt, K.A., Moffett, B.F., Hartmann, S., Wex, H., Hill, T.C.J., Glasgo, E.D., Reitz, L.A., Augustin-Bauditz, S., Beall, B.F.N., Bullerjahn, G.S., Fröhlich-Nowoisky, J., Grawe, S., Lubitz, J., Stratmann, F., McKay, R.M.L., 2018. Terrestrial origin for abundant riverine nanoscale ice-nucleating particles. Environmental Science & Technology 52, 12358-12367.

Lin, P., Fleming, L.T., Nizkorodov, S.A., Laskin, J., Laskin, A., 2018. Comprehensive molecular characterization of atmospheric brown carbon by high resolution mass spectrometry with electrospray and atmospheric pressure photoionization. Analytical Chemistry 90, 12493-12502.

HYDROSPHERE GEOCHEMISTRY




Catalán, N., Casas-Ruiz, J.P., Arce, M.I., Abril, M., Bravo, A.G., Campo, R., Estévez, E., Freixa, A., Giménez-Grau, P., González-Ferreras, A.M., Gómez-Gener, L., Lupon, A., Martínez, A., Palacin-Lizarbe, C., Poblador, S., Rasines-Ladero, R., Reyes, M., Rodríguez-Castillo, T., Rodríguez-Lozano, P., Sanpera-Calbet, I., Tornero, I., Pastor, A., 2018. Behind the scenes: Mechanisms regulating climatic patterns of dissolved organic carbon uptake in headwater streams. Global Biogeochemical Cycles 32, 1528-1541.

Dean, J.F., van Hal, J.R., Dolman, A.J., Aerts, R., Weedon, J.T., 2018. Filtration artefacts in bacterial community composition can affect the outcome of dissolved organic matter biolability assays. Biogeosciences 15, 7141-7154.



Grieman, M.M., Aydin, M., McConnell, J.R., Saltzman, E.S., 2018. Burning-derived vanillic acid in an Arctic ice core from Tunu, northeastern Greenland. Climate of the Past 14, 1625-1637.


Krickov, I.V., Lim, A.G., Manasypov, R.M., Loiko, S.V., Shirokova, L.S., Kirpotin, S.N., Karlsson, J., Pokrovsky, O.S., 2018. Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across a 1700 km latitudinal transect. Biogeosciences 15, 6867-6884.

Lemaitre, N., Planchon, F., Planquette, H., Dehairs, F., Fonseca-Batista, D., Roukaerts, A., Deman, F., Tang, Y., Mariez, C., Sarthou, G., 2018. High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes. Biogeosciences 15, 6417-6437.

Li Yung Lung, J.Y.S., Tank, S.E., Spence, C., Yang, D., Bonsal, B., McClelland, J.W., Holmes, R.M., 2018. Seasonal and geographic variation in dissolved carbon biogeochemistry of rivers draining to the Canadian Arctic Ocean and Hudson Bay. Journal of Geophysical Research: Biogeosciences 123, 3371-3386.



Nowak, A., Hodson, A., Turchyn, A.V., 2018. Spatial and temporal dynamics of dissolved organic carbon, chlorophyll, nutrients, and trace metals in maritime Antarctic snow and snowmelt. Frontiers in Earth Science 6, 201. doi: 210.3389/feart.2018.00201.

Old, G.H., Naden, P.S., Harman, M., Bowes, M.J., Roberts, C., Scarlett, P.M., Nicholls, D.J.E., Armstrong, L.K., Wickham, H.D., Read, D.S., 2019. Using dissolved organic matter fluorescence to identify the provenance of nutrients in a lowland catchment; the River Thames, England. Science of The Total Environment 653, 1240-1252.



Thume, K., Gebser, B., Chen, L., Meyer, N., Kieber, D.J., Pohnert, G., 2018. The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle. Nature 563, 412-415.

Vonk, J.E., Drenzek, N.J., Hughen, K.A., Stanley, R.H.R., McIntyre, C., Montluçon, D.B., Giosan, L., Southon, J.R., Santos, G.M., Druffel, E.R.M., Andersson, A.A., Sköld, M., Eglinton, T.I., 2019. Temporal deconvolution of vascular plant-derived fatty acids exported from terrestrial watersheds. Geochimica et Cosmochimica Acta 244, 502-521.

Wang, N., Luo, Y.-W., Polimene, L., Zhang, R., Zheng, Q., Cai, R., Jiao, N., 2018. Contribution of structural recalcitrance to the formation of the deep oceanic dissolved organic carbon reservoir. Environmental Microbiology Reports 10, 711-717.

Wünsch, U.J., Geuer, J.K., Lechtenfeld, O.J., Koch, B.P., Murphy, K.R., Stedmon, C.A., 2018. Quantifying the impact of solid-phase extraction on chromophoric dissolved organic matter composition. Marine Chemistry 207, 33-41.

SOIL GEOCHEMISTRY


Hernandez-Soriano, M.C., Dalal, R.C., Warren, F.J., Wang, P., Green, K., Tobin, M.J., Menzies, N.W., Kopittke, P.M., 2018. Soil organic carbon stabilization: Mapping carbon speciation from intact microaggregates. Environmental Science & Technology 52, 12275-12284.

Jiang, Y., Zhou, H., Chen, L., Yuan, Y., Fang, H., Luan, L., Chen, Y., Wang, X., Liu, M., Li, H., Peng, X., Sun, B., 2018. Nematodes and microorganisms interactively stimulate soil organic carbon turnover in the macroaggregates. Frontiers in Microbiology 9, 2803. doi: 2810.3389/fmicb.2018.02803.


Natali, C., Bianchini, G., Vittori Antisari, L., Natale, M., Tessari, U., 2018. Carbon and nitrogen pools in Padanian soils (Italy): Origin and dynamics of soil organic matter. Chemie der Erde 78, 490-499.


Sierra, C.A., Hoyt, A.M., He, Y., Trumbore, S.E., 2018. Soil organic matter persistence as a stochastic process: Age and transit time distributions of carbon in soils. Global Biogeochemical Cycles 32, 1574-1588.

vandenEnden, L., Frey, S.D., Nadelhoffer, K.J., LeMoine, J.M., Lajtha, K., Simpson, M.J., 2018. Molecular-level changes in soil organic matter composition after 10 years of litter, root and nitrogen manipulation in a temperate forest. Biogeochemistry 141, 183-197.

Remote Sensing-Hydrocarbon Seepage


Jakubowicz, M., Dopieralska, J., Kaim, A., Skupien, P., Kiel, S., Belka, Z., 2019. Nd isotope composition of seep carbonates: Towards a new approach for constraining subseafloor fluid circulation at hydrocarbon seeps. Chemical Geology 503, 40-51.



Nicholson, D.P., Michel, A.P.M., Wankel, S.D., Manganini, K., Sugrue, R.A., Sandwith, Z.O., Monk, S.A., 2018. Rapid mapping of dissolved methane and carbon dioxide in coastal ecosystems using the ChemYak autonomous surface vehicle. Environmental Science & Technology 52, 13314-13324.



Shigaev, V.Y., 2018. Foundations of petroleum prediction based on the activation of geochemical processes by direct current. Russian Geology and Geophysics 59, 1508-1513.


Wang, Q., Chen, D., Peckmann, J., 2019. Iron shuttle controls on molybdenum, arsenic, and antimony enrichment in Pliocene methane-seep carbonates from the southern Western Foothills, Southwestern Taiwan. Marine and Petroleum Geology 100, 263-269.


JOURNAL OF ASIAN EARTH SCIENCES 168, SPECIAL ISSUE: SOUTH CHINA SEA SEEP





Chen, J., Song, H., Guan, Y., Pinheiro, L.M., Geng, M., 2018. Geological and oceanographic controls on seabed fluid escape structures in the northern Zhongjiannan Basin, South China Sea. Journal of Asian Earth Sciences 168, 38-47.

Wang, J., Wu, S., Yao, Y., 2018. Quantifying gas hydrate from microbial methane in the South China Sea. Journal of Asian Earth Sciences 168, 48-56.




Gong, S., Hu, Y., Li, N., Feng, D., Liang, Q., Tong, H., Peng, Y., Tao, J., Chen, D., 2018. Environmental controls on sulfur isotopic compositions of sulfide minerals in seep carbonates from the South China Sea. Journal of Asian Earth Sciences 168, 96-105.

Li, N., Yang, X., Peng, J., Zhou, Q., Chen, D., 2018. Paleo-cold seep activity in the southern South China Sea: Evidence from the geochemical and geophysical records of sediments. Journal of Asian Earth Sciences 168, 106-111.



Wang, X., Li, N., Feng, D., Hu, Y., Bayon, G., Liang, Q., Tong, H., Gong, S., Tao, J., Chen, D., 2018. Using chemical compositions of sediments to constrain methane seepage dynamics: A case study from Haima cold seeps of the South China Sea. Journal of Asian Earth Sciences 168, 137-144.

Zhang, B., Pan, M., Wu, D., Wu, N., 2018. Distribution and isotopic composition of foraminifera at cold-seep Site 973-4 in the Dongsha area, northeastern South China Sea. Journal of Asian Earth Sciences 168, 145-154.

Zhu, X., Mao, S., Sun, Y., Jia, G., Wu, N., Wu, D., Guan, H., Yan, W., 2018. Organic molecular evidence of seafloor hydrocarbon seepage in sedimentary intervals down a core in the northern South China Sea. Journal of Asian Earth Sciences 168, 155-162.

Guan, H., Birgel, D., Peckmann, J., Liang, Q., Feng, D., Yang, S., Liang, J., Tao, J., Wu, N., Chen, D., 2018. Lipid biomarker patterns of authigenic carbonates reveal fluid composition and seepage intensity at Haima cold seeps, South China Sea. Journal of Asian Earth Sciences 168, 163-172.


Wang, Q., Tong, H., Huang, C.-Y., Chen, D., 2018. Tracing fluid sources and formation conditions of Miocene hydrocarbon-seep carbonates in the central Western Foothills, Central Taiwan. Journal of Asian Earth Sciences 168, 186-196.


Xi, S., Zhang, X., Du, Z., Li, L., Wang, B., Luan, Z., Lian, C., Yan, J., 2018. Laser Raman detection of authigenic carbonates from cold seeps at the Formosa Ridge and east of the Pear River Mouth Basin in the South China Sea. Journal of Asian Earth Sciences 168, 207-224.

Source Rocks/Depositional Environments



Chen, G., Gang, W., Liu, Y., Wang, N., Jiang, C., Sun, J., 2019. Organic matter enrichment of the Late Triassic Yanchang Formation (Ordos Basin, China) under dysoxic to oxic conditions: Insights from pyrite framboid size distributions. Journal of Asian Earth Sciences 170, 106-117.

Cheng, P., Xiao, X., Tian, H., Wang, X., 2018. Water content and equilibrium saturation and their influencing factors of the lower Paleozoic overmature organic-rich shales in the Upper Yangtze Region of southern China. Energy & Fuels 32, 11452-11466.

Cheng, Q., Guanghui, H., Zhang, M., Wenjun, Z., Xi, L., 2019. Distribution and source significance of 2-methylalkanes in coal-measure source rocks, northwest China. Journal of Petroleum Science and Engineering 174, 257-267.

Costanzo-Álvarez, V., Rapalini, A.E., Aldana, M., Díaz, M., Kietzmann, D., Iglesia-Llanos, M.P., Cabrera, A., Luppo, T., Vallejo, M.D., Walther, A.M., 2019. A combined rock-magnetic and EPR study about the effects of hydrocarbon-related diagenesis on the magnetic signature of oil shales (Vaca Muerta formation, southwestern Argentina). Journal of Petroleum Science and Engineering 173, 861-879.


Ghiran, M.D., Popa, M.E., Mariş, I., Gheorghe, Ş., 2018. Petrography and geochemistry of dispersed organic matter in the Oligocene source rocks of the central-western part of the Getic Depression, Romania. International Journal of Coal Geology 200, 153-165.

Gottardi, R., Adams, L.M., Borrok, D., Teixeira, B., 2019. Hydrocarbon source rock characterization, burial history, and thermal maturity of the Steele, Niobrara and Mowry Formations at Teapot Dome, Wyoming. Marine and Petroleum Geology 100, 326-340.

Grohmann, S., Fietz, S.W., Littke, R., Daher, S.B., Romero-Sarmiento, M.F., Nader, F.H., Baudin, F., 2018. Source rock characterization of Mesozoic to Cenozoic organic matter rich marls and shales of the Eratosthenes Seamount, Eastern Mediterranean Sea. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 49.

Hackley, P.C., Lünsdorf, N.K., 2018. Application of Raman spectroscopy as thermal maturity probe in shale petroleum systems: Insights from natural and artificial maturation series. Energy & Fuels 32, 11190-11202.

He, C., Ji, L., Su, A., Wu, Y., Zhang, M., Zhou, S., Li, J., Hao, L., Ma, Y., 2019. Source-rock evaluation and depositional environment of black shales in the Triassic Yanchang Formation, southern Ordos Basin, north-central China. Journal of Petroleum Science and Engineering 173, 899-911.

Hewaidy, A.G.A., Makled, W.A., El Garhy, M.M., Baioumi, A.H., Mostafa, T.F., 2019. Aspects of palyno-organic facies analysis: Comprehensive evaluation of the source rocks and age of some subsurface Lower Cretaceous core materials in the north Western Desert, Egypt. Marine and Petroleum Geology 99, 498-525.

Huang, C., Zhang, J., Hua, W., Yue, J., Lu, Y., 2018. Sedimentology and lithofacies of lacustrine shale: A case study from the Dongpu sag, Bohai Bay Basin, Eastern China. Journal of Natural Gas Science and Engineering 60, 174-189.

Jegede, T.O., Adekola, S.A., Akinlua, A., 2018. Trace element geochemistry of kerogens from the central Niger Delta. Journal of Petroleum Exploration and Production Technology 8, 999-1007.


Kong, W., Tu, D., Wan, Y., Zhao, Y., Zang, X., 2018. Organic geochemistry and depositional architecture of Jimusaer oil shale, Junggar Basin, NC China. Oil Shale 35, 291–303.

Lu, Z., Chen, S., He, Q., Li, Y., Zhang, J., Wu, Q., 2018. Relationship between methylphenanthrene distribution and organic matter maturity: a case study of Yangchang Formation Chang 7 source rocks, Erdos Basin, China. Petroleum Science and Technology 36, 1718-1724.

Ma, P., Li, Y., Wang, C., Zheng, L., Lv, D., Zou, Y., Li, S., 2018. Oligocene-Miocene source rocks of the Zhongcang Basin: Implications for hydrocarbon potential differentiation between lake basins in Central Tibet. International Journal of Coal Geology 199, 124-137.

Reyes, J., Jiang, C., Lavoie, D., Armstrong, D.K., Milovic, M., Robinson, R., 2018. Organic petrographic analysis of artificially matured chitinozoan- and graptolite-rich Upper

Ordovician shale from Hudson Bay Basin, Canada. International Journal of Coal Geology 199, 138-151.

Russell, P., 2018. Recent advances in routine core analysis on the Montney Formation. Bulletin of Canadian Petroleum Geology 66, 363-393.



Testamanti, M.N., Rezaee, R., 2019. Considerations for the acquisition and inversion of NMR T2

data in shales. Journal of Petroleum Science and Engineering 174, 177-188.


Wang, Y., Liu, H., Song, G., Hao, X., Zhu, D., Zhu, D., 2018. Formation mechanism of carbonates in the lacustrine muddy shale and it implication for shale oil and gas: A case study of source rocks in Member 4 and Member 3 of Shahejie Formation, Dongying sag. Petroleum Research 3, 248-258.


Wu, Y., Zhang, J., 2018. Geochemical characteristics and identification criteria of effective source rock in Mesozoic Yanchang Formation, southern margin of Ordos Basin. International Journal of Oil, Gas and Coal Technology 19, 379-395.



Zhang, K., Song, Y., Jiang, S., Jiang, Z., Jia, C., Huang, Y., Wen, M., Liu, W., Xie, X., Liu, T., Wang, P., Shan, C.a., Wu, Y., 2019. Mechanism analysis of organic matter enrichment in different sedimentary backgrounds: A case study of the Lower Cambrian and the Upper Ordovician-Lower Silurian, in Yangtze region. Marine and Petroleum Geology 99, 488-497.

Zhang, Y.-Y., He, Z.-L., Jiang, S., Lu, S.-F., Xiao, D.-S., Chen, G.-H., Zhao, J.-H., 2018. Controls on the organic carbon content of the lower Cambrian black shale in the southeastern margin of Upper Yangtze. Petroleum Science 15, 709-721.

Zhao, Y., Cai, J.-G., Lei, T.-Z., Yang, Y., 2018. A geochemical investigation of the free and carbonate-bound organic matter in the clay-sized fraction of argillaceous source rocks and its significance for biogenic interpretation. Petroleum Science 15, 681-694.


Unconventional Resources


Alfarge, D., Wei, M., Bai, B., 2019. Evaluating the performance of hydraulic-fractures in unconventional reservoirs using production data: Comprehensive review. Journal of Natural Gas Science and Engineering 61, 133-141.




Chatellier, J.Y., Simpson, K., Perez, R., Tribovillard, N., 2018. Geochemically focused integrated approach to reveal reservoir characteristics linked to better Montney productivity potential. Bulletin of Canadian Petroleum Geology 66, 516-551.


Chen, G., Lu, S., Liu, K., Xue, Q., Han, T., Xu, C., Tong, M., Pang, X., Ni, B., Lu, S., 2019. Critical factors controlling shale gas adsorption mechanisms on different minerals investigated using GCMC simulations. Marine and Petroleum Geology 100, 31-42.



DiStefano, V.H., McFarlane, J., Stack, A.G., Perfect, E., Mildner, D.F.R., Bleuel, M., Chipera, S.J., Littrell, K.C., Cheshire, M.C., Manz, K.E., Anovitz, L.M., 2019. Solvent-pore interactions in the Eagle Ford shale formation. Fuel 238, 298-311.


Feng, Z., Dong, D., Tian, J., Wu, W., Cai, Y., Shi, Z., Peng, W., 2019. Geochemical characteristics of Lower Silurian shale gas in the Changning-Zhaotong exploration blocks, southern periphery of the Sichuan Basin. Journal of Petroleum Science and Engineering 174, 281-290.

Germanou, L., Ho, M.T., Zhang, Y., Wu, L., 2018. Intrinsic and apparent gas permeability of heterogeneous and anisotropic ultra-tight porous media. Journal of Natural Gas Science and Engineering 60, 271-283.

Ghanizadeh, A., Clarkson, C.R., Vahedian, A., Ardakani, O.H., Wood, J.M., Sanei, H., 2018. Laboratory-based characterization of pore network and matrix permeability in the Montney Formation: Insights from methodology comparisons. Bulletin of Canadian Petroleum Geology 66, 472-498.

Han, H., Pang, P., Li, Z.-l., Shi, P.-t., Guo, C., Liu, Y., Chen, S.-j., Lu, J.-g., Gao, Y., 2019. Controls of organic and inorganic compositions on pore structure of lacustrine shales of Chang 7 member from Triassic Yanchang Formation in the Ordos Basin, China. Marine and Petroleum Geology 100, 270-284.

Hu, G., Sun, C., Huang, J., Xu, G., Zhu, J., 2018. Evolution of shale microstructure under microwave irradiation stimulation. Energy & Fuels 32, 11467-11476.

Kazak, A., Chugunov, S., Chashkov, A., 2018. Integration of large-area scanning-electron-microscopy imaging and automated mineralogy/petrography data for selection of nanoscale pore-space characterization sites. SPE-191369-PA 21, 821-836.

Lan, Y., Yang, Z., Wang, P., Yan, Y., Zhang, L., Ran, J., 2019. A review of microscopic seepage mechanism for shale gas extracted by supercritical CO2 flooding. Fuel 238, 412-424.

Li, C., Ou, C., 2018. Modes of shale-gas enrichment controlled by tectonic evolution. Acta Geologica Sinica - English Edition 92, 1934-1947.


Liang, B., Du, M., Yanez, P.P., 2019. Subsurface well spacing optimization in the Permian Basin. Journal of Petroleum Science and Engineering 174, 235-243.


Liu, L., Wang, Y., Chen, Y., Shen, B., Gao, X., 2018. Gas occurrence and accumulation characteristics of Cambrian–Ordovician shales in the Tarim Basin, northwest China. Acta Geologica Sinica - English Edition 92, 1948-1958.


Lotfiyar, A., Chehrazi, A., Swennen, R., Ghasemi Siani, M., 2018. Geochemical, geological, and petrophysical evaluation of Garau Formation in Lurestan basin (west of Iran) as a shale gas prospect. Arabian Journal of Geosciences 11, 653.

Luo, S., Lutkenhaus, J.L., Nasrabadi, H., 2018. Multiscale fluid-phase-behavior simulation in shale reservoirs using a pore-size-dependent equation of state. SPE-191369-PA 21, 806-820.


Nicot, J.-P., Gherabati, A., Darvari, R., Mickler, P.J., 2018. Salinity reversal and water freshening in the Eagle Ford Shale, Texas, USA. ACS Earth and Space Chemistry 2, 1087-1094.

Piotrowski, P.K., Tasker, T.L., Burgos, W.D., Dorman, F.L., 2018. Applications of thermal desorption coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for hydrocarbon fingerprinting of hydraulically fractured shale rocks. Journal of Chromatography A 1579, 99-105.



Qi , C., Wang, X., Wang, W., Liu, J., Tuo, J., Liu, K., 2018. Three-dimensional fine characterization method of micro-fractures in shale reservoirs. Acta Petrolei Sinica 39, 1175-1185

Qian, K.-R., He, Z.-L., Liu, X.-W., Chen, Y.-Q., 2018. Intelligent prediction and integral analysis of shale oil and gas sweet spots. Petroleum Science 15, 744-755.

Ren, J., Zheng, Q., Guo, P., Peng, S., Wang, Z., Du, J., 2019. Pore-scale lattice Boltzmann simulation of two-component shale gas flow. Journal of Natural Gas Science and Engineering 61, 46-70.

Sang, G., Liu, S., Zhang, R., Elsworth, D., He, L., 2018. Nanopore characterization of mine roof shales by SANS, nitrogen adsorption, and mercury intrusion: Impact on water adsorption/retention behavior. International Journal of Coal Geology 200, 173-185.

Sang, Q., Zhang, S., Li, Y., Dong, M., Bryant, S., 2018. Determination of organic and inorganic hydrocarbon saturations and effective porosities in shale using vacuum-imbibition method. International Journal of Coal Geology 200, 123-134.

Su, H., Jia, N., Yang, Y., Wang, Z., Jiang, Z., Feng, L., Yang, J., Lv, W., 2018. Micro-pore structure and oil displacement mechanism analysis for deep zone and low permeability reservoir in Mobei oilfield. Petroleum Research 3, 159-164.


Tang, X., 2019. Surface thermodynamics of hydrocarbon vapors and carbon dioxide adsorption on shales. Fuel 238, 402-411.

Tang, X., Jiang, S., Jiang, Z., Li, Z., He, Z., Long, S., Zhu, D., 2019. Heterogeneity of Paleozoic Wufeng-Longmaxi formation shale and its effects on the shale gas accumulation in the Upper Yangtze Region, China. Fuel 239, 387-402.



Wang, Q., Huang, L., 2019. Molecular insight into competitive adsorption of methane and carbon dioxide in montmorillonite: Effect of clay structure and water content. Fuel 239, 32-43.

Wang, Y., Liao, B., Kong, Z., Sun, Z., Qiu, L., Wang, D., 2018. Oscillating electric field effects on adsorption of the methane–water system on kaolinite surface. Energy & Fuels 32, 11440-11451.

Xi, Z., Tang, S., Wang, J., Yang, G., Li, L., 2018. Formation and development of pore structure in marine-continental transitional shale from northern China across a maturation gradient: insights from gas adsorption and mercury intrusion. International Journal of Coal Geology 200, 87-102.


Xu, Q., Xu, F., Jiang, B., Zhao, Y., Zhao, X., Ding, R., Wang, J., 2018. Geology and transitional shale gas resource potentials in the Ningwu Basin, China. Energy Exploration & Exploitation 36, 1482-1497.

Xu, Z., Jiang, S., Yao, G., Liang, X., Xiong, S., 2019. Tectonic and depositional setting of the lower Cambrian and lower Silurian marine shales in the Yangtze Platform, South China: Implications for shale gas exploration and production. Journal of Asian Earth Sciences 170, 1-19.

Yang, S., Wu, W., Xu, J., Ji, D., Chen, Z., Wei, Y., 2018. Modeling of methane/shale excess adsorption under reservoir conditions. SPE-191369-PA 21, 1027-1034.

Yang, Y., Mavko, G., 2018. Mathematical modeling of microcrack growth in source rock during kerogen thermal maturation. American Association of Petroleum Geologists Bulletin 102, 2519-2535.

Zhang, H., Shi, J.-T., Li, X.-F., 2018. Optimization of shale gas reservoir evaluation and assessment of shale gas resources in the Oriente Basin in Ecuador. Petroleum Science 15, 756-771.

Zhang, M., Fu, X., Zhang, Q., Cheng, W., 2019. Research on the organic geochemical and mineral composition properties and its influence on pore structure of coal-measure shales in Yushe-Wuxiang Block, South Central Qinshui Basin, China. Journal of Petroleum Science and Engineering 173, 1065-1079.


Zhang, Q., Liang, F., Pang, Z., Jiang, S., Zhou, S., Zhang, J., 2019. Lower threshold of pore-throat diameter for the shale gas reservoir: Experimental and molecular simulation study. Journal of Petroleum Science and Engineering 173, 1037-1046.

Zhang, S., Cao, Y., Liu, K., Jahren, J., Xi, K., Zhu, R., Yang, T., Cao, X., Wang, W., 2019. Characterization of lacustrine mixed fine-grained sedimentary rocks using coupled chemostratigraphic-petrographic analysis: A case study from a tight oil reservoir in the Jimusar Sag, Junggar Basin. Marine and Petroleum Geology 99, 453-472.



Zheng, X., Zhang, B., Sanei, H., Bao, H., Meng, Z., Wang, C., Li, K., 2019. Pore structure characteristics and its effect on shale gas adsorption and desorption behavior. Marine and Petroleum Geology 100, 165-178.

Abstracts


https://doi.org/10.1007/s12517-018-4054-9

The Badr Concession exists in Abu Gharadig basin, which is a great oil province in Western Desert, Egypt. This work concerned on studying the geochemical characteristics and organic source of crudes produced from Abu Roash “C” (AR/C) Member in BED15-1, BED15-3, and BED15-4 wells using gas chromatography (GC) analysis. Also, the BasinMod Software is used to construct models of burial history that detect thermal maturity and generation timing for Cretaceous sources based on

modeled Vitrinite reflectance (%Ro). The oil samples are not biodegraded, due to the existence of an intact paraffin envelope in all three oils as revealed from low normal-alkane/isoprenoids and the distribution of different light hydrocarbons. These crudes have pristane/phytane (Pr/Ph) ratio that ranged from 1.03 to 1.08 indicating that those oils are generated from mixed organic matter such as algae and submerged macrophyts which are the main constituents which are deposited and preserved in lacustrine environment under reducing to suboxic condition. The Pr/nC17 and Ph/nC18 ratios indicate that these crudes are mature. Also, the models of burial history indicate that Abu Roash Formation reached mid maturation stage and these results are in agreement with GC results. Generally, the hydrocarbon generation began in Late Cretaceous and reached the peak during the Tertiary.

Abia, A.L.K., Alisoltani, A., Ubomba-Jaswa, E., Dippenaar, M.A., 2019. Microbial life beyond the grave: 16S rRNA gene-based metagenomic analysis of bacteria diversity and their functional profiles in cemetery environments. Science of The Total Environment 655, 831-841.

http://www.sciencedirect.com/science/article/pii/S004896971834659X

Recent studies have identified cemeteries as potential environmental reservoirs of multi-drug resistant pathogenic bacteria that could contaminate groundwater sources posing public health threats. However, these findings were based on the identification of culturable bacteria and at times not below burial grounds. Investigation on the bacterial diversity and functional profiles of bacterial communities above and below burial grounds in human cemeteries are few. The current study used high-throughput sequencing techniques to determine the bacterial composition and their associated functional profiles in cemetery soil samples collected at the surface and below burial ground in two South African cemeteries (Maitland Cemetery in Cape Town and Fontein Street Cemetery in Middelburg) to evaluate the potential health threat to surrounding populations through contamination of groundwater. Significant differences were observed between sample depths with the clustering of the surface (0 m) and the 2 m samples into separate groups. Pseudomonas and Corynebacterium were the most abundant genera across all samples. Pseudomonas and Rhodococcus were the dominant genera in the 2 m samples while Prauserella and Staphylococcus were dominant in the surface samples. The 2 m samples showed a lower alpha diversity but recorded higher proportions of human diseases functional classes compared to the surface samples. Human disease functional profiles revealed involvement, in infectious (cholera), neurodegenerative (Alzheimer's disease) cardiovascular (hypertrophic cardiomyopathy) immune system (Systemic lupus erythematosus) metabolic (Type I & II diabetes) diseases and cancer. Antibiotic resistance and antibiotics synthesis signatures were also identified. Thus, cemeteries could be potential sources of microbial and antibiotic pollution in groundwater, especially in areas with shallow water tables such as Maitland. Selection of sites for use as cemeteries should, therefore, require a proper understanding of the hydrogeological characteristics of the selected site. However, further studies are required to trace the actual movement of these pollutants into groundwater resources.


http://www.sciencedirect.com/science/article/pii/S0378381218304539

Knowledge of the conditions at which asphaltenes precipitate from petroleum fluids is useful in the development of enhanced oil recovery scenarios and field development plans. In this work we present a semi-empirical linear model for approximating onset pressure by means of a Linear Extrapolation of

Normalized Cohesive Energy (LENCE). A normalized cohesive energy function is found to correlate linearly with temperature along the asphaltene onset curve for several crude oils from different regions. The linear trend is observed from simulation results using the perturbed-chain version of the Statistical Associating Fluid Theory Equation of State (PC-SAFT EoS). LENCE can be used to approximate the asphaltene onset pressure (AOP) for petroleum fluids at different temperatures from knowledge of two experimental onset pressures. Several case studies are presented to demonstrate the capability of LENCE to accurately predict asphaltene onset pressure as well as detecting experimental uncertainties in reported measurements from near infrared (NIR) and high pressure microscopy (HPM) experiments. LENCE model can reproduce AOP modeling results from PC-SAFT with an average absolute percent deviation of 2.38%, with 5 times faster computational speed. It is found that PC-SAFT predicts a minimum temperature at which an upper asphaltene onset exists. Below this temperature, asphaltenes are inherently unstable in solution as predicted by PC-SAFT. This behavior seems to be a characteristic of SAFT-based models and is not yet supported by experimental evidence. Compared to PC-SAFT, the LENCE model exhibits improved characteristics for the liquid-liquid phase boundary in the low temperature region.

Adam, N., Perner, M., 2018. Microbially mediated hydrogen cycling in deep-sea hydrothermal vents. Frontiers in Microbiology 9, 2873. doi: 10.3389/fmicb.2018.02873.

https://www.frontiersin.org/article/10.3389/fmicb.2018.02873

Deep-sea hydrothermal vents may provide one of the largest reservoirs on Earth for hydrogen-oxidizing microorganisms. Depending on the type of geological setting, hydrothermal environments can be considerably enriched in hydrogen (up to millimolar concentrations). As hot, reduced hydrothermal fluids ascend to the seafloor they mix with entrained cold, oxygenated seawater, forming thermal and chemical gradients along their fluid pathways. Consequently, in these thermally and chemically dynamic habitats biochemically distinct hydrogenases (adapted to various temperature regimes, oxygen and hydrogen concentrations) from physiologically and phylogenetically diverse Bacteria and Archaea can be expected. Hydrogen oxidation is one of the important inorganic energy sources in these habitats, capable of providing relatively large amounts of energy (237 kJ/mol H2) for driving ATP synthesis and autotrophic CO2 fixation. Therefore, hydrogen-oxidizing organisms play a key role in deep-sea hydrothermal vent ecosystems as they can be considerably involved in light-independent primary biomass production. So far, the specific role of hydrogen-utilizing microorganisms in deep-sea hydrothermal ecosystems has been investigated by isolating hydrogen-oxidizers, measuring hydrogen consumption (ex situ), studying hydrogenase gene distribution and more recently by analyzing metatranscriptomic and metaproteomic data. Here we summarize this available knowledge and discuss the advent of new techniques for the identification of novel hydrogen-uptake and -evolving enzymes from hydrothermal vent microorganisms.

Adamopoulou, T., Deridder, S., Desmet, G., Schoenmakers, P.J., 2018. Two-dimensional insertable separation tool (TWIST) for flow confinement in spatial separations. Journal of Chromatography A 1577, 120-123.


Spatial comprehensive two-dimensional liquid chromatography (xLC×xLC) may be an efficient approach to achieve high peak capacities in relatively short analysis times, thanks to parallel second-dimension separations [1,2]. A key issue to reach the potential of xLC×xLC is to achieve adequate flow control and confinement of the analytes to the desired regions, i.e. confinement in the first-dimension direction and subsequently homogeneous flow in the second dimension. To achieve these

goals we propose the TWIST concept (TWo-dimensional Insertable Separation Tool), a modular device that includes an internal first-dimension (1D) part that is cylindrical and rotatable. This internal part features a series of through-holes, each of which is perpendicular to the direction of the 1D flow. The internal part is inserted in the cylindrical casing of the external part. The internal diameter of the casing is marginally larger than the external diameter of the internal part. The external part also comprises a flow distributor and second-dimension (2D) channels. During the 1D injection and development, the channel is placed in a position where the through-holes are facing the wall of the external part, such that the liquid remains confined within the 1D channel. Thereafter, to realize the transfer to the second dimension (2D injection), the 1D channel is rotated, so that the holes of the internal part are aligned with the holes on the external part, allowing a transversal flow of the 2D mobile phase from the distributor through the 1D channel and eventually into the 2D area.

Adepoju, A., Adekola, S.A., Omotoye, S., Akinlua, A., 2018. Light hydrocarbon geochemistry of crude oils from Eastern Niger Delta. Petroleum Science and Technology 36, 1573-1581.

https://doi.org/10.1080/10916466.2018.1490767

Geochemical evaluation of oil samples from the eastern part of the Niger Delta divided into western, eastern, and central sections of the study area was carried out for the characterization of their light hydrocarbons content in order to correlate oils from different parts. The hydrocarbons in the oil samples were determined using gas chromatographic (GC) technique. The results obtained showed that CPI, Pr/Ph, Pr/nC17, and Ph/nC18 ratios ranged from 0.99–1.55, 2.19–4.79, 0.92–2.35, and 0.27–0.47, respectively. The Pr/nC17 versus Ph/nC18 plot showed that the oils were derived from terrestrial organic materials that were deposited under oxic to suboxic conditions. They are moderately matured with minimal effect of biodegradation on most of the oil samples although two of the oils showed relatively higher degradation. Both bivariate and multivariate plots of the light hydrocarbon ratios differentiated the western and central oils from the eastern oils. The classification of the oils into families was not based on origin but rather on post generative alterations that include reservoir conditions and possibly migration effects. The light hydrocarbon parameters identified can be used in the correlation tools.

Ado, M.R., Greaves, M., Rigby, S.P., 2019. Numerical simulation of the impact of geological heterogeneity on performance and safety of THAI heavy oil production process. Journal of Petroleum Science and Engineering 173, 1130-1148.


The Toe-to-Heel Air Injection (THAI) in-situ combustion process is an efficient way to extract heavy oil and bitumen. However, such reservoirs are often geologically heterogeneous. This work studied the impact of a range of different geological heterogeneities, often found in bitumen deposits, on the performance and safety of THAI. These heterogeneities included random heterogeneity, layered reservoirs, shaly reservoirs, and semi-permeable cap-rocks. A further aim was to also develop potential remedial measures, such as selective well placement. It was found that the degree of symmetry assumed for the reservoir model had a substantial impact on the predicted level of oil production. This is of particular relevance to otherwise apparently symmetrical well placement designs such as staggered line drive. While the presence of impermeable zones resulted in the decrease in the overall oxygen utilisation for shaly reservoirs, compared to simply low permeability reservoirs, there was no evidence of oxygen breakthrough due to preferential channelling into the production well. In layered reservoirs, the development of a rich oil bank during THAI operation depended upon the distribution of permeability around the horizontal producer (HP), and did not

occur when there was high permeability just above the HP. It has been shown that the proper representation of the cap-rock in reservoir models for the simulation of THAI is essential in order to accurately mimic the full pattern of heat distribution into the oil zone of the reservoir, and, thence, fuel lay-down. While THAI can operate stably with a permeable cap-rock, vertical permeabilities above ∼1–3 mD led to significant loss of combustion gases from the reservoir.

Afshar Mogaddam, M.R., Mohebbi, A., Pazhohan, A., Khodadadeian, F., Farajzadeh, M.A., 2019. Headspace mode of liquid phase microextraction: A review. TrAC Trends in Analytical Chemistry 110, 8-14.


In recent years, liquid phase microextraction (LPME) as a solvent–minimized and microscale implementation of sample pretreatment procedure of liquid–liquid extraction has been introduced and obtained great attention among the researchers due to its simplicity, low cost, rapidity, and efficiency. Developments have led to different approaches of LPME such as headspace mode of liquid phase microextraction (HS mode of LPME) which is used in the cases of volatile and semi–volatile analytes. In HS mode of LPME, the extractant is suspended in the headspace of analytes solution and has no contact with the sample solution which leads to eliminate interferences problem. The present review discusses HS mode of LPME with the focus on its historical developments, principles, configurations, inherent limitations, and pros and cons. Herein, recent analytical applications of the method used in the isolation and trace enrichment prior to analysis of various compounds are reviewed. The future direction of the researches in this field and general trend toward the commercial applications are also considered.


https://doi.org/10.1007/s11242-018-1132-0

Each of the two major mineral components found in shale samples—organic matter (OM) and inorganic matter (iOM)—has a distinct pore system revealed by scanning electron microscope images, low-pressure nitrogen adsorption, and high-pressure mercury injection tests. Although a vast amount of research has been conducted to detect and measure pore sizes in OM and iOM separately, the connectivity of the pores in these two components remains unclear. In permeability models, pore connectivity between OM and iOM components plays an important role in studying and predicting fluid flow. We studied pore connectivity between OM and iOM by developing pore-network models to mimic the composite nature of distributed OM patches in shale. Input parameters to generate network models were porosity, pore- and throat-size distribution, and total organic content. Mercury injection and capillary-pressure curves were then simulated through generated network models using percolation theory. To study the effects of pore connectivity between OM and iOM, we changed the size and locale of OM patches in the generated network models. Simulation results showed that the locale of OM affects mercury saturation (location and numbers of invaded pores) at given applied pressures. To study the effect of pore-size overlap between OM and iOM pores, we simulated mercury injection for two groups of constructed pore networks: non-overlapping and overlapping. In non-overlapping cases, first all iOM pores were invaded with mercury; then, only OM pores at very high pressure were invaded. In overlapping cases, OM and iOM pores can be invaded simultaneously because some of the pores have similar sizes in both components. The simulated capillary-pressure curves show distinct behavior in the non-overlapping and overlapping cases. Non-overlapping capillary-pressure curves show a sudden increase when OM pores are invaded, whereas overlapping

capillary-pressure curves are smoother. Results of this work increase understanding of the connectivity of pores from measured capillary-pressure curves for further implementation in permeability-predictive models.

Agi, A., Junin, R., Gbonhinbor, J., Onyekonwu, M., 2018. Natural polymer flow behaviour in porous media for enhanced oil recovery applications: a review. Journal of Petroleum Exploration and Production Technology 8, 1349-1362.

https://doi.org/10.1007/s13202-018-0434-7

When a reservoir is flooded with polymer, the mobility ratio between the displaced fluid and the displacing fluid become favourable compared to the conventional water flooding. In the oil and gas industry, the synthetic polymer polyacrylamide in hydrolysed form and the biopolymer xanthan are being used for this purpose. However, the polyacrylamide is susceptible to high temperature and salinity. Also, its synthetic nature makes it harmful to the environment. The biopolymer xanthan has the problem of degradation and both are very expensive. With the shortfall in crude oil price and the high cost of exploitation and drilling new wells, there is need to look inward and think out of the box in formulating new improved polymers that can combat these problems. Natural polymers from agricultural and forest produce are abundant in nature, cheap and environmentally friendly. These agricultural and forest produce contain starch and cellulose which are known to have rigid and long polysaccharide chains that can withstand the harsh reservoir conditions. But the design of a polymer flood or a permeability-modified process involving polymer requires knowledge about the polymer flow mechanism and the rheological behaviour of the porous media. This paper, therefore, reviews the available natural polymers that can be used for enhanced oil recovery applications and the mechanism affecting their flow behaviour in porous media. The emphasis is on the physical aspect of the flow, the microscopic rheological behaviour of the natural polymers. The dominant mechanism of the flow process was adsorption, mechanical entrapment and hydrodynamic retention. It was observed that the polymer exhibited non-Newtonian, pseudoplastic and shear-thinning behaviours. The literature review on oil displacement test indicates that natural polymers can recover additional oil from an oil field. Environmental application issues associated with the application of natural polymers have opened new frontier for research and are also highlighted herein.

Ahmadi, Y., Aminshahidy, B., 2018. Effects of hydrophobic CaO and SiO2 nanoparticles on Asphaltene Precipitation Envelope (APE): an experimental and modeling approach. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 56.

https://doi.org/10.2516/ogst/2018052

An experimental and modeling approach was developed in this research to investigate the effects of CO2, new synthesized CaO and commercial SiO2 nanoparticle concentrations on the Asphaltene Precipitation Envelope (APE). First, the effects of different temperatures and CO2 concentrations on asphaltene precipitation trends were observed. Second, the impact of CaO and SiO2 nanoparticle concentrations on asphaltene precipitation were observed in the presence of CO2 at different temperatures. Third, Advanced Redlich-Kwong-Soave (RKSA) equation of state (EOS) was considered to modify Multiflash (Infochem Co.) software from the aspect of entering physical characteristics of CaO and SiO2 nanoparticles as pseudo components. Fourth, the developed model was used for predicting the effects of CO2, CaO and SiO2 concentrations on APE in ranges that no experimental data existed. At constant CO2 concentration and temperature during natural depletion, asphaltene precipitation increased above saturation pressure, while below saturation pressure, asphaltene precipitation decreased (solution gas evolved from crude oil and made it richer). As

temperature increased at constant CO2 concentration, asphaltene precipitation decreased, while it was observed that the saturation pressures increased. Although two different trends were observed in upper asphaltene onsets at different temperatures and CO2 concentrations, in wide ranges of data, as temperature increased, asphaltene upper onset pressure increased. CaO and SiO2 nanoparticles decreased asphaltene precipitations in the presence of CO2, but CaO had better applications for reducing asphaltene precipitation. The proposed Software/RKSA EOS model was in good agreement with the obtained experimental data, and it was applicable for predicting the effects of CO2, CaO and SiO2 nanoparticles concentration on APE.


https://doi.org/10.1007/s12517-018-4027-z

The present work provides high-resolution modeling of the thermal maturation of the Eocene Thebes Formation using a multi-1D approach. The model focuses not solely on the thermal maturity but also on timing of hydrocarbon generation (primary generation and secondary cracking), adsorption by organic matter, and expulsion. The time-lapse conceptual model was developed using well log data, geochemical analyses, and composite logs. The stratigraphic sequence of the Belayim Marine oil field was subdivided into a time series based on the tectonic framework of the Gulf of Suez. An elevated basal heat flow has been assigned throughout the rifting phases and basin evolution. The simulation developed for seven wells reveals variations in burial, thermal history, and accordingly the thermal maturity. The predicted thermal maturity ranges from immature to mature with a different tendency to generate hydrocarbons (both primary generation of oil and/or gas secondary cracking) dependent on kerogen type, basin development, and burial history. Hydrocarbon generation (oil) starts after the Messinian Time Event during the deposition of the Post-Zeit Formation. Hydrocarbon generation was related to burial rather than basin evolution for the 113-M-27, BM-23, BM-65, and BM-70 wells. Conversely, generation correlated principally to basin development particularly Messinian Time Event for the 113-M-34 well. Expulsion occurred subsequent to generation of thermogenic gas (secondary cracking of generated oil). It is not possible to investigate the relationship between the production index and thermal maturity as a consequence of expulsion that reduced the S1 values. The different levels of thermal maturity (potential, active, and effective source rock) allow for the differentiation of regions of potential hydrocarbon accumulation that were charged from the Thebes Formation.

Ahrendt, S.R., Quandt, C.A., Ciobanu, D., Clum, A., Salamov, A., Andreopoulos, B., Cheng, J.-F., Woyke, T., Pelin, A., Henrissat, B., Reynolds, N.K., Benny, G.L., Smith, M.E., James, T.Y., Grigoriev, I.V., 2018. Leveraging single-cell genomics to expand the fungal tree of life. Nature Microbiology 3, 1417-1428.

https://doi.org/10.1038/s41564-018-0261-0

Environmental DNA surveys reveal that most fungal diversity represents uncultured species. We sequenced the genomes of eight uncultured species across the fungal tree of life using a new single-cell genomics pipeline. We show that, despite a large variation in genome and gene space recovery from each single amplified genome (SAG), ≥90% can be recovered by combining multiple SAGs. SAGs provide robust placement for early-diverging lineages and infer a diploid ancestor of fungi. Early-diverging fungi share metabolic deficiencies and show unique gene expansions correlated with

parasitism and unculturability. Single-cell genomics holds great promise in exploring fungal diversity, life cycles and metabolic potential.

Aichner, B., Ott, F., Słowiński, M., Noryśkiewicz, A.M., Brauer, A., Sachse, D., 2018. Leaf wax n-alkane distributions record ecological changes during the Younger Dryas at Trzechowskie paleolake (northern Poland) without temporal delay. Climate of the Past 14, 1607-1624.

https://doi.org/10.5194/cp-14-1607-2018

While of higher plant origin, a specific source assignment of sedimentary leaf wax n-alkanes remains difficult. In addition, it is unknown how fast a changing catchment vegetation would be reflected in sedimentary leaf wax archives. In particular, for a quantitative interpretation of n-alkane C and H isotope ratios in terms of paleohydrological and paleoecological changes, a better understanding of transfer times and dominant sedimentary sources of leaf wax n-alkanes is required.

In this study we tested to what extent compositional changes in leaf wax n-alkanes can be linked to known vegetation changes by comparison with high-resolution palynological data from the same archive. We analyzed leaf wax n-alkane concentrations and distributions in decadal resolution from a sedimentary record from Trzechowskie paleolake (TRZ, northern Poland), covering the Late Glacial to early Holocene (13360–9940yrBP). As an additional source indicator of targeted n-alkanes, compound-specific carbon isotopic data have been generated in lower time resolution. The results indicated rapid responses of n-alkane distribution patterns coinciding with major climatic and paleoecological transitions. We found a shift towards higher average chain length (ACL) values at the Allerød–Younger Dryas (YD) transition between 12680 and 12600yrBP, coevaled with a decreasing contribution of arboreal pollen (mainly Pinus and Betula) and a subsequently higher abundance of pollen derived from herbaceous plants (Poaceae, Cyperaceae, Artemisia), shrubs, and dwarf shrubs (Juniperus and Salix). The termination of the YD was characterized by a successive increase in n-alkane concentrations coinciding with a sharp decrease in ACL values between 11580 and 11490yrBP, reflecting the expansion of woodland vegetation at the YD–Holocene transition. A gradual reversal to longer chain lengths after 11200yrBP, together with decreasing n-alkane concentrations, most likely reflects the early Holocene vegetation succession with a decline of Betula.

These results show that n-alkane distributions reflect vegetation changes and that a fast (i.e., subdecadal) signal transfer occurred. However, our data also indicate that a standard interpretation of directional changes in biomarker ratios remains difficult. Instead, responses such as changes in ACL need to be discussed in the context of other proxy data. In addition, we find that organic geochemical data integrate different ecological information compared to pollen, since some gymnosperm genera, such as Pinus, produce only a very low amount of n-alkanes and for this reason their contribution may be largely absent from biomarker records. Our results demonstrate that a combination of palynological and n-alkane data can be used to infer the major sedimentary leaf wax sources and constrain leaf wax transport times from the plant source to the sedimentary sink and thus pave the way towards quantitative interpretation of compound-specific hydrogen isotope ratios for paleohydrological reconstructions.

Akberdin, I.R., Collins, D.A., Hamilton, R., Oshchepkov, D.Y., Shukla, A.K., Nicora, C.D., Nakayasu, E.S., Adkins, J.N., Kalyuzhnaya, M.G., 2018. Rare earth elements alter redox balance in Methylomicrobium alcaliphilum 20ZR. Frontiers in Microbiology 9, 2735. doi: 10.3389/fmicb.2018.02735.


Background: Rare Earth Elements (REEs) control methanol utilization in both methane- and methanol-utilizing microbes. It has been established that the addition of REEs leads to the transcriptional repression of MxaFI-MeDH [a two-subunit methanol dehydrogenase (MeDH), calcium-dependent] and the activation of XoxF-MeDH (a one-subunit MeDH, lanthanum-dependent). Both enzymes are pyrroquinoline quinone-dependent alcohol dehydrogenases and show significant homology; however, they display different kinetic properties and substrate specificities. This study investigates the impact of the MxaFI to XoxF switch on the behavior of metabolic networks at a global scale.

Results: In this study we investigated the steady-state growth of Methylomicrobium alcaliphilum 20ZR in media containing calcium (Ca) or lanthanum (La, a REE element). We found that cells supplemented with La show a higher growth rate compared to Ca-cultures; however, the efficiency of carbon conversion, estimated as biomass yield, is higher in cells grown with Ca. Three complementary global-omics approaches–RNA-seq transcriptomics, proteomics, and metabolomics–were applied to investigate the mechanisms of improved growth vs. carbon conversion. Cells grown with La showed the transcriptional activation of the xoxF gene, a homolog of the formaldehyde-activating enzyme (fae2), a putative transporter, genes for hemin-transport proteins, and nitrate reductase. In contrast, genes for mxaFI and associated cytochrome (mxaG) expression were downregulated. Proteomic profiling suggested additional adjustments of the metabolic network at the protein level, including carbon assimilation pathways, electron transport systems, and the tricarboxylic acid (TCA) cycle. Discord between gene expression and protein abundance changes points toward the possibility of post-transcriptional control of the related systems including key enzymes of the TCA cycle and a set of electron-transport carriers. Metabolomic data followed proteomics and showed the reduction of the ribulose-monophosphate (RuMP) pathway intermediates and the increase of the TCA cycle metabolites.

Conclusion: Cells exposed to REEs display higher rates of growth but have lower carbon conversion efficiency compared to cells supplemented with Ca. The most plausible explanation for these physiological changes is an increased conversion of methanol into formate by XoxF-MeDH, which further stimulates methane oxidation but limits both the supply of reducing power and flux of formaldehyde into the RuMP pathway.

Al-Hajeri, M.M., Bowden, S.A., 2018. Origin of oil geochemical compositional heterogeneity in the Radhuma and Tayarat formations heavy oil carbonate reservoirs of Burgan Field, south Kuwait. Arabian Journal of Geosciences 11, 649.

https://doi.org/10.1007/s12517-018-3995-3

This is a qualitative assessment study to understand origin controlling lateral/geographic and vertical/stratigrahic heterogeneity of Radhuma (Palaeocene) and Tayarat (Maastrichian) Formation heavy oil reservoirs in the Burgan Field in south Kuwait. Data from oil analyses, including physical properties, bulk chemical composition, sulphur content, molecular chemical composition, and carbon and sulphur isotopes, were used to characterise the different oils in the reservoirs. Geochemical fingerprinting and characterisation suggest that the key impact on compositional heterogeneity has been the mixing of some petroleum—by the addition of lighter oil to extra-heavy oil. Therefore, the proposed complex filling history model for the Radhuma and Tayarat reservoirs consists of six episodes: two oil entrapments and four thermochemical sulphate reduction (TSR) fluid pulses. Finally, it is postulated that lighter fresh charge oils in the Burgan Field were sourced upward from deeper reservoirs associated with the reactivation of deep-seated faults as a result of structural compression events during Upper Cretaceous and Neogene time.

Al-Mudhafar, W.J., 2018. From coreflooding and scaled physical model experiments to field-scale enhanced oil recovery evaluations: Comprehensive review of the gas-assisted gravity drainage process. Energy & Fuels 32, 11067-11079.

https://doi.org/10.1021/acs.energyfuels.8b01023

The gas-assisted gravity drainage (GAGD) process has been suggested to improve oil recovery in both secondary and tertiary stages through immiscible and miscible injection modes. In contrast to continuous gas injection and water-alternating gas, the GAGD process takes advantage of the natural segregation of reservoir fluids to provide gravity-stable oil displacement and improve oil recovery. In the GAGD process, the gas is injected through vertical wells at the top of the reservoir to formulate a gas cap that allows oil and water to drain downward to the reservoir bottom, where horizontal producer(s) are placed. Extensive experimental works and limited reservoir-scale evaluation studies have been conducted to test the effectiveness of the GAGD process performance. In this paper, a comprehensive literature review is presented to summarize all of the references about concepts, principles, and field-scale evaluations of the GAGD process. Particularly, this paper presents an introduction to the mechanisms of CO2–rock–fluid interactions, gas enhanced oil recovery injection approaches, the GAGD process physical model, the factors influencing the GAGD process, and a review of all of the previous field-scale evaluation studies. Furthermore, the validation of the GAGD process in reservoir-scale applications is fully discussed by focusing on its weaknesses with respect to the optimal implementation design for achieving maximum oil recovery.



In the present study, a facile environmentally friendly approach was described to prepare monodisperse iron oxide (Fe3O4) nanoparticles (IONPs) by low temperature solution route. The synthesized nanoparticles were characterized using x-ray diffraction spectroscopy (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) measurements, Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric analysis (TGA) analyses. XRD patterns revealed high crystalline quality of the nanoparticles. SEM micrographs showed the monodispersed IONPs with size ranging from 6 to 9 nm. Synthesized nanoparticles demonstrated MICs of 32, 64, and 128 μg/ml against Gram negative bacteria i.e., Serratia marcescens, Escherichia coli, and Pseudomonas aeruginosa, respectively, and 32 μg/ml against Gram positive bacteria Listeria monocytogenes. IOPNs at its respective sub-MICs demonstrated significant reduction of alginate and exopolysaccharide production and subsequently demonstrated broad-spectrum inhibition of biofilm ranging from 16 to 88% in the test bacteria. Biofilm reduction was also examined using SEM and Confocal Laser Scanning Microscopy (CLSM). Interaction of IONPs with bacterial cells generated ROS contributing to reduced biofilm formation. The present study for the first time report that these IONPs were effective in obliterating pre-formed biofilms. Thus, it is envisaged that these nanoparticles with broad-spectrum biofilm inhibitory property could be exploited in the food industry as well as in medical settings to curtail biofilm based infections and losses.

Alfarge, D., Wei, M., Bai, B., 2019. Evaluating the performance of hydraulic-fractures in unconventional reservoirs using production data: Comprehensive review. Journal of Natural Gas Science and Engineering 61, 133-141.


Understanding the performance of the reservoir productivity in the post-stimulation conditions has recently gained an extensive emphasis from the specialist researchers and operators. Although there have been different tools used to evaluate the fracturing process and to predict the well performance, using production data as an indirect tool to calibrate the fracturing design and to forecast the reservoir performance has been considered the most potential technique. However, different methods with a high ambiguity have been used in this area of research over the last decade. Therefore; developing, screening, and specializing different methods and techniques to diagnose and evaluate the post-fracture reservoir performance by using flowback data has a significant priority. Determining the performance of hydraulic fractures from flowback data is considered the actual calibration to estimate the effective volume, length, height, conductivity, and width of hydraulic fractures. This paper presents a comprehensive review on most of the approaches, which have been recently introduced in this area of research, including their applicability, pros and cons. Furthermore, this study explains how each method can be valid at a specific time range. The potential tools, which could be more successful to be used in this direction of research, have been extensively discussed and recommended.

Allwood, A.C., Rosing, M.T., Flannery, D.T., Hurowitz, J.A., Heirwegh, C.M., 2018. Reassessing evidence of life in 3,700-million-year-old rocks of Greenland. Nature 563, 241-244.

https://doi.org/10.1038/s41586-018-0610-4

The Palaeoarchean supracrustal belts in Greenland contain Earth’s oldest rocks and are a prime target in the search for the earliest evidence of life on Earth. However, metamorphism has largely obliterated original rock textures and compositions, posing a challenge to the preservation of biological signatures. A recent study of 3,700-million-year-old rocks of the Isua supracrustal belt in Greenland described a rare zone in which low deformation and a closed metamorphic system allowed preservation of primary sedimentary features, including putative conical and domical stromatolites1 (laminated accretionary structures formed by microbially mediated sedimentation). The morphology, layering, mineralogy, chemistry and geological context of the structures were attributed to the formation of microbial mats in a shallow marine environment by 3,700 million years ago, at the start of Earth’s rock record. Here we report new research that shows a non-biological, post-depositional origin for the structures. Three-dimensional analysis of the morphology and orientation of the structures within the context of host rock fabrics, combined with texture-specific analyses of major and trace element chemistry, show that the ‘stromatolites’ are more plausibly interpreted as part of an assemblage of deformation structures formed in carbonate-altered metasediments long after burial. The investigation of the structures of the Isua supracrustal belt serves as a cautionary tale in the search for signs of past life on Mars, highlighting the importance of three-dimensional, integrated analysis of morphology, rock fabrics and geochemistry at appropriate scales.

Almeida, G.M.F., Leppänen, M., Maasilta, I.J., Sundberg, L.-R., 2018. Bacteriophage imaging: past, present and future. Research in Microbiology 169, 488-494.


The visualization of viral particles only became possible after the advent of the electron microscope. The first bacteriophage images were published in 1940 and were soon followed by many other publications that helped to elucidate the structure of the particles and their interaction with the bacterial hosts. As sample preparation improved and new technologies were developed, phage imaging became important approach to morphologically classify these viruses and helped to understand its importance in the biosphere. In this review we discuss the main milestones in phage imaging, how it affected our knowledge on these viruses and recent developments in the field.

Alvarez, J.O., Tovar, F.D., Schechter, D.S., 2018. Improving oil recovery in the Wolfcamp reservoir by soaking/flowback production schedule with surfactant additives. SPE Reservoir Evaluation & Engineering 21, 1083-1096.

https://doi.org/10.2118/187483-PA

Improving oil recovery from unconventional liquid reservoirs (ULRs) is a major challenge. We have demonstrated in previous laboratory studies the effect of surfactants on spontaneous imbibition and oil recovery by means of wettability alteration and interfacial-tension (IFT) reduction. Thereby, fracture-treatment performance and consequently oil recovery could be improved by adding surfactants to stimulation fluids when a soaking/flowback production schedule is applied. This study evaluates the ability of different groups of surfactants to improve oil recovery in ULRs by experimentally simulating the fracture treatment to represent surfactant imbibition in a ULR core fracture during soaking and flowback. In addition, we analyze the effects of wettability and IFT alteration as well as surfactant adsorption on the process. A coreflooding system was combined with the computed-tomography (CT) scanner to dynamically visualize the fluid movement as it penetrates the ULR sample in real time as well as compare oil recovery between surfactants and water without additive. Wolfcamp sidewall cores were longitudinally fractured and loaded into an aluminum/carbon-composite core holder. Two different types of surfactants—anionic and nonionic/cationic—as well as water without surfactants were injected through the fractures at reservoir conditions to evaluate their effectiveness in penetrating into the fractures and recovering oil from a ULR core. Then, a soaking/flowback production scheme was used to simulate fracture treatment and flowback. Changes in core wettability and IFT were determined by contact-angle (CA) and pendant-drop methods. Coreflooding results showed that surfactant solutions had higher imbibition and recovered more oil from liquid-rich core compared with water alone. The soaking/flowback production schedule aided by surfactants was able to recover up to 14% of the original oil in place (OOIP), whereas water alone recovered up to 2% of the OOIP. These observations qualitatively agree with wettability- and IFT-alteration measurements. Core wettability shifted from an original oil-wet to a final water-wet state, and surfactants reduced IFT to moderately low values. In addition, surfactants showed adsorption capacity following a Langmuir-type adsorption profile. The results showed that the addition of surfactants to completion fluids and the use of a soaking/flowback production scheme could improve oil recovery by wettability alteration and IFT reduction, maximizing well performance after stimulation. These findings provide an important understanding for designing completion-fluid treatments and flowback schedules for ULRs.


https://doi.org/10.5194/bg-2018-398

The weathering of silicates is a major control on atmospheric CO2 at geologic time scales. It was proposed to enhance this process to actively remove CO2 from the atmosphere. While there are some studies that propose and theoretically analyze the application of rock powder on agricultural land, results from field experiments are still scarce. In order to evaluate the efficiency and side effects of Enhanced Weathering, a mesocosm experiment was set up and agricultural soil from Belgium was amended with olivine-bearing dunite ground to two different grain sizes, while distinguishing setups with and without crops. Based on measurements of Mg, Si, pH, and DIC, the additional weathering effect of olivine could be confirmed. Calculated weathering rates are up to three orders of magnitude lower than found in other studies. The calculated CO2 consumption by weathering was comparably low with 2.3 to 4.9 CO2tkm−2a−1. One identified cause was preferential flow leading to a low water-rock interaction time for a significant water volume in the setup, not addressed in previous Enhanced Weathering experiments for CO2 consumption. Correction for preferential flow leads to fluxes about a magnitude higher, confirming that this process and surface runoff in the field must be included in assessments for the CO2 consumption potential of Enhanced Weathering in general. Pore water Mg/Si molar ratios suggest that dissolved Si from the added minerals stays in the system over the observation period, because a cation depleted Si layer forms on the reactive mineral surface of freshly ground rocks. This layer has not reached equilibrium thickness within the first two years. The release of potentially harmful trace elements is an acknowledged side effect of Enhanced Weathering. Primarily Ni and Cr are elevated in soil solution, while Ni concentrations exceed the limits of drinking water quality. The use of olivine, rich in Ni and Cr, is not recommend and alternative rock sources are suggested for the application.

Amirmoshiri, M., Zeng, Y., Chen, Z., Singer, P.M., Puerto, M.C., Grier, H., Bahrim, R.Z.K., Vincent-Bonnieu, S., Farajzadeh, R., Biswal, S.L., Hirasaki, G.J., 2018. Probing the effect of oil type and saturation on foam flow in porous media: Core-flooding and nuclear magnetic resonance (NMR) imaging. Energy & Fuels 32, 11177-11189.


The success of foam displacement in porous media largely depends on its stability, which is adversely impacted by the presence of oil. In this study, we present the results of an experimental investigation into the effect of oil type and saturation on foam rheology in Berea sandstone using the nuclear magnetic resonance imaging technique. The results of foam quality scan in the presence of remaining hexadecane was compared with those from the oil-free case. We showed that the calculated apparent viscosity values in the presence of remaining hexadecane were higher than those in the absence of oil except at very high foam qualities. This was attributed to the dominance of relative permeability reduction and generation of oil-in-water emulsions over the foam-weakening effect of oil. A closer analysis of the fluid distribution further allowed us to quantify the relative significance of the identified oil displacement mechanisms, namely, the increased capillary number, and the micellar solubilization. Additionally, we correlated the foam strength with the oil saturation from the foam-oil co-injection tests. Because of the detrimental effect of oil on foam stability, it is found that the apparent viscosity first decreases with increasing oil (hexadecane and octane) saturation; then, due to oil emulsification, apparent viscosity increases with oil saturation (or more strictly with the oil fractional flow). Compared to octane, hexadecane resulted in less foam destabilization and higher oil emulsification. The co-injection experiment with crude oil exhibited a similar behavior to octane. Findings from this study suggest that, despite the destabilizing impact of oil on foam, the resulting steady-state apparent viscosities could be much larger than the viscosity of the in situ oil. This leads to a favorable mobility ratio during the oil-displacement process.

Amshoff, P., Weger, T., Ostertag-Henning, C., 2018. Dissolution kinetics of CO2 and CO2-SO2 mixtures in water and brine at geological storage conditions of 16 MPa and 333 K. International Journal of Greenhouse Gas Control 79, 173-180.


To minimize the costs of geological storage of carbon dioxide captured from different emitting sources, the purification steps to decrease the concentrations of accessory gases such as sulfur dioxide (SO2) should be optimized according to the needs of the geological storage complexity. SO2 might acidify the formation water and influence chemical reactions in the subsurface reservoir. For adequate predictions of the impact of processes influenced by the accessory gases on the near-well rock integrity, injectivity and long term storage capacity, kinetic data for the mass transfer of CO2 and SO2 into the aqueous formation waters at in situ conditions are crucial.

In this study the mass transfer of CO2 and SO2 was investigated from pure CO2 or a CO2-SO2 mixture into pure water or saline water (S = 250 g L−1) at conditions of 16 MPa pressure and a temperature of 333 K in a stirred titanium batch reactor. At the same stirrer speed of 190 rpm the mass transfer coefficient φKL of CO2 into water was determined to be 12.9 cm h−1, which is approximately a third of that of SO2 with φKL(SO2) = 34.9 cm h−1. The presence of SO2 did not affect the dissolved equilibrium CO2 concentration (1.17 ± 0.03 mol L−1 in pure water, 0.50 ± 0.02 mol L−1 in brine) or the mass transfer coefficient for CO2. In less than two hours the equilibrium between the aqueous phase and the CO2-SO2 phase was attained. At equilibrium, ca. 60% of the SO2 was dissolved into the aqueous phase and the rest remained in the supercritical CO2 phase. The Henry constant Hcp for SO2 under the experimental conditions was determined to be 2.7 mol m-³ Pa−1. The different mass transfer coefficients of CO2 and SO2 – and other accessory gases – should be included in geochemical models to adequately describe the distribution of these trace gases in the reservoir and address the impact of reactive trace gas compounds on fluid-rock reactions.



This review discusses the identification and quantification of microplastic (MP) using Raman microspectroscopy (RM). It addresses scientists investigating MP in environmental and food samples. We show the benefits and limitations of RM from a technical point of view (sensitivity, smallest particle sizes, speed optimizations, analysis artefacts and background effects) and provide an assessment of the relevance of lab analyses and their interpretation (sample sizes for the analysis, uncertainty of the analysis). All parts are complimented by extensive literature data and a theoretical derivation of the concepts. We conclude with suggestions for a feasible and meaningful RM analysis of MP samples.

Antony, R., Willoughby, A.S., Grannas, A.M., Catanzano, V., Sleighter, R.L., Thamban, M., Hatcher, P.G., 2018. Photo-biochemical transformation of dissolved organic matter on the surface of the coastal East Antarctic ice sheet. Biogeochemistry 141, 229-247.

https://doi.org/10.1007/s10533-018-0516-0

Recent studies have highlighted the composition and complexity of dissolved organic matter (DOM) in glacial environments. Climate-induced changes to glacier runoff are projected to be an important

source of DOM to coastal ecosystems. Photochemical and microbial (termed photo-biochemical) degradation of DOM would determine its fate on the glacier surface and in recipient coastal ecosystems. In order to understand the molecular imprints of photo-biochemical alteration of DOM, in situ field experiments were conducted over a period of 35 days in a coastal Antarctic site and DOM molecularly characterised using ultrahigh-resolution mass spectrometry. We show that the biogeochemistry of DOM is highly complex and intimately connected with microbial and photochemical processes operating individually or in combination. Photo-biochemical processes resulted in shifts in the nitrogen, sulfur, and phosphorous content of the DOM. These processes are also an important mechanism for transforming refractory DOM, like dissolved black carbon and carboxylic rich alicyclic molecules from the snow surface. This study is unique, as it provides new molecular-level information on compounds that comprise the photo- and bio-labile, photo- and bio-refractory, as well as photo- and bio-produced fractions of the supraglacial DOM pool. These insights into the interactions between microbes, light, and specific components of the DOM pool highlight the need for studies focused on the biogeochemistry of supraglacial carbon and its response to a changing climate.

Arenillas, I., Arz, J.A., Gilabert, V., 2018. Blooms of aberrant planktic foraminifera across the K/Pg boundary in the Western Tethys: causes and evolutionary implications. Paleobiology 44, 460-489.

http://www.bioone.org/doi/abs/10.1017/pab.2018.16

We report a detailed study of the different categories and types of abnormal morphologies in planktic foraminifera recognizable in the lowermost Danian, mainly from the El Kef and Aïn Settara sections, Tunisia. Various types of abnormalities in the test morphology were identified, including protuberances near the proloculus, abnormal chambers, double or twinned ultimate chambers, multiple ultimate chambers, abnormal apertures, distortion in test coiling, morphologically abnormal tests, attached twins or double tests, and general monstrosities. Detailed biostratigraphic and quantitative studies of the Tunisian sections documented a major proliferation of aberrant planktic foraminifera (between approximately 5% and 18% in relative abundance) during the first 200 Kyr of the Danian, starting immediately after the Cretaceous/Paleogene (K/Pg) boundary mass extinction (spanning from the Guembelitria cretacea Zone to the lower part of the P. pseudobulloides Zone). This contrasts with the proportionately low frequency of aberrant tests (generally <2%) identified within the uppermost Maastrichtian, suggesting more stable environmental conditions during the last ~ 50–100 Kyr of the Cretaceous. Two main pulses with abundant aberrant tests were recognized in the earliest Danian, the one recorded in the well-known K/Pg boundary clay being the more intense of those (maxima of >18%). These main pulses of aberrants coincide approximately with relevant quantitative and evolutionary turnovers in the planktic foraminiferal assemblages. In this paper, we explore the relation of these high values of the foraminiferal abnormality index with the environmental changes induced by the meteorite impact of Chicxulub in Yucatan, Mexico, and the massive eruptions of the Deccan Traps, India.

Arias-Ortiz, A., Masqué, P., Garcia-Orellana, J., Serrano, O., Mazarrasa, I., Marbà, N., Lovelock, C.E., Lavery, P.S., Duarte, C.M., 2018. Reviews and syntheses: 210Pb-derived sediment and carbon accumulation rates in vegetated coastal ecosystems – setting the record straight. Biogeosciences 15, 6791-6818.

https://www.biogeosciences.net/15/6791/2018/

Vegetated coastal ecosystems, including tidal marshes, mangroves and seagrass meadows, are being increasingly assessed in terms of their potential for carbon dioxide sequestration worldwide.

However, there is a paucity of studies that have effectively estimated the accumulation rates of sediment organic carbon (Corg), also termed blue carbon, beyond the mere quantification of Corg stocks. Here, we discuss the use of the 210Pb dating technique to determine the rate of Corg accumulation in these habitats. We review the most widely used 210Pb dating models to assess their limitations in these ecosystems, often composed of heterogeneous sediments with varying inputs of organic material, that are disturbed by natural and anthropogenic processes resulting in sediment mixing and changes in sedimentation rates or erosion. Through a range of simulations, we consider the most relevant processes that impact the 210Pb records in vegetated coastal ecosystems and evaluate how anomalies in 210Pb specific activity profiles affect sediment and Corg accumulation rates. Our results show that the discrepancy in sediment and derived Corg accumulation rates between anomalous and ideal 210Pb profiles is within 20% if the process causing such anomalies is well understood. While these discrepancies might be acceptable for the determination of mean sediment and Corg accumulation rates over the last century, they may not always provide a reliable geochronology or historical reconstruction. Reliable estimates of Corg accumulation rates might be difficult at sites with slow sedimentation, intense mixing and/or that are affected by multiple sedimentary processes. Additional tracers or geochemical, ecological or historical data need to be used to validate the 210Pb-derived results. The framework provided in this study can be instrumental in reducing the uncertainties associated with estimates of Corg accumulation rates in vegetated coastal sediments.

Aromokeye, D.A., Richter-Heitmann, T., Oni, O.E., Kulkarni, A., Yin, X., Kasten, S., Friedrich, M.W., 2018. Temperature controls crystalline iron oxide utilization by microbial communities in methanic ferruginous marine sediment incubations. Frontiers in Microbiology 9, 2574. doi: 10.3389/fmicb.2018.02574.


Microorganisms can use crystalline iron minerals for iron reduction linked to organic matter degradation or as conduits for direct interspecies electron transfer (mDIET) to syntrophic partners, e.g., methanogens. The environmental conditions that lead either to reduction or conduit use are so far unknown. We investigated microbial community shifts and interactions with crystalline iron minerals (hematite and magnetite) in methanic ferruginous marine sediment incubations during organic matter (glucose) degradation at varying temperatures. Iron reduction rates increased with decreasing temperature from 30°C to 4°C. Both hematite and magnetite facilitated iron reduction at 4°C, demonstrating that microorganisms in the methanic zone of marine sediments can reduce crystalline iron oxides under psychrophilic conditions. Methanogenesis occurred, however, at higher rates with increasing temperature. At 30°C, both hematite and magnetite accelerated methanogenesis onset and maximum process rates. At lower temperatures (10°C and 4°C), hematite could still facilitate methanogenesis but magnetite served more as an electron acceptor for iron reduction than as a conduit. Different temperatures selected for different key microorganisms: at 30°C, members of genus Orenia, Halobacteroidaceae, at 10°C, Photobacterium and the order Clostridiales, and at 4°C Photobacterium and Psychromonas were enriched. Members of the order Desulfuromonadales harboring known dissimilatory iron reducers were also enriched at all temperatures. Our results show that crystalline iron oxides predominant in some natural environments can facilitate electron transfer between microbial communities at psychrophilic temperatures. Furthermore, temperature has a critical role in determining the pathway of crystalline iron oxide utilization in marine sediment shifting from conduction at 30°C to predominantly iron reduction at lower temperatures.


https://doi.org/10.5194/cp-2018-152

Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleolimnology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. Here, we report seasonally resolved measurements of brGDGT production in the water column, in catchment soils, and in a sediment core from Basin Pond, a small, deep inland lake in Maine, USA. We find similar brGDGT distributions in both water column and lake sediment samples but the catchment soils have distinct brGDGT distributions suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the down-core sedimentary signal. Seasonally, depth-resolved measurements indicate that most brGDGT production occurs in late fall, and at intermediate depths (18–30m) in the water column. We utilize these observations to help interpret a Basin Pond brGDGT-based temperature reconstruction spanning the past 900 years. This record exhibits trends similar to a pollen record from the same site and also to regional and global syntheses of terrestrial temperatures over the last millennium. However, the Basin Pond temperature record shows higher-frequency variability than has previously been captured by such an archive in the northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic or solar activity. This first brGDGT-based multi-centennial paleoreconstruction from this region contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.

Bai, L., Carlton, D.D., Schug, K.A., 2018. Complex mixture quantification without calibration using gas chromatography and a comprehensive carbon reactor in conjunction with flame ionization detection. Journal of Separation Science 41, 4031-4037.

https://doi.org/10.1002/jssc.201800383

Quantification of complex carbon-containing mixtures is typically a very time-intensive task with regards to the calibration process. A gas chromatograph with a flame ionization detector yields strong responses to organic compounds and provides a wide linear range over many orders of magnitude; however, responses for highly functionalized and heteroatom-containing compounds can be variable. Here, a commercial Polyarc microreactor unit, placed before the flame ionization detector, was investigated as a means of normalizing carbon response across all compounds. The device includes two catalytic reaction chambers, ultimately converting all carbon atoms to methane evenly for flame ionization detection. Three groups of different complex mixtures from n-alkane to terpene and polymer mixtures were analyzed to evaluate the potential for calibration-free quantitation of the new detector arrangement. We have obtained accurate quantification results without time-consuming calibration processes. The quantification of a terpene mixture and a polymer mixture confirms the ability of the detector for analyzing samples that either have complex physical or structural properties or wide concentration range. In summary, compared to other detectors, this methanizer ? flame ionization detection system provides a simplified workflow, which can eliminate calibration steps and increase throughput.

Bakrač, K., Ilijanić, N., Miko, S., Hasan, O., 2018. Evidence of sapropel S1 formation from Holocene lacustrine sequences in Lake Vrana in Dalmatia (Croatia). Quaternary International 494, 5-18.


The sediment core from Lake Vrana (between 1000 and 500 cm) on the eastern Adriatic coast was analyzed using palynological and geochemical approaches to detect environmental changes during the

Holocene. The deepest sediments (between 1000 and 967 cm) in Lake Vrana could correspond to Late Pleistocene to Holocene transition. Although this interval is not dated, it is indicated by the palynological record. After that, the Holocene warming is evident and the observed dark layers are identified as Holocene sapropel S1, known in the eastern Mediterranean (10.8–6.1 cal kyr BP). Sapropelic layer S1a in Lake Vrana sediment core is evident between 905 and 790 cm and it ended at 7.9 cal kyr BP. It is formed in a very shallow freshwater ecosystem, dominated by cyanobacteria Gleocapsa and terrigenous detritus as a consequence of runoff. Periodically anoxic condition occurred. The geochemical signature of sapropelic layer S1a from Lake Vrana is consistent with post-depositional oxidation due to transition to the bottom water oxygenation evidenced in elevated Mn and Mn peak at the end of sapropelic layer S1a deposition. Sapropelic layer S1b, deposited between 7.4 and 6.4 cal kyr BP, is characterized by amorphous organic matter. The two sapropelic layers are separated by the horizon at 7.9–7.4 cal kyr BP, corresponding to the drier climate conditions, indicated by the presence of Poaceae, Ericaceae, Juniperus and Pistacia. This horizon reflects regional climatic cooling associated with reduced levels of precipitation that interrupted a period of generally higher precipitation. Based on geochemical data, Total organic carbon (TOC) and Nitrogen (N), the sapropelic layers are characterized by elevated values comparing to the rest of the core.

The new records allow reconstruction of paleoenvironmental changes on land, which give insight into the processes and climate conditions that led to the formation of S1. The evidence indicates that: (i) S1 sapropelic layer in Lake Vrana sediments is an organic-poor deposit; (ii) the S1 period in the study area can be divisible into two sub-phases (S1a and S1b). The key factor that initiated the formation of S1 was increased discharge of freshwater into the Lake Vrana basin during warmer and wetter climate in the Early Holocene.



There is a growing interest in mudrocks as a result of their potential as hydrocarbon reservoirs, in the storage of carbon dioxide, and as repositories for nuclear waste. Methods for characterising mudrocks are fast evolving in order to better characterise their very small grain sizes. Grain-size analysis of mudrock is challenging and time-consuming and there is need to develop a fast, effective and objective method for accurately determining the grain size of this group of rocks. We suggest that this is best achieved by using high-resolution electron microscopy to study both the microstructure and grain size of mudrocks at the same time. The contribution presents grain-size analysis from scanning electron microscopy (SEM) through image analysis of the Feret (or calliper) diameter of grains. The method has been tested on 7 mudrock samples from two IODP Expeditions and compared with results from standard laser diffraction granulometry. Image analysis shows that all the samples fall within the clayey silt to silty clay range with average grain size from fine silt to medium silt. Closely comparable results and statistical parameters were obtained by laser diffractometry. Linear plots of grain percentage at corresponding phi values show strong positive correlation between the two techniques with R-square values typically ranging between 0.76 and 0.96. Image analysis of grain size as described herein gives comparable and generally smoother normal distribution curves than the laser diffraction technique for all the seven samples. The procedures involved in the proposed method for analysing grain size of fine-grained sediments are rapid, automated, devoid of human subjectivity and precise.

Bao, R., Blattmann, T.M., McIntyre, C., Zhao, M., Eglinton, T.I., 2019. Relationships between grain size and organic carbon 14C heterogeneity in continental margin sediments. Earth and Planetary Science Letters 505, 76-85.

http://www.sciencedirect.com/science/article/pii/S0012821X18306095

The deposition and long-term burial of sedimentary organic matter (OM) on continental margins comprises a fundamental component of the global carbon cycle. A key unknown in interpretation of carbon isotope records of sedimentary OM is the extent to which OM accumulating in continental shelf and slope sediments is influenced by dispersal and redistribution processes. Here, we present results from an extensive survey of organic carbon (OC) characteristics of grain size fractions (ranging from <20 to 250 μm) retrieved from Chinese marginal sea surface sediments in order to assess the extent to which the abundance and isotope composition of OM in shallow shelf seas is influenced by hydrodynamic processes. Our findings show that contrasting relationships exist between 14C contents of OC and grain size in surface sediments associated with two different hydrodynamic modes, suggesting that transport pathways and mechanisms imparted by the different hydrodynamic conditions exert a strong influence on 14C contents of OM in continental shelf sediments. In deeper regions and erosional areas, we infer that bedload transport exerts the strongest influence on (decreases) OC 14C contents of the coarser fraction, while resuspension processes induce OC 14C depletion of intermediate grain size fractions in shallow inner-shelf settings. We use the inter-fraction spread in Δ14C values, defined here as H14, to argue that the hydrodynamic processes amplify overall 14C heterogeneity within corresponding bulk sediment samples. The magnitude and footprint of this heterogeneity carries implications for our understanding of carbon cycling in shallow marginal seas.



The composition of an ionic aqueous solution can modify the wettability behavior of a liquid/liquid/solid system. This behavior is of great importance for oil extraction and some separation processes. Here we model the contact angle and wettability on the basis of a tridimensional classical density functional theory (DFT) and Young equation for a brine/oil/solid surface system. We propose the inclusion of dispersion interaction between surface-ion and oil-ion. The equilibrium contact angle is found through the minimization of the grand potential. The approach presented here is promising and due to its versatility can be expanded to systems with some peculiarities such as roughness and thin film.

Barili, R., Neilson, J.E., Brasier, A.T., Goldberg, K., Pastro Bardola, T., De Ros, L.F., Leng, M., 2018. Carbon isotopes, stratigraphy, and environmental change: the Middle–Upper Cambrian Positive Excursion (SPICE) in Port au Port Group, western Newfoundland, Canada. Canadian Journal of Earth Sciences 55, 1209-1222.

https://doi.org/10.1139/cjes-2018-0025

In many basins, Upper Cambrian carbonate successions display intervals with a positive carbon isotope excursion (CIE) of up to +5‰. In North America, this marks the boundary between the Sauk II–III super-sequences. A Steptoean positive carbon isotope excursion (SPICE) locality previously identified in the Port au Port peninsula, western Newfoundland, has been revisited and an additional

potential SPICE locality found. In both locations, a CIE is found to be associated with a prominent bioherm and sandstone layer within a sequence of carbonate rocks. At March Point columnar stromatolites occur, whereas at Felix Cove thrombolites can be seen. In the latter, the sandstone immediately overlies the thrombolites coincident with the CIE, whereas at March Point a dolomitized grainstone occurs above the stromatolites. The sandstone at this locality post-dates the CIE. Although lower than the SPICE in some localities, a positive CIE is present in both sections: March Point (+1.1‰) and Felix Cove (+1.8‰). Additionally, δ13Corg rises from −30.0‰ to −22.0‰ at March Point and from −27‰ to −24.0‰ at Felix Cove and, in accordance with previously published work, we suggest that this could be the SPICE. Comparison of the stratigraphy and petrography between the two localities suggest that both depositional and diagenetic factors could have influenced the nature of the interpreted SPICE in Newfoundland. It is also possible that the local carbon isotopic signature may have been influenced by a semi-restricted depositional and early diagenetic environment related to the paleogeographic configuration rather than the global marine excursion.


https://doi.org/10.5194/bg-2018-450

Estuaries worldwide are known to act as filters of land-derived N loads, yet their variable environmental settings can affect microbial nitrogen (N) retention and removal and thus the coastal filter function. We investigated microbial N-retention (nitrification, ammonium assimilation) and N-removal (denitrification, anammox) in the aphotic benthic systems (here defined as: bottom boundary layer [BBL] and sediment) of two Baltic Sea estuaries that differ in riverine N loads, trophic state, bottom topography, and sediment type. Contrary to our expectations, nitrification rates (5–227nmolL−1d−1) in the BBL neither differed between the eutrophied Vistula estuary and the oligotrophic Öre estuary, nor between seasons. Ammonium assimilation rates were slightly higher in the oligotrophic Öre estuary in spring but did not differ between estuaries in summer (9–704nmolL−1d−1). In the sediment, no anammox was found in either estuary and denitrification rates were higher in the eutrophied (349±117µmolNm−2d−1) than in the oligotrophic estuary (138±47µmolNm−2d−1). Irrespective of their differences, in both estuaries the quality of the mainly phytoplankton-derived particulate organic matter (POM) – evaluated by means of C:N and POC:Chl.a ratios – seemed to control N-cycling processes through the availability of particulate organic N and C as substrate sources. Our data suggest, that in stratified estuaries, phytoplankton-derived POM is an essential link between riverine N loads and benthic N cycling and may function as a temporary N reservoir via long particle residence time or coastal parallel transport. Even at low process rates, effective coastal filtering would thus be achieved by the increased time available for the recycling of N via microbial retention processes until its permanent removal via denitrification.

Bassez, M.-P., 2018. Water near its supercritical point and at alkaline pH for the production of ferric oxides and silicates in anoxic conditions. A new hypothesis for the synthesis of minerals observed in banded iron formations and for the related geobiotropic chemistry inside fluid inclusions. Origins of Life and Evolution of Biospheres 48, 289-320.

https://doi.org/10.1007/s11084-018-9560-y

An alternative hypothesis for the origin of the banded iron formations and the synthesis of prebiotic molecules is presented here. I show the importance of considering water near its supercritical point and at alkaline pH. It is based on the chemical equation for the anoxic oxidation of ferrous iron into

ferric iron at high-subcritical conditions of water and high pH, that I extract from E-pH diagrams drawn for corrosion purposes (Geophysical Research Abstracts Vol 15, EGU2013–22 Bassez 2013, Orig Life Evol Biosph 45(1):5-13, Bassez 2015, Procedia Earth Planet Sci 17, 492-495, Bassez 2017a, Orig Life Evol Biosph 47:453-480, Bassez 2017b). The sudden change in solubility of silica, SiO2, at the critical point of water is also considered. It is shown that under these temperatures and pressures, ferric oxides and ferric silicates can form in anoxic terrains. No Fe II oxidation by UV light, neither by oxygen is needed to explain the minerals of the Banded Iron Formations. The intervention of any kind of microorganisms, either sulfate-reducing, or FeII-oxidizing or O2-producing, is not required. The chemical equation for the anoxic oxidation of ferrous iron is applied to the hydrolyses of fayalite, Fe2SiO4 and ferrosilite, FeSiO3. It is shown that the BIF minerals of the Hamersley Group, Western Australia, and the Transvaal Supergroup, South Africa, are those of fayalite and ferrosilite hydrolyses and carbonations. The dissolution of crustal fayalite and ferrosilite during water-rock interaction needs to occur at T&P just below the critical point of water and in a rising water which is undersaturated in SiO2. Minerals of BIFs which can then be ejected at the surface from venting arcs are ferric oxide hydroxides, hematite, FeIII-greenalite, siderite. The greenalite dehydrated product minnesotaite forms when rising water becomes supersaturated in SiO2, as also riebeckite and stilpnomelane. Long lengths of siderite without ferric oxides neither ferric silicates can occur since the exothermic siderite formation is not so much dependent in T&P. It is also shown that the H2 which is released during hydrolysis/oxidation of fayalite/ferrosilite can lead to components of life, such as macromolecules of amino acids which are synthesized from mixtures of (CO, N2, H2O) in Sabatier-Senderens/Fischer-Tropsch & Haber-Bosch reactions or microwave or gamma-ray excitation reactions. I propose that such geobiotropic synthesis may occur inside fluid inclusions of BIFs, in the silica chert, hematite, FeIII-greenalite or siderite. Therefore, the combination of high-subcritical conditions of water, high solubility of SiO2 at these T&P values, formation of CO also at these T&P, high pH and anoxic water, leads to the formation of ferric minerals and prebiotic molecules in the process of geobiotropy.

Bäuchle, M., Lüdecke, T., Rabieh, S., Calnek, K., Bromage, T.G., 2018. Quantification of 71 detected elements from Li to U for aqueous samples by simultaneous-inductively coupled plasma-mass spectrometry. RSC Advances 8, 37008-37020.

http://dx.doi.org/10.1039/C8RA07070A

Quantitative analysis of multi-element concentrations in aqueous solutions, such as water, beverages and biofluids, has long been performed by sequential inductively coupled plasma-mass spectrometry. Recently, a fully simultaneous mass spectrum monitoring ICP-MS instrument that fits a compact Mattauch–Herzog geometry (MH-ICP-MS) with a permanent magnet and a large, spatially resolving semiconductor ion detector has been introduced. This technology allows coverage of the complete inorganic relevant mass range from 6Li to 238U in a single measurement, which helps to mitigate the restriction on the number of inorganic elements whose concentrations may be routinely measured from one sample, thus reducing operational assay times and aqueous sample volumes for evaluations across the breadth of the periodic table. We report here on a detailed method for utilizing MH-ICP-MS to detect all elements of the relevant inorganic spectrum in aqueous samples; 7 types of water, 4 types of beverage, and 4 biofluid biological samples. With this method 71 elements can be routinely detected simultaneously in seconds and in as little as 1–4 mL sample, when using a specific set of calibration and internal standards. Quantitative results reveal distinct element patterns between each sample and within types of samples, suggesting that different types of aqueous solutions can be recognized and distinguished by their elemental patterns. The method has implications for understanding elemental distribution and concentration for many fields, including nutrition, studies of

the biosphere, ecological stoichiometry, and environmental health fields, among others, where broad elemental information is actually required.

Baumann, L.M.F., Taubner, R.-S., Bauersachs, T., Steiner, M., Schleper, C., Peckmann, J., Rittmann, S.K.M.R., Birgel, D., 2018. Intact polar lipid and core lipid inventory of the hydrothermal vent methanogens Methanocaldococcus villosus and Methanothermococcus okinawensis. Organic Geochemistry 126, 33-42.


For the first time, a comprehensive documentation of the core and intact polar lipid composition of the hydrogenotrophic, (hyper)thermophilic, methanogenic archaea Methanocaldococcus villosus strain DSM 22612T and Methanothermococcus okinawensis strain DSM 14208T is provided. Intact polar lipids of both organisms consist almost exclusively of glycolipids. M. villosus has mainly diglycosidic and some monoglycosidic head groups. In contrast, M. okinawensis is typified by more monoglycosidic than diglycosidic head groups and some phosphoglycosidic head groups. Both strains exhibit mainly diether lipids, namely archaeol and macrocyclic archaeol, which together account for 95% of the total core lipids. M. villosus reveals more macrocyclic archaeol (55%) than archaeol (39%). In M. okinawensis the ratio is almost reversed (35% macrocyclic archaeol; 59% archaeol). Both organisms also show minor relative abundances of GDD-0 (glycerol dialkyl diether) and GMD-0 (glycerol monoalkyl diether). The two methanogens also contained minute abundances of tetraether lipids. GDGT-0 (glycerol dialkyl glycerol tetraether) was dominant and accompanied by smaller amounts of GMGT-0 (glycerol monoalkyl glycerol tetraether) and GTGT-0 (glycerol trialkyl glycerol tetraether). Two isomers of GMGT-0 occurred in both organisms, whereas one was predominant in M. villosus and the other one in M. okinawensis. The detection of macrocyclic archaeol represents the first report of this compound in the genus Methanothermococcus. GTGT-0 and GMGT-0 have so far not been described in any representative of both genera, and two isomers of GMGT-0 not in any other organism. These new observations will be instrumental for the interpretation of archaeal-derived molecular fossils in environmental samples.

Beale, D.J., Pinu, F.R., Kouremenos, K.A., Poojary, M.M., Narayana, V.K., Boughton, B.A., Kanojia, K., Dayalan, S., Jones, O.A.H., Dias, D.A., 2018. Review of recent developments in GC–MS approaches to metabolomics-based research. Metabolomics 14, 152.

https://doi.org/10.1007/s11306-018-1449-2

Background: Metabolomics aims to identify the changes in endogenous metabolites of biological systems in response to intrinsic and extrinsic factors. This is accomplished through untargeted, semi-targeted and targeted based approaches. Untargeted and semi-targeted methods are typically applied in hypothesis-generating investigations (aimed at measuring as many metabolites as possible), while targeted approaches analyze a relatively smaller subset of biochemically important and relevant metabolites. Regardless of approach, it is well recognized amongst the metabolomics community that gas chromatography-mass spectrometry (GC–MS) is one of the most efficient, reproducible and well used analytical platforms for metabolomics research. This is due to the robust, reproducible and selective nature of the technique, as well as the large number of well-established libraries of both commercial and ‘in house’ metabolite databases available.

Aim of review: This review provides an overview of developments in GC–MS based metabolomics applications, with a focus on sample preparation and preservation techniques. A number of chemical derivatization (in-time, in-liner, offline and microwave assisted) techniques are also discussed.

Electron impact ionization and a summary of alternate mass analyzers are highlighted, along with a number of recently reported new GC columns suited for metabolomics. Lastly, multidimensional GC–MS and its application in environmental and biomedical research is presented, along with the importance of bioinformatics.

Key scientific concepts of review: The purpose of this review is to both highlight and provide an update on GC–MS analytical techniques that are common in metabolomics studies. Specific emphasis is given to the key steps within the GC–MS workflow that those new to this field need to be aware of and the common pitfalls that should be looked out for when starting in this area.

Beccaria, M., Franchina, F.A., Nasir, M., Mellors, T., Hill, J.E., Purcaro, G., 2018. Investigation of mycobacteria fatty acid profile using different ionization energies in GC–MS. Analytical and Bioanalytical Chemistry 410, 7987-7996.

https://doi.org/10.1007/s00216-018-1421-z

Gas chromatography (GC) coupled with electron ionization (EI) mass spectrometry (MS) is a well-established technique for the analysis of volatile and semi-volatile compounds. The main advantage is the highly repeatable fragmentation of the compounds into the ion source, generating intense and diagnostic fragmentation when the ionization is performed at 70 eV; this is considered the standard ionization condition and has been used for creating many established databases, which are of great support in the analyte identification process. However, such an intense fragmentation often causes the loss of the molecular ion or more diagnostic ions, which can be detrimental for the identification of homologous series or isomers, as for instance fatty acids. To obtain this information chemical or soft ionization can be used, but dedicated ion sources and conditions are required. In this work, we explored different ionization voltages in GC–EI–MS to preserve the intensity of the molecular ion using a conventional quadrupole MS. Twenty, 30, 50, and 70 eV were tested using a mixture of fatty acid methyl esters standards. Intensity and repeatability of the most informative ions were compared. Twenty and 70 eV were then used to analyze the fatty acid composition of six different strains of mycobacteria. Two approaches were used for elaborating the data: (1) a single average spectrum of the entire chromatogram was derived, which can be considered (in terms of concept) as a direct EI–MS analysis; (2) the actual chromatographic separation of the compounds was considered after automatic alignment. The results obtained are discussed herein.



Atmospheric methane concentration shows a well-known decrease over the first half of the Holocene following the Northern Hemisphere summer insolation before it started to increase again to preindustrial values. There is a debate about what caused this change in the methane concentration evolution, in particular, whether an early anthropogenic influence or natural emissions led to the reversal of the atmospheric CH4 concentration evolution. Here, we present new methane concentration and stable hydrogen and carbon isotope data measured on ice core samples from both Greenland and Antarctica over the Holocene. With the help of a two-box model and the full suite of CH4 parameters, the new data allow us to quantify the total methane emissions in the Northern Hemisphere and Southern Hemisphere separately as well as their stable isotopic signatures, while interpretation of isotopic records of only one hemisphere may lead to erroneous conclusions. For the first half of the Holocene our results indicate an asynchronous decrease in Northern Hemisphere and

Southern Hemisphere CH4 emissions by more than 30 Tg CH4 yr−1 in total, accompanied by a drop in the northern carbon isotopic source signature of about −3 ‰. This cannot be explained by a change in the source mix alone but requires shifts in the isotopic signature of the sources themselves caused by changes in the precursor material for the methane production. In the second half of the Holocene, global CH4 emissions increased by about 30 Tg CH4 yr−1, while preindustrial isotopic emission signatures remained more or less constant. However, our results show that this early increase in methane emissions took place in the Southern Hemisphere, while Northern Hemisphere emissions started to increase only about 2000 years ago. Accordingly, natural emissions in the southern tropics appear to be the main cause of the CH4 increase starting 5000 years before present, not supporting an early anthropogenic influence on the global methane budget by East Asian land use changes.

Becker, C., Jochmann, M.A., Schmidt, T.C., 2019. An overview of approaches in liquid chromatography flame ionization detection. TrAC Trends in Analytical Chemistry 110, 143-149.


Several attempts to combine high performance liquid chromatography (HPLC) with flame ionization detection (FID) have been made since the 1960s. Elaborated systems were developed to overcome problems such as detector overload by use of organic solvents in HPLC or transfer of non-volatile analytes into FID. Almost twenty years after the first successful applications by solvent evaporation based techniques, subcritical water high temperature liquid chromatography opened the door for novel approaches to combine HPLC with FID. Direct coupling without pre-evaporation steps of signal disturbing organic solvents became possible and new instrumental developments resulted in capillary jet interface systems. These systems are suitable for a broad range of volatile and non-volatile analytes, which led to a significant increase of publications. This review discusses the most important developments of LC/FID coupling and summarizes its field of applications.

Beier, J., Anthes, N., Wahl, J., Harvati, K., 2018. Similar cranial trauma prevalence among Neanderthals and Upper Palaeolithic modern humans. Nature 563, 686-690.

https://doi.org/10.1038/s41586-018-0696-8

Neanderthals are commonly depicted as leading dangerous lives and permanently struggling for survival. This view largely relies on the high incidences of trauma that have been reported and have variously been attributed to violent social behaviour, highly mobile hunter-gatherer lifestyles or attacks by carnivores. The described Neanderthal pattern of predominantly cranial injuries is further thought to reflect violent encounters with large prey mammals, resulting from the use of close-range hunting weapons. These interpretations directly shape our understanding of Neanderthal lifestyles, health and hunting abilities, yet mainly rest on descriptive, case-based evidence. Quantitative, population-level studies of traumatic injuries are rare. Here we reassess the hypothesis of higher cranial trauma prevalence among Neanderthals using a population-level approach—accounting for preservation bias and other contextual data—and an exhaustive fossil database. We show that Neanderthals and early Upper Palaeolithic anatomically modern humans exhibit similar overall incidences of cranial trauma, which are higher for males in both taxa, consistent with patterns shown by later populations of modern humans. Beyond these similarities, we observed species-specific, age-related variation in trauma prevalence, suggesting that there were differences in the timing of injuries during life or that there was a differential mortality risk of trauma survivors in the two groups. Finally, our results highlight the importance of preservation bias in studies of trauma prevalence.

Belahbib, H., Summers, Z.M., Fardeau, M.-L., Joseph, M., Tamburini, C., Dolla, A., Ollivier, B., Armougom, F., 2018. Towards a congruent reclassification and nomenclature of the thermophilic species of the genus Pseudothermotoga within the order Thermotogales. Systematic and Applied Microbiology 41, 555-563.


The phylum Thermotogae gathers thermophilic, hyperthermophic, mesophilic, and thermo-acidophilic anaerobic bacteria that are mostly originated from geothermally heated environments. The metabolic and phenotypic properties harbored by the Thermotogae species questions the evolutionary events driving the emergence of this early branch of the universal tree of life. Recent reshaping of the Thermotogae taxonomy has led to the description of a new genus, Pseudothermotoga, a sister group of the genus Thermotoga within the order Thermotogales. Comparative genomics of both Pseudothermotoga and Thermotoga spp., including 16S-rRNA-based phylogenetic, pan-genomic analysis as well as signature indel conservation, provided evidence that Thermotoga caldifontis and Thermotoga profunda species should be reclassified within the genus Pseudothermotoga and renamed as Pseudothermotoga caldifontis comb. nov. (type strain=AZM44c09T) and Pseudothermotoga profunda comb. nov. (type strain=AZM34c06T), respectively. In addition, based upon whole-genome relatedness indices and DNA–DNA Hybridization results, the reclassification of Pseudothermotoga lettingae and Pseudothermotoga subterranea as latter heterotypic synonyms of Pseudothermotoga elfii is proposed. Finally, potential genetic elements resulting from the distinct evolutionary story of the Thermotoga and Pseudothermotoga clades are discussed.

Belt, S.T., 2018. Source-specific biomarkers as proxies for Arctic and Antarctic sea ice. Organic Geochemistry 125, 277-298.


Over the last decade or so, certain source-specific C25 highly branched isoprenoid (HBI) lipid biomarkers have emerged as useful proxies for Arctic and Antarctic sea ice. Thus, IP25 (Ice proxy with 25 carbon atoms) and IPSO25 (Ice proxy for the Southern Ocean with 25 carbon atoms) represent binary measures of past seasonal sea ice in the Arctic and Antarctic, respectively. A further tri-unsaturated HBI (generally referred to as HBI III) appears to provide proxy evidence for the region of open water found adjacent to sea ice (i.e. the marginal ice zone (MIZ)) in both polar regions. This review provides an update on current knowledge pertaining to each proxy. The first section focuses on describing those studies that have aimed to establish the underlying features of each proxy, including source identification and spatial distribution characteristics. The second section presents some important analytical considerations pertinent to the accurate identification and quantification of HBI biomarkers. The third section describes how each HBI proxy is normally interpreted within the sedimentary record for palaeo sea ice reconstruction purposes. This includes the interpretation of individual and combined biomarker profiles such as the PIP25 index and multivariate decision tree models. A summary of all previous palaeo sea ice reconstructions based on HBIs is also given, which includes examples that clarify or reinforce our understanding of the individual or combined biomarker signatures. Some knowledge gaps and areas for future research are also briefly described.

Benton, M.J., Bernardi, M., Kinsella, C., 2018. The Carnian Pluvial Episode and the origin of dinosaurs. Journal of the Geological Society 175, 1019.

http://jgs.lyellcollection.org/content/175/6/1019.abstract

We present new evidence for a major inflection point in the history of tetrapods on land, a jump in the diversification of archosauromorphs, primarily dinosaurs, at 232–230 Ma. This corresponds to a long-noted changeover in Triassic terrestrial tetrapod faunas from those dominated by synapsids, many of them holdovers from the Permian, to those dominated by dinosaurs. The dinosaur explosion is shown here to correspond in timing to the Carnian Pluvial Episode (CPE), dated at 232 Ma, a time of increased rainfall and perturbation of oceans and atmospheres, followed by substantial aridification. The rock record through the CPE confirms that this event shared many characters with other mass extinctions driven by eruption of large igneous provinces, in this case the Wrangellia flood basalts of the west coast of North America. If this was a catastrophic extinction event, then the environmental perturbations of the CPE explain the sharp disappearance of various terrestrial tetrapods, and the subsequent sharp rise of dinosaurs and perhaps other clades too, especially those that constitute much of the modern terrestrial faunas, such as lissamphibians, turtles, crocodiles, lizards and mammals.Supplementary material: The sampled tetrapod faunas, geological ages, and details of the R code method and results are available at https://doi.org/10.6084/m9.figshare.c.4111439

Bera, G., Parkerton, T., Redman, A., Turner, N.R., Renegar, D.A., Sericano, J.L., Knap, A.H., 2018. Passive dosing yields dissolved aqueous exposures of crude oil comparable to the CROSERF (Chemical Response to Oil Spill: Ecological Effects Research Forum) water accommodated fraction method. Environmental Toxicology and Chemistry 37, 2810-2819.

https://doi.org/10.1002/etc.4263

The Chemical Response to Oil Spill: Ecological Effects Research Forum's water accommodated fraction procedure was compared with 2 alternative techniques in which crude oil was passively dosed from silicone tubing or O‐rings. Fresh Macondo oil (MC252) was dosed at 30 mg/L using each approach to investigate oil dissolution kinetics, which was monitored by fluorometry as estimated oil equivalents (EOEs). Subsequent experiments with each dosing method were then conducted at multiple oil loadings. Following equilibration, test media were analytically characterized for polyaromatic hydrocarbons (PAHs) using gas chromatography (GC)–mass spectrometry and dissolved oil using biomimetic solid‐phase microextraction (SPME). The results showed that equilibrium was achieved within 72 h for all methods. Measured PAH concentrations were compared with oil solubility model predictions of dissolved exposures. The concentration and composition of measured and predicted dissolved PAHs varied with oil loading and were consistent between dosing methods. Two‐dimensional GC compositional data for this oil were then used to calculate dissolved toxic units for predicting MC252 oil acute toxicity across the expected range of species sensitivities. Predicted toxic units were nonlinear with loading and correlated to both EOE and biomimetic SPME. Passive dosing methods provide a practical strategy to deliver and maintain dissolved oil concentrations while avoiding the complicating role that droplets can introduce in exposure characterization and test interpretation.


https://doi.org/10.1029/2017GB005854

The global ocean contains a massive reservoir of dissolved organic carbon (DOC), rivaling the atmosphere's pool of CO2. The most recalcitrant fractions have mean radiocarbon ages of ~4,000 years in the Atlantic to ~6,000 years in the Pacific. Knowing the radiocarbon signatures of DOC and the molecular composition of dissolved organic matter (DOM) is crucial to develop understanding of

the persistence and lifetime of the DOC pool. In this research, we collected samples from the deep North Pacific in August 2013 (aboard the RV Melville) to couple the Δ14C content of solid‐phase‐extracted DOM (Δ14C‐SPE‐DOM) with its molecular composition in the ocean's oldest deep waters. We find that deep waters in this region held a mean Δ14C‐SPE‐DOM value of −554 ± 9‰ (~6,400 14C years), substantially more depleted than that in the deep Atlantic, which held a mean Δ14C‐SPE‐DOM value of −445 ± 5‰. While we find a more degraded molecular composition of DOM in the deep Pacific than the deep Atlantic, the molecular formulae within the Island of Stability (Lechtenfeld et al., 2014, https://doi.org/10.1016/j.gca.2013.11.009), are largely retained. These results imply that a fraction of deep DOM is resistant to removal and present in both the deep Atlantic and Pacific Oceans.

Berke, M.A., Cartagena Sierra, A., Bush, R., Cheah, D., O'Connor, K., 2019. Controls on leaf wax fractionation and δ2H values in tundra vascular plants from western Greenland. Geochimica et Cosmochimica Acta 244, 565-583.


Hydrogen isotope ratios of leaf waxes are used to reconstruct past hydroclimate because they are a reflection of meteoric water, but the interpretation of these signatures from ancient sedimentary archives relies on a thorough understanding of the drivers of modern isotope variability and controls on fractionation. These studies are particularly valuable in the high latitudes, regions especially vulnerable to rapid climate change and increasingly used for plant-based proxy reconstructions of past hydroclimate, but also where modern vegetation is understudied compared to the lower latitudes. Here we investigate δ2H values from leaf wax n-alkanes of vascular tundra plants in the Kangerlussuaq area of western Greenland. We collected a variety of common tundra species to study possible interspecies variability in δ2H values including dwarf shrubs (Betula nana, Empetrum hermaphroditum, Salix glauca), forbs and graminoids (Vaccinium uliginosum, Rhododendron tomentosum, and Calamagrostis lapponica), a horsetail species (Equisetum arvense), and a submerged aquatic macrophyte from a local lake (Stuckenia filiformis). Using previously measured leaf and stem waters to help constrain potential drivers of leaf wax n-alkane δ2H values, we find that the overall net fractionation (εapp) from the studied species is −75 ± 20‰. The εapp at Kangerlussuaq is consistent with other studies of Arctic vegetation that find smaller εapp than from the majority of lower latitude sites. The fractionation of leaf water and xylem water (ε lw/xw) and the fractionation of xylem water and precipitation (εxw/p) are both relatively constant, suggesting stable leaf and soil related fractionations across species. Estimates of biosynthetic fractionation (εbio), as evidenced from the fractionation of the δ2H values of n-alkanes and leaf water (εwax/lw), are not constant across species as sometimes assumed, and are small (average of εbio is −120 ± 27‰) compared to many published estimates. This supports a significant role in εbio shaping the εapp in this high latitude setting, where lipid biosynthesis may be driving differences in n-alkane δ2H values. This finding suggests that lipids in the Kangerlussuaq plants studied rely on the use of some proportion of different hydrogen sources during lipid synthesis, such as stored NADPH. The cumulative results of this survey of Kangerlussuaq area n-alkane δ2H values and water-wax fractionations suggest that fractionation in the high latitudes during the short summer growing season may play an important role in governing the small εapp compared to many low latitude sites. Better understanding of appropriate εapp and the importance of εbio in controlling plant wax fractionation from the high latitudes is necessary for future reconstructions of hydroclimate using leaf wax δ2H values in these regions.

Bernasconi, S.M., Müller, I.A., Bergmann, K.D., Breitenbach, S.F.M., Fernandez, A., Hodell, D.A., Jaggi, M., Meckler, A.N., Millan, I., Ziegler, M., 2018. Reducing uncertainties in carbonate clumped

isotope analysis through consistent carbonate-based standardization. Geochemistry, Geophysics, Geosystems 19, 2895-2914.

https://doi.org/10.1029/2017GC007385

Abstract About a decade after its introduction, the field of carbonate clumped isotope thermometry is rapidly expanding because of the large number of possible applications and its potential to solve long-standing questions in Earth Sciences. Major factors limiting the application of this method are the very high analytical precision required for meaningful interpretations, the relatively complex sample preparation procedures, and the mass spectrometric corrections needed. In this paper we first briefly review the evolution of the analytical and standardization procedures and discuss the major remaining sources of uncertainty. We propose that the use of carbonate standards to project the results to the carbon dioxide equilibrium scale can improve interlaboratory data comparability and help to solve long-standing discrepancies between laboratories and temperature calibrations. The use of carbonates reduces uncertainties related to gas preparation and cleaning procedures and ensures equal treatment of samples and standards. We present a set of carbonate standards of diverse composition, discuss how they can be used to correct for mass spectrometric biases, and demonstrate that their use significantly improves the comparability among four laboratories. We propose that the use of these standards or of a similar set of carbonate standards will improve the comparability of data across laboratories.

Betlem, P., Senger, K., Hodson, A., 2019. 3D thermobaric modelling of the gas hydrate stability zone onshore central Spitsbergen, Arctic Norway. Marine and Petroleum Geology 100, 246-262.


Dissociation of onshore natural gas hydrates (NGHs) could lead to the release of methane directly to the atmosphere, especially in Arctic regions such as Svalbard, where enhanced climate warming has the capacity to promote rapid methane evasion to the atmosphere following the decay of permafrost and glacier ice. Here we present the first assessment of the NGH stability zone (GHSZ) in central Spitsbergen, a climate-sensitive part of Svalbard where thermobaric conditions appear favourable for onshore NGH formation. We developed an approach incorporating regionally constrained 3-dimensional parameterisation of temperature, pressure and phase boundary (93% methane, 7% ethane, 35 ppt salinity) to define the GHSZ. This resulted in an up to 650 m thick (mean: 308 m) GHSZ covering 74.8% of the study area, thickening significantly in the east where the climate is colder. Perturbation of the base case parameters was undertaken to quantify the sensitivity of the GHSZ to the variation in environmental conditions across the study area. We present 26 examples of these deterministic scenarios and show that the largest changes in the GHSZ were observed when either the ethane content (to 20%) or the regional pore water pressure (to 125% hydrostatic) were increased. The GHSZ also increased markedly when the geothermal gradient was reduced from 33 to 26 °C km−1, but was almost completely inhibited by a dry gas (100% methane), greater salinity (50 ppt), or exposure to an increase in surface temperatures relative to the mean annual air temperature (e.g., by 2 °C). Most parameters affected both the upper and the lower stability boundary of the GHSZ, with the exception of the geothermal gradient, which impacted primarily upon the latter. Given that Svalbard is host to a proven petroleum system, we conclude that NGHs almost certainly exist onshore Svalbard.

Bialy, S., Loeb, A., 2018. Could solar radiation pressure explain 'Oumuamua's peculiar acceleration? arXiv:1810.11490v2 [astro-ph.EP].

https://arxiv.org/abs/1810.11490

'Oumuamua (1I/2017 U1) is the first object of interstellar origin observed in the Solar system.

Recently, Micheli et al. (2018) reported that 'Oumuamua showed deviations from a Keplerian orbit at a high statistical significance.

The observed trajectory is best explained by an excess radial acceleration Δa∝r −2 , where r is the distance of 'Oumuamua from the Sun. Such an acceleration is naturally expected for comets, driven by the evaporating material. However, recent observational and theoretical studies imply that 'Oumuamua is not an active comet. We explore the possibility that the excess acceleration results from Solar radiation pressure. The required mass-to-area ratio is m/A≈0.1 g cm −2 . For a thin sheet, this requires a width of w≈0.3−0.9 mm. We find that although extremely thin, such an object would survive an interstellar travel over Galactic distances of ∼5 kpc , withstanding collisions with gas and dust-grains as well as stresses from rotation and tidal forces. We discuss the possible origins of such an object including the possibility that it might be a lightsail of artificial origin. Our general results apply to any light probes designed for interstellar travel.

Bianchini, K., Morrissey, C.A., 2018. Assessment of shorebird migratory fueling physiology and departure timing in relation to polycyclic aromatic hydrocarbon contamination in the Gulf of Mexico. Environmental Science & Technology 52, 13562-13573.

https://doi.org/10.1021/acs.est.8b04571

Shorebirds depend on staging sites in the Gulf of Mexico that are frequently subject to pollution by oil and its toxic constituents, polycyclic aromatic hydrocarbons (PAHs). It was hypothesized that PAH contamination lowers staging site quality for migratory shorebirds, with consequences for fueling and departure timing. Sediment total PAH concentrations were measured at six staging sites along the Texas and Louisiana Gulf Coast. Sites in Louisiana were expected to have higher total PAH concentrations as they were more heavily impacted by the Deepwater Horizon oil spill. From 2015 to 2017, 165 Sanderling (Calidris alba) and 55 Red knots (C. canutus) were captured at these same sites during their northward migration (late April to mid May). Mass, body morphometrics, and plasma metabolite measurements were taken to determine fuel loads and fueling rates, and a subset of birds (120 Sanderling and 39 Red knots) received a coded radio tag to determine departure dates using the Motus telemetry array. Compared to Texas sites, sediment in Louisiana had higher total PAH concentrations, dominated by heavier 6 ring indeno[1,2,3-cd]pyrene (48%). Plasma metabolite profiles suggested that fueling rates for Sanderling, but not Red knots, tended to be lower in Louisiana, and both species departed later than the study average from Louisiana. However, multiple factors, including migration patterns, food supply, and other contaminants, also likely influenced fueling and departures. PAH contamination in the Gulf of Mexico remains an ongoing issue that may be impacting the staging site quality and migration timing of long-distance migratory birds.

Bindeman, I.N., Lee, J.E., 2018. The possibility of obtaining ultra-low-δ18O signature of precipitation near equatorial latitudes during the Snowball Earth glaciation episodes. Precambrian Research 319, 211-219.


Hydrothermally-altered rocks with ultra-low-δ18O and δD were discovered in Karelia, Russia, over 500 km along the Belomorian Belt of the Baltic Shield. The ages of low δ18O and δD values are 2.41 Ga and 2.29 Ga, corresponding to the first and third Paleoproterozoic Snowball earth glacial episodes.

Paleogeographic reconstruction suggests low latitudes for Baltica throughout Paleoproterozoic ice ages, requiring an effective distillation of water isotopes over short transport distances. Here we summarize how to use hydrothermally altered rocks to infer δ18O value of altering meteoric waters, then use an idealized General Circulation Model to test climate states with variable amount of ice cover and to check the hydrologic possibility of ultra-low-δ18O precipitation at low latitudes. Our model results suggest that the low δ18O values in precipitation is best achieved if the area of open water is quite narrow around the equator between latitudes 5°S and 5°N, or the Jormungand climate state. The δ18O of precipitation is high (>−15‰) over open water where high-δ18O vapor from ocean mixes with low-δ18O atmospheric water vapor. As such, a position of about 5–10° north or south of the equator is needed in order to achieve low δ18O of precipitation from an open water source. Our results suggest a slushball climate state with wide areas of open water is less likely to produce ultra-low-δ18O rocks for the low latitude position of Baltica.


http://www.ajsonline.org/content/318/8/861.abstract

Weathering, erosion, and redeposition of exhumed rock-derived or “petrogenic” organic carbon (OC) co-occurs with the burial of biospheric OC within sediments, modulating atmospheric CO2 and O2 over geologic time. Disentangling the geochemical fingerprint of petrogenic OC from biospheric OC in sedimentary organic matter, as well as quantifying the influence of its remineralization and burial on atmospheric CO2/O2, has been the focus of numerous observational and geochemical modeling studies. In 1938, Matti Sauramo recognized that petrogenic OC is entrained in a “simple carbon” cycle operating alongside the “complicated” greater rest of the carbon cycle. Sauramo's achievements were preceded by Charles Lyell's thoughts on the subject a century earlier, and by observations of reworked palynomorphs in the modern environment made by palynologists in the 19th Century. Towards the present, palynologists, organic petrologists, and geochemists have all made key advances, while their impact often did not radiate beyond their respective bodies of literature. This highlights the importance not only of further investigations focused on the continued pursuit of new information, but also on studies of the history of relevant disciplines in order to place new findings in appropriate context. Petrogenic OC cycling has emerged as a key process for constraining global carbon budgets, long-term biogeochemical cycles and associated variations in atmospheric chemistry. While petrogenic OC is now recognized as a significant component of bulk sedimentary OC in modern systems, its cycling throughout Earth's history - including during pivotal episodes such as supercontinent amalgamation and late Proterozoic Snowball Earth events followed by greenhouse conditions - remains largely unexplored.

Blattmann, T.M., Wessels, M., McIntyre, C.P., Eglinton, T.I., 2019. Petrogenic organic carbon retention in terrestrial basins: A case study from perialpine Lake Constance. Chemical Geology 503, 52-60.


Inland waters play a major role in the global carbon cycle, with particulate organic carbon (POC) burial in terrestrial wetlands surpassing that in ocean sediments. Lake Constance, the second largest lake at the periphery of the European Alps, receives POC sourced from both aquatic and terrestrial productivity as well as petrogenic OC (OCpetro) from bedrock erosion. Distinguishing POC inputs to lake sediments is key to assessing carbon flux and fate as reworked OCpetro represents neither a net sink of atmospheric CO2 nor source of O2. New stable and radiocarbon isotopic data indicate that 11 (9–12) Gg/yr of OCpetro is buried in Lake Constance with underlying sediments on average containing

0.3 (0.25–0.33) wt% OCpetro. Extrapolation of these results suggests that 27 TgOCpetro/yr (12–54 TgOC/yr) could be subject to temporary geological storage in lakes globally, which is comparable to estimates of 43−25+61 TgOCpetro/yr delivered to the ocean by rivers (Galy et al., 2015). More studies are needed to quantify OCpetro burial in inland sedimentary reservoirs in order to accurately account for atmospheric carbon sequestration in terrestrial basins.

Bobe, R., Carvalho, S., 2018. The decline of Africa's largest mammals. Science 362, 892-893.

http://science.sciencemag.org/content/362/6417/892.abstract

The human species is causing profound climatic, environmental, and biotic disruptions on a global scale. In the present time (now called the Anthropocene), most species of large terrestrial herbivores are threatened with extinction as their populations decline and their geographic ranges collapse under the pressure of human hunting, poaching, and encroachment (1). Although the scale of ongoing anthropogenic ecological disruptions is unprecedented, human-driven extinctions are not new: There is strong evidence that humans played a major role in the wave of megafaunal losses at the end of the Pleistocene, between about 10,000 and 50,000 years ago (2). But when did humans, or our ancestors, begin to have such a profound effect on large herbivores to the point of causing extinctions? On page 938 of this issue, Faith et al. (3) provide evidence to help answer this question. They track the number of megaherbivore species (mammals weighing more than 1000 kg) in eastern Africa from the late Miocene, about 7 million years ago, to the present. Their analysis indicates that megaherbivore diversity began to decline in the early Pliocene, about 4.6 million years ago.

Hominins—species on our side of the evolutionary divergence that separated us from the chimpanzees—first appeared in Africa in the late Miocene, about 7 million years ago. The late Miocene was a time of global climatic and environmental change, with an expansion of grasslands (with C4 photosynthesis) in tropical latitudes and an increasing frequency of fires (4). At that time, large mammals were abundant in eastern Africa. At Lothagam, for example, in the Turkana Basin of Kenya, there were 10 species of megaherbivores (5), including the earliest records of the elephant family, Elephantidae. Near Lothagam is the early Pliocene site of Kanapoi, with a rich fossil record dated to about 4.2 million years ago. Kanapoi has the earliest record of the hominin genus Australopithecus (6), which coexisted with at least 11 species of megaherbivores: five proboscideans, two rhinocerotids, two giraffids, and two hippopotamids, along with a diverse fauna of large carnivores that included giant otters, hyenas, two species of saber-tooth felids, and three species of crocodiles (7). Kanapoi, at about 4.2 million years ago, with an area of 32 km2, had twice the number of megaherbivore species as the entire continent of Africa has today. Among the five species of proboscideans, there were the ancestors of the modern African and Asian elephants, Loxodonta and Elephas, respectively. From their first appearance in eastern Africa, both elephants fed predominantly on increasingly abundant grasses (8). It is probable that these elephants and other megaherbivores played a beneficial role for early hominins by opening up wooded environments, thereby resulting in the mix of woodlands and grasslands where hominins seemed to thrive (5, 9). Thus, at Kanapoi and other sites in Africa during the Pliocene (5.3 to 2.6 million years ago) early hominins lived in proboscidean-dominated landscapes. These hominins were relatively small (∼45 kg) and left no known traces of tool-assisted behaviors. They were primarily terrestrial omnivores that used trees for refuge and food, and it is likely that they competed for resources with other mammals like suids and monkeys, but had little impact on megaherbivores. Moving forward in time from 4.2 million years ago to 1.5 million years ago, three hominin species, including Homo erectus, possibly Homo habilis, and Paranthropus boisei, inhabited another set of sites in the Turkana Basin. By then, hominins were procuring animal resources by using stone tools, as the abundant archaeological evidence makes clear, and they were probably beginning to use fire (10). There is no evidence of systematic hunting of very large mammals, so direct effects of hominins on megaherbivores were limited. But if

hominins were beginning to use fire 1.5 million years ago, what was the impact on the landscape and on the foraging patterns of the largest terrestrial mammals?

Early hominins in eastern Africa lived in a rapidly changing landscape, in which grasslands were becoming more prevalent, and a whole suite of grazing mammals were rapidly evolving and diversifying (11). Elephas was successfully adapting to these changing African landscapes during the Pleistocene when it became a dominant megaherbivore. But even this widely distributed and abundant grazer became extinct in Africa toward the late Pleistocene, surviving in Asia until today. Loxodonta became rare after the early Pliocene, only to reemerge in the middle and late Pleistocene as a browser and mixed-feeder rather than a grazer (8).

Faith et al. propose that expanding grasslands, declining concentrations of atmospheric CO2, and competition with smaller browsing mammals all contributed to the decline of megaherbivore species richness. However, it is not clear what ecological roles hominins played throughout the long evolutionary history of megaherbivores in Africa, and how these roles changed over time and varied across geographic space. Another question is when hominins became systematic predators of animals larger than themselves. Could periods of marked seasonality, with peaks of drought, result in a “fallback” predation strategy, whereby carnivores preyed heavily on proboscideans? As documented in modern African landscapes (12), predation on young, vulnerable individuals in species with very slow life histories could have irreparable effects on the long-term viability of megaherbivore populations. As fires became more frequent beginning in the late Miocene (4), they may have altered landscapes and affected the foraging, ranging patterns, and dispersal of large herbivores. Also, what new pathogens emerged with the new landscapes of eastern Africa and what was their effect in the oldest and youngest individuals within these large mammal populations? The causes of megaherbivore decline are probably complex, multidimensional, and varied across time and space. The precise timing of key hominin behavioral innovations remains poorly constrained by the current archaeological and paleontological records. Indeed, the role that hominins played is still open to question.

References1. W. J. Ripple et al., Sci. Adv. 1, e1400103 (2015). 2. C. Sandom, S. Faurby, B. Sandel, J.-C. Svenning, Proc. R. Soc. B 281, 20133254 (2014).3. J. T. Faith, J. Rowan, A. Du, P. L. Koch, Science 362, 938 (2018).4. W. J. Bond, Front. Plant Sci. 5, 749 (2015).5. L. Werdelin, W. J. Sanders, Eds., Cenozoic Mammals of Africa (Univ. California Press, Berkeley,

2010).6. C. V. Ward, J. M. Plavcan, F. K. Manthi, J. Hum. Evol. 10.1016/j.jhevol.2017.07.008

(2018).Google Scholar7. J. M. Harris, M. G. Leakey, Eds., Geology and Vertebrate Paleontology of the Early Pliocene Site

of Kanapoi, Northern Kenya (Natural History Museum of Los Angeles County, Los Angeles, 2003), vol. 498.

8. T. E. Cerling, J. M. Harris, M. G. Leakey, Oecologia 120, 364 (1999).9. J. Kingdon, in Mammals of Africa, J. Kingdon et al., Eds. (Bloomsbury, London, 2013), vol. 1,

pp. 75–100.10. G. L. Isaac, B. Isaac, Eds., Plio-Pleistocene Archaeology: Koobi Fora Research Project

(Clarendon, Oxford, 1997), vol. 5.11. T. E. Cerling et al., Proc. Natl. Acad. Sci. U.S.A. 112, 11467 (2015).12. A. J. Loveridge, J. E. Hunt, F. Murindagomo, D. W. Macdonald, J. Zool. (Lond.) 270, 523 (2006).

Boccadoro, C., Krolicka, A., Receveur, J., Aeppli, C., Le Floch, S., 2018. Microbial community response and migration of petroleum compounds during a sea-ice oil spill experiment in Svalbard. Marine Environmental Research 142, 214-233.


This paper concerns the migration of oil through sea-ice and the biodegradation of different hydrocarbons in sea-ice and seawater following in situ oil spills in megacosms exposed to winter and spring conditions in Svalbard (80°N). Hydrocarbon-degrading microbes were detected in ice cores and the analysis of metabolically active bacterial populations in the different layers of sea-ice indicate significant population shifts following oil exposure, whether dispersant addition or oil burning was carried out or not. The presence of dispersant in the system was associated with the most pronounced and fastest population shifts out of all exposures, as well as lower bacterial diversity as measured by the Shannon index. Microorganisms were metabolically most active in the bottom layer of the sea ice and our data confirmed the predominance of Oleispira and Colwellia aestuarii in sea-ice. Migration of polycyclic aromatics through the sea-ice layer was observed when dispersant was added to the oil, and the presence of oil degrading organisms below the ice-layer was consistent with biodegradation taking place. Given the thickness and concentration of the oil-layer frozen into the ice, the bioavailability of the hydrocarbons was nevertheless limited. Consequently, much of the bulk of the oil remained intact.


https://doi.org/10.1080/10916466.2018.1496104

Environmental pollution by crude oil during petroleum exploration is a global issue of concern. It largely alters the physicochemical property of soil and water which makes them toxic for crops and aquatic organisms to survive. Bacillus cereus strain DRDU1 (Genbank accession no. KF273330.1) is an endospore forming potential hydrocarbon degrader which was isolated from an automobile engine. The isolate could achieve up to 96 and 84% kerosene and crude oil degradation with respective cfu of (6.3 ± 2.31) × 109 and (13.67 ± 2.52) × 108 cells/mL. On the other hand it also showed its potential to degrade 74 and 67% of kerosene and crude oil in nitrate (N) and phosphate (P) deficient media with corresponding cfu (10 ± 1.73) × 108 and (6 ± 2.65) × 106 cells/mL. This indicates its potential to survive under nutrient stress condition. The strain was reported to be capable of producing biosurfactant which may play role in petroleum biodegradation and may be a potential tool for Microbial Enhanced Oil Recovery (MEOR) studies in future. Herein the presence of sfp gene in the isolate was confirmed which may be responsible for its ability to synthesize biosurfactant for hydrocarbon degradation and also for its stress tolerant potential. It was further characterized and the hypothetical protein sequence encoded by this gene is also proposed.



Transmission Electron Microscopy Tomography (TEMT) stands as a novel and alternative tool to tridimensionally model the nano-scale pores of rocks. In this study it is flanked with traditional Mercury Capillary Injection Porosimetry (MICP), Nitrogen adsorption Porosimetry (NP) and

Scanning Electron Microscopy (SEM) analysis, to test a sample belonging to an Upper Triassic doloston cropping out in Northern Calabria.

MICP revealed low values of porosity and permeability, 2.3% and the 0.11 mD respectively. Nanopores account for the 94% of the pore volume, whereas the remaining 6% is represented by micropores. The integrated MICP and NP pore size distribution (PSD) shows the presence of a dominant pore diameter population coincident with 50 nm, with minor peaks at diameters of 12 μm, 850, 25, 13, 6, 2 nm. However, since the PSD peaks of the two techniques do not match, a comparison of the two curves is necessary to better characterized the overlapping area.

SEM imaging analysis showed the presence of nano-scale intercrystalline and intracrystalline pores. The first corresponds with the spaces among dolomite crystals and, as suggested by the NP analysis, shows a wedge/slit morphology. The second appears with a prevailing polygonal section or as tight microfractures. Since SEM provides exclusively two-dimensional images, the morphology and development of these pores was obtained through TEMT 3D reconstruction.

The 3D model showed the presence of open cavities, fractures and blind/isolated pores. Cavities cross the entire dolomite crystals and can present a constant (sub-prismatic pores) or variable channel section (funnel-shaped pores) that can reduce its aperture, as observed, of also more than a ten factor (e.g. from 300 nm to 20 nm). Fractures, commonly developing on the existing cleavage surfaces, cut the crystal faces for 300–350 nm, reducing its aperture (maximum of 20–30 nm) from the edge towards the inner part of the crystal. Lastly, blind/isolated pores can assume diameters and thickness of 250 nm. They show a sub-cubic morphology and, can be filled by solid, liquid or gaseous inclusions.

Bravo, A.G., Peura, S., Buck, M., Ahmed, O., Mateos-Rivera, A., Herrero Ortega, S., Schaefer, J.K., Bouchet, S., Tolu, J., Björn, E., Bertilsson, S., 2018. Methanogens and iron-reducing bacteria: The overlooked members of mercury-methylating microbial communities in boreal lakes. Applied and Environmental Microbiology 84, Article e01774-18.

http://aem.asm.org/content/84/23/e01774-18.abstract

Abstract: Methylmercury is a potent human neurotoxin which biomagnifies in aquatic food webs. Although anaerobic microorganisms containing the hgcA gene potentially mediate the formation of methylmercury in natural environments, the diversity of these mercury-methylating microbial communities remains largely unexplored. Previous studies have implicated sulfate-reducing bacteria as the main mercury methylators in aquatic ecosystems. In the present study, we characterized the diversity of mercury-methylating microbial communities of boreal lake sediments using high-throughput sequencing of 16S rRNA and hgcA genes. Our results show that in the lake sediments, Methanomicrobiales and Geobacteraceae also represent abundant members of the mercury-methylating communities. In fact, incubation experiments with a mercury isotopic tracer and molybdate revealed that only between 38% and 45% of mercury methylation was attributed to sulfate reduction. These results suggest that methanogens and iron-reducing bacteria may contribute to more than half of the mercury methylation in boreal lakes.

Importance: Despite the global awareness that mercury, and methylmercury in particular, is a neurotoxin to which millions of people continue to be exposed, there are sizable gaps in the understanding of the processes and organisms involved in methylmercury formation in aquatic ecosystems. In the present study, we shed light on the diversity of the microorganisms responsible for methylmercury formation in boreal lake sediments. All the microorganisms identified are associated with the processing of organic matter in aquatic systems. Moreover, our results show that the well-

known mercury-methylating sulfate-reducing bacteria constituted only a minor portion of the potential mercury methylators. In contrast, methanogens and iron-reducing bacteria were important contributors to methylmercury formation, highlighting their role in mercury cycling in the environment.

Bray, M.S., Lenz, T.K., Haynes, J.W., Bowman, J.C., Petrov, A.S., Reddi, A.R., Hud, N.V., Williams, L.D., Glass, J.B., 2018. Multiple prebiotic metals mediate translation. Proceedings of the National Academy of Sciences 115, 12164-12169.

https://doi.org/10.1073/pnas.1803636115

Significance: Ribosomes are found in every living organism, where they are responsible for the translation of messenger RNA into protein. The ribosome’s centrality to cell function is underscored by its evolutionary conservation; the core structure has changed little since its inception ∼4 billion years ago when ecosystems were anoxic and metal-rich. The ribosome is a model system for the study of bioinorganic chemistry, owing to the many highly coordinated divalent metal cations that are essential to its function. We studied the structure, function, and cation content of the ribosome under early Earth conditions (low O2, high Fe2+, and high Mn2+). Our results expand the roles of Fe2+ and Mn2+ in ancient and extant biochemistry as cofactors for ribosomal structure and function.

Abstract: Today, Mg2+ is an essential cofactor with diverse structural and functional roles in life’s oldest macromolecular machine, the translation system. We tested whether ancient Earth conditions (low O2, high Fe2+, and high Mn2+) can revert the ribosome to a functional ancestral state. First, SHAPE (selective 2′-hydroxyl acylation analyzed by primer extension) was used to compare the effect of Mg2+, Fe2+, and Mn2+ on the tertiary structure of rRNA. Then, we used in vitro translation reactions to test whether Fe2+ or Mn2+ could mediate protein production, and quantified ribosomal metal content. We found that (i) Mg2+, Fe2+, and Mn2+ had strikingly similar effects on rRNA folding; (ii) Fe2+ and Mn2+ can replace Mg2+ as the dominant divalent cation during translation of mRNA to functional protein; and (iii) Fe and Mn associate extensively with the ribosome. Given that the translation system originated and matured when Fe2+ and Mn2+ were abundant, these findings suggest that Fe2+ and Mn2+ played a role in early ribosomal evolution.

Brezinski, K., Gorczyca, B., 2019. An overview of the uses of high performance size exclusion chromatography (HPSEC) in the characterization of natural organic matter (NOM) in potable water, and ion-exchange applications. Chemosphere 217, 122-139.


Natural organic matter (NOM) constitutes the terrestrial and aquatic sources of organic plant like material found in water bodies. As of recently, an ever-increasing amount of effort is being put towards developing better ways of unraveling the heterogeneous nature of NOM. This is important as NOM is responsible for a wide variety of both direct and indirect effects: ranging from aesthetic concerns related to taste and odor, to issues related to disinfection by-product formation and metal mobility. A better understanding of NOM can also provide a better appreciation for treatment design; lending a further understanding of potable water treatment impacts on specific fractions and constituents of NOM. The use of high performance size-exclusion chromatography has shown a growing promise in its various applications for NOM characterization, through the ability to partition ultraviolet absorbing moieties into ill-defined groups of humic acids, hydrolysates of humics, and low molecular weight acids. HPSEC also has the ability of simultaneously measuring absorbance in the UV–visible range (200–350 nm); further providing a spectroscopic fingerprint that is simply

unavailable using surrogate measurements of NOM, such as total organic carbon (TOC), ultraviolet absorbance at 254 nm (UV254), excitation-emission matrices (EEM), and specific ultraviolet absorbance at 254 nm (SUVA254). This review mainly focuses on the use of HPSEC in the characterization of NOM in a potable water setting, with an additional focus on strong-base ion-exchangers specifically targeted for NOM constituents.

Briggs, D.E.G., Liu, H.P., McKay, R.M., Witzke, B.J., 2018. The Winneshiek biota: exceptionally well-preserved fossils in a Middle Ordovician impact crater. Journal of the Geological Society 175, 865.


The Winneshiek Shale (Middle Ordovician, Darriwilian) was deposited in a meteorite crater, the Decorah impact structure, in NE Iowa. This crater is 5.6 km in diameter and penetrates Cambrian and Ordovician cratonic strata. It was probably situated close to land in an embayment connected to the epicontinental sea; typical shelly marine taxa are absent. The Konservat-Lagerstätte within the Winneshiek Shale is important because it represents an interval when exceptional preservation is rare. The biota includes the earliest eurypterid, a giant form, as well as a new basal chelicerate and the earliest ceratiocarid phyllocarid. Conodonts, some of giant size, occur as bedding plane assemblages. Bromalites and rarer elements, including a linguloid brachiopod and a probable jawless fish, are also present. Similar fossils occur in the coeval Ames impact structure in Oklahoma, demonstrating that meteorite craters represent a novel and under-recognized setting for Konservat-Lagerstätten.

Broecker, W., 2018. CO2: Earth’s climate driver. Geochemical Perspectives 7, 117-196.

http://www.geochemicalperspectives.org/online/v7n2

As we struggle to cope with the ongoing buildup of CO2 produced by burning fossil fuels, can we acquire guidance from the geologic record? Although our ability to reconstruct past atmospheric CO2 content reliably is currently confined to the last 800 thousand years, we do have compelling evidence that this greenhouse gas played a key role throughout the Earth’s history. It certainly compensated for the young Sun’s lower luminosity. There is no question that it bailed us out of two snowball episodes or that it led to a brief 5 °C warming at the onset of the Eocene. Less certain is that diminishing atmospheric CO2 content was responsible for the global cooling that began 50 million years ago when the Indian subcontinent collided with Asia. Finally, it colluded with changing seasonality, ocean circulation re-organisation and iron fertilisation to generate the 100 thousand year glacial cycles that dominated the last half-million years.

Buchanan, P.J., Matear, R.J., Chase, Z., Phipps, S.J., Bindoff, N.L., 2018. Ocean carbon and nitrogen isotopes in CSIRO Mk3L-COAL version 1.0: A tool for palaeoceanographic research. Geoscientific Model Development Discussions 2018, 1-44.

https://www.geosci-model-dev-discuss.net/gmd-2018-225/

The isotopes of carbon (δ13C) and nitrogen (δ15N) are commonly used proxies for understanding the ocean. When used in tandem, they provide powerful insight into physical and biogeochemical processes. Here, we detail the implementation of δ13C and δ15N in the ocean component of an Earth system model. We evaluate our simulated δ13C and δ15N against contemporary measurements, place the model's performance alongside other isotope enabled models, and document the response of δ13C and δ15N to changes in ecosystem functioning. The model combines the Commonwealth Scientific and Industrial Research Organisation Mark 3L (CSIRO Mk3L) climate system model with the

Carbon of the Ocean, Atmosphere and Land (COAL) biogeochemical model. The oceanic component of CSIRO Mk3L-COAL has a resolution of 1.6° latitude × 2.8° longitude and resolves multi-millennial timescales, running at a rate of ∼400 years per day. We show that this coarse resolution, computationally efficient model adequately reproduces water column and coretop δ13C and δ15N measurements, making it a useful tool for palaeoceanographic research. Changes to ecosystem function involve varying phytoplankton stoichiometry, varying CaCO3 production based on calcite saturation state, and varying N2 fixation via iron limitation. We find that large changes in CaCO3 production have little effect on δ13C and δ15N, while changes in N2 fixation and phytoplankton stoichiometry have substantial and complex effects. Interpretations of palaeoceanographic records are therefore open to multiple lines of interpretation where multiple processes imprint on the isotopic signature, such as in the tropics where denitrification, N2 fixation and nutrient utilisation influence δ15N. Hence, there is significant scope for isotope enabled models to provide more robust interpretations of the proxy records.

Byerly, B.L., Lowe, D.R., Drabon, N., Coble, M.A., Burns, D.H., Byerly, G.R., 2018. Hadean zircon from a 3.3 Ga sandstone, Barberton greenstone belt, South Africa. Geology 46, 967-970.

http://dx.doi.org/10.1130/G45276.1

Hadean zircons hold the promise of providing a rare window into the crustal development and surface evolution of early Earth. To date, the only known sources of abundant Hadean zircons are sedimentary units in the Jack Hills and Mount Narryer regions of Western Australia. Here we describe a sedimentary layer, termed the Green Sandstone Bed, dated at ca. 3306 Ma, in the Barberton greenstone belt, South Africa, that contains abundant zircons ranging from 3300 to 4100 Ma, many of which predate the oldest known rocks in the greenstone belt at ca. 3550 Ma. This adds to a very small number of known Hadean zircon-bearing localities and is particularly important due to its low degree of thermal metamorphism (lower greenschist facies) and negligible strain. There is a high probability that primary mineral compositions of zircon and other heavy minerals present in this bed are well preserved.



Microplastics (MPs, <5 mm) have been reported as emerging environmental contaminants, but reliable data are still lacking. We compared the two most promising techniques for MP analysis, namely, Raman and Fourier transform infrared (FTIR) spectroscopy, by analyzing MPs extracted from North Sea surface waters. Microplastics >500 μm were visually sorted and manually analyzed by μ-Raman and attenuated total reflection (ATR)-FTIR spectroscopy. Microplastics ≤500 μm were concentrated on gold-coated filters and analyzed by automated single-particle exploration coupled to μ-Raman (ASPEx-μ-Raman) and FTIR imaging (reflection mode). The number of identified MPs >500 μm was slightly higher for μ-Raman (+23%) than ATR-FTIR analysis. Concerning MPs ≤500 μm, ASPEx-μ-Raman quantified two-times higher MP numbers but required a four-times higher analysis time compared to FTIR imaging. Because ASPEx-μ-Raman revealed far higher MP concentrations (38–2621 particles m–3) compared to the results of previous water studies (0–559 particles m–3), the environmental concentration of MPs ≤500 μm may have been underestimated until now. This may be attributed to the exceptional increase in concentration with decreasing MP

size found in this work. Our results demonstrate the need for further research to enable time-efficient routine application of ASPEx-μ-Raman for reliable MP counting down to 1 μm.



Faecal sterols and stable isotopes (δ13C and δ15N) from bulk organic matter (OM) were analysed in three sedimentary cores collected in two subtropical bays located in the South Atlantic to evaluate historical trends in the sewage input and to track possible changes in the bulk isotopic composition of OM in recent decades. The values of δ13C and δ15N ranged from −27.4 to −25.0‰ and from 0.5 to 3.9‰, respectively, without a clear trend in the variation over the whole period covered by sediment cores and with no conclusive interpretation of a specific range value typically related to the sewage input for these areas. The maximum coprostanol concentration was 0.19 μg g−1 in the upper 4 cm of one core, which was not considered contaminated by evaluation of the sterols diagnostic ratios. Even at low levels, the coprostanol concentrations followed variations in urban and economical regional development. Baseline values for faecal sterols (in average between 0.03 and 0.05 μg g−1), which may represent a previous non-impacted environment scenarios, were calculated for use in comparative perspectives for future evaluations of the sewage input and contamination.



Oily wastewater is a large waste stream produced by a number of industries. This wastewater often forms stable oil-in-water (O/W) emulsion. These emulsions require demulsification in order to effectively treat the water prior to release. Although biological demulsification of O/W emulsion has advantages over traditional approaches, its development is at a preliminary stage with few demulsifying bacteria reported and a need for effective screening methods for such bacteria. In this study, thirty-seven marine O/W emulsion demulsifying bacterial strains belonging to 5 genera and 15 species were reported. Cell hydrophobicity and interfacial activity played key roles in the emulsion breaking. One of the highly effective demulsifying bacteria, Halomonas venusta strain N3-2A was identified and characterized. Both its extracellular biosurfactant and cell surface contributed to demulsification resulting in breaking of 92.5% of the emulsion within 24 h. A high throughput and effective screening strategy targeting O/W emulsion breaking bacteria using oil spreading test coupled with cell hydrophobicity test was proposed. In addition, the 37 demulsifying bacteria showed a certain degree of species/genus specific patterns of surface activity and cell hydrophobicity. The reported bacteria and the screening strategy have promising potential for the biological demulsification of O/W emulsions and oily wastewater treatment.

Caniani, D., Calace, S., Mazzone, G., Caivano, M., Mancini, I.M., Greco, M., Masi, S., 2018. Removal of hydrocarbons from contaminated soils by using a thermally expanded graphite sorbent. Bulletin of Environmental Contamination and Toxicology 101, 698-704.

https://doi.org/10.1007/s00128-018-2395-4

Lab-scale experiments on three soil matrices featured by increasing granulometry (sea sand, silica sand and gravel) were carried out in order to evaluate the adsorption capability and the removal efficiency of a new graphene-based material. Soil samples, firstly contaminated with different quantities of used lubricant oil up to final concentrations of 12.5, 25.0, 50.0 g kg−1, were treated with an opportune amount of thermally expanded graphite (TEG) (i.e. 1/10, 1/20, 1/40 as TEG/pollutant ratio). Results show that the removal efficiency of TEG is directly correlated to the contamination level of the soil. The best removal efficiency (87.04%) was obtained during the treatment of gravel samples at the maximum contamination level by using the highest dosage of TEG. A good removal efficiency (80.83%) was also achieved using lower TEG/pollutant ratio. Moreover, TEG at ratio 1/10 showed worse removal efficiencies in treating sea (81.17%) and silica sand (63.52%) than gravel. In this study, also the thermal regeneration was investigated in order to evaluate a possible reuse of TEG with subsequent technical and economic advantages. TEG-technique proves to be technologically and economically competitive with other currently used technologies, revealing the best choice for the remediation of hydrocarbon-contaminated soils.

Cao, S., Na, G., Li, R., Ge, L., Gao, H., Jin, S., Hou, C., Gao, Y., Zhang, Z., 2018. Fate and deposition of polycyclic aromatic hydrocarbons in the Bransfield Strait, Antarctica. Marine Pollution Bulletin 137, 533-541.


Fifteen polycyclic aromatic hydrocarbons (PAHs) were detected in seawater and atmosphere of Bransfield Strait. The concentration of ∑15[PAH] in the atmosphere ranged from 3.75 to 8.53 ng m−3, and three-ring PAHs were the most abundant compounds. Dissolved ∑15[PAH] in seawater ranged from 5.42 to 34.37 ng L−1, and the level of PAHs was markedly different on each side of the strait. The air–sea gas exchange process and molecular diagnostic ratios were calculated, results showed that the environmental behavior of PAHs was net deposition along this cruise. Given the changes in global transport routes of pollutants under global warming, the role of long-range transport (LRT) may be enhanced. Taking the Antarctic as a sink of PAHs due to the LRT and net deposition, PAHs will continue to load into the seawater of this area via atmospheric deposition, which contributes to improving our understanding of the environmental behavior of PAHs.



The Permian shale reservoir in southern Anhui province, East China is regarded as a promising target for shale gas exploration. In order to investigate the characteristics of shale pore structures and their controlling factors, total organic carbon (TOC), Rock-eval, organic petrology, X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), nitrogen gas adsorption (N2GA), mercury intrusion porosimetry (MIP) and helium pycnometry were conducted on the Permian shales collected from two shale gas parameter wells. The results indicate that the BET surface areas determined by N2GA method vary between 1.05 and 49.25 m2/g. The porosities derived from MIP and helium pycnometry tests are in the range of 0.68%–8.9% and 1.15%–9.79%, respectively. FE-SEM reveals that organic matter (OM) pores and cracks are well developed in the Permian shales, though some OM grains contain few pores, which might be related to the maceral composition. At a high maturity stage, vitrinite do not develop secondary OM pores, and sapropelinite generally develop abundant OM pores. However, solid bitumen occupies

interparticle space between minerals grains, and generally contains a small amount of pores documented in studied samples. The TOC contents have a positive relationship with the BET surface areas, suggesting OM is a primary factor in micropore and fine mesopore (<10 nm) development. TOC content has a positive relationship with porosity for samples with TOC<6.16%, but samples with TOC>6.16% usually have a low porosity probably due to compaction and/or different organic fractions. Residual bitumen (S1) is weakly and negatively correlated with Hg-porosity, due to residual bitumen filling in OM and mineral pores and reducing the total porosity. In addition, BET surface area decreases with increasing clay mineral content and Hg-porosity decreases with increasing quartz content, illustrating that clay mineral is unfavorable to the development of micropores and fine mesopores and high content of quartz may reduce macropore space. Finally, the shales of the Gufeng and Dalong Formations display a higher TOC content and a better physical property than the Longtan Formation shales and appear to be superior prospective shale gas exploration potential.

Carlson, K., Bement, L.C., Carter, B.J., Culleton, B.J., Kennett, D.J., 2018. A Younger Dryas signature in bison bone stable isotopes from the southern Plains of North America. Journal of Archaeological Science: Reports 21, 1259-1265.


Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios from bison bone collagen recovered from Paleoindian bison kill sites provide a record of the B/A, YD, and EH climates in the North American southern Plains. This record is compared to the stable C isotopes derived from previously published, dated paleosols from the region. Together these data sources define a local response of the southern Plains grassland structure to the changing climatic conditions, specifically temperature and precipitation, during the Pleistocene/Holocene transition, including a Clovis drought and late Folsom warmup and drying.

Carmody, S., Davis, J., Tadi, S., Sharp, J.S., Hunt, R.K., Russ, J., 2018. Evidence of tobacco from a Late Archaic smoking tube recovered from the Flint River site in southeastern North America. Journal of Archaeological Science: Reports 21, 904-910.


Tobacco use was widespread amongst the indigenous populations throughout North and South America prior to European contact; however, the geographical and temporal spread of the plant is poorly understood. Organic residue analysis is providing a new source of information on the diffusion of tobacco based on the presence of nicotine extracted from smoking pipes recovered from archaeological contexts. Using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) we identified nicotine in a Late Archaic (1685-1530 cal B.C) smoking pipe from the Flint River site in Northern Alabama. This evidence suggests the exploitation of tobacco spread into the southeastern North America nearly a millennium earlier than the current hypothesis on the rate of dispersion of tobacco in pre-Columbian North America.

Carraro, L., Hartikainen, H., Jokela, J., Bertuzzo, E., Rinaldo, A., 2018. Estimating species distribution and abundance in river networks using environmental DNA. Proceedings of the National Academy of Sciences 115, 11724-11729.


Significance: Organisms leave traces of DNA in their environment [environmental DNA (eDNA)], such as cells in mucus or feces. When extracted from water or soil, eDNA can be used to track the presence of a target species or the composition of entire communities. In rivers, eDNA dynamics are modulated by transport and decay. Here, we use hydrologically based models to reconstruct the upstream distribution and abundance of target species throughout a river network from eDNA measurements. We validate our method by estimating the catchment-wide biomass distribution of a sessile invertebrate and its parasite, causing disease in salmonids. This work unlocks the power of eDNA for monitoring biodiversity across broad geographies in a way hitherto unfeasible with traditional survey approaches.

Abstract: All organisms leave traces of DNA in their environment. This environmental DNA (eDNA) is often used to track occurrence patterns of target species. Applications are especially promising in rivers, where eDNA can integrate information about populations upstream. The dispersion of eDNA in rivers is modulated by complex processes of transport and decay through the dendritic river network, and we currently lack a method to extract quantitative information about the location and density of populations contributing to the eDNA signal. Here, we present a general framework to reconstruct the upstream distribution and abundance of a target species across a river network, based on observed eDNA concentrations and hydro-geomorphological features of the network. The model captures well the catchment-wide spatial biomass distribution of two target species: a sessile invertebrate (the bryozoan Fredericella sultana) and its parasite (the myxozoan Tetracapsuloides bryosalmonae). Our method is designed to easily integrate general biological and hydrological data and to enable spatially explicit estimates of the distribution of sessile and mobile species in fluvial ecosystems based on eDNA sampling.


https://www.clim-past.net/14/1819/2018/

Although it has long been assumed that the glacial–interglacial cycles of atmospheric CO2 occurred due to increased storage of CO2 in the ocean, with no change in the size of the active carbon inventory, there are signs that the geological CO2 supply rate to the active pool varied significantly. The resulting changes of the carbon inventory cannot be assessed without constraining the rate of carbon removal from the system, which largely occurs in marine sediments. The oceanic supply of alkalinity is also removed by the burial of calcium carbonate in marine sediments, which plays a major role in air–sea partitioning of the active carbon inventory. Here, we present the first global reconstruction of carbon and alkalinity burial in deep-sea sediments over the last glacial cycle. Although subject to large uncertainties, the reconstruction provides a first-order constraint on the effects of changes in deep-sea burial fluxes on global carbon and alkalinity inventories over the last glacial cycle. The results suggest that reduced burial of carbonate in the Atlantic Ocean was not entirely compensated by the increased burial in the Pacific basin during the last glacial period, which would have caused a gradual buildup of alkalinity in the ocean. We also consider the magnitude of possible changes in the larger but poorly constrained rates of burial on continental shelves, and show that these could have been significantly larger than the deep-sea burial changes. The burial-driven inventory variations are sufficiently large to have significantly altered the δ13C of the ocean–atmosphere carbon and changed the average dissolved inorganic carbon (DIC) and alkalinity concentrations of the ocean by more than 100µM, confirming that carbon burial fluxes were a dynamic, interactive component of the glacial cycles that significantly modified the size of the active

carbon pool. Our results also suggest that geological sources and sinks were significantly unbalanced during the late Holocene, leading to a slow net removal flux on the order of 0.1PgCyr−1 prior to the rapid input of carbon during the industrial period.

Caruthers, A.H., Gröcke, D.R., Kaczmarek, S.E., Rine, M.J., Kuglitsch, J., Harrison III, W.B., 2018. Utility of organic carbon isotope data from the Salina Group halite (Michigan Basin): A new tool for stratigraphic correlation and paleoclimate proxy resource. GSA Bulletin 130, 1782-1790.

http://dx.doi.org/10.1130/B31972.1

Long-term global carbon isotope records (δ13Ccarb and δ13Corg) for the Silurian have been largely derived from unrestricted open-marine carbonates and shales. Here, we demonstrate how organic carbon harvested from halite-dominated evaporite deposits in a restricted intracratonic basin can be used to produce a carbon isotope record. Inorganic and organic carbon isotope data were generated and compared from four subsurface cores from the Silurian Michigan Basin, representing unrestricted carbonate and restricted evaporite/carbonate deposition. The δ13Ccarb and δ13Corg records exhibit a number of long-term trends and major carbon isotope excursions (CIE) that are correlated with the globally identified Ireviken, Mulde, and Linde events. These data provide temporal and stratigraphic constraints in rocks where paleontological data are sparse or absent. They also potentially highlight the effect of enhanced local evaporation on isotope fractionation. This new technique for generating a long-term organic carbon isotope profile from Silurian halite sequences, which can be correlated to the global curve, is of broad interest to the geoscience and paleoclimate science communities. These data not only provide a valuable tool for understanding the chronostratigraphic framework within an evaporative interior basin, but they also provide a rare temporal link between periods of prolonged evaporite deposition and events of known paleoclimate change.



The atmosphere–land–ocean dynamics of semivolatile organic compounds in polar regions is poorly understood, also for the abundant and ubiquitous polycyclic aromatic hydrocarbons (PAHs). We report the concentrations and fluxes of PAHs in a polar coastal ecosystem (Livingston Island, Antarctica). From late spring (December 2014) to late summer (February 2015), we sampled air, snow, coastal seawater, plankton, and the fugacity in soils and snow. The concentrations of PAHs in seawater were low but increased during the austral summer. The PAH concentrations in snow were significantly higher than in coastal seawater. Soil–air fugacity ratios showed a net volatilization of PAH when soils were covered with lichens, and close to air–soil equilibrium for bare soils. Concentrations in surface snow were also close to equilibrium with atmospheric PAHs. Conversely, there was a net diffusive deposition of PAHs to coastal seawater during late spring, but a net volatilization from seawater during late summer. Volatilization fluxes were correlated with seawater temperature and salinity, consistent with a key role of snowmelt to the fluxes and dissolved phase concentrations during the austral summer. The comprehensive assessment provided here shows that the fugacity amplification in snow is transferred to soils and coastal seawater supporting PAH concentrations and fluxes.

Cassarino, L., Coath, C.D., Xavier, J.R., Hendry, K.R., 2018. Silicon isotopes of deep sea sponges: new insights into biomineralisation and skeletal structure. Biogeosciences 15, 6959-6977.


The silicon isotopic composition (δ30Si) of deep sea sponges' skeletal element – spicules – reflects the silicic acid (DSi) concentration of their surrounding water and can be used as natural archives of bottom water nutrients. In order to reconstruct the past silica cycle robustly, it is essential to better constrain the mechanisms of biosilicification, which are not yet well understood. Here, we show that the apparent isotopic fractionation (δ30Si) during spicule formation in deep sea sponges from the equatorial Atlantic ranges from −6.74‰ to −1.50‰ in relatively low DSi concentrations (15 to 35µM). The wide range in isotopic composition highlights the potential difference in silicification mechanism between the two major classes, Demospongiae and Hexactinellida. We find the anomalies in the isotopic fractionation correlate with skeletal morphology, whereby fused framework structures, characterised by secondary silicification, exhibit extremely light δ30Si signatures compared with previous studies. Our results provide insight into the processes involved during silica deposition and indicate that reliable reconstructions of past DSi can only be obtained using silicon isotope ratios derived from sponges with certain spicule types.

Catalán, N., Casas-Ruiz, J.P., Arce, M.I., Abril, M., Bravo, A.G., Campo, R., Estévez, E., Freixa, A., Giménez-Grau, P., González-Ferreras, A.M., Gómez-Gener, L., Lupon, A., Martínez, A., Palacin-Lizarbe, C., Poblador, S., Rasines-Ladero, R., Reyes, M., Rodríguez-Castillo, T., Rodríguez-Lozano, P., Sanpera-Calbet, I., Tornero, I., Pastor, A., 2018. Behind the scenes: Mechanisms regulating climatic patterns of dissolved organic carbon uptake in headwater streams. Global Biogeochemical Cycles 32, 1528-1541.

https://doi.org/10.1029/2018GB005919

Large variability in dissolved organic carbon (DOC) uptake rates has been reported for headwater streams, but the causes of this variability are still not well understood. Here we assessed acetate uptake rates across 11 European streams comprising different ecoregions by using whole‐reach pulse acetate additions. We evaluated the main climatic and biogeochemical drivers of acetate uptake during two seasonal periods. Our results show a minor influence of sampling periods but a strong effect of climate and dissolved organic matter (DOM) composition on acetate uptake. In particular, mean annual precipitation explained half of the variability of the acetate uptake velocities (VfAcetate) across streams. Temperate streams presented the lowest VfAcetate, together with humic‐like DOM and the highest stream respiration rates. In contrast, higher VfAcetate were found in semiarid streams, with protein‐like DOM, indicating a dominance of reactive, labile compounds. This, together with lower stream respiration rates and molar ratios of DOC to nitrate, suggests a strong C limitation in semiarid streams, likely due to reduced inputs from the catchment. Overall, this study highlights the interplay of climate and DOM composition and its relevance to understand the biogeochemical mechanisms controlling DOC uptake in streams.

Plain Language Summary. Headwater streams receive and degrade organic carbon and nutrients from the surrounding catchments. That degradation can be assessed by measuring the uptake of simple compounds of carbon or nitrogen such as acetate or nitrate. Here we determine the variability in acetate and nitrate uptake rates across headwater streams and elucidate the mechanisms behind that variability. The balance between nutrients, the composition of the organic materials present in the streams, and the climatic background is at interplay.

Cawood, P.A., Zhao, G., Yao, J., Wang, W., Xu, Y., Wang, Y., 2018. Reconstructing South China in Phanerozoic and Precambrian supercontinents. Earth-Science Reviews 186, 173-194.


The history of the South China Craton and the constituent Yangtze and Cathaysia blocks are directly linked to Earth's Phanerozoic and Precambrian record of supercontinent assembly and dispersal. Exposed Archean rocks are limited to isolated fragments in the Yangtze Block that preserve a record of Meso- to Neo-Archean magmatism, sedimentation and metamorphism associated with a period of global craton formation and stabilization that corresponds with the assembly of the Kenor supercontinent/supercraton. However, there are insufficient data to link its history with other similar aged cratons. The tectonostratigraphic record in South China in the Paleoproterozoic, corresponding with the assembly of Nuna, suggests that rock units in the Yangtze Block were spatially linked with northwestern Laurentia and possibly Siberia, whereas Cathaysia was joined to northern India. During the formation of Rodinia at the end of the Mesoproterozoic through to that of Pangea in the mid-Paleozoic, Cathaysia remained joined to northern India. Early Neoproterozoic supra-subduction zone magmatic arc-back arc assemblages ranging in age from ~1000Ma to 810Ma occur within Cathaysia, along its northwestern margin, and along the southeastern margin of the Yangtze Block. These rocks provide a record of convergent plate interaction, which continued along the western margin of the Yangtze Block until around 700Ma and correlates with similar along strike subduction zone magmatism in northwest India, Seychelles and Madagascar. During the final assembly of Gondwana in the early Paleozoic suturing of India-South China with the Western Australia-Mawson blocks along the Kuunga Orogen resulted in the accretion of the Sanya Block of Hainan Island with the rest of Cathaysia. The accretion of Laurussia to Gondwana in the mid-Paleozoic to form Pangea corresponds with the initiation of lithospheric extension along the northern margin of Gondwana and the separation of a number of continental blocks, including South China, which then drifted northward across the Paleo-Tethys to collide with the Asian segment of Pangea in the Permo-Triassic.



The applicability of two organic geochemical proxies (U37K' based on alkenones and TEX86

H based on glycerol dialkyl glycerol tetraethers) for ocean temperatures was investigated on a regional scale in the SE Brazilian continental margin (Campos Basin) using 53 core-top sediments. In 71% of the samples for U37

K' and 85% for TEX86H, the estimated annual mean sea surface temperature (SST) is comparable to the climatological annual mean data, with deviations within the calibration error. The surface TEX86

H estimates reflects the surface mixed layer, while the depth-integrated (0–200 m) TEX86H estimates showed better agreement with temperatures at 100–200 m depth. In addition, the SST-U37

K' results were more consistent (73% of the samples) using a winter calibration rather than an annual mean calibration. This seasonal effect might be ascribed to an increase in the abundance of haptophytes in the region during the winter. Exceptions to these general trends were observed for both proxies as a strong cold bias in reconstructed temperature in a few samples in the southern portion of the studied region, which may be related to (i) a predominant subsurface habitat of Thaumarchaeota combined with enhanced primary production and flux of particles during upwelling and (ii) alkenones being laterally transported from adjacent colder waters. Effects of river input of terrestrially sourced GDGTs on TEX86

H are not evident. Overall, our findings show that U37K' and

TEX86H are suitable temperature proxies for paleoclimate studies at a regional scale in the SE

Brazilian continental margin, but on a local scale the effects of upwelling must be taken in consideration.

Cecil, J.H., Garcia, D.C., Giannone, R.J., Michener, J.K., 2018. Rapid, parallel identification of catabolism pathways of lignin-derived aromatic compounds in Novosphingobium aromaticivorans. Applied and Environmental Microbiology 84, Article e01185-18.


Abstract: Transposon mutagenesis is a powerful technique in microbial genetics for the identification of genes in uncharacterized pathways. Recently, the throughput of transposon mutagenesis techniques has been dramatically increased through the combination of DNA barcoding and high-throughput sequencing. Here, we show that when applied to catabolic pathways, barcoded transposon libraries can be used to distinguish redundant pathways, decompose complex pathways into substituent modules, discriminate between enzyme homologs, and rapidly identify previously hypothetical enzymes in an unbiased genome-scale search. We used this technique to identify two genes, desC and desD, which are involved in the degradation of the lignin-derived aromatic compound sinapic acid in the nonmodel bacterium Novosphingobium aromaticivorans. We show that DesC is a methyl esterase acting on an intermediate formed during sinapic acid catabolism, providing the last enzyme in a proposed catabolic pathway. This approach will be particularly useful in the identification of complete pathways suitable for heterologous expression in metabolic engineering.

Importance: The identification of the genes involved in specific biochemical transformations is a key step in predicting microbial function from nucleic acid sequences and in engineering microbes to endow them with new functions. We have shown that new techniques for transposon mutagenesis can dramatically simplify this process and enable the rapid identification of genes in uncharacterized pathways. These techniques provide the necessary scale to fully elucidate complex biological networks such as those used to degrade mixtures of lignin-derived aromatic compounds.

Cersoy, S., Zirah, S., Marie, A., Zazzo, A., 2019. Toward a versatile protocol for radiocarbon and proteomics analysis of ancient collagen. Journal of Archaeological Science 101, 1-10.


Ancient bone proteins provide a plethora of information regarding the identity, period, and diet/environment of animal species through proteomic analysis, radiocarbon dating and isotopic analysis respectively. However, each technique imposes specific constraints for bone protein extraction. Despite the sample preciousness and heterogeneity, these analyses are not routinely performed on the same aliquot. Protocol for radiocarbon dating are the most restrictive in terms of sample preparation and their effects have seldom been evaluated at the molecular level. Here, several extraction protocols were tested using modern and archaeological bones. Molecular characterization of the extracts was performed using electrophoresis and proteomics. Protocol-induced biases in peptide sequences and their effect on species identification were evaluated using database searching and partial de novo sequencing. This work shows that extraction protocols corresponding to mild bone decalcification conditions and using ultrafiltration are the most suitable for species identification.

Chatellier, J.Y., Simpson, K., Perez, R., Tribovillard, N., 2018. Geochemically focused integrated approach to reveal reservoir characteristics linked to better Montney productivity potential. Bulletin of Canadian Petroleum Geology 66, 516-551.

https://pubs.geoscienceworld.org/cspg/bcpg/article/66/2/516/565809/geochemically-focused-integrated-approach-to

A multidisciplinary study addressed the unconventional Montney reservoir with new or modified tools invoking geochemical data. More than 1100 metres of cores from the Altares and Cypress fields in northeast British Columbia gave a solid stratigraphic framework to test reservoir parameters such as rock fabric, pore throat sizes, brittleness and hydrocarbon fill, integrating petrophysical data with XRF, XRD, brittleness core measurements and mercury injection capillary pressures.

Organic geochemistry was key to understand and calibrate pore throat sizes using a phase envelope comparison of isotube and isojar gas compositions; larger differences being linked to smaller pore throats. This was combined with Pittman R30 pore throat calculations from logs and with bitumen content calculated from NMR indicating that some Upper Montney units with larger pore throats are filled with bitumen that corresponds to an early migration of liquid hydrocarbon. Bitumen rich zones have been associated with enrichment in sulfur and samarium. Pore size restriction in the Lower Montney is linked to high clay content and to quartz cement as determined by XRF analysis.

Brittleness prediction (Young’s modulus) using XRD has been achieved with a new formula specific to the Altares Field in which only Feldspars have a positive relationship with brittleness; all published XRD base formula gave much poorer results. Brittleness prediction was also achieved using one single XRF element: chromium which is proxy to clay content and as such has a negative relationship. The reason for the poor predictability using other single XRF elements is the difference in lithological content and textures of the Upper and Lower Montney.

Isotope compositions gave supporting evidence for high reservoir pressure gradients associated with secondary gas cracking overpressure, allowing recognition of fault bounded reservoir compartments. Isotope data also revealed the presence of horizontal detachments confirmed by increased bed dips seen on image logs.

Open fractures filled with dry gas found associated with compressive structures have been identified using gas chromatography; no microseismic events have been found associated with the identified zones of open fractures and, in one well with production logs, 92% of the production came from unstimulated intervals.

Among the novelties of the present work are the analyses of data in 3–D and even 4–D (time) whereas previous work had remained static or studied in a 2–D context; thus, carbon isotopes and DFIT data were analyzed in 3–D or against TVDss.



The Lower Cretaceous Shahai and Jiufotang Formation in Fuxin Basin, located northwest of Liaoning Province, with stable planar distribution contains abundant shale gas reserves, which are key horizons in the exploration breakthrough of the Mesozoic continental shale gas in northeastern China. FuYe-1 (FY-1) well was recently drilled, and it is an important shale gas parameter well in the Fuxin Basin area. A total of 60 shale samples were collected from Shahai and Jiufotang Formation of FuYe-1 well

and DY-1 well in this work. A series of experiments including organic matter vitrinite reflectance, X-ray Diffraction (XRD) analysis, total carbonate content (TOC) measurement, scanning electron microscopy, low-temperature nitrogen adsorption, and methane isothermal adsorption were conducted through the samples. The final results revealed that in FuYe-1 well, the shale of the Lower Cretaceous Shahai and Jiufotang Formations has a maturity of 0.46–1.68% (average of 0.92%), which is at the immature-high maturity stage. The kerogens are mostly of types II–III. The mineral components are dominated by clay minerals and quartz, with an average of 21.39% and 30.89%, respectively. The main controlling factors of the methane adsorption capacity are the TOC content, the total clay content, and the shale pore structure. Langmuir’s volume (VL) of the shale ranges between 0.17 and 1.98m3/t (with an average of 1.21 m3/t). The methane adsorption capacity is positively correlated with the content of the total clay minerals and quartz, but varies in different clay minerals. The specific surface area of the shale and the total pore volume were calculated by BET and BJH, the macropore ratio of which is negatively correlated with the methane adsorption capacity, whereas the specific surface area and the total pore volume of the mesopores and micropores ratio are positively correlated with the methane adsorption capacity, indicating that the content of the micropores and mesopores is the major contributor to the specific surface area of shale.

Chen, G., Gang, W., Liu, Y., Wang, N., Jiang, C., Sun, J., 2019. Organic matter enrichment of the Late Triassic Yanchang Formation (Ordos Basin, China) under dysoxic to oxic conditions: Insights from pyrite framboid size distributions. Journal of Asian Earth Sciences 170, 106-117.


Pyrite framboids are spherical or ellipsoidal compact aggregates of submicron pyrite microcrystals. The various lithologies in the Chang 7 Member of the Upper Triassic Yanchang Formation contain abundant pyrite framboids, which provide an opportunity to understand the fluctuation in paleoredox conditions and relative sedimentation rates during deposition. The measured diameters of the pyrite framboids in the Chang 7 Member are characterized by large mean diameters (9.7–16.6 μm) with a wide distribution range that plots in the area indicative of dysoxic to oxic paleoredox conditions during deposition of the Chang 7 sediments. Based on correlation analysis, the strong correlation between paleoredox-sensitive trace elements ratios (V/Cr, U/Th, and Cu/Zn) and the mean size of framboids indicate that the latter can serve as a reliable indicator of paleoredox conditions. The results of the framboid size distribution can also be interpreted through Crystal Size Distribution Theory (CSDT). According to CSDT, the relative sedimentation rate of the Chang 7 Member fluctuated during deposition in parallel with fluctuation in lacustrine levels. Furthermore, the strongly positive correlation between total organic carbon (TOC) and paleoredox conditions indicates that although relatively high sedimentation rate may have contributed to the dysoxic-oxic conditions that were harmful to the preservation of organic matter, but it may also have brought nutrients to increase productivity. Similarly, the correlation between TOC and relative sedimentation rates suggests that the relative sedimentation rates can affect organic matter enrichment in several ways. A high sedimentation rate is favourable for the preservation of organic matter, which can be prevented from oxidation, but large amounts of sediments can dilute the organic matter, which reduces the organic matter abundance in a potential source rock.

Chen, G., Lu, S., Liu, K., Xue, Q., Han, T., Xu, C., Tong, M., Pang, X., Ni, B., Lu, S., 2019. Critical factors controlling shale gas adsorption mechanisms on different minerals investigated using GCMC simulations. Marine and Petroleum Geology 100, 31-42.


Understanding the adsorption mechanisms of different gas molecules on various minerals is crucial for accurately modelling shale gas adsorption behaviors and for objectively evaluating adsorbed gas contents under geological conditions. We simulated the adsorption behaviors of CH4, CO2 and N2 on both organic matter and inorganic minerals at 60 °C and 90 °C over a range of pressures up to 50 MPa by using the Grand Canonical Monte Carlo (GCMC) method. It has been found that both the comprehensive effect of the adsorption sites with differential adsorption capacity and the distribution density of the adsorption sites on the organic matter and inorganic mineral surfaces control the adsorption capacity in terms of per unit surface area of minerals. For individual minerals with a certain adsorption capacity in terms of per unit surface area, the specific surface area of individual minerals is the critical factor that determines the adsorption capacity in terms of per unit mass of the minerals. The interaction among gas molecules also affects the adsorption behavior slightly. We further compared the adsorption capacity among various gas molecules on both organic matter and inorganic minerals by inspecting the strength and distribution density of the adsorption sites on mineral surfaces, the specific surface area of the minerals and the interaction strength among gas molecules. These investigations allowed us to identify the key factors controlling shale gas adsorption mechanisms on different minerals, which provide some helpful insights for both of the exploration and the development of shale gas.

Chen, H., Zhao, L., Hu, S., Yuan, Z., Guo, J., 2018. High-rate production of short-chain fatty acids from methane in a mixed-culture membrane biofilm reactor. Environmental Science & Technology Letters 5, 662-667.

https://doi.org/10.1021/acs.estlett.8b00460

The bioconversion of methane to liquid chemicals has attracted much attention. However, the production rate reported to date has been far lower than what is required for economical viability. This is partly due to the low solubility of methane, the low mass transfer rate, and low microbial activities. This study demonstrates a production rate of close to 10 g of short-chain fatty acids (SCFAs) per liter per day with a mixed-culture biofilm growing in a membrane biofilm reactor (MBfR). Hollow fiber membranes were used both to deliver a high flux of methane and to provide a surface on which slow-growing microorganisms could form biofilms with intensified activities. The rate achieved is nearly 2 orders of magnitude higher than the highest SCFA production rate reported to date and is close to the rates required for practical applications (∼12–120 g L–1 day–1). The consortium in the biofilm was dominated by methanogens Methanosarcina and Methanobacterium and acid-producing bacteria Sporolactobacillus and Propionispora, suggesting likely roles of these organisms in the bioconversion of methane into SCFAs. This work shows a methane-based MBfR represents a promising technology for achieving high-rate production of chemicals from methane.

Chen, J., Li, T., Wu, S., 2018. Changes in the properties of conventional crude oil before and after CO2 flooding. Petroleum Science and Technology 36, 1642-1648.

https://doi.org/10.1080/10916466.2018.1496117

In order to enhance oil recovery of a conventional oil reservoir by CO2 flooding, the changes in the properties of the crude oil before and after CO2 flooding are systematically investigated by on-site sampling and experimental testing. The results show that, after CO2 flooding, the light hydrocarbons of the produced crude oil is increased and the heavy hydrocarbons of the produced crude oil is decreased due to the deposition of resins and asphaltenes in the pores of the formation. In addition, the produced fluid (a mixture of oil and water) has a high water separation rate, the oil- water interface has a high tension value, and the crude oil has a high acid value and a low viscosity. The

conclusions can provide a certain guidance for high-efficiency development of a conventional oil reservoir by CO2 flooding.

Chen, J., Song, H., Guan, Y., Pinheiro, L.M., Geng, M., 2018. Geological and oceanographic controls on seabed fluid escape structures in the northern Zhongjiannan Basin, South China Sea. Journal of Asian Earth Sciences 168, 38-47.


Mega-pockmarks, which can reach a few kilometers in width and a few hundred meters in depth, and associated fluid escape features in the Northern Zhongjiannan Basin, South China Sea, have received much attention in the recent years, due to their large variety of morphologies and sizes. In this work, an integrated interpretation of detailed multibeam bathymetry, conventional multi-channel seismic reflection and seismic oceanography sections covering the northern Zhongjiannan Basin, South China Sea, are used to image the seafloor morphology, the subsurface geology and the water column, in order to better understand the geological and oceanographic controls on the formation and evolution of the widespread fluid escape features in this region. Regional uplift and volcanism took place in this area near the Palaeogene–Neogene boundary and, during the Neogene–Quaternary post-rift thermal subsidence period, differential subsidence and diapirism deformed the overlying kilometer-scale successions. Mainly after the Miocene, focused flow of fluids originated at depth occurred along gas pipes, polygonal faults, tapered reflectors and faults into the shallow sediments, resulting in intense fluid blowouts and complex fluid escape structures on the seafloor. Our results show that elongated pockmarks, pockmark gullies and gullies in the northern slope are generally controlled by underlying buried channels and gullies. However, pockmark gullies and gullies in the southern slope are controlled by gravity sliding/slumping, along with crescent pockmarks developing parallel to water depth contours. To varying degrees, intense fluid escape activities associated with mud diapirism and gas escape in the study area resulted in mud extrusion and the formation of mud volcanoes, complex seabed morphologies and irregular pockmarks. Mega-pockmarks, collapse structures and blind valleys have formed at the apexes of tectonic uplifts related to volcanism and above basement highs, which suggests that these processes played a role in creating pathways for fluid escape. Bottom currents associated with the South China Sea Western Boundary Current, imaged here for the first time with the seismic oceanographic method, mainly flow to the south, and erode the seafloor, making pockmark walls and slopes of gullies and channels in the north steeper than those in the south. Some fluid escape structures, such as the mega-pockmarks and pockmark gullies, are buried by sediment transported by the bottom currents. Turbidity currents flowing downslope along the long pockmark gullies also erode the seafloor and make the NW slopes of the mud volcanoes less steep than those in the SE. Eddies imaged by the seismic sections may also play a role in transporting sediment to the deep sea in this area. Some of the reported fluid escape structures are still active, as indicated by the fluid pathways that reach the seafloor and plumes in the water column imaged by the seismic sections.



Current displacing agents for enhanced oil recovery (EOR), i.e., water, gas, foam, and common nanofluid, suffer plenty of problems in ultralow-permeability reservoirs, with a limited oil recovery. A novel agent, amphiphilic graphene oxide (H–GO), is confirmed to be effective in EOR under such

unconventional conditions. We present the fundamental mechanisms for the improved performance by H–GO. Specifically, the effectiveness of H–GO is experimentally verified from multiple perspectives, including emulsifying ability, interfacial activity, and wettability alteration action. Experimental observations show that H–GO has excellent emulsifying ability that the amphiphilic Janus nanosheet is inclined to move onto the oil–water interface. Pickering emulsion formed by H–GO and oil, with an average droplet diameter of only 2.66 μm, is considerably stable, which can be maintained for at least 30 days. Besides, H–GO reduces the oil–water interfacial tension to 0.493 mN/m, 1 order of magnitude lower than that between the common nanoparticle and oil. H–GO shows better wettability alteration efficiency compared to a common nanoparticle. Consistently, micromodel tests show that H–GO gives a promising sweep and displacement efficiency to oil. As a result of these advantages of H–GO, the oil on the rock surface can be separated and form the emulsion or oil zone easily, leading to the incremental recovery of 10.83% using only H–GO (1 mg/mL) in an ultralow-permeability core. The study provides a novel approach for EOR in ultralow-permeability reservoirs. The high performance, convenient operation, and environmental protection make H–GO flooding have great potential for oilfield practice.


https://doi.org/10.1080/10916466.2018.1493503

This study implements an adaptive neuro-fuzzy inference system (ANFIS) approach to predict the precipitation amount of the asphaltene using temperature (T), dilution ratio (Rv), and molecular weight of different n-alkanes. Results are then evaluated using graphical and statistical error analysis methods, confirming the model’s great ability for appropriate prediction of the precipitation amount. Mean squared error and determination coefficient (R2) values of 0.036 and 0.995, respectively are obtained for the proposed ANFIS model. Results are then compared to those from previously reported correlations revealing the better performance of the proposed model.

Chen, W., Hartman, R.L., 2018. Methane hydrate intrinsic dissociation kinetics measured in a microfluidic system by means of in situ Raman spectroscopy. Energy & Fuels 32, 11761-11771.


The present work investigates the dissociation kinetics of methane (sI) hydrate in a thermoelectrically cooled microfluidic system with in situ Raman spectroscopy. The dissociation profile of methane (sI) hydrate was measured under different Reynolds numbers (0.42–4.16), pressures (60.2 to 80.1 bar), and temperature driving force ([Teq – 0.1 K] to [Teq + 0.3 K]). A theoretical model was derived from first-principles to describe the contributions of heat transfer and intrinsic kinetics on the dissociation rate of methane hydrate. It was observed that the dimensionless ratio of heat transfer to the intrinsic dissociation rate depended on the initial thickness of methane hydrate, temperature driving force, pressure, and the time. Intrinsic kinetics dominated where the initial thickness of methane hydrate was in the range of 10 μm and the temperature driving force was low. Increasing initial thickness of methane hydrate resulted in a switch to a heat-transfer-limited dissociation. Our results support that the “memory effect” previously reported is the result of dissociation limited by intrinsic kinetics. Furthermore, this work introduces a new laboratory method of unusually sensitive microscale control of the dissociation conditions, while generating molecular-level insight. Our findings support that microfluidics with in situ Raman spectroscopy are excellent laboratory tools to understand methane

hydrate dissociation with potentially much broader utility to the field. Methane hydrates play an important role in energy production and storage and the atmospheric and oceanic sciences.

Chen, Y., Qin, Y., Li, Z., Shi, Q., Wei, C., Wu, C., Cao, C., Qu, Z., 2019. Differences in desorption rate and composition of desorbed gases between undeformed and mylonitic coals in the Zhina Coalfield, Southwest China. Fuel 239, 905-916.


Desorption is routinely employed for assessing the recoverability of coalbed gas resources. However, desorption behavior is strongly affected by coal structure. Canister desorption experiments on undeformed and mylonitic coals collected from drill holes in the Zhina Coalfield (Southwest China) were conducted to study temporal desorption rates and gas compositional shifts. Low-pressure N2 and CO2 adsorption tests revealed that the micropores, mesopores, and macropores in mylonitic coal have larger pore volumes and greater specific surface areas compared to those of undeformed coal. The “ink-bottle-shaped” pore is the main type of pore structure in mylonitic coal, whereas undeformed coal shows well-developed slit-shaped pores with good interconnectivity. The detailed desorption experiments in this study lasted 61 d and 110 h for undeformed and mylonitic coal, respectively. For undeformed coal, CH4 and C2H6 concentrations steadily increased with desorption time, whereas N2 and CO2 concentrations progressively decreased. The gas compositional shift of mylonitic coal during the entire desorption process could be divided into two stages: an initial stage, when CH4 and C2H6 concentrations in the desorbed gas increased (within the first 12 h), and a later stage, when they decreased rapidly; N2 and CO2 concentrations exhibited the opposite trend. The two-stage gas compositional shifts in mylonitic coal are likely linked to its pore structure. Gases in the “parallel-plate-shaped” pores of undeformed coal are mobile, whereas those in ink-bottle-shaped pores of mylonitic coal have restricted mobility. This is because CO2 and N2 can enter the narrow throats (with diameters of 3.3–3.8 Å) of ink-bottle-shaped pores, which are inaccessible to CH4 and C2H6 because of their larger diameter, causing the late-desorbed gas of mylonitic coal to be relatively enriched in CO2 and N2. The initial desorption rate of mylonitic coal is much greater than that of undeformed coal, which is closely related to developed microfractures in mylonitic coal. The desorption rate of undeformed coal is a power function of time, whereas that of mylonitic coal can be divided into two stages in which the relationship between desorption rate and time is a power function. The results suggest that the two-stage desorption rate is attributable to the molecular sieve effect due to the presence of massive ink-bottle-shaped pores in mylonitic coal.

Chen, Y., Wu, N., Liang, D., Hu, R., 2018. Numerical simulation on the resistivity of hydrate-bearing sediment based on fractal pore model. Natural Gas Industry 38, 128-134.

http://www.cngascn.com:81/ngi_wk/EN/abstract/abstract18667.shtml

Resistivity method is an important method to determine the saturation of natural gas hydrate (hereinafter “hydrate” for short), and numerical simulation is effective to research the resistivity characteristics of hydrate bearing sediments. The pore models established in the past cannot reflect the actual pore structure because there are fewer constraint conditions. Based on the self-similar characteristic of natural sediments, we selected the Sierpinski Carpet with its total side length of 3 and particle's side length of 1 as the fractal pore model of sediment, and according to the equivalent resistance network, we established an electrical conductivity model of hydrate bearing sediments. In this paper, the effects of porosity, interstitial water conductivity and sediment skeleton conductivity on the relationship between the resistivity of hydrate-bearing sediment and the hydrate saturation were analyzed using this model. And following research results were obtained. First, the resistivity of

hydrate-bearing sediment can be expressed as the function of porosity, area ratio, microstructure size, interstitial water conductivity, sediment skeleton conductivity and empiric parameter. Second, sediment resistivity increases with the decrease of interstitial water conductivity and porosity. Third, the resistivity of hydrate-bearing sediment increases with the increase of hydrate saturation. Fourth, when the hydrate saturation is high, the resistivity of hydrate-bearing sediment decreases significantly with the increase of sediment skeleton conductivity. In conclusion, when the hydrate saturation is in a certain range, the calculation result of this fractal pore model is in line with the experimental data and logging data with a higher accuracy.

Cheng, C., Li, S., Xie, X., Cao, T., Manger, W.L., Busbey, A.B., 2019. Permian carbon isotope and clay mineral records from the Xikou section, Zhen'an, Shaanxi Province, central China: Climatological implications for the easternmost Paleo-Tethys. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 407-422.


Permian carbon isotopic and clay mineralogical records were recovered from the carbonates in the Xikou section, a complete and uninterrupted Upper Carboniferous to Lower Triassic carbonate-dominated succession exposed in Zhen'an, Shaanxi Province, central China, which were used to document carbon isotopic signatures and climatic changes affecting the easternmost Paleo-Tethys region during the Permian. Both carbon isotope and clay mineralogical data suggest fluctuating climatic conditions and trends that can be approximately correlated with eastern Australian glaciations and North American craton during the Artinskian to Capitanian Stages. Two global carbon isotopic anomalies across the Permian-Triassic boundary and the Guadalupian-Lopingian Series boundary were detected for the first time in the stratigraphic record of the South Qinling micro-continental block. The Capitanian Stage comprises an early phase of climatic warming followed by a later phase of climatic cooling. The Kungurian Stage represents a climatic warming interval and the main phase of deglaciation during the Late Paleozoic Ice Age (LPIA). A δ13C positive shift across the boundary of the Artinskian to Kungurian Stages, together with the following negative excursion recorded in the early Kungurian Stage can be used as an indicator for the boundary between the Artinskian and Kungurian Stage.

Cheng, I., Wen, D., Zhang, L., Wu, Z., Qiu, X., Yang, F., Harner, T., 2018. Deposition mapping of polycyclic aromatic compounds in the oil sands region of Alberta, Canada and linkages to ecosystem impacts. Environmental Science & Technology 52, 12456-12464.


This study produced gridded deposition estimates of polycyclic aromatic compounds (PACs), including 17 polycyclic aromatic hydrocarbons (PAHs), 21 alkylated PAHs (alk-PAHs), and 5 dibenzothiophenes (DBTs), over the oil sands region of Alberta, Canada and surrounding communities. Gridded annual total deposition of PACs in 2011 ranged from 55 to 175 000 μg m–2 yr–1

and the mean and median fluxes were 1700 and 760 μg m–2 yr–1, respectively. The domain-wide mean dry and wet deposition were 600 and 1100 μg m–2 yr–1. PAHs, alk-PAHs and DBTs contributed 19%, 74%, and 7% to the total dry deposition, and 42%, 49%, and 9% to the total wet deposition. Dominant chemical species contributing to total deposition were naphthalene, retene and phenanthrene for PAHs and C2-benz[a]anthracene/triphenylene/chrysene, C2-fluoranthene/pyrene and C2-fluorene for alk-PAHs. The highest PAC deposition was found over the surface mineable area, which received 9 times the deposition flux of outlying areas. Additional deposition hotspots were also observed south of the surface mineable area notably over in situ bitumen production sites.

The deposition of alk-PAHs impacted a more extensive area than that of PAHs or DBTs. This result suggests that atmospheric deposition is a key process in wildlife exposure to PACs across the region.

Cheng, M., Li, C., Chen, X., Zhou, L., Algeo, T.J., Ling, H.-F., Feng, L.-J., Jin, C.-S., 2018. Delayed Neoproterozoic oceanic oxygenation: Evidence from Mo isotopes of the Cryogenian Datangpo Formation. Precambrian Research 319, 187-197.


The Neoproterozoic oxygenation event (NOE) likely began earlier than 800 Ma, raising oxygen levels in the Earth’s atmosphere-ocean system and, thus, setting the stage for the emergence and diversification of animals. However, the redox history of the oceans during the following Cryogenian Period (∼720–635 Ma) remains poorly constrained. Here, we present a biogeochemical study based on Mo-isotope (this study) and Fe, C, Mo abundance data (previously reported data) for black shales of the ∼660-Ma Datangpo Formation in the Minle section of the Nanhua Basin, South China. Iron speciation data indicate that the study samples were most likely deposited under euxinic conditions. The studied samples yield two clusters of δ98Mo data: +0.98‰ to +1.14‰ [+1.06 ± 0.06 (SD) ‰] and −0.13‰ to +0.68‰ (+0.65 ± 0.31‰), respectively, with the higher values found mostly in the lowermost black shales. The variably lower δ98Mo values probably do not reflect contemporaneous open-ocean seawater composition owing to lower aqueous H2S concentrations caused by substantial watermass restriction (as evidenced by Mo-TOC covariation patterns), whereas the high δ98Mo values may record contemporaneous Cryogenian seawater values. The seawater δ98Mo values from our study at ∼660 Ma are similar to previously reported seawater δ98Mo values at ∼750 Ma (+1.11‰) and ∼640 Ma (+1.15‰), implying the existence of widespread oceanic anoxia throughout the Cryogenian. Because the subsequent Ediacaran Period shows evidence of greater oceanic oxygenation based on multiple geochemical proxies, our findings suggest that the process of oceanic oxygenation proceeded slowly during the Cryogenian Period. This may have been an important factor in delaying the first appearance of metazoans until the late Cryogenian and their diversification until the Ediacaran.

Cheng, P., Xiao, X., Tian, H., Wang, X., 2018. Water content and equilibrium saturation and their influencing factors of the lower Paleozoic overmature organic-rich shales in the Upper Yangtze Region of southern China. Energy & Fuels 32, 11452-11466.


The geochemical and petrophysical characteristics of the Lower Paleozoic shales (the Lower Silurian Longmaxi Formation and the Lower Cambrian Niutitang Formation) in southern China have been well documented in recent years. However, the water content in these shales is less studied. Since water and hydrocarbons concomitantly distribute in the pore spaces of the shale reservoir, the water in the shale reservoir is important to the evaluation and development of its hydrocarbon resources. In the present study, the water content (CIW) and equilibrium saturation (SEW) of the two sets of overmature organic-rich shales, which were, respectively, collected from the Niutitang Formation of Fengye 1 well (FY1) and the Longmaxi Formation of Youqian 1 well (YQ1) in the Upper Yangtze Region of southern China, were investigated. The results show that the CIW of the FY1 and YQ1 shales is 4.17–5.29 mg/g and 3.70–5.06 mg/g, respectively; the SEW of the FY1 and YQ1 shales is 34.23–42.72% and 38.07–45.51%, respectively; and both sets of shales are in a subirreducible water-equilibrated state. The CIW and CEIW of these shales have positive correlations with their TOC content, total porosity, surface area, and pore volume of both the micropores and nonmicropores, but the SEW has negative correlations with these parameters, indicating that the organic matter in these shales holds some water

and that the TOC content mainly controls the CIW, CEIW, and SEW. According to the regression lines in the TOC content vs CIW plots and the TOC content vs CEIW plots, the water equilibrium saturations of the organic-hosted pores (SOW) and inorganic-hosted pores (SIW) were estimated. The SIW of these shales is greater than the SOW, and the SIW/SOW ratio of the FY1 and YQ1 shales is 2.28 and 2.04, respectively, quantitatively indicating that the organic-hosted pores of these overmature shales are less hydrophilic than the inorganic-hosted pores. Therefore, for a set of overmature shales (FY1 or YQ1), with increasing TOC contents, the organic-hosted pore content increases and provides more storage space for the water in the shales, but the bulk hydrophilia of the shales reduces, leading to an increase in the CIW and CEIW and a decrease in the SEW.

Cheng, Q., Guanghui, H., Zhang, M., Wenjun, Z., Xi, L., 2019. Distribution and source significance of 2-methylalkanes in coal-measure source rocks, northwest China. Journal of Petroleum Science and Engineering 174, 257-267.


GC-MS analysis was conducted on 59 coal-measure source rock (CSR) samples in the study area. Between nC14 and nC38, a series of 2-methylalkanes were detected. The 2-methylalkanes distribution can be summarized into 3 distribution modes: Front peak-type, Middle peak-type and Behind peak-type distribution. The same distribution mode is distributed at different maturity stages, and there are different distribution modes at the same thermal evolution stages, indicating that the distribution was slightly influenced by thermal evolution. C27-C28-C29 regular sterane triangulation is a template which is commonly used to judge the source of organic matter and sedimentary environment. But it is not applicable to judgment of the source of organic matter of coal-measure source rock (CSR) as higher plants are the basic substance. The organic matter constitution in CSR is still complicated, we need to know secondary organic matter in CSR except for plant so as to analyze the sedimentation and diagenetic environment. Within C17- C22 -C28 2-methylalkanes (iC17-iC22-iC28) triangulation, samples with Front peak-type distribution of 2-methylalkanes are distributed near the 2-methylalkane C17 (iC17) end member. Samples with Middle peak-type distribution are distributed near the 2-methylalkane C22 (iC22) end member. Samples with Behind peak-type distribution are distributed near the 2-methylalkane C28 (iC28) end member. In combination with distribution characteristics of isoprenoid alkenes and biomarker compounds, different regions in the iC17-iC22-iC28 triangulation can be divided into different sources of organic matter and sedimentary environment. Based on this, the iC17-iC22-iC28 triangulation used to judge the parent material organic matter of CSR was established. In comparison with C27-C28-C29 regular sterane triangulation, it is more effective to judge the source of organic matter in CSR with iC17-iC22-iC28 triangulation.



In this study, we propose a two-step strategy for tracking oil-spill trajectories. First, an X-band radar is established to monitor oil spills. Accordingly, we propose a radar image-processing technique for identifying the oil slicks from the nautical radar images. Second, we apply the SCHISM to determine the water surface elevations and currents at the event site and obtain the trajectories of the oil slicks using a Lagrangian particle-tracking method incorporated in the SCHISM. An oil-spill event caused by the container ship T. S. Taipei is used as a case study for testing the capability of the proposed oil-tracking strategy. The SCHISM simulation results for the fouled coastline obtained using the wind

data from a nearby data buoy agree quite well with those obtained from field observations. However, the predicted fouled coastline based on the forecasted wind data is unsatisfactory. The reasons for the unsatisfactory prediction are discussed and revealed.

Christensen, L.F.B., Hansen, L.M., Finster, K., Christiansen, G., Nielsen, P.H., Otzen, D.E., Dueholm, M.S., 2018. The sheaths of Methanospirillum are made of a new type of amyloid protein. Frontiers in Microbiology 9, 1099. doi: 10.3389/fmicb.2015.01099.


The genera Methanospirillum and Methanosaeta contain species of anaerobic archaea that grow and divide within proteinaceous tubular sheaths that protect them from environmental stressors. The sheaths of Methanosaeta thermophila PT are composed of the 60.9 kDa major sheath protein MspA. In this study we show that sheaths purified from Methanospirillum hungatei JF-1 are regularly striated tubular structures with amyloid-like properties similar to those of M. thermophila PT. Depolymerizing the sheaths from M. hungatei JF-1 allowed us to identify a 40.6 kDa protein (WP_011449234.1) that shares 23% sequence similarity to MspA from M. thermophila PT (ABK14853.1), indicating that they might be distant homologs. The genome of M. hungatei JF-1 encodes six homologs of the identified MspA protein. Several homologs also exist in the related strains Methanospirillum stamsii Pt1 (7 homologs, 28–66% sequence identity), M. lacunae Ki8-1 C (15 homologs, 29–60% sequence identity) and Methanolinea tarda NOBI-1 (2 homologs, 31% sequence identity). The MspA protein discovered here could accordingly represent a more widely found sheath protein than the MspA from M. thermophila PT, which currently has no homologs in the NCBI Reference Sequence database (RefSeq).

Coiro, M., Chomicki, G., Doyle, J.A., 2018. Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of the relationship of angiosperms and Gnetales. Paleobiology 44, 490-510.

http://www.bioone.org/doi/abs/10.1017/pab.2018.23

The placement of angiosperms and Gnetales in seed plant phylogeny remains one of the most enigmatic problems in plant evolution, with morphological analyses (which have usually included fossils) and molecular analyses pointing to very distinct topologies. Almost all morphology-based phylogenies group angiosperms with Gnetales and certain extinct seed plant lineages, while most molecular phylogenies link Gnetales with conifers. In this study, we investigate the phylogenetic signal present in published seed plant morphological data sets. We use parsimony, Bayesian inference, and maximum-likelihood approaches, combined with a number of experiments with the data, to address the morphological–molecular conflict. First, we ask whether the lack of association of Gnetales with conifers in morphological analyses is due to an absence of signal or to the presence of competing signals, and second, we compare the performance of parsimony and model-based approaches with morphological data sets. Our results imply that the grouping of Gnetales and angiosperms is largely the result of long-branch attraction (LBA), consistent across a range of methodological approaches. Thus, there is a signal for the grouping of Gnetales with conifers in morphological matrices, but it was swamped by convergence between angiosperms and Gnetales, both situated on long branches. However, this effect becomes weaker in more recent analyses, as a result of addition and critical reassessment of characters. Even when a clade including angiosperms and Gnetales is still weakly supported by parsimony, model-based approaches favor a clade of Gnetales and conifers, presumably because they are more resistant to LBA. Inclusion of fossil taxa weakens rather than strengthens support for a relationship of angiosperms and Gnetales. Our analyses

finally reconcile morphology with molecules in favoring a relationship of Gnetales to conifers, and show that morphology may therefore be useful in reconstructing other aspects of the phylogenetic history of the seed plants.

Colson, P., Levasseur, A., La Scola, B., Sharma, V., Nasir, A., Pontarotti, P., Caetano-Anollés, G., Raoult, D., 2018. Ancestrality and mosaicism of giant viruses supporting the definition of the fourth TRUC of microbes. Frontiers in Microbiology 9, 2668. doi: 10.3389/fmicb.2018.02668.


Giant viruses of amoebae were discovered in 2003. Since then, their diversity has greatly expanded. They were suggested to form a fourth branch of life, collectively named ‘TRUC’ (for “Things Resisting Uncompleted Classifications”) alongside Bacteria, Archaea, and Eukarya. Their origin and ancestrality remain controversial. Here, we specify the evolution and definition of giant viruses. Phylogenetic and phenetic analyses of informational gene repertoires of giant viruses and selected bacteria, archaea and eukaryota were performed, including structural phylogenomics based on protein structural domains grouped into 289 universal fold superfamilies (FSFs). Hierarchical clustering analysis was performed based on a binary presence/absence matrix constructed using 727 informational COGs from cellular organisms. The presence/absence of ‘universal’ FSF domains was used to generate an unrooted maximum parsimony phylogenomic tree. Comparison of the gene content of a giant virus with those of a bacterium, an archaeon, and a eukaryote with small genomes was also performed. Overall, both cladistic analyses based on gene sequences of very central and ancient proteins and on highly conserved protein fold structures as well as phenetic analyses were congruent regarding the delineation of a fourth branch of microbes comprised by giant viruses. Giant viruses appeared as a basal group in the tree of all proteomes. A pangenome and core genome determined for Rickettsia bellii (bacteria), Methanomassiliicoccus luminyensis (archaeon), Encephalitozoon intestinalis (eukaryote), and Tupanvirus (giant virus) showed a substantial proportion of Tupanvirus genes that overlap with those of the cellular microbes. In addition, a substantial genome mosaicism was observed, with 51, 11, 8, and 0.2% of Tupanvirus genes best matching with viruses, eukaryota, bacteria, and archaea, respectively. Finally, we found that genes themselves may be subject to lateral sequence transfers. In summary, our data highlight the quantum leap between classical and giant viruses. Phylogenetic and phyletic analyses and the study of protein fold superfamilies confirm previous evidence of the existence of a fourth TRUC of life that includes giant viruses, and highlight its ancestrality and mosaicism. They also point out that best evolutionary representations for giant viruses and cellular microorganisms are rhizomes, and that sequence transfers rather than gene transfers have to be considered.

Costanzo-Álvarez, V., Rapalini, A.E., Aldana, M., Díaz, M., Kietzmann, D., Iglesia-Llanos, M.P., Cabrera, A., Luppo, T., Vallejo, M.D., Walther, A.M., 2019. A combined rock-magnetic and EPR study about the effects of hydrocarbon-related diagenesis on the magnetic signature of oil shales (Vaca Muerta formation, southwestern Argentina). Journal of Petroleum Science and Engineering 173, 861-879.


A combined study of rock-magnetism and electronic-paramagnetic resonance (EPR) was performed in core samples from an oil well in the Vaca Muerta Formation (SW Argentina). The aim of this work was to characterize the effects of hydrocarbon-related diagenesis on the magnetic signature of oil shales. Similar research has been previously conducted in near-surface sediments affected by oil and gas microseepage, so as to establish a relationship between micromagnetic anomalies and the

underlying reservoirs. The EPR technique was employed to measure minute concentrations of organic matter free radicals (OMFRs), Fe3+ and Mn2+. These results, and the concentrations of extractable organic matter (EOM), were compared with mass-specific magnetic susceptibility (χ) and natural remanent magnetization (NRM). The reactive OMFRs, resulting from the thermal degradation of a kerogen that yields a slightly-biodegraded crude oil, seem to have acted on the primary Fe oxides and sulfides through two diagenetic stages. The first stage might have partially dissolved these minerals. Consequently, a number of depth levels show a decrease of both χ and NRM, against an increase of the OMFRs. On the other hand, for a core-interval between 2663 and 2695 m (P18/P24), a second diagenetic stage could have produced partial replacement of framboidal pyrite by authigenic pyrrhotite, as recognized by scanning electron microscopy (SEM), electron X-ray energy dispersion (EDX) experiments and the analysis of the thermomagnetic and IRM curves. Thus, within P18/P24, magnetic parameters increase in direct proportion with the amount of OMFRs. The lithologies encompassed by P18/P24 show small levels of Mn2+, a proxy directly related to calcareous cementation. Moreover, Gamma Ray, resistivity and neutron porosity well logs reveal distinctive features for P18/P24, as well as an increase of hydrocarbon content, contrasting with the rest of the section analyzed. The hydrocarbon-induced magnetic anomalies in these oil shales seem to be conditioned mostly by their petrophysical properties.

Craig, J., Hakhoo, N., Bhat, G.M., Hafiz, M., Khan, M.R., Misra, R., Pandita, S.K., Raina, B.K., Thurow, J., Thusu, B., Ahmed, W., Khullar, S., 2018. Petroleum systems and hydrocarbon potential of the North-West Himalaya of India and Pakistan. Earth-Science Reviews 187, 109-185.


The Himalayan orogeny has shaped the sedimentary basins of the region, where continuous deformation formed both ‘conventional’ and ‘unconventional’ petroleum systems at multiple stratigraphic levels ranging in the age from Precambrian to Neogene. Himalaya is considered to be prospective for hydrocarbon exploration because of its suitable tectono-sedimentary environment, oil/gas shows, and the presence of commercial oil and gas discoveries in broadly similar structural settings in the eastern and western regions. Although detailed surface geological mapping, the acquisition of geological data and the drilling of wells has considerably improved the understanding of the geological and structural setting and the hydrocarbon potential of the NW Himalaya, commercial discoveries have remained largely elusive.

In the NW Himalaya the Precambrian-Cambrian sequences that are of primary interest include the Salt Range Formation (Potwar Basin), and also some sequences in the Lesser-and-Sub-Himalaya, such as the Proterozoic Sirban Limestone Formation; in the Kashmir and Bhadarwah-Chamba basins further to the northeast, and in the Garhwal Group and the Krol belt in the southeast.

The Palaeozoic sedimentary rocks exposed within the Lesser Himalaya and the Tethyan Himalaya (represented by the Kashmir, Zanskar-Spiti, Kinnaur-Uttarakhand and Kumaon basins) have been subjected to low grade metamorphism, and presently have no significant hydrocarbon generation potential. The Cambrian Khewra and the Permian Tobra formations form hydrocarbon bearing reservoirs in the East Potwar. The Palaeozoic stratigraphy of the Zanskar Tethyan Himalaya in northern India is rather similar to that of the Peshawar Basin in Pakistan. The thick argillaceous successions are the best potential hydrocarbon source rock horizons within the Palaeozoic.

The Mesozoic and Early Eocene successions of the Tethyan Himalaya were deposited in the shallow southern margin of the Tethys Ocean. In the western Himalaya, the Tethyan Himalayan succession is exposed in Kashmir, Zanskar, Chamba and Spiti basins. The Mesozoic successions include thick sequences of organic material rich argillaceous sediments. The Triassic and Jurassic strata are

generally poorly developed or absent in the eastern Potwar Basin, while they get thicker towards the west Potwar and Kohat basins. The sandstones of Jurassic age are proven reservoirs, and potential source rocks are present. The Mesozoic succession of the Kashmir Basin is represented by the formations of the Triassic age. Some of the shales contain organic matter (OM) and could represent viable hydrocarbon source rocks, while some of the limestones, dolomites and sandstones have sufficient reservoir characteristics. The OM content of the argillaceous sediments within the Mesozoic-Tertiary succession of the Zanskar-Spiti Basin (Ladakh Himalaya) is appropriate for hydrocarbon generation.

The Cenozoic foreland basin of the Himalayan orogen was deformed by a southward migrating thrust system during the Late Miocene-Quaternary. The Sub-Himalaya Zone contains a sequence of Cenozoic sedimentary rocks divided into the Subathu and Dharamsala (=Murree) formations, and Siwalik Group. Hydrocarbon source rocks are present in the Subathu and Dharamsala formations; while the Lower Siwalik, Kasauli and Dagshai formations contain potential sandstone reservoirs. The Eocene Subathu Formation is a key exploration target in the NW Himalaya with both potential hydrocarbon source and reservoir rocks sealed by a thick clay sequence. The coeval shales within the Patala and Nammal formations are considered to be the main source rocks in the Potwar Basin, whereas, the fractured carbonates of Palaeocene and Early Eocene age are the main reservoirs. The Miocene Murree Formation is the youngest oil-producing horizon in the Potwar Basin. Palaeocene Hangu Sandstone and Lockhart Limestone are the main reservoirs in the Kohat Basin. The stratigraphy of Kohat-Potwar Basin extends into Margalla, Kalachitta and Samana Ranges. In these ranges the Jurassic-Eocene strata is exposed, so sub-thrust sheets could have hydrocarbon potential.

In the NW Himalaya, the surface gas seeps are characterised by a high nitrogen content, and are either thermogenic or biogenic in origin, while the gases encountered in the wells are typically methane rich (dry) with low nitrogen concentrations, indicating thermogenic origin. There appears to be a strong linear correlation between the relative concentration of methane and nitrogen in the Himalayan fore-deep gas shows. There are numerous references to biogenic gas seeps in the Plio-Pleistocene sediments and lignite fields in the Kashmir Valley, and also in the shallow Plio-Pleistocene sediments in the Peshawar Basin.

The evolution and establishment of the key petroleum system elements, the generation, expulsion, migration and accumulation (entrapment) of hydrocarbons at multiple stratigraphic levels in NW Himalaya has been controlled by the regional tectonic events. These events are associated with the source rock burial and maturation history, coupled with hydrocarbon generation, ‘peak oil’ and subsequent migration occurring concomitantly with the peak activity along the major regional thrusts. The complex and variable structural geometries have allowed a variety of traps beneath sections where source rocks have adequate burial depth, and where traps have not been breached. In NW Himalaya, the key to understand the direct relationship between tectonics and the evolution of petroleum systems are the accurate estimates for the timing of the related tectonics and that of the hydrocarbon generation, accumulation and critical moment. Here, the exploration has been hampered by the structural complexity, difficult terrain, drilling complications and poor seismic data quality. Timing of the trap formation vs. hydrocarbon charge, trap integrity, seal presence and capacity, and reservoir quality are the key geological risks that have to be addressed.

Crede, L.-S., Liu, W., Evans, K.A., Rempel, K.U., Testemale, D., Brugger, J., 2019. Crude oils as ore fluids: An experimental in-situ XAS study of gold partitioning between brine and organic fluid from 25 to 250 °C. Geochimica et Cosmochimica Acta 244, 352-365.


Organic matter can be associated with mineralization in hydrothermal ore deposits. One hypothesis is that this organic matter represents remnants of organic fluids (crude oils) that were competing with aqueous fluids for metal transport and contributed to metal endowment. We investigated the transport of gold (Au) in model oil compounds (S-free n-dodecane, CH3(CH2)10CH3, DD; and S-bearing 1-dodecanethiol, CH3(CH2)10CH2SH; DDT) from 25 °C to 250 °C using in-situ synchrotron X-ray absorption spectroscopy (XAS) experiments to determine the speciation and the structural properties of gold complexes in the aqueous- and oil-based fluids. For most experiments, DD or DDT were in contact with Au-bearing acidified water, or acidified water plus 10wt% NaCl (pH25°C = 1.85 in both cases). Gold rapidly partitioned from the aqueous phase into DD and DDT. Below 125 °C, Au(III)Cl is dominant in the DD and the adjacent water with a refined coordination number (CN) of chloride of 4.0(3) and an AuCl bond length of 2.28 Å, consistent with the tetrachloroaurate complex (AuCl4

−) being stable in both the aqueous and organic phases. In contrast, Au(III) is rapidly reduced in the presence of DDT and an Au(I) complex dominates in both water and adjacent DDT with a CN of sulfur ∼2.0, suggesting a [RS-Au-SR]− (RS = DDT with deprotonated thiol group) complex with AuS bond lengths ranging from 2.29(1)Å to 2.31(3)Å. In an open system of DDT in contact with water, of which the water and DDT were analyzed separately, AuCl4− was dominant in the water phase, and Au(RS)2− dominant in DDT, possibly due to different equilibration kinetics in the beaker and glassy carbon tube.

Since sulfur and organothiol compounds are ubiquitous and abundant components in natural oils, this study demonstrates the potential of natural oils to scavenge and enrich gold from co-existing gold-bearing brines. In particular, Au(I) organothiol complexes may contribute to transport in low-temperature (<125 °C) ore fluids such as those in basinal environments – in both hydrothermal fluids and oils. At temperatures ≥125 °C, gold was reduced to metallic gold in all experiments, suggesting that organo-stabilized nanoparticles may be the major form of gold to be scavenged, concentrated or transported in crude oils at these conditions. The results imply that brine-oil interactions may enrich Au in oils, and that oils may be an effective ore fluid in sedimentary environments.

Crede, L.-S., Rempel, K.U., Hu, S.-Y., Evans, K.A., 2018. An experimental method for gold partitioning between two immiscible fluids: Brine and n-dodecane. Chemical Geology 501, 35-50.


Organic matter can be found in many different types of ore deposits, but its role in ore-forming processes is not yet fully understood. Here, we present an experimental method that can be used to determine the partition coefficient (DAu

org/aq: partition coefficient of Au between an hydrocarbon and an aqueous fluid) of gold between two immiscible liquids, and thus whether liquid hydrocarbon fluids such as petroleum can act as ore fluids and transport gold or other metals of interest. To investigate liquid hydrocarbons in the presence of an aqueous liquid doped with gold, we modified the HFS-340Z hydrothermal flow system (Coretest Systems, Inc.) to enable sampling at hydrothermal P-T conditions (≤150 °C and ~5 bar) of each of two density-stratified immiscible liquids. A saline aqueous solution (10 wt% NaCl) was doped with gold and heated with n-dodecane (CH3(CH2)10CH3) to 105 °C and 150 °C. Each brine sample was directly followed by an organic sample until three samples of each liquid were taken. Aqua regia was added to the brine samples to stabilize the gold before ICP-MS analyses. Each organic sample was digested chemically with a mixture of ultra-pure nitric acid and hydrogen peroxide to generate carbon free solutions prior to ICP-MS analysis. This procedure generates reproducible partition coefficients for gold, or presumably any other metal, between hydrocarbon and aqueous liquids, if passivation procedures of the HFS-340Z hydrothermal flow system are strictly followed and error sources are monitored rigorously. The preferred DAu

org/aq between n-dodecane and the brine is 0.05 ± 0.04.

Curry, A., 2018. Early Mongolians ate dairy, but lacked the gene to digest it. Science 362, 626-627.


More than 3000 years ago, herds of horses, sheep, and cows or yaks dotted the steppes of Mongolia. Their human caretakers ate the livestock and honored them by burying the animal bones with their own. Now, analysis of deposits on ancient teeth shows that early Mongolians milked their animals as well. That may not seem surprising. But the DNA of the same ancient individuals shows that as adults they lacked the ability to digest lactose, a key sugar in milk.

The findings deepen an emerging puzzle, challenging an oft-told tale of how people evolve lactase persistence, the ability to produce a milk-digesting enzyme as adults. From other studies, “We know now dairying was practiced 4000 years before we see lactase persistence,” says Christina Warinner of the Max Planck Institute for the Science of Human History in Jena, Germany. With its long history and culture of dairying, “Mongolia shows us how.”

As University of Copenhagen paleoproteomicist Matthew Collins, who was not on the team, puts it, “We thought we understood everything, but then we got more data and see how naïve we were.”

Most people in the world lose the ability to digest lactose after childhood. But in pastoralist populations, the story went, culture and DNA changed hand in hand. Mutations that allowed people to digest milk as adults would have given their carriers an advantage, enabling them to access a rich, year-round source of fat and protein. Dairying spread along with the adaptation, explaining why it is common in herding populations in Europe, Africa, and the Middle East.

But a closer look at cultural practices around the world has challenged that picture. In modern Mongolia, for example, traditional herders get more than a third of their calories from dairy products. They milk seven kinds of mammals, yielding diverse cheeses, yogurts, and other fermented milk products, including alcohol made from mare's milk. “If you can milk it, they do in Mongolia,” Warinner says. And yet 95% of those people are lactose intolerant.

Warinner wondered whether dairying arose recently in Mongolia or whether early Mongolians had lactase persistence and then lost it in a population turnover. Ancient people there might have picked up such mutations from the famed Yamnaya herders—about a third of whom were lactase persistent—who swept east and west from central Eurasia 5000 years ago.

To find answers, her team analyzed human remains from six sites of the Deer Stone-Khirigsuur Complex, a Mongolian culture that between 1300 B.C.E. and 900 B.C.E. built burial mounds marked with standing stones. Because those nomads rarely built permanent structures, and constant winds strip away the soil along with pot fragments and trash pits, archaeological evidence for diet is scarce. So Warinner's Max Planck colleague Shevan Wilkin took dental calculus—the hard plaque that builds up on teeth—from nine skeletons and tested it for key proteins.

The calculus yielded milk proteins from sheep, goats, and bovines such as yak or cow. Yet DNA from teeth and leg bones showed the herders were lactose intolerant. And they carried only a trace of DNA from the Yamnaya, the team reports this week in the Proceedings of the National Academy of Sciences. “They're exploiting these animals for dairying even though they're not lactase persistent,” Collins says.

That disconnect between dairy and DNA isn't limited to Mongolia. Researchers recently found milk proteins on pots at Çatalhöyük in Turkey, which at 9000 years old dates to the beginnings of domestication, 4 millennia before lactase persistence appears. “There seem to be milk proteins

popping up all over the place, and the wonderful evolution we expected to see isn't happening,” Collins says.

Modern Mongolians digest dairy by using bacteria to digest lactose for them, turning milk into yogurt and cheese, along with a rich suite of dairy products unknown in the Western diet. Ancient pastoralists may have adopted similar strategies. “Control and manipulation of microbes is core to this whole transformation … that enables them to have a dairying culture,” Warinner says.

Geneticists are going back to the drawing board to understand why lactase persistence is common—and apparently selected for—in some dairying populations but absent in others. “Why is there a signal of natural selection if there was already a cultural solution?” asks Joachim Burger, a geneticist at Johannes Gutenberg University in Mainz, Germany.

How dairying reached Mongolia is also a puzzle. The Yamnaya's widespread genetic signature shows they replaced many European and Asian Bronze Age populations. But they seem to have stopped at the Altai Mountains west of Mongolia. “Culturally, it's a really dynamic period, but the people themselves don't seem to be changing,” Warinner says. She thinks even though the Yamnaya didn't contribute their genes to East Asia, they did spread their culture, including dairying. “It's a local population that has adopted the steppe way of life.”

Given these surprising results, Warinner has a new goal: To figure out just which microbes helped Mongolians digest milk.

Dai, X., Song, H., Wignall, P.B., Jia, E., Bai, R., Wang, F., Chen, J., Tian, L., 2018. Rapid biotic rebound during the late Griesbachian indicates heterogeneous recovery patterns after the Permian-Triassic mass extinction. GSA Bulletin 130, 2015-2030.

http://dx.doi.org/10.1130/B31969.1

New fossil data from two Early Triassic (Griesbachian to Dienerian) sections from South China show unusually high levels of both benthic and nektonic taxonomic richness occurring in the late Griesbachian. In total, 68 species (including 26 newly originated species) representing mollusks, brachiopods, foraminifers, conodonts, ostracods, and echinoderms occur in the late Griesbachian, indicating well-established and relatively complex marine communities. Furthermore, the nekton shows higher origination rates than the benthos. Analyses of the sedimentary facies and size distribution of pyrite framboids show that this high-diversity interval is associated with well-oxygenated environments. In contrast to the previously suggested scenario, which inferred that persistently harsh environmental conditions impeded the biotic recovery during the Early Triassic, our new findings, combined with recent work, indicate a fitful regional recovery pattern after the Permian-Triassic crisis, resulting in three main diversity highs: late Griesbachian–early Dienerian, early–middle Smithian, and Spathian. The transient rebound episodes were therefore influenced by both extrinsic local (e.g., redox condition, temperature) and intrinsic (e.g., biological tolerances, origination rates) parameters.

Dal Poggetto, G., Castañar, L., Foroozandeh, M., Kiraly, P., Adams, R.W., Morris, G.A., Nilsson, M., 2018. Unexploited dimension: New software for mixture analysis by 3D diffusion-ordered NMR spectroscopy. Analytical Chemistry 90, 13695-13701.

https://doi.org/10.1021/acs.analchem.8b04093

3D DOSY experiments have the potential to provide unique and valuable information, but they are underused, in part because of the lack of efficient processing software. Here, we illustrate the power of 3D DOSY and present MAGNATE, Multidimensional Analysis for the GNAT Environment, an open-source and free software package for the analysis of pulsed field gradient (PFG) 3D NMR diffusion data, distributed under the GNU General Public License. The new software makes it possible for the first time to efficiently analyze and visualize 3D diffusion (e.g., 3D HSQC–DOSY) data using both univariate (e.g., DOSY) and multivariate (e.g., OUTSCORE) methods in a user-friendly graphical interface. The software can be used either independently or as a module in the GNAT program.

Davies, A.J., John, C.M., 2019. The clumped (13C–18O) isotope composition of echinoid calcite: Further evidence for “vital effects” in the clumped isotope proxy. Geochimica et Cosmochimica Acta 245, 172-189.


Carbonate clumped isotope thermometry is based on the thermodynamically dependent relative abundance of 13C–18O bonds (quantified as Δ47) within the carbonate crystal lattice. The clumping of 13C–18O in carbonates is based on a self-reaction of isotope exchange that occurs rapidly at near neutral pH. Similar Δ47-temperature relationships between biogenic and inorganically precipitated carbonate in initial studies led to the promise of a proxy free of biologically driven disequilibrium effects, commonly referred to as “vital effects”. This has been largely the case for most organisms investigated. Biologically mediated disequilibrium precipitation has however been reported in corals and cephalopods and brachiopod molluscs. Echinoderms, despite their complex inter-cellular bio-mineralization strategy, large inter-skeletal fractionation of δ18O, δ13C and rapid calcite precipitation have however not been previously investigated with regards to their clumped isotope composition. We present clumped isotopic composition (Δ47) of 25 inter-skeletal elements of 5 echinoid species with varying growth temperatures. We found no statistically significant inter-skeletal variation in Δ47 in all echinoid species measured, a surprising find given the important inter-skeletal variability reported for δ13C and δ18O. Our echinoid Δ47-temperature calibration however shows a statistically significant positive offset from Δ47-temperature calibration for inorganic calcite of 0.014‰. The pattern of isotopic fractionation in δ18O and Δ47 of echinoderms is not consistent with CO2 hydration or hydroxylation, diffusion or the high-Mg calcite composition of echinoid calcite. Positive offsets in the Δ47 of echinoid calcite may however relate to deviations in the pH of the calcifying fluid from the pH at which equilibrium calcite is precipitated.

de Bar, M.W., Stolwijk, D.J., McManus, J.F., Sinninghe Damsté, J.S., Schouten, S., 2018. A Late Quaternary climate record based on long-chain diol proxies from the Chilean margin. Climate of the Past 14, 1783-1803.

https://www.clim-past.net/14/1783/2018/

In this study we have applied different indices based on long-chain diols, i.e., the long-chain diol index (LDI) as a proxy for past SST, the diol index as an indicator of past upwelling conditions, and the nutrient diol index (NDI) as a proxy for nitrate and phosphate concentrations in seawater. The proxies were analyzed in marine sediments recovered at ODP Site 1234, located within the Peru–Chile upwelling system, with a ∼2 kyr resolution covering the last 150 kyr. We also generated TEXH86 and UK′37 temperature and planktonic δ18O records, as well as total organic carbon (TOC) and accumulation rates (ARs) of TOC and lipid biomarkers (i.e., C37 alkenones, GDGTs, dinosterol, and loliolide) to reconstruct past phytoplankton production. The LDI-derived SST record covaries

with TEXH86- and UK′37-derived SST records as well as with the planktonic δ18O record, implying that the LDI reflects past SST variations at this site. TOC and phytoplankton AR records indicate increased export production during the last interglacial (MIS 5), simultaneous with a peak in the abundance of preserved Chaetoceros diatoms, suggesting intensified upwelling during this period. The diol index is relatively low during the upwelling period, but peaks before and after this period, suggesting that Proboscia diatoms were more abundant before and after the period of upwelling. The NDI reveals the same trends as the diol index, suggesting that the input of nitrate and phosphate was minimal during upwelling, which is unrealistic. We suggest that the diol index and NDI should perhaps be considered as indicators for Proboscia productivity instead of upwelling conditions or nutrient concentrations.

Dean, J.F., van Hal, J.R., Dolman, A.J., Aerts, R., Weedon, J.T., 2018. Filtration artefacts in bacterial community composition can affect the outcome of dissolved organic matter biolability assays. Biogeosciences 15, 7141-7154.


Inland waters are large contributors to global carbon dioxide (CO2) emissions, in part due to the vulnerability of dissolved organic matter (DOM) to microbial decomposition and respiration to CO2 during transport through aquatic systems. To assess the degree of this vulnerability, aquatic DOM is often incubated in standardized biolability assays. These assays isolate the dissolved fraction of aquatic OM by size filtration prior to incubation. We test whether this size selection has an impact on the bacterial community composition and the consequent dynamics of DOM degradation using three different filtration strategies: 0.2 µm (filtered and inoculated), 0.7 µm (generally the most common DOM filter size) and 106 µm (unfiltered). We found that bacterial community composition, based on 16S rRNA amplicon sequencing, was significantly affected by the different filter sizes. At the same time, the filtration strategy also affected the DOM degradation dynamics, including the δ13C signature. However, the dynamics of these two responses were decoupled, suggesting that filtration primarily influences biolability assays through bacterial abundance and the presence of their associated predators. By the end of the 41-day incubations all treatments tended to converge on a common total DOM biolability level, with the 0.7 µm filtered incubations reaching this point the quickest. These results suggest that assays used to assess the total biolability of aquatic DOM should last long enough to remove filtration artefacts in the microbial population. Filtration strategy should also be taken into account when comparing results across biolability assays.

Dececchi, T.A., Narbonne, G.M., Greentree, C., Laflamme, M., 2018. Phylogenetic relationships among the Rangeomorpha: the importance of outgroup selection and implications for their diversification. Canadian Journal of Earth Sciences 55, 1223-1239.


The Rangeomorpha are the oldest, most diverse, and most disparate clade of Ediacaran macrofossils. Easily identifiable by their self-similar branching pattern, they occupied epibenthic niche space ranging from the lowest-tiered and recumbent taxa up to metre-long upright fronds. A phylogenetic analysis using the largest and most complete character set known for this group scored for 14 separate taxa was undertaken to resolve their internal relationships and test previous hypotheses of their evolutionary and ecological history. Owing to the lack of consensus on the relationship amongst Ediacaran clades, several permutations with different potential outgroup taxa were performed. Across these analyses, there is a strong signal for an upright frondose ancestral state for this clade, likely displaying primary branches that were double-sided, nonrotated, with the lower-tiered and recumbent

forms being derived members of a single subclade. This has implications on the life history reconstruction as well as taxonomic implications for this clade and the origins of large multicellular life in the late Ediacaran.

Delgado, L., Batezelli, A., Luna, J., 2018. Petroleum geochemical characterization of Albian-Oligocene sequences in the Campos Basin: “Case study: Eastern Marlim oilfield, offshore, Brazil”. Journal of South American Earth Sciences 88, 715-735.


The current research was performed in the eastern portion of the Marlim oilfield to identify the hydrocarbon-generating potential of the Albian-Oligocene sequences (Macaé Group, Ubatuba and Carapebus formations) in the Campos Basin, Brazil. On the basis of petroleum geochemical proxies, an integrated approach was developed using source rock characterizations to establish the distribution of source rock properties, such as organic matter content, hydrocarbon-generating potential, thermal maturity and stratigraphic thickness. The outcomes of a comprehensive petroleum geochemical characterization were integrated with cuttings and core sample descriptions, biostratigraphic controls, well log analyses and 2-D/3-D seismic interpretations. Our results reveal that for the Albian-Oligocene deposits, the key geochemical properties required to develop hydrocarbon source kitchens converge in specific locations, demonstrating a variable hydrocarbon potential ranging from poor to excellent and suggesting the existence of local generation pods in the central and principally northern portions of the research area. The accumulation and preservation of the organic matter were influenced by the paleo-topography and tectonic controls, and the lowest concentrations of organic carbon were attributed to significant siliciclastic dilution taking place mostly toward the middle and southern portions of the Eastern Marlim oilfield. Lateral variations in both the lithofacies and organic facies are the main conditions controlling the behavior of the petroleum potential in the investigated sediments. Our results indicate that the Macaé Group has sufficient source-rock potential, maturation patterns, and hydrocarbon-generating potential to be considered as an active source rock in the Eastern Marlim oilfield, where the petroleum geochemical properties converge and are adequate to generate hydrocarbon compounds. In addition, the Ubatuba and Carapebus formations are also likely to generate oil and/or gas, but due to their relatively low maturity, it is difficult to establish that these rocks can be active source rocks in the study area.


https://doi.org/10.1080/10916466.2018.1504070

Shale gas is essentially non-traditional natural gas (NG). Shale gas can be considered an unusual alternative energy source. Shale gas production is a method of obtaining the NG trapped between deep underground rocks. Shale gas production is not economical, except for horizontal drilling and hydraulic fracturing methods. Advanced analysis of shale gaseous samples can be done using gas chromatography, mass spectrometry and other modern testing methods. The Orsat apparatus includes three absorption pipettes containing chemical solutions that absorb gases. Absorbents are a 33% by weight aqueous solution of potassium hydroxide (KOH) for carbon dioxide (CO2), alkali pyrogallol for oxygen (O2) and ammoniacal cuprous for carbon monoxide (CO) measurement. Oxygen is absorbed in alkaline pyrogallol or in a chromous solution. Shale gas can be analyzed best gas chromatographically. The capillary column can be separated from all the hydrocarbons and their isomers by alumina, which is used as a stationary phase in the gas chromatographic column, because alumina is highly selective for hydrocarbons. Silica is a specific adsorbent that exhibits greater

applicability for hydrocarbons. The chemical contents of shale gas are similar to those of the conventional NG. The processing, transfer and storage and distribution of shale gas are assumed to be similar to the conventional NG.

Deng, H., Fu, M., Huang, T., Gluyas, J.G., Tong, M., Wang, X., Zhou, W., Liu, F., 2018. Ahdeb oil field, Mesopotamian Basin, Iraq: Reservoir architecture and oil charge history. American Association of Petroleum Geologists Bulletin 102, 2447-2480.

http://archives.datapages.com/data/bulletns/2018/12dec/BLTN17089/bltn17089.html

The Ahdeb oil field is located in the Mesopotamian Basin of central Iraq within a northwest–southeast-trending anticline. Seven oil-bearing layers exist in the eastern area in the field, but there is only one oil-bearing layer in the western area. This study reveals that the reservoir filling process resulted from the difference in the elements in the petroleum system, the oil generation and migration process, and the formation of the structural trap. Most oils in the field, with pristane/phytane < 1 and a high relative abundance of hopanes exceeding C30, were generated from the Upper Jurassic–Lower Cretaceous Chia Gara Formation, whereas some oils were generated from the Lower Cretaceous Ratawi and Zubair Formations. The mid-Upper Cretaceous reservoirs in the field are composed of lime grainstones, packstones, and wackestones.

The main oil accumulation occurred during the Maastrichtian, coinciding with peak oil generation from the Chia Gara Formation with a 50% transformation ratio from organic matter to oil. The reservoirs of the eastern structural trap in the field were filled with large amounts of medium to heavy oils. After the formation of two structural traps in the western area in the mid-Miocene, oils pre-existing in the second layer of the Khasib Formation in the east began migrating toward the structural traps in the west during the late Miocene, as verified by relatively higher 1-/4-methylcarbazole and 1,8-/2,7-dimethycarbazole ratios of oils in the west than that in the east and residual solid bitumen in the east. The strike-slip fault might also have restricted oil or gas migration during the Miocene, limiting oil accumulation in the west.



The phase equilibria of H2O–CO2–NaCl systems is of general interest to many scientific disciplines and technical fields. One aspect is the CO2-mediated corrosion of oil country tubular goods in deep saline aquifers. In this study, CO2 solubility experiments were conducted in simulated oil and gas well environments using a novel experimental apparatus and method. The solubility of CO2in deionised water and NaCl solutions was measured at temperatures of 303.15–363.15 K and pressures of 50–250 bar. The impacts of temperature, pressure and salinity on CO2 solubility are analysed quantitatively and qualitatively and are consistent with published data. CO2 solubility increases with pressure in all cases, and pressure inhibits the effect of temperature on CO2 solubility to some extent. An interesting phenomenon is that CO2 solubility increases with pressure much faster at low pressures than at high ones. A transition pressure of 150 bar was determined at medium-low temperature and low salinity.



Groundwater ecosystems host diverse and complex microbial communities that play important roles in the biogeochemical processing of organic matter and in the maintenance of drinking water quality. Here we investigated the microbial community in suspended particulate matter (SPM) of biogeochemically distinct groundwaters (Hainich Critical Zone Exploratory) by analyzing branched and isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs) from bacteria and archaea, respectively. The contributions of those lipids derived from dead and living organisms were determined by analyses of the core lipid distributions of core and intact polar GDGTs. We compared the groundwater GDGT distributions to the ones from soils of potential recharge areas and with archaeal 16S rRNA-gene based community reconstructions to estimate their origin in these terrestrial subsurface environments and thus their potential use for evaluating soil inputs into groundwater. In soils, the relative abundance of intact polar branched GDGTs (brGDGTs) was lower than that of isoprenoid GDGTs (isoGDGTs; 2% vs 5% of total GDGTs), while the opposite trend (71% vs 22% of total GDGTs) was observed in the core lipid pools. This supports previous observations that soil brGDGT-producing bacteria might be more active and thus have higher regeneration rates than the isoGDGT-producing archaea. We found similar trends in the groundwater that might indicate higher activity (i.e., cell division) of brGDGT-producing bacteria than of isoGDGT-producing archaea. The higher relative abundance of the hexamethylated brGDGT in the groundwater SPM (mean 65 ± 9%, n = 5) than in soils (mean 16 ± 7%, n = 22) indicated an in situ origin of brGDGT-producing bacteria. Higher contributions of penta- and tetra-methylated brGDGTs, which suggested some inputs from soil bacteria, was only detected in two out of seven groundwater samples. The strong correlation between core and intact polar isoGDGTs (R2 = 0.99, n = 7) in groundwater SPM indicated low disturbance (e.g., surface inputs) and suggested indigenous archaeal communities in the groundwater. This was supported by the results from a previous 16S rRNA-gene study that detected distinct archaeal groups in soils and groundwater. This first GDGT study in groundwater demonstrated that even dynamic karstic subsurface environments host an indigenous bacterial and archaeal community that is adapted to the living conditions. Furthermore, fast recharge events are likely detectable using tetraether lipids from the soil microbial community.

DiStefano, V.H., McFarlane, J., Stack, A.G., Perfect, E., Mildner, D.F.R., Bleuel, M., Chipera, S.J., Littrell, K.C., Cheshire, M.C., Manz, K.E., Anovitz, L.M., 2019. Solvent-pore interactions in the Eagle Ford shale formation. Fuel 238, 298-311.


The effect of solvent extraction on pore space was examined on a suite of samples from the Eagle Ford Shale Formation with varying lithologies and maturities. Several solvents ─toluene, cyclohexane, methanol, dichloromethane, and hydrochloric acid─ were contacted with shale samples, extracting the compatible organic matter. The porosity in these extracted shale samples was compared to unmodified samples. The amount and type of organic matter extracted were determined using Gas Chromatography ─ Mass Spectrometry, and the porosity was determined by (Ultra) Small Angle Neutron Scattering. Mostly alkanes and aromatics were detected in the extracts, but other portions of bitumen may also have been present. Only higher molecular weight alkanes were extracted with hydrochloric acid, suggesting that physical dissolution of carbonate minerals may have liberated this portion of organic matter and the solvent was not able to penetrate the bitumen and kerogen to extract the lower molecular weight alkanes. Additionally, a decrease in porosity with extraction was

observed and attributed to a dominant mechanism of kerogen swelling due to kerogen-solvent interaction.

Dombrowski, N., Teske, A.P., Baker, B.J., 2018. Expansive microbial metabolic versatility and biodiversity in dynamic Guaymas Basin hydrothermal sediments. Nature Communications 9, Article 4999.

https://doi.org/10.1038/s41467-018-07418-0

Microbes in Guaymas Basin (Gulf of California) hydrothermal sediments thrive on hydrocarbons and sulfur and experience steep, fluctuating temperature and chemical gradients. The functional capacities of communities inhabiting this dynamic habitat are largely unknown. Here, we reconstructed 551 genomes from hydrothermally influenced, and nearby cold sediments belonging to 56 phyla (40 uncultured). These genomes comprise 22 unique lineages, including five new candidate phyla. In contrast to findings from cold hydrocarbon seeps, hydrothermal-associated communities are more diverse and archaea dominate over bacteria. Genome-based metabolic inferences provide first insights into the ecological niches of these uncultured microbes, including methane cycling in new Crenarchaeota and alkane utilization in ANME-1. These communities are shaped by a high biodiversity, partitioning among nitrogen and sulfur pathways and redundancy in core carbon-processing pathways. The dynamic sediments select for distinctive microbial communities that stand out by expansive biodiversity, and open up new physiological perspectives into hydrothermal ecosystem function.

Dong, L., Jia, G., Li, Q., Li, L., Shi, J., Zhang, C.L., 2018. Intact polar glycosidic GDGTs in sediments settle from water column as evidenced from downcore sediment records. Chemical Geology 501, 12-18.


The origins of intact polar lipid glycerol dialkyl glycerol tetraethers (IPL-GDGTs) with glycosidic headgroups that are present in deep-sea sediments are still unclear. Here, we tried to clarify this issue by comparing variations in TEX86 temperatures and compositions of IPL (dihexose (DH) and monohexose (MH) head groups) and core lipid (CL) GDGTs in a sediment core covering a period since the last glacial time in the northern South China Sea (SCS). Haptophyte-derived alkenones were also analyzed to provide an independent paleo-sea surface temperature (SST) record. The sedimentary DH-GDGTs were composed mainly of DH-GDGT-1, -2, -3, and the crenarchaeol isomer. In contrast, both the sedimentary MH- and CL-GDGTs were composed mainly of crenarchaeol and GDGT-0. However, in each pool of GDGTs, crenarchaeol correlated significantly with other GDGT compounds, suggesting a shared origin. The DH-TEX86-derived temperature values were systematically higher than, but well correlated with CL-TEX86 and UK'37-derived SST values, showing an expected glacial-interglacial increase. This finding suggests that the DH-GDGTs could have originated mainly from the upper water column and may have been well preserved in sediments for a long time. However, the MH-TEX86-derived temperature did not display such a climatic pattern but exhibited unexpected higher values during the last glacial period. We propose that the elevated glacial MH-TEX86-derived temperature was likely associated with the ammonia limitation and subsequently reduced ammonia oxidation rate in seawater during the last glacial period. This study indicates that the sedimentary glycosidic GDGTs could settle mainly from the water column rather than being produced in situ.



Properties of gas hydrate are commonly investigated in laboratory by simulators or studied using the hydrate samples recovered from permafrost and marine sediments. Here synthetic gas hydrate (SGH) is quickly formed for the first time by fluids and bubbles erupted from the active cold seeps at the Formosa Ridge in the South China Sea (SCS). SGH samples are in situ detected by a Raman insertion probe for gas hydrate (RiP-Gh) which is deployed by the remotely operated vehicle (ROV) Faxian. Both spatial and temporal in situ Raman spectra of the SGH samples are acquired in order to determine the structure and the evolution of the synthetic gas hydrate. Authigenic carbonate debris or other debris serving as nucleation particles, which is found in the in situ Raman spectra of SGH samples for the first time, may be one factor that can promote the formation of synthetic gas hydrate. The gas-water interface demonstrated by the observation results, also contributes to the quick formation of SGH samples, which agrees well with the previous study. In situ Raman spectra of three SGH samples which have been placed on the seafloor for 0 h, 4 h and 21 h respectively are acquired. Laboratory Raman spectra of one sample which has been surprisingly found and recovered after 9840 h (410 days) since formed on the seafloor are also acquired. The Raman spectra of the four SGH samples indicate that the methane large-to-small cage occupancy ratios of the hydrates vary from 1.01 to 1.39, and the ratios of methane large-to-gas of the hydrates increase from 0.53 to 1.55. Overall, our work suggests a new explanation for the quick formation of gas hydrate compared to that in laboratory simulation work, and reveals the evolution of synthetic gas hydrate after quick formation, which provides a new insight for the study of natural gas hydrate.



We integrated the results of field surveys with a mesocosm experiment to quantify the ecological impacts of a gasoline and diesel spill on a third-order stream in western Colorado (United States). The spill caused a massive fish-kill of brown trout (Salmo trutta) and mottled sculpin (Cottus bairdii), which extended several kilometers downstream. Despite significant decreases in petroleum hydrocarbon concentrations, subsequent surveys indicated little recovery of fish populations 4 years after the spill. Benthic macroinvertebrate communities were also affected, yet some metrics commonly used to assess stream ecological integrity (e.g., total abundance and species richness) showed no difference between impacted and reference sites. The failure of some groups to recover 2.5 years after the spill was likely a result of their comparatively slow reproduction and recolonization rates. To support our hypothesis that effects observed in the field resulted from petroleum exposure, we conducted a mesocosm experiment in which benthic macroinvertebrate communities were exposed to a simulated diesel spill. We observed significant decreases in the abundance of most macroinvertebrate groups at the lowest exposure concentration (75 mg/L diesel) and a strong concentration-dependent drift response across all groups. Our study suggests that relatively small petroleum spills can significantly affect stream communities, and these effects may persist several years after sediment concentrations return to background levels.

Ekau, W., Auel, H., Hagen, W., Koppelmann, R., Wasmund, N., Bohata, K., Buchholz, F., Geist, S., Martin, B., Schukat, A., Verheye, H.M., Werner, T., 2018. Pelagic key species and mechanisms driving energy flows in the northern Benguela upwelling ecosystem and their feedback into biogeochemical cycles. Journal of Marine Systems 188, 49-62.


The northern Benguela Upwelling System (nBUS) has been facing increasing temperatures and decreasing dissolved oxygen (DO) levels over the last decades. This has implications for key processes and trophic interactions within the ecosystem including shifts in community composition, distribution ranges, and trophic levels, changes in energy flows and migration patterns with feedbacks to biogeochemical processes. Here we summarise the results gained from the GENUS project (Geochemistry and Ecology of the Namibian Upwelling System) focussing on the geochemical and ecological structures and processes dominating the pelagic component of the nBUS. Spatial and temporal distribution patterns of key species of zooplankton and fish larvae yielded biomass estimates (5 to 81 g Wet Mass m−2 (10 to 90% quantile) with a median of 19.5 g Wet Mass m−2 for the upper 200 m) and potential impacts on the vertical carbon flux. Vertical distribution ranges of key taxa were determined reflecting their specific abilities to tolerate hypoxia and, hence, their different adaptive mechanisms to cope with the Oxygen Minimum Zone (OMZ). The shoaling of the 2.5 mL O2 L−1-oxycline (0.24 m y−1) constrains sensitive species and hampers daily and seasonal vertical migrations. It may also affect the ability of organisms to maintain themselves within nearshore habitats by hindering vertical migration into deeper onshore currents. Respiration rates of key species were determined with one standard method (optode respirometry), showing an average respiration rate of 54.6 mL O2 d−1 (g Dry Mass)−1 for the bulk fraction of mesozooplankton, allowing also the estimate of DO consumption by mesozooplankton at different depth layers. Stable isotopic ratios (N, C) revealed trophic interactions and positions of zooplankton and fish. Our results reveal many players within a small range of trophic levels and a dominance of zooplankton taxa (copepods, euphausiids) in terms of biomass over small pelagic fish (sardine, anchovy), essential to consider for future higher-resolution ecosystem modelling.

Emeis, K., Eggert, A., Flohr, A., Lahajnar, N., Nausch, G., Neumann, A., Rixen, T., Schmidt, M., Van der Plas, A., Wasmund, N., 2018. Biogeochemical processes and turnover rates in the Northern Benguela Upwelling System. Journal of Marine Systems 188, 63-80.


Biogeochemical cycles of carbon, nutrients, and oxygen transmit mean states, trends and variations of the physical realm in coastal upwelling systems to their food webs and determine their role in regional budgets of greenhouse gases. This contribution focuses on biogeochemical processes in the northern Benguela Upwelling System (NBUS), where low oxygen levels in upwelling source water are a major influence on carbon and nutrient cycles. Based on measurements during numerous expeditions and results of 3-D regional ecosystem modeling (project GENUS; Geochemistry and Ecology of the Namibian Upwelling System) we here examine source water character, effects of low oxygen conditions on nutrient masses and ratios, and of diazotrophic N2-fixation on productivity of the system and its transition to the adjacent eastern South Atlantic. In available observations, the effects of denitrification in water and sediment and phosphate release from sediments are minor influences on nitrate:phosphate ratios of the system, and excess phosphate in aged upwelling water is inherited from upwelling source water. Contrary to expectation and model results, the low N:P ratios do not trigger diazotrophic N2-fixation in the fringes of the upwelling system, possibly due to a lack of seeding populations of Trichodesmium. We also examine the flux of carbon from the sea surface to either sediment, the adjacent sub-thermocline ocean, or to regenerated nutrients and CO2. Observed

fluxes out of the surface mixed layer are significantly below modeled fluxes, and suggest that regeneration of nutrients and CO2 is unusually intense in the mixed layer. This contributes to very high fluxes of CO2 from the ocean to the regional atmosphere, which is not compensated for by N2-fixation. Based on observations, the NBUS thus is a significant net CO2 source (estimated at 14.8TgCa−1), whereas the CO2 balance is closed by N2-fixation in the model. Methane concentrations were low in surface waters in on-line measurements during 1 expedition, and based on these our estimate for the emission of methane for the entire Benguela system is below 0.2TgCH4 a−1.

Enge, A.J., Wanek, W., Heinz, P., 2018. Preservation effects on isotopic signatures in benthic foraminiferal biomass. Marine Micropaleontology 144, 50-59.


Foraminiferal samples for stable isotope analysis are frequently preserved after field collection or during cruises despite the lack of knowledge if and how preservation changes the elemental and stable isotope composition of the protists. Thus, the aim of this study was to investigate the effects of preservation on natural and stable isotope-enriched foraminifera. We tested the following preservation methods on specimens of the benthic foraminifer Ammonia sp. (without surrounding sediment): drying at room temperature, freezing (−25 °C in seawater), ethanol with and without Rose Bengal (RB), and formalin with and without RB. Natural specimens were preserved for 14, 90, and 240 days, while stable isotope-enriched specimens were preserved for 30 days following a pulse-chase feeding experiment. Regardless of type and length, preservation caused a significant loss of carbon (biomass) of up to 42% and lower nitrogen contents in most treatments. Already preservation for 14 days significantly affected δ13C and δ15N signatures, with the strongest shifts caused by freezing at −25 °C in seawater and formalin fixation (with RB). With longer preservation time, the gap between foraminiferal δ13C signatures and the control signal increased for all preservation methods except for 96% ethanol. The observed shifts in the δ13C signatures in the differently preserved foraminifera are in a range of shifts that are found in the signatures of natural foraminifera and are caused by the uptake of various food sources. Applying different preservation methods therefore can bias trophic interpretations based on natural isotope abundances. Preservation of stable isotope-enriched foraminifera in ethanol (with and without RB) resulted in significantly lower carbon uptake estimates, while freezing caused significantly lower nitrogen uptake estimates. Our findings suggest that, if possible, any storage or preservation should be avoided, especially in formalin or at −25 °C with seawater; otherwise storage should be kept as short as possible. Of all tested methods, drying foraminifera at room temperature was the least affecting method with comparatively low variation among replicates. Comparison of biomass, isotope signatures and uptake estimates obtained from differently preserved specimens should be considered carefully, as differences might not be caused naturally, but by alterations of the cytoplasm during preservation.



Climates during the Paleozoic varied from greenhouse to transitional to icehouse and siliciclastic successions deposited during those times have stratigraphic architectures consistent with magnitudes and frequencies of sea-level fluctuations at the time of deposition. Three Central Appalachian Basin Paleozoic successions, the Early Cambrian Chilhowee Group, the Late Devonian Foreknobs Formation, and the Early Pennsylvanian Breathitt Group, are compared and contrasted to develop

models that relate stratigraphic architectures to greenhouse, transitional and icehouse conditions existing on Earth. Within the upper portion of the Early Cambrian Chilhowee Group, the Hampton and Erwin Formations represent a succession of 2 Myr (3rd-order) sequences consisting of stacked, 40–80 kyr (5th-order), marine parasequences that record low-magnitude, high-frequency sea-level changes consistent with greenhouse conditions. The Late Devonian Foreknobs Formation consists of a series of 0.8–1.0 Myr (3rd-order) composite sequences comprised of stacked unconformity-bounded, 225 to 450 kyr (4th-order) sequences, each containing 40 to 65 kyr (5th-order), marine parasequences. The bases of the unconformity-bounded sequences are marked by erosional surfaces (regressive surfaces of marine erosion, fluvial deposits, or paleosols) indicative of sea-level drops of 10 to 45 m consistent with a transitional greenhouse to icehouse climate. The Early Pennsylvanian Breathitt Group consists of stacked, unconformity-bounded, 100 kyr (4th-order) sequences that lack parasequences. Unconformity-bounded sequences are comprised of (from bottom to top): lowstand incised valley, braided alluvial deposits; transgressive tidal estuarine deposits; and progradational, highstand deltaic deposits. Depths of incised valleys and vertical transition into estuarine facies imply sea-level changes of >50 m consistent with icehouse conditions. This study demonstrates that siliciclastic successions preserve a record of sea-level changes consistent with greenhouse, transitional, and icehouse conditions on the Paleozoic Earth.

Estrela, R., Valio, A., 2018. Superflare ultraviolet impact on Kepler-96 system: A glimpse of habitability when the ozone layer first formed on Earth. Astrobiology 18, 1414-1424.

https://doi.org/10.1089/ast.2017.1724

Kepler-96 is an active solar-type star harboring a Super-Earth planet in close orbit. Its age of 2.3 gigayears is the same as the Sun when there was a considerable increase of oxygen in Earth's atmosphere due to micro-organisms living in the ocean. We present the analysis of superflares seen on the transit light curves of Kepler-96b. The model used here simulates the planetary transit in a flaring star. By fitting the observational data with this model, it is possible to infer the physical properties of the flares, such as their duration and the energy released. We found three flares within the energy range of superflares, where the biggest superflare observed was found to have an energy of 1.81 × 1029 J (1.81 × 1035 ergs). The goal is to analyze the biological impact of these superflares on a hypothetical Earth in the habitable zone of Kepler-96, assuming this planet has protection through different scenarios: an Archean and present-day atmospheres. Also, we compute the attenuation of the flare ultraviolet (UV) radiation through an Archean ocean. The conclusion is that considering the increase in the UV flux by the strongest superflare emission, Escherichia coli and Deinococcus radiodurans could survive on the surface of the planet only if there was an ozone layer present on the planet atmosphere. However, they could escape from the hazardous UV effects at a depth of 28 and 12 m below the ocean surface, respectively. For smaller superflares contribution, D. radiodurans could survive in the surface even in an Archean atmosphere with no ozone.

Ezeldin, F.M., Xie, X., 2018. Source rock evaluation and thermal maturity modeling of Jake oil fields, Fula sub-basin, Muglad Basin, Sudan. Arabian Journal of Geosciences 11, 664.

https://doi.org/10.1007/s12517-018-3889-4

Comprehensive source rock evaluation, burial history modeling, and thermal maturity of oil generation have been investigated in petroleum system of Jake oil fields. The consideration of geological, geochemical, and palynofacies data was used for source rock and thermal maturity. Basin Mod® software was applied to construct the burial and thermal histories and to determine the timing of hydrocarbon generation and expulsion. The modeling was achieved through transient heat flow and

collaborated with measured %Ro. The Lower Cretaceous Abu Gabra Formation was believed to be organic-rich shale and characterized by source rock of excellent abundance and potential that possesses total organic carbon (TOC) ranging from 0.37 to 6.27 wt% and production yield 1.31–49.23 mg HC/g rock. Kerogens can be classified as oil-prone types I–II. Vitrinite reflectance (Ro) and Tmax values suggested that most samples were of early maturation for oil generation. Palynofacies and geochemical combination indicated that amorphous phytoclasts of plant debris were dominated by high TOC and hydrogen index (HI), whereas assemblage kerogens confirmed the presence of oil source rock. Geohistory models showed the highest rapid subsidence rates during the Early-Late Cretaceous. The results demonstrated that petroleum could be generated in the upper (1950–2500 m) and the lower intervals (2550 total depth) of Jake South field. Maturity and hydrocarbon generation modeling indicated that the source rocks reached the early maturation stage in the Early Cretaceous (127 Ma) at a temperature of 90 °C. The middle maturation stage began in the Late Cretaceous (64 Ma) with a temperature of 110 °C. Essential oil generation started approximately 63 Ma ago and continues to the present day.

Fadeev, E., Salter, I., Schourup-Kristensen, V., Nöthig, E.-M., Metfies, K., Engel, A., Piontek, J., Boetius, A., Bienhold, C., 2018. Microbial communities in the East and West Fram Strait during sea ice melting season. Frontiers in Marine Science 5, 429. doi: 10.3389/fmars.2018.00429.

https://www.frontiersin.org/article/10.3389/fmars.2018.00429

Climate models project that the Arctic Ocean may experience ice-free summers by the second half of this century. This may have severe repercussions on phytoplankton bloom dynamics and the associated cycling of carbon in surface waters. We currently lack baseline knowledge of the seasonal dynamics of Arctic microbial communities, which is needed in order to better estimate the effects of such changes on ecosystem functioning. Here we present a comparative study of polar summer microbial communities in the ice-free (eastern) and ice-covered (western) hydrographic regimes at the LTER HAUSGARTEN in Fram Strait, the main gateway between the Arctic and North Atlantic Oceans. Based on measured and modeled biogeochemical parameters, we tentatively identified two different ecosystem states (i.e., different phytoplankton bloom stages) in the distinct regions. Using Illumina tag-sequencing, we determined the community composition of both free-living and particle-associated bacteria as well as microbial eukaryotes in the photic layer. Despite substantial horizontal mixing by eddies in Fram Strait, pelagic microbial communities showed distinct differences between the two regimes, with a proposed early spring (pre-bloom) community in the ice-covered western regime (with higher representation of SAR11, SAR202, SAR406 and eukaryotic MALVs) and a community indicative of late summer conditions (post-bloom) in the ice-free eastern regime (with higher representation of Flavobacteria, Gammaproteobacteria and eukaryotic heterotrophs). Co-occurrence networks revealed specific taxon-taxon associations between bacterial and eukaryotic taxa in the two regions. Our results suggest that the predicted changes in sea ice cover and phytoplankton bloom dynamics will have a strong impact on bacterial community dynamics and potentially on biogeochemical cycles in this region.

Faith, J.T., Rowan, J., Du, A., Koch, P.L., 2018. Plio-Pleistocene decline of African megaherbivores: No evidence for ancient hominin impacts. Science 362, 938-941.


Abstract: It has long been proposed that pre-modern hominin impacts drove extinctions and shaped the evolutionary history of Africa’s exceptionally diverse large mammal communities, but this hypothesis has yet to be rigorously tested. We analyzed eastern African herbivore communities

spanning the past 7 million years—encompassing the entirety of hominin evolutionary history—to test the hypothesis that top-down impacts of tool-bearing, meat-eating hominins contributed to the demise of megaherbivores prior to the emergence of Homo sapiens. We document a steady, long-term decline of megaherbivores beginning ~4.6 million years ago, long before the appearance of hominin species capable of exerting top-down control of large mammal communities and predating evidence for hominin interactions with megaherbivore prey. Expansion of C4 grasslands can account for the loss of megaherbivore diversity.

Editor's summary. Megaherbivore extinctions in Africa: Human ancestors have been proposed as drivers of extinctions of Africa's diverse large mammal communities. Faith et al. challenge this view with an analysis of eastern African herbivore communities spanning the past ∼7 million years (see the Perspective by Bobe and Carvalho). Megaherbivores (for example, elephants, rhinos, and hippos) began to decline about 4.6 million years ago, preceding evidence for hominin consumption of animal tissues by more than 1 million years. Instead, megaherbivore decline may have been triggered by declining atmospheric carbon dioxide and expansion of grasslands.



Micro-nano scale pores can accurately and fastly be measured by the nuclear magnetic resonance (NMR) technique, which provides a new method to quantitatively characterize pore structures in tight sandstone. Based on the method of calibration of mercury pressure data for NMR T2 spectrum, for the measurement inaccuracy due to the mercury saturation less than 100% in tight sandstone, the mercury pressure curve and T2 spectrum is used to cumulate from the maximum pore on the right boundary to the small pores in the left, the range of pore-throat radius measured by the mercury injection in the leftward cumulative curve is selected as a comparable interval of NMR pore-throat radius, and the longitudinal interpolation method and the least square method are utilized to construct the distribution curve of pore-throat radius transformed by T2 spectrum. The modified method is used to obtain NMR T2 spectrum, conversion coefficient of pore-throat radius and pore-throat radius distribution of the Carboniferous-Permian tight sandstone gas reservoirs in the eastern Linqing depression, and characteristics of reservoir pore structures are quantitatively investigated; in addition, in combination with analysis of thin section and scanning electron microscopy, the reservoir effectiveness and cause of the pore structure variability in the tight sandstone are also well studied. The results show that the NMR pore-throat radius curve obtained by the modified method has a high consistency with the mercury injection curve, and the NMR test accuracy of tight sandstone is significantly improved. In the study area, the pore-throat radius of the Carboniferous-Permian tight sandstone mainly ranges from 0.002 to 2 μm, the pore is generally submicro-nano scale, but the pore-throat radius distribution of different types of sandstone varies significantly. The lithic quartz sandstone is rich in siliceous matter and poor in plastic detritus and matrix, generally dominated by submicro-scale pore-throats including micro-scale pore-throats; lithic feldspar sandstone and quartz-rich feldspar lithic sandstone are rich in quartz and poor in plastic detritus and matrix, dominated by submicro-nano scale pore-throats (nano-scale pore-throats predominantly); the lithic fragment-rich feldspar lithic sandstone and lithic sandstone are poor in quartz and rich in plastic detritus and matrix, mainly dominated by nano-scale pore-throats smaller than 0.05 μm. Micropetrographic components are key factors to control pore structure difference and reservoir effectiveness, and the reservoir quality may be macroscopically controlled by sedimentary microfacies; the lithic quartz sandstones of coarse- and fine-grained point bar/riverbed microfacies are the most favorable reservoirs; the lithic feldspar sandstone of fine-grained point bar microfacies, the quartz-rich feldspar lithic sandstone of fine-

grained distributary channel and barrier bar microfacies are relatively favorable reservoirs, while both lithic fragment-rich feldspar lithic sandstone and lithic sandstone of tidal-flat facies are ineffective reservoirs with very poor porosity and permeability.

Fantasia, A., Föllmi, K.B., Adatte, T., Bernárdez, E., Spangenberg, J.E., Mattioli, E., 2018. The Toarcian Oceanic Anoxic Event in southwestern Gondwana: an example from the Andean Basin, northern Chile. Journal of the Geological Society 175, 883.


Palaeoenvironmental and palaeoclimatic changes during the Toarcian Oceanic Anoxic Event (T-OAE) are reported from two successions deposited in the Andean Basin (Chile), based on a high-resolution biostratigraphic (calcareous nannofossils), sedimentological, mineralogical and geochemical analysis. A large negative carbon-isotope excursion was identified in a lower Toarcian storm-dominated marl–limestone alternation, underlining the global extent of the carbon-cycle perturbation and the occurrence of episodic high-energy conditions during the T-OAE. Low total organic carbon content and absence of redox-sensitive trace-element enrichment indicate that the dynamic depositional conditions did not favour the development of oxygen-depleted conditions and the preservation of organic matter. The decrease in kaolinite reflects a shift to more arid conditions, whereas the increase in the chemical index of alteration at the onset of the T-OAE is probably related to a change in the sediment source. Less hydrolytic activity probably promoted a decrease in nutrient input in the Andean Basin. Mercury anomalies support the link between the onset of the Karoo–Ferrar large igneous province activity, the carbon cycle perturbation and the generated environmental change. This paper presents one of the most complete T-OAE studies from the southern hemisphere, and reveals that regional conditions strongly modulated the expression of this global event in the Andean Basin.Supplementary material: the complete dataset, the coefficient of correlation (r) for major and trace elements, and the nannofossil assemblages are available at: https://doi.org/10.6084/m9.figshare.c.4133687



Despite slow nutrient supply to the subtropical surface ocean, its rates of annual inorganic carbon drawdown and net oxygen production are similar to those of nutrient-rich high latitude waters. This surprisingly rapid carbon drawdown, if due to the production and export of marine biomass, cannot be explained in terms of known nutrient supply mechanisms. Moreover, carbon budgets have failed to detect the export of this organic matter. One possible explanation is the export of nutrient-poor organic matter with a composition that avoids detection as sinking particles. We describe three signs of the decomposition of such organic matter in the shallow Sargasso Sea subsurface. First, summertime oxygen consumption at 80–400 m occurs without the rate of nitrate and phosphate production expected from the remineralization of marine biomass, matching the observed summertime mixed layer inorganic carbon drawdown. Second, a seasonal change in the 18O/16O of subsurface nitrate suggests summertime heterotrophic bacterial nitrate assimilation down to ~400 m, as may be required for the remineralization of nutrient-poor organic matter. Third, incubation of subsurface seawater leads to nitrate drawdown and heterotrophic bacterial growth, supporting the thermocline nitrate 18O/16O evidence for heterotrophic nitrate assimilation. These three pieces of evidence suggest the export of nutrient-poor organic matter from the surface at a rate adequate to

explain net community production in the Sargasso Sea. We propose that transparent exopolymer particles or related compounds, generated by a nutrient-limited upper ocean ecosystem, comprise this nutrient-poor export, and that its properties cause its flux out of the euphotic zone to be underestimated by sediment traps. Such nutrient-poor organic matter would contribute little to fisheries, deep ocean carbon dioxide storage, or organic carbon burial, so that it may change our view of the significance of net community production in the subtropical ocean.



The South China Sea (SCS) basin is characterized by a highly unique, diverse, and dynamic seep system. The continuous development of hydrocarbon explorations, and in recent years the methane hydrate exploration and production testing have generated a great amount of seismic profiles and borehole data. Along with seismic profiles for identifying gas-charged sediments, manned submersibles and remotely operated vehicles have been used for seafloor observation and sampling.

Since 1999, large efforts have been made to discover and report the cold seeps and their manifestations. This special issue of South China Sea Seep includes 20 papers investigating methane inventories, fluxes and its role in the carbon cycle and biodiversity. The first paper by Feng D et al. (2018) gives an overview of the seafloor manifestations and the biogeochemistry of seep-influenced environments and ecosystems. The following two papers by Wang JL et al. (2018a) and Wang XJ et al. (2018b) focus on the seismic studies of subsurface free gas and fluid pathways that feeding surface gas hydrates and seafloor seeps. Chen et al. 2018 provide special insight into the diversity and seafloor expressions of seeps, e.g., pockmarks and mud volcanoes. The quantification and distribution features of gas hydrate reservoir are discussed by Wang JL et al. (2018c) and Su et al. (2018), respectively.

The understanding of the biogeochemical processes at seeps and their fingerprints in sedimentary records has also been significantly improved. In particular, the dynamics of subsurface fluid flow and associated geochemical responses (Feng et al., 2018, Hu et al., 2018) are much better understood. The biological, microbiological and biogeochemical processes at seeps are discussed in a couple of contributions (Gong et al., 2018, Li et al., 2018, Lin et al., 2018, Wan et al., 2018, Wang et al., 2018d, Zhang et al., 2018, Zhu et al., 2018). These papers reveal the possible mechanism of methane biogeochemical cycle, document various microbial communities, and distinguish the gas and fluid source, as well as establish potential geochemical markers for seeps.

Guan et al. (2018), Yang et al. (2018) and Wang QX et al. (2018e) report geochemical markers on both modern and ancient methane authigenic carbonate and provide time constraints and geological factors controlling the seepages. Du et al. (2018) and Xi et al. (2018) use the Raman spectroscopy to detect the gas hydrates and authigenic carbonates, which advance our understanding of the dynamics of seep and hydrate systems.

The seep studies in this special issue set the stage for a new and promising, yet challenging investigation of the interplay between carbon cycling and climate change. We propose that the South China Sea seeps should be considered as fascinating natural laboratories and key candidates for ecosystem monitoring and protection. We look forward to the prosperity of seep investigation in this area in the next 10 years, and to the significant advancement it will bring.



Three decades after the discovery of cold seep systems, various sites of hydrocarbon seepage have been found in the South China Sea (SCS). Over the past decade, these sites have become model systems for understanding the variability of hydrocarbon seepage and associated biogeochemical processes. In this review, we describe the cold seep systems of the SCS with an emphasis on seafloor manifestations, fluid sources, biogeochemical processes, and macroecology. Seafloor features associated with seeps include mud volcanoes, pockmarks, and carbonate deposits. A common characteristic of cold seeps is the occurrence of authigenic (i.e., in situ precipitated) carbonate minerals. These carbonates commonly exhibit low δ13C and high δ18O values, suggesting the incorporation of methane-derived carbon and oxygen derived from gas hydrate water. Biogeochemical processes such as sulfate-driven anaerobic oxidation of methane (SD-AOM), the key process at seeps, have been studied in detail with the aim of establishing geochemical proxies to trace these processes into the geological past. We also detail the features characterizing seep ecosystems. Understanding the impact of decomposing methane hydrate on the marine carbon budget remains challenging and requires additional seafloor observations as well as models predicting how gas hydrate responds to changing conditions such as temperature increase, sea level rise, and episodic mass wasting.



Several tens of methane (CH4) seepage sites have been discovered in the northern South China Sea (SCS) during the investigation and exploration of gas hydrates and cold seeps over the past decade. However, our knowledge about methane seepage in the southern SCS remains scarce, especially in the Beikang Basin on the southern slope of the SCS. Four piston cores (BH-CL18, BH-CL23, BH-CL29 and BH-CL35) were collected in the Beikang Basin to understand CH4 cycling in shallow sediments. The extrapolated depths of the sulfate–methane transition zones (SMTZ) of the four cores are between 5.3 and 8.8 mbsf. By simulating the porewater profiles of SO4

2−, CH4, DIC and PO43−

using the reaction-transport model, we estimated that the dissolved SO42− was predominantly

consumed by the anaerobic oxidation of methane (AOM) at rates of 27.5 mmol m−2 yr−1 in BH-CL18, 28.1 mmol m−2 yr−1 in BH-CL23, 43.1 mmol m−2 yr−1 in BH-CL29 and 39.4 mmol m−2 yr−1 in BH-CL35, respectively. Due to intense AOM, almost all the methane sourced from subsurface sediments was depleted within the SMTZ, resulting in negligible benthic methane fluxes. The kink-type depth SO4

2− profile of BH-CL23 was apparently attributable to an enhanced methane flux, which was not captured by the steady-state modelling. Furthermore, highly depleted δ13C values of the dissolved inorganic carbon (DIC) in BH-CL18 (−43.6‰), BH-CL23 (−44‰) and BH-CL29 (−51.2‰) also indicated a methane-derived DIC. In contrast, relatively higher δ13C values in BH-CL35 suggested a mixture of 13C-enriched DIC produced by methanogenesis, as shown by the reversal toward more 13C-enriched DIC below 4.2 mbsf in BH-CL29. To our knowledge, this is the first quantitative study dealing with methane cycling in the shallow sediments of the southern SCS and may have considerable implications for understanding the poorly investigated cold seep and gas hydrate systems on the continental slope of the southern SCS.

Feng, Z., Dong, D., Tian, J., Wu, W., Cai, Y., Shi, Z., Peng, W., 2019. Geochemical characteristics of Lower Silurian shale gas in the Changning-Zhaotong exploration blocks, southern periphery of the Sichuan Basin. Journal of Petroleum Science and Engineering 174, 281-290.


Recent significant breakthroughs have been made of the Lower Silurian shale gas in the Changning-Zhaotong blocks recently, the key exploration area of China. Through comparative research of the gas geochemistry, Longmaxi Formation shale gas is mainly composed of methane (98.8%), with extremely low wetness coefficient (0.49%), and possesses negligible quantities of ethane and propane. The Non-hydrocarbon gases are mainly composed of small-scale quantities of N2 and CO2 of mixed origin. Enriched δ13C1 (from −29.4‰ to −26.7‰) and δ13C2 (from −34.5‰ to −31.6‰) values, together with sapropelic organic matter, indicate a typical overmature oil-type gas. Abnormal geochemical characteristics of shale gas (δ13C1 > δ13C2 > δ13C3) result from merged secondary impacts in the high-maturity and well-confined shale reservoirs, like the mixing of secondary cracking gases, Rayleigh fractionation of C2 when transition metals and water undergo redox reactions. Notable geographic variation can also be observed, as the δ13C1 and δ13C2 values of the Longmaxi Formation become more positive toward the thrust-faulted folds developed in the southern CZ blocks.

Feng, Z., Wei, H., Guo, Y., Bomfleur, B., 2018. A conifer-dominated Early Triassic flora from Southwest China. Science Bulletin 63, 1462-1463.


The end-Permian mass extinction is the greatest biotic crisis in Earth history. Most marine species (>95%) and many land tetrapods (>70%) disappeared within a very short time interval [1]. Previous studies of this dramatic event mainly have focused on evolutionary patterns in animal groups prior to the extinction, and on their recovery during the Early Triassic [2]. Although some macroevolutionary scenarios have been postulated for the changes in land-plant vegetation through the Permian and Triassic, the severity of extinction and, the timing and radiation pattern in the recovery of plant groups during the Early Triassic are still debated [3]. Hitherto there has been little information about plant life in the wake of the end-Permian extinction event, mainly because of the scarcity of records of earliest Triassic plant-bearing deposits worldwide. Here we report on an Early Triassic flora from Southwest China that provides a rare glimpse into the post-extinction vegetation in the (sub)tropics of Cathaysia.

More than 500 plant fossils were collected from a single bed in the top part of the lowermost Triassic Dongchuan Formation near Lubei village of northern Huize County in Yunnan Province, Southwest China. Direct age assessment of the terrestrial formation itself is difficult due to the lack of index fossils. In the study area, however, the Dongchuan Formation overlies the recently refined uppermost Permian Kayitou Formation, and overlain by the Olenekian Jialingjiang Formation [4]. The Dongchuan Formation is considered to be correlative with the marine Feixianguan Formation [5], it is thus that the inferred Induan (early Early Triassic) age of the formation is resulted from an entirely lithostratigraphic correlation equating terrestrial red beds with fossiliferous marine rocks.

The plant-bearing bed contains mass accumulations of branch fragments of Albertia (Fig. 1a–e), a poorly known genus of Agathis-like conifer foliage defined by broad, obovate to elliptical leaves with longitudinal striae and rounded apex [6]. Albertia had long been exclusively from the Buntsandstein (Lower Triassic) of the Vosges Mountains and the Rhineland until it was reported also from coeval deposits of South and North China [7]. In the present collection, the most common remains are branch and leafy-twig fragments with helically arranged leaves (Fig. 1c), but a few larger, complanate

branch fragments have also been found (Fig. 1d). The leaves have a narrowed base, a broad, obovate, concave, multi-veined lamina and an obtuse to mucronate apex (Fig. 1e, f). The material is most similar to Albertia latifolia and A. elliptica based on the broad dimensions and stout appearance of the leaves. Additional plant remains include rare specimens of sphenophyte stems (Paracalamites stenocostatus; Fig. 1g), osmundalean fern foliage (Anomopteris sp. cf. A. mougeotii; Fig. 1h) and a few undetermined seeds. In addition, we recovered a single Lepacyclotes-like sporophyll, characterised by a prominent midrib, free lateral wings flanking the proximal portion, and an elongate acuminate tip (Fig. 1i).

Fichou, D., Morlock, G.E., 2018. Office chromatography: Miniaturized all-in-one open-source system for planar chromatography. Analytical Chemistry 90, 12647-12654.


Current high-performance-thin-layer-chromatography instrumentation is offline and stepwise automated. However, moderate miniaturization offers many advantages and together with the transfer of modern print and media technologies to the field of chromatography (office chromatography) it opens up new avenues. This is demonstrated in an all-in-one open-source system developed for planar chromatography and especially for ultrathin-layer chromatography. Using an InkShield board to control a thermal inkjet cartridge, picoliter drops were printed at a resolution of 96 dpi on the adsorbent layer. Using Marlin, a popular firmware in 3D printing, Cartesian movement of the print head was made possible for full control of the printing process. Open-source software was developed to control the device in each operation step. Sample solutions and mobile phase were inkjet-printed, exemplarily shown for the analysis of dye- or paraben-mixture solutions. Light-emitting diodes (LEDs) were investigated for documentation. For example, deep UV LEDs gave access to 254 nm light, and RGB LEDs gave access to the visible-light range. Calibration functions with correlation coefficients superior to 0.999 were obtained by videodensitometry. The developed modular open-source hardware was compact (26 × 31 × 26 cm3), light (<3 kg), and affordable (€810). For the given analyses, the footprint of current instrumentation needed was miniaturized by a factor of 9. The highly reduced material design complies with green chemistry and lean laboratory. The design and instruction to reproduce the all-in-one open-source system were made freely available at https://github.com/OfficeChromatography. It is intended to boost progress and understanding by the nature of do it yourself.


https://doi.org/10.1111/maps.13130

Acid‐resistant residues (ARR) were separated from the Saratov (L4) meteorite with the aim to shed more light on the origin of the planetary noble gases (the Q‐gases) in meteorites and the nature of their carrier phase (Q‐phase). Eleven fractions were obtained by HCl and HCl+HF etching, ultrasonication, and subsequent density separation of the ARR in isopropanol and isopropanol+NaOH. Two aliquots of the fractions were also treated with H2O2 and HNO3 to investigate any influence of the oxidizing agent on the Q‐gases retention. The separated ARR fractions have been analyzed for C, N, and noble gases using step combustion. Raman and TEM analyses of the carbonaceous phase structures have also been applied for some of the fractions. This appears to be one of the most detailed investigations of the ARR fractions so far. The important

observation made for the ARR fraction studied by TEM is the presence of abundant curved graphene stacks with a variable number of layers. Significant amounts of single‐ and bilayer graphenes and nanosized chromite grains partly covered with graphene layers are also observed. The principal features of the Q noble gases in the studied ARR fractions are the following. (1) Elemental composition of the Q‐gases depends on the extraction protocol. The most interesting is that upon H2O2 oxidation, the noble gases are retained in the sequence Xe<Ar≪He, while after HNO3 it is in the sequence He≪Xe<Ar. (2) The resistance of the Q‐phase against the thermochemical treatment is lower than for the graphite‐like phase. The results of the current work together with literature data suggest that nongraphitizing curved graphene‐like carbon sheets are the most plausible carrier of the Q‐gases.

Fors, Y., Isaksson, S., 2019. GCMS analyses of direct methylated lipids in binders used in 18th–19th century folk painted interiors in Hälsingland, Sweden. Journal of Archaeological Science: Reports 23, 127-136.


Paint fragments were collected from painted 18th and 19th century interiors from traditional buildings in Hälsingland, Sweden. The aim was to identify binders used by the artists by direct-methylation and GCMS analyses of the lipid fraction in the samples. The lipid content was categorized as mainly animal, plant-based or mixed. The study indicates that used colour tone and possibly also underlying foundation (wood, paper or textile) is essential for the artists´ choice of binder components. Animal-lipid based compounds were found to be used for a wide variety of colours, including mixed colour and several light colour tones. Animal and sometimes mixed lipids seem also to be characteristic for colour fragments from paper and textiles. Red, black and blue colours are quite common among the mixed-lipid category. However, half of blue, green and black colours were found in the vegetable lipid group. A tendency towards the plant-lipids was also indicated in colour samples painted on wood. Many different forms of terpenoids were found among the wood samples, suggesting that its origin can be traced mainly to wood composites, such as extractives.

French, B.M., McKay, R.M., Liu, H.P., Briggs, D.E.G., Witzke, B.J., 2018. The Decorah structure, northeastern Iowa: Geology and evidence for formation by meteorite impact. GSA Bulletin 130, 2062-2086.

http://dx.doi.org/10.1130/B31925.1

The Decorah structure, recently discovered in northeastern Iowa, now appears as an almost entirely subsurface, deeply eroded circular basin 5.6 km in diameter and ∼200 m deep, that truncates a near-horizontal series of Upper Cambrian to Lower Ordovician platform sediments. Initial analysis of geological and well-drilling data indicated characteristics suggestive of meteorite impact: a circular outline, a shallow basin shape, discordance with the surrounding geology, and a filling of anomalous sediments: (1) the organic-rich Winneshiek Shale, which hosts a distinctive fossil Lagerstätte, (2) an underlying breccia composed of fragments from the surrounding lithologies, and (3) a poorly known series of sediments that includes shale and possible breccia. Quartz grains in drill samples of the breccia unit contain abundant distinctive shock-deformation features in ∼1% of the individual quartz grains, chiefly planar fractures (cleavage) and planar deformation features (PDFs). These features provide convincing evidence that the Decorah structure originated by meteorite impact, and current models of meteorite crater formation indicate that it formed as a complex impact crater originally ∼6 km in diameter. The subsurface characteristics of the lower portion of the structure are not well known; in particular, there is no evidence for the existence of a central uplift, a feature generally

observed in impact structures of comparable size. The current estimated age of the Decorah structure (460–483 Ma) suggests that it may be associated with a group of Middle Ordovician impact craters (a terrestrial “impact spike”) triggered by collisions in the asteroid belt at ca. 470 Ma.

Fuentes-Lema, A., Sanleón-Bartolomé, H., Lubián, L.M., Sobrino, C., 2018. Effects of elevated CO2 and phytoplankton-derived organic matter on the metabolism of bacterial communities from coastal waters. Biogeosciences 15, 6927-6940.


Microcosm experiments to assess the bacterioplankton's response to phytoplankton-derived organic matter obtained under current and future ocean CO2 levels were performed. Surface seawater enriched with inorganic nutrients was bubbled for 8 days with air (current CO2 scenario) or with a 1000ppm CO2 air mixture (future CO2 scenario) under solar radiation. The organic matter produced under the current and future CO2 scenarios was subsequently used as an inoculum. Triplicate 12L flasks filled with 1.2µm of filtered natural seawater enriched with the organic matter inocula were incubated in the dark for 8 days under CO2 conditions simulating current and future CO2 scenarios, to study the bacterial response. The acidification of the media increased bacterial respiration at the beginning of the experiment, while the addition of the organic matter produced under future levels of CO2 was related to changes in bacterial production and abundance. This resulted in a 67% increase in the integrated bacterial respiration under future CO2 conditions compared to present CO2 conditions and 41% higher integrated bacterial abundance with the addition of the acidified organic matter compared to samples with the addition of non acidified organic matter. This study demonstrates that the increase in atmospheric CO2 levels can impact bacterioplankton metabolism directly, by changes in the respiration rate, and indirectly, by changes on the organic matter, which affected bacterial production and abundance.



Reservoir solid bitumen is pervasive throughout the Sinian Dengying Formation dolomites of the Sichuan Basin and neighboring areas, yet its origin remains controversial. Optical and scanning electron microscope (SEM) studies of the Dengying Formation were carried out to elucidate the nature and origin of the solid bitumen. Solid bitumen in dissolution pores, intercrystal pores, and stylolites appears to have formed in association with regional hydrocarbon charging processes. Reservoir solid bitumen displays a variety of morphologies, each of which appears to reflect different precursor hydrocarbons. Massive/crust-like solid bitumen was probably derived from solid precursors whereas finger-like solid bitumen likely evolved from liquid precursors. Sheet-like and thin skinned globular solid bitumen appeared to have precipitated from wet gas precursors. Analyzed solid bitumen is characterized by high random reflectance (average = 3.4%) and bireflectance values (4.2–6.9%), exhibits strong optical anisotropy, and displays different coke structures, including granular mosaic, domain, and fibrous. The coke textures, which appear to reflect the nature of bitumen precursors, formed by physical coalescence of mesophase spheres and parallel arrangement of laminated aromatic sheets in association with a rapid heating event. The inferred thermal episode, which is evidenced by the presence of hydrothermal minerals, including saddle dolomite, quartz, authigenic illite, and barite, may have been associated with the Late Permian eruption of the Emeishan Traps. Thus, widespread solid bitumen in the Dengying Formation reflects the effects of

hydrothermal alteration rather than the impact of normal burial-related thermal maturation. Further, the close association of sold bitumen and authigenic kaolinite indicates that natural deasphalting plays a role in the formation of reservoir solid bitumen.

Gao, Y., Wu, S., Feng, L., 2019. Rapid and direct determination of fatty acids and glycerides profiles in Schisandra chinensis oil by using UPLC-Q/TOF-MSE. Journal of Chromatography B 1104, 157-167.


Fatty acids and glycerides are globally accepted quality and nutrition indicators of oils. Schisandra chinensis (S. chinensis) is a good functional oil source, with an oil content of 10–50% (dry weight). In this study, the UPLC-Q/TOF-MSE technique was developed to profile FFA and glycerides in the S. chinensis oils directly. The results showed that all of the 36 FFA calibration equations of the mixture standard had good linear relationships (R2 > 0.99). The limit of detection for the tested compounds ranged from 0.0001 to 0.0200 μg/mL, while the limit of quantification ranged from 0.0005 to 0.1300 μg/mL. In total, seventeen FFAs, six diglycerides and 20 triglycerides were identified. Linoleic, oleic, stearic and palmitic acids were the most abundant FFAs in the S. chinensis oils. It was also found that S. chinensis oil is rich in the L-L, L-L-L, O-L-L and O-L-O glycerides. These results will be helpful for the use of this technique in physicochemical evaluation and for further application development.

Garanina, I.A., Fisunov, G.Y., Govorun, V.M., 2018. BAC-BROWSER: The tool for visualization and analysis of prokaryotic genomes. Frontiers in Microbiology 9, 2827. doi: 10.3389/fmicb.2018.02827.


Prokaryotes are actively studied objects in the scope of genomic regulation. Microbiologists need special tools for complex analysis of data to study and identification of regulatory mechanism in bacteria and archaea.

We developed a tool BAC-BROWSER, specifically for visualization and analysis of small prokaryotic genomes. BAC-BROWSER provides tools for different types of analysis to study a wide set of regulatory mechanisms of prokaryotes:

- transcriptional regulation by transcription factors (TFs), analysis of TFs, their targets, and binding sites.

- other regulatory motifs, promoters, terminators and ribosome binding sites- transcriptional regulation by variation of operon structure, alternative starts or ends of

transcription.- non-coding RNAs, antisense RNAs- RNA secondary structure, riboswitches- GC content, GC skew, codon usage

BAC-browser incorporated free programs accelerating the verification of obtained results: primer design and oligocalculator, vector visualization, the tool for synthetic gene construction. The program is designed for Windows operating system and freely available for download in http://smdb.rcpcm.org/tools/index.html.


https://doi.org/10.1038/s41561-018-0227-0

Emission budgets are defined as the cumulative amount of anthropogenic CO2 emission compatible with a global temperature-change target. The simplicity of the concept has made it attractive to policy-makers, yet it relies on a linear approximation of the global carbon–climate system’s response to anthropogenic CO2 emissions. Here we investigate how emission budgets are impacted by the inclusion of CO2 and CH4 emissions caused by permafrost thaw, a non-linear and tipping process of the Earth system. We use the compact Earth system model OSCAR v2.2.1, in which parameterizations of permafrost thaw, soil organic matter decomposition and CO2 and CH4 emission were introduced based on four complex land surface models that specifically represent high-latitude processes. We found that permafrost carbon release makes emission budgets path dependent (that is, budgets also depend on the pathway followed to reach the target). The median remaining budget for the 2 °C target reduces by 8% (1–25%) if the target is avoided and net negative emissions prove feasible, by 13% (2–34%) if they do not prove feasible, by 16% (3–44%) if the target is overshot by 0.5 °C and by 25% (5–63%) if it is overshot by 1 °C. (Uncertainties are the minimum-to-maximum range across the permafrost models and scenarios.) For the 1.5 °C target, reductions in the median remaining budget range from ~10% to more than 100%. We conclude that the world is closer to exceeding the budget for the long-term target of the Paris Climate Agreement than previously thought.

Gathungu, R.M., Larrea, P., Sniatynski, M.J., Marur, V.R., Bowden, J.A., Koelmel, J.P., Starke-Reed, P., Hubbard, V.S., Kristal, B.S., 2018. Optimization of electrospray ionization source parameters for lipidomics to reduce misannotation of in-source fragments as precursor ions. Analytical Chemistry 90, 13523-13532.


Lipidomics requires the accurate annotation of lipids in complex samples to enable determination of their biological relevance. We demonstrate that unintentional in-source fragmentation (ISF, common in lipidomics) generates ions that have identical masses to other lipids. Lysophosphatidylcholines (LPC), for example, generate in-source fragments with the same mass as free fatty acids and lysophosphatidylethanolamines (LPE). The misannotation of in-source fragments as true lipids is particularly insidious in complex matrixes since most masses are initially unannotated and comprehensive lipid standards are unavailable. Indeed, we show such LPE/LPC misannotations are incorporated in the data submitted to the National Institute of Standards and Technology (NIST) interlaboratory comparison exercise. Computer simulations exhaustively identified potential misannotations. The selection of in-source fragments of highly abundant lipids as features, instead of the correct recognition of trace lipids, can potentially lead to (i) missing the biologically relevant lipids (i.e., a false negative) and/or (ii) incorrect assignation of a phenotype to an incorrect lipid (i.e., false positive). When ISF is not eliminated in the negative ion mode, ∼40% of the 100 most abundant masses corresponding to unique phospholipids measured in plasma were artifacts from ISF. We show that chromatographic separation and ion intensity considerations assist in distinguishing precursor ions from in-source fragments, suggesting ISF may be especially problematic when complex samples are analyzed via shotgun lipidomics. We also conduct a systematic evaluation of electrospray ionization (ESI) source parameters on an Exactive equipped with a heated electrospray ionization (HESI-II) source with the objective of obtaining uniformly appropriate source conditions for a wide range of lipids, while, at the same time, reducing in-source fragmentation.

Gbadamosi, A.O., Kiwalabye, J., Junin, R., Augustine, A., 2018. A review of gas enhanced oil recovery schemes used in the North Sea. Journal of Petroleum Exploration and Production Technology 8, 1373-1387.

https://doi.org/10.1007/s13202-018-0451-6

The rate of replacement of produced oil and gas reserves by new discoveries is in a state of steady decline. Instead of searching for rare new oil fields, it is more economically justified to improve production from the existing and known fields. This is often achieved using enhanced oil recovery (EOR) technologies. The application of EOR in the North Sea dates to the mid-1970’s with most of the fields being flooded with gas due to their light oils. Following a critical review of relevant published literature, the EOR methods in the past five decades are: water alternating gas (WAG), miscible gas injection (MGI), foam assisted water alternating gas (FAWAG), simultaneous water and gas (SWAG), and microbial enhanced oil recovery. The first part of this paper explores the advantages and limitations of the field implementation of gas EOR methods in North Sea oil fields. In the second part, new screening criteria of WAG, SWAG, MGI and FAWAG were developed by performing statistical analysis of the data from the past field experiences, especially in the North Sea. The screening criteria of the future methods are clearly documented in the literature and therefore not covered in this study. From the screening criteria, it has been identified that most North Sea fields qualify for WAG. This explains why WAG has been the most common scheme in the North Sea. FAWAG should also be implemented either after WAG or SWAG when the residual oil saturation is < 20%.

Gebauer, S., Grenfell, J.L., Lehmann, R., Rauer, H., 2018. Effect of geologically constrained environmental parameters on the atmosphere and biosphere of Early Earth. ACS Earth and Space Chemistry 2, 1112-1136.

https://doi.org/10.1021/acsearthspacechem.8b00088

The Great Oxidation Event (GOE) about 2.3 gigayears ago denotes the first major rise of atmospheric molecular oxygen (O2) in Earth’s history. As a consequence, the planet experienced the emergence of widespread habitability and complex life. Recently, there has been a revolution in improved methods for constraining geological data for atmospheric pressure, composition, and ocean temperature of the early Earth. We investigate the effect of this revised data upon processes which drove the GOE. Results suggest that increasing Archean carbon dioxide (CO2) produces increased O2 with height due to enhanced CO2 photolysis. This is counterbalanced by stronger O2 destruction as a result of enhanced carbon monoxide (CO) (from increased CO2) and nitrogen oxides (NOx) (from decreased hydroxyl via increased CO). Pre-GOE atmospheres with low O2 yet high CO2 could counteract O2 accumulation. For low surface pressures of 0.5 bar, O2 decreases between 0.5 to 0.005 bar. This arose mainly from O2 destruction via hydrogen oxides from enhanced water from higher temperatures for p < 0.01 bar and weaker O2 production via less ultraviolet radiation that initiates ozone production via CO2 photolysis. Shortly before the GOE, ∼20% lower net primary productivity (NPP) can maintain comparable O2 as for a 1 bar atmosphere and, hence, the accumulation of O2 produced by a photosynthetic biosphere is supported. We identify new O2 production and destruction pathways with NOx containing species for Archean Earth for high CO2 atmospheres and low/high surface pressure. On increasing ocean temperatures, NPP is reduced due to lower O2 solubility before the GOE. This facilitates atmospheric O2 accumulation.



Coagulation is an important process to remove organics from water. The molecular composition and structure of organic matter influence water quality in many ways, and the lack of information regarding the organics removed by different coagulants makes it challenging to optimize coagulation processes and ensure reclaimed water safety. In this paper, we investigated coagulation of secondary biological effluent from a municipal sewage treatment plant with different coagulants. We emphasized investigation of organics removal characteristics at the molecular level using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with electrospray ionization (ESI). We found that conventional coagulants can only partially remove condensed polycyclic aromatics and polyphenols with low H/C (H/C < 0.7) and highly unsaturated and phenolic compounds and aliphatic compounds with high O/C (O/C > 0.6). A new coagulant, CBHyC, had better removal efficiencies for all organics with different element compositions and molecular structures, especially organics that are resistant to conventional coagulants such as highly unsaturated and phenolic compounds and aliphatic compounds located in 0.3 < O/C < 0.8 and 1.0 < H/C < 2.0 regions and sulfur-containing compounds with higher O/C (e.g., anionic surfactants and their metabolites or coproducts). This study provides molecular insights into the organics removed by different coagulants and provides data supporting the possible optimization of advanced wastewater treatment processes.


http://rspb.royalsocietypublishing.org/content/285/1891/20182004.abstract

Microorganisms are the chief primary producers within present-day deep-sea hydrothermal vent ecosystems, and play a fundamental role in shaping the ecology of these environments. However, very little is known about the microbes that occurred within, and structured, ancient vent communities. The evolutionary history, diversity and the nature of interactions between ancient vent microorganisms and hydrothermal vent animals are largely undetermined. The oldest known hydrothermal vent community that includes metazoans is preserved within the Ordovician to early Silurian Yaman Kasy massive sulfide deposit, Ural Mountains, Russia. This deposit contains two types of tube fossil attributed to annelid worms. A re-examination of these fossils using a range of microscopy, chemical analysis and nano-tomography techniques reveals the preservation of filamentous microorganisms intimately associated with the tubes. The microfossils bear a strong resemblance to modern hydrothermal vent microbial filaments, including those preserved within the mineralized tubes of the extant vent polychaete genus Alvinella. The Yaman Kasy fossil filaments represent the oldest animal–microbial associations preserved within an ancient hydrothermal vent environment. They allude to a diverse microbial community, and also demonstrate that remarkable fine-scale microbial preservation can also be observed in ancient vent deposits, suggesting the possible existence of similar exceptionally preserved microfossils in even older vent environments.

Georgiou, C.D., 2018. Functional properties of amino acid side chains as biomarkers of extraterrestrial life. Astrobiology 18, 1479-1496.

https://doi.org/10.1089/ast.2018.1868

The present study proposes to search our solar system (Mars, Enceladus, Europa) for patterns of organic molecules that are universally associated with biological functions and structures. The functions are primarily catalytic because life could only have originated within volume/space-constrained compartments containing chemical reactions catalyzed by certain polymers. The proposed molecular structures are specific groups in the side chains of amino acids with the highest catalytic propensities related to life on Earth, that is, those that most frequently participate as key catalytic groups in the active sites of enzymes such as imidazole, thiol, guanidinium, amide, and carboxyl. Alternatively, these or other catalytic groups can be searched for on non-amino-acid organic molecules, which can be tested for certain hydrolytic catalytic activities. The first scenario assumes that life may have originated in a similar manner as the terrestrial set of α-amino acids, while the second scenario does not set such a requirement. From the catalytic propensity perspective proposed in the first scenario, life must have invented amino acids with high catalytic propensity (His, Cys, Arg) in order to overcome, and be complemented by, the low catalytic propensity of the initially available abiogenic amino acids. The abiogenic and the metabolically invented amino acids with the lowest catalytic propensity can also serve as markers of extraterrestrial life when searching for patterns on the basis of the following functional propensities related to protein secondary/quaternary structure: (1) amino acids that are able to form α-helical intramembrane peptide domains, which can serve as primitive transporters in protocell membrane bilayers and catalysts of simple biochemical reactions; (2) amino acids that tend to accumulate in extremophile proteins of Earth and possibly extraterrestrial life. The catalytic/structural functional propensity approach offers a new perspective in the search for extraterrestrial life and could help unify previous amino acid–based approaches.

Germanou, L., Ho, M.T., Zhang, Y., Wu, L., 2018. Intrinsic and apparent gas permeability of heterogeneous and anisotropic ultra-tight porous media. Journal of Natural Gas Science and Engineering 60, 271-283.


Accurate prediction of unconventional gas production requires deep understanding of the permeability of complex rock samples. Several predictive expressions of permeability, which include either simplifications of the porous media structure or the flow mechanisms, have been proposed recently. The main objective of this research is to quantify the impact of solid matrix complexity on both intrinsic and apparent permeability. To this end, numerous two-dimensional random porous media structures are constructed using the quartet structure generation set algorithm. Parametric and statistical analysis reveals the importance of the specific surface area of pores, tortuosity, heterogeneity and degree of anisotropy. Special focus is given to the directional dependency of the permeability on isotropic and anisotropic geometries, considering the great impact of anisotropy on the laboratory evaluation of permeability data and the anisotropic nature of shale rocks. Simulation results, for the same value of porosity, clearly indicate the drastic improvement of permeability due to the reduction of specific surface area of pores and their height to width ratio. This suggests that rock matrix complexity has significant impact on permeability and should not be neglected while forming permeability formulations for porous media. Finally, the results of the apparent permeability, obtained by solving the gas kinetic equation, are taken into consideration to demonstrate the enhancement ratio, slip factor and their correlation with the aforementioned parameters. Semi-analytical expressions for intrinsic and apparent permeability, considering continuum and slip flow respectively, are derived. The proposed formulations, suitable for both isotropic and anisotropic structures, have the advantage of not entailing any numerical or experimental data as input.

Ghalamizade Elyaderani, S.M., Jafari, A., 2019. Microfluidics experimental study in porous media applied for nanosilica/alkaline flooding. Journal of Petroleum Science and Engineering 173, 1289-1303.


This study examines for the first time the impact of silica nanoparticle on alkaline flooding with the aim of enhancing heavy oil recovery. The results show that the presence of silica nanoparticle and its increased concentration in alkaline-nanoparticle solution may cause an interfacial tension whose rates in equal concentrations of nanoparticle and two types of alkali is greater in the case of sodium carbonate than sodium hydroxide. Also, alkaline-nanoparticle solution - as against pure alkaline solution - has a higher capacity for wettability alteration of the medium from oil-wet to water-wet. In fact, the contact angle can vary from 140° to about 60-40° in the alkaline solution and in the presence of the nanoparticle; this value can reach even about 10°. The phase behavior test also indicated that the presence of nanoparticle in an alkaline solution has no effect on the type of emulsion formed (water-in-oil), and only the number of droplets of water and their size will change in oil. The viscosity test also proved that increase of the nanoparticle's concentration could improve fluid viscosity by 0.6 cp in sodium carbonate solution and 3 cp in sodium hydroxide solution. Moreover, the results of the design of experiments and flooding analysis revealed that in alkaline-nanoparticle flooding, alkali concentration plays a more important role in increasing oil recovery than the concentration of the nanoparticle. Also, the presence of nanoparticle in alkaline flooding up to the optimal concentration of nanoparticle leads to an increase in oil extraction. This rise of oil recovery is about 3% in sodium carbonate flooding and about 11% in sodium hydroxide flooding; also, an increase beyond the optimal concentration will reduce the amount of oil recovery. In addition, the presence of silica nanoparticle in alkaline flooding can reduce formation damage if low concentration of nanoparticle is utilized.

Ghanizadeh, A., Clarkson, C.R., Vahedian, A., Ardakani, O.H., Wood, J.M., Sanei, H., 2018. Laboratory-based characterization of pore network and matrix permeability in the Montney Formation: Insights from methodology comparisons. Bulletin of Canadian Petroleum Geology 66, 472-498.

https://pubs.geoscienceworld.org/cspg/bcpg/article/66/2/472/565807/laboratory-based-characterization-of-pore-network

This work presents results from an ongoing laboratory study investigating pore network characteristics and matrix permeability of selected intervals within the Montney Formation (Western Canada). The primary objectives are to: 1) compare different laboratory-based methodologies for determination of porosity and matrix permeability; 2) characterize the pore network attributes (porosity, pore size distribution (PSD), dominant pore throat size, specific surface area) and matrix permeability of the selected target intervals; and 3) analyse the effects of different controlling factors (anisotropy, effective stress, bitumen saturation) on matrix permeability. Eight selected pairs of core plugs, drilled vertically and horizontally, are analysed in this study. These core plugs are obtained from a vertical interval of 15 m within the fine-grained intervals of the Upper Montney Formation in British Columbia (Canada). The experimental techniques used for characterization include: bitumen reflectance (BRo); RockEval pyrolysis; helium pycnometry; Archimedes, caliper and 3D laser scanner analyses; low-pressure gas (N2) adsorption; pulse-decay; and crushed-rock gas (N2, He) permeability measurements.

Excluding one of the samples (a laminated vertical core plug): 1) the slipcorrected pulse-decay gas (N2) permeability values (measured at effective stress of 15.8 MPa) and apparent crushed-rock gas (He) permeability values generally increase with increasing porosity (4.2–8.1%), ranging from

1.4·10−5 to 8.6·10−4 mD: and 2) the slip-corrected pulse-decay (N2) permeability values (1.2·10−4−8.6·10-4 mD) are consistently higher than apparent crushed-rock (He) permeability values (1.4·10−5−1·10-4 mD). Pulse-decay (N2) permeability values measured parallel to bedding (horizontal core plugs) are consistently between 10% and 25 times higher than those measured perpendicular to bedding (vertical core plugs). Based on a single pair of laminated core plugs analysed in this study, the degree of permeability anisotropy (ratio between parallel and perpendicular permeability values) appears to be significantly higher for the laminated core plugs (up to 25 times) than bioturbated core plugs (up to 3.5 times). Compared to pulse-decay (N2) permeability values, there is a minimal discrepancy (considering the maximum experimental error margin) between the crushed-rock gas permeability values that were measured on pairs of horizontal/vertical core plugs after crushing/sieving. In a gross sense, slip-corrected pulse-decay (N2) permeability values decrease with increasing bitumen saturation.

Applying multiple analysis techniques on a selected suite of core plugs and crushed-rock materials derived from them, this study provides: 1) valuable insight into the causes of observed variations in porosity/permeability values obtained from laboratory-based techniques; and 2) an integrated description of pore network characteristics and matrix permeability for selected fine-grained intervals within the Montney Formation.

Gharibshahi, R., Jafari, A., Ahmadi, H., 2019. CFD investigation of enhanced extra-heavy oil recovery using metallic nanoparticles/steam injection in a micromodel with random pore distribution. Journal of Petroleum Science and Engineering 174, 374-383.


The present study simulated thermal enhanced oil recovery (steam and nanoparticles) for the first time using computational fluid dynamics. To better visualize fluid flow in the reservoir, a 2D micromodel generated by commercial grid generation tools was used as the porous medium. Four parameters that have a great impaction on the process were studied to determine the best combination of factors to attain maximum oil recovery. Type of nanoparticle, volume fraction of nanoparticles, diameter of nanoparticles and temperature of injected fluid were examined using the Taguchi method. All governing equations were solved in Fluent software based on finite volume. The numerical results were in a good agreement with the experimental results and the data shows that Al2O3 nanoparticles have the greatest potential for enhanced oil recovery in comparison with CuO and Fe3O4 nanoparticles. Decreasing the diameter of the nanoparticles and increasing their volume fraction in the base fluid and the temperature of the injected fluid improved oil recovery and a large amount of oil was produced from the porous medium. Injecting the nanofluid at an optimal level decreased the viscosity of the extra heavy oil from 35 to 25 Pa s.

Ghiran, M.D., Popa, M.E., Mariş, I., Gheorghe, Ş., 2018. Petrography and geochemistry of dispersed organic matter in the Oligocene source rocks of the central-western part of the Getic Depression, Romania. International Journal of Coal Geology 200, 153-165.


The aims of this study include the evaluation and interpretation of Oligocene source rocks from the Central-Western part of the Getic Depression, Romania, and the identification of their maturation and their hydrocarbon potential. 24 argillite samples belonging to the source rocks were studied using organic petrography and geochemistry methods, including Rock-Eval pyrolysis, and the following sets of results were obtained: maceral diversity, values of vitrinite reflectance, thermal alteration

index, and organic geochemical values. The Oligocene disperse organic matter contains both, humic and terrestrial organic matter, as well as sapropelic, marine, algal matter, represented by telalginite and lamalginite. Several anoxic deep marine water intervals were recorded in the Getic Depression. The samples are immature, with Tmax values ranging between 415 °C and 434.5 °C, and random vitrinite reflectance of 0.32% and 0.53%. The samples yield a total organic content between 0.55% and 5.71%, with a hydrogen index between 9 and 379 mg/g, showing two types of kerogen: a. mixed type II-III kerogen, indicating a generative potential for hydrocarbon and gas, and b. type III kerogen, indicating a gas generative potential.



One of the challenges in the petroleum hydrocarbon contaminated groundwater remediation by oxygen releasing compounds (ORCs) is to identify the remediation mechanism and determine the impact of ORCs on the environment and the intrinsic groundwater microorganisms. In this research, the application of encapsulated magnesium peroxide (MgO2) nanoparticles in the permeable reactive barrier (PRB) for bioremediation of the groundwater contaminated by toluene and naphthalene was studied in the continuous flow sand-packed plexiglass columns within 50 d experiments. For the biodiversity studies, next generation sequencing (NGS) of the 16S rRNA gene was applied. The results showed that naphthalene was metabolized (within 20 days) faster than toluene (after 30 days) by microorganisms of the aqueous phase. By comparing the contaminant removal in the biotic (which resulted in the complete contaminant removal) and abiotic (around 32% removal for naphthalene and 36% for toluene after 50 d) conditions, the significant role of microorganisms on the decontamination process was proved. Furthermore, the attached microbial communities on the porous media were visualized by scanning electron microscopy (SEM). Microbial community structure analysis by NGS technique revealed that the microbial species which were able to degrade toluene and naphthalene such as P. putida and P. mendocina respectively were stimulated by addition of MgO2 nanoparticles. The presented study resulted in a momentous insight into the application of MgO2 nanoparticles in the hydrocarbon compounds removal from groundwater.

Giardina, M., McCurry, J.D., Cardinael, P., Semard-Jousset, G., Cordero, C., Bicchi, C., 2018. Development and validation of a pneumatic model for the reversed-flow differential flow modulator for comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1577, 72-81.


The development of the reversed fill/flush modulator represents a significant advancement in flow-modulated, comprehensive two-dimensional gas chromatography (GC × GC). Compared to the forward flush/fill modulator, the reversed-flow modulator is less susceptible to baseline anomalies and peak tailing as a result of modulator channel overfilling or insufficient purging of high concentration analytes. Flow reversal requires the addition of a bleed capillary not present in the forward-flow modulator. Selecting the appropriate restriction of the bleed capillary is critical. If the bleed capillary is too restrictive, eluate from the first-dimension column can split between the modulator channel and second-dimension column, which also results in baseline artifacts. To gain a better understanding of the reversed-flow modulator, a comprehensive pneumatic model was developed. The model was validated by comparing calculated and measured hold-up times. The

errors in calculated hold-up times were less than 1% of the measured values. The model can be used to predict first-dimension eluate splitting and determine the optimal bleed capillary dimensions to prevent its occurrence. Calculation of the modulator hold-up time can be used to determine the maximum collection time to ensure comprehensive analysis and optimal flush times for partial fill operation.

Gibbons, A., 2018. Eruption made 536 ‘the worst year to be alive’. Science 362, 733-734.


Ask medieval historian Michael McCormick what year was the worst to be alive, and he's got an answer: “536.” Not 1349, when the Black Death wiped out half of Europe. Not 1918, when the flu killed 50 million to 100 million people, mostly young adults. But 536. In Europe, “It was the beginning of one of the worst periods to be alive, if not the worst year,” says McCormick, a historian and archaeologist who chairs the Harvard University Initiative for the Science of the Human Past.

A mysterious fog plunged Europe, the Middle East, and parts of Asia into darkness, day and night—for 18 months. “For the sun gave forth its light without brightness, like the moon, during the whole year,” wrote Byzantine historian Procopius. Temperatures in the summer of 536 fell 1.5°C to 2.5°C, initiating the coldest decade in the past 2300 years. Snow fell that summer in China; crops failed; people starved. The Irish chronicles record “a failure of bread from the years 536–539.” Then, in 541, bubonic plague struck the Roman port of Pelusium, in Egypt. What came to be called the Plague of Justinian spread rapidly, wiping out one-third to one-half of the population of the eastern Roman Empire and hastening its collapse, McCormick says.

Historians have long known that the middle of the sixth century was a dark hour in what used to be called the Dark Ages, but the source of the mysterious clouds has long been a puzzle. Now, an ultraprecise analysis of ice from a Swiss glacier by a team led by McCormick and glaciologist Paul Mayewski at the Climate Change Institute of The University of Maine (UM) in Orono has fingered a culprit. At a workshop at Harvard this week, the team reported that a cataclysmic volcanic eruption in Iceland spewed ash across the Northern Hemisphere early in 536. Two other massive eruptions followed, in 540 and 547. The repeated blows, followed by plague, plunged Europe into economic stagnation that lasted until 640, when another signal in the ice—a spike in airborne lead—marks a resurgence of silver mining, as the team reports in Antiquity this week.

To Kyle Harper, provost and a medieval and Roman historian at The University of Oklahoma in Norman, the detailed log of natural disasters and human pollution frozen into the ice “give us a new kind of record for understanding the concatenation of human and natural causes that led to the fall of the Roman Empire—and the earliest stirrings of this new medieval economy.”

Ever since tree ring studies in the 1990s suggested the summers around the year 540 were unusually cold, researchers have hunted for the cause. Three years ago polar ice cores from Greenland and Antarctica yielded a clue. When a volcano erupts, it spews sulfur, bismuth, and other substances high into the atmosphere, where they form an aerosol veil that reflects the sun's light back into space, cooling the planet. By matching the ice record of these chemical traces with tree ring records of climate, a team led by Michael Sigl, now of the University of Bern, found that nearly every unusually cold summer over the past 2500 years was preceded by a volcanic eruption. A massive eruption—perhaps in North America, the team suggested—stood out in late 535 or early 536; another followed in 540. Sigl's team concluded that the double blow explained the prolonged dark and cold.

Mayewski and his interdisciplinary team decided to look for the same eruptions in an ice core drilled in 2013 in the Colle Gnifetti Glacier in the Swiss Alps. The 72-meter-long core entombs more than 2000 years of fallout from volcanoes, Saharan dust storms, and human activities smack in the center of Europe. The team deciphered this record using a new ultra–high-resolution method, in which a laser carves 120-micron slivers of ice, representing just a few days or weeks of snowfall, along the length of the core. Each of the samples—some 50,000 from each meter of the core—is analyzed for about a dozen elements. The approach enabled the team to pinpoint storms, volcanic eruptions, and lead pollution down to the month or even less, going back 2000 years, says UM volcanologist Andrei Kurbatov.

In ice from the spring of 536, UM graduate student Laura Hartman found two microscopic particles of volcanic glass. By bombarding the shards with x-rays to determine their chemical fingerprint, she and Kurbatov found that they closely matched glass particles found earlier in lakes and peat bogs in Europe and in a Greenland ice core. Those particles in turn resembled volcanic rocks from Iceland. The chemical similarities convince geoscientist David Lowe of The University of Waikato in Hamilton, New Zealand, who says the particles in the Swiss ice core likely came from the same Icelandic volcano. But Sigl says more evidence is needed to convince him that the eruption was in Iceland rather than North America.

Either way, the winds and weather systems in 536 must have been just right to guide the eruption plume southeast across Europe and, later, into Asia, casting a chilly pall as the volcanic fog “rolled through,” Kurbatov says. The next step is to try to find more particles from this volcano in lakes in Europe and Iceland, in order to confirm its location in Iceland and tease out why it was so devastating.

A century later, after several more eruptions, the ice record signals better news: the lead spike in 640. Silver was smelted from lead ore, so the lead is a sign that the precious metal was in demand in an economy rebounding from the blow a century before, says archaeologist Christopher Loveluck of the University of Nottingham in the United Kingdom. A second lead peak, in 660, marks a major infusion of silver into the emergent medieval economy. It suggests gold had become scarce as trade increased, forcing a shift to silver as the monetary standard, Loveluck and his colleagues write in Antiquity. “It shows the rise of the merchant class for the first time,” he says.

Still later, the ice is a window into another dark period. Lead vanished from the air during the Black Death from 1349 to 1353, revealing an economy that had again ground to a halt. “We've entered a new era with this ability to integrate ultra–high-resolution environmental records with similarly high resolution historical records,” Loveluck says. “It's a real game changer.”



The aim of this study was to compare two methods for determining the fatty acid methyl ester content of biodiesel by applying high-performance liquid chromatography (HPLC-UV) and the reference method based on gas chromatography (GC). The samples of biodiesel were also analyzed by 1H NMR. External standards were used for the quantification of fatty acid methyl esters by HPLC-UV. The analytical curves of the methyl oleate, methyl linoleate, and methyl linolenate standards showed good linearity (coefficient of determination ≥ 0.995). Cochran’s test was used to assess the homoscedasticity of the analytical curves. The limits of detection and quantitation were found:

0.0018% mass and 0.0054% mass for methyl oleate, 0.0002% mass and 0.0007% mass for methyl linoleate, and 0.0001% mass and 0.0004% mass for methyl linolenate. The accuracy of the HPLC-UV method was assessed by determining recovery (%), which resulted on values between 81.7 ± 0.2 and 110.9 ± 0.1. Precision was assessed by determining repeatability (%), which was found to be between 0.2 and 1.3. The proposed HPLC-UV method proved efficient in determining the fatty acid methyl ester content of biodiesel and the paired t-test showed it to correlate well with the reference method (GC).

Gizatullin, B., Gafurov, M., Rodionov, A., Mamin, G., Mattea, C., Stapf, S., Orlinskii, S., 2018. Proton–radical interaction in crude oil—a combined NMR and EPR study. Energy & Fuels 32, 11261-11268.


We present a detailed study of electron/nuclear interaction in a specific crude oil by continuous-wave and pulsed EPR, electron–nuclear double resonance (ENDOR) at W-band (94 GHz), and fast field-cycling dynamic nuclear polarization (FFC-DNP) at X-band. A perceptible non-Overhauser (solid) effect is found at room temperature as a result of the polarization transfer from the intrinsic oil “free” radicals to the 1H nuclei with different dynamics. On the basis of the analysis of the longitudinal nuclear relaxation times, three dynamical components described by different electron–proton coupling parameters were found, which in combination with ENDOR provides information about the distribution of the radicals in the high-molecular oil components.

Goetsch, C., Conners, M.G., Budge, S.M., Mitani, Y., Walker, W.A., Bromaghin, J.F., Simmons, S.E., Reichmuth, C., Costa, D.P., 2018. Energy-rich mesopelagic fishes revealed as a critical prey resource for a deep-diving predator using quantitative fatty acid signature analysis. Frontiers in Marine Science 5, 430. doi: 10.3389/fmars.2018.00430.


Understanding the diet of deep-diving predators can provide essential insight to the trophic structure of the mesopelagic ecosystem. Comprehensive population-level diet estimates are exceptionally difficult to obtain for elusive marine predators due to the logistical challenges involved in observing their feeding behavior and collecting samples for traditional stomach content or fecal analyses. We used quantitative fatty acid signature analysis (QFASA) to estimate the diet composition of a wide-ranging mesopelagic predator, the northern elephant seal (Mirounga angustirostris), across five years. To implement QFASA, we first compiled a library of prey fatty acid (FA) profiles from the mesopelagic eastern North Pacific. Given the scarcity of a priori diet data for northern elephant seals, our prey library was necessarily large to encompass the range of potential prey in their foraging habitat. However, statistical constraints limit the number of prey species that can be included in the prey library to the number of dietary FAs in the analysis. Exceeding that limit could produce non-unique diet estimates (i.e., multiple diet estimates fit the data equally well). Consequently, we developed a novel ad-hoc method to identify which prey were unlikely to contribute to diet and could, therefore, be excluded from the final QFASA model. The model results suggest that seals predominantly consumed small mesopelagic fishes, including myctophids (lanternfishes) and bathylagids (deep sea smelts), while non-migrating mesopelagic squids comprised a third of their diet, substantially less than suggested by previous studies. Our results revealed that mesopelagic fishes, particularly energy-rich myctophids, were a critical prey resource, refuting the long-held view that elephant seals are squid specialists.



The Berriasian–early Valanginian time interval is well represented in the Rio Mayer Formation in the Río Guanaco area (Austral Basin, Argentina). From this locality, well preserved belemnite shells of the genus Belemnopsis sp. and black shales are used to unravel the main palaeoenvironmental conditions of the seas at these high palaeo-latitudes (60°) of southern South America during the Early Cretaceous. Rare earth elements plus yttrium (REY) analyses performed in belemnites rostra reveal Ce anomalies and Y/Ho values that together suggest high oxidizing superficial seawater conditions. On the other hand, sedimentological, ichnological and geochemical (TOC, Ce anomaly and MnO) data, analyzed from the black shale matrix of belemnites, show that they may have been deposited on the bottom of the basin under oxygen deficiency. Cathodoluminescence, scanning electron microscopy, major and trace element geochemistry allowed determining the best preserved microtextures of the belemnites in order to obtain reliable δ18O and δ13C results. Palaeotemperatures calculated from the δ18O results, characterized the studied marine interval from Austral Basin as warm. The belemnites from this Lower Cretaceous succession may have lived under well oxygenated and warm seawater conditions, which were markedly different from those recorded in seafloor sediments (black shales) deposited under suboxic to anoxic conditions. The integration of global palaeotemperature data for the Berriasian–early Valanginian interval, allows suggesting a different gradient for the austral Patagonia at the Southern Hemisphere in relation to those recorded in the Northern Hemisphere.

Gong, S., Hu, Y., Li, N., Feng, D., Liang, Q., Tong, H., Peng, Y., Tao, J., Chen, D., 2018. Environmental controls on sulfur isotopic compositions of sulfide minerals in seep carbonates from the South China Sea. Journal of Asian Earth Sciences 168, 96-105.


Authigenic carbonates and pyrite associated with sulfate-driven anaerobic oxidation of methane (AOM) at methane seeps provide archives to explore the biogeochemical processes involved and seepage dynamics over time. The wide range and extremely high δ34S values of pyrite (δ34Spy) have been used to trace the AOM-related processes. However, the detailed mechanism for this phenomenon is not well understood. We propose that the characteristics of δ34Spy were mainly controlled by the competition between sulfate reduction and sulfate supply, as well as the redox condition. To test this hypothesis, we investigated Sr/Ca and Mg/Ca ratios, trace element compositions, pyrite contents and sulfur isotopic compositions in seep carbonates from Site F and Haima in the northern South China Sea. Calcite and aragonite contents were distinguished through the Sr/Ca and Mg/Ca ratios. The data show that aragonites are always associated with relatively low δ34Spy values compared to calcites. The Mo contents show a good correlation with pyrite contents in calcites and aragonites, and the slope in aragonites is larger than that in calcites. This relationship indicates that the aragonite precipitated in a relatively open system with higher Mo availability. Thus, we conclude that sulfides with low δ34S values formed at high supply of sulfate under the relatively open system with respect to diffusive replenishment of sulfate, where the carbonate precipitation occurred close to the seafloor due to a strong methane flux. Under vigorous methane flux simultaneously, the high potential of less anoxic conditions, which could limit the additional pyrite accumulation and/or favor the microbial disproportionation, could also be the cause of the low δ34Spy, as supported by samples from the Haima sites. Evidence for this assumption is based on the occurrence of bivalve shells and less enrichment in As and Sb. Conversely, the positive δ34Spy values

result from near to complete exhaustion of dissolve sulfate via AOM within a deeper sulfate-methane transition zone, where Mo is less available. The combination of a detailed elemental study of authigenic carbonates with sulfur isotopic composition of sulfide minerals in carbonates is a promising tool for reconstructing the dynamics of seep intensities at modern and, potentially, geological seep sites.



In 2003, the excavation of the ancient site Baochuanchang Shipyard was carried out in Nanjing, China and this shipyard was believed to have been the workshop where the huge vessels of Zheng He's fleet were built and maintained. Several pieces of ancient putty were found here, and a small piece was sampled and analyzed in this paper to study its components and structure. The results of X-ray diffraction (XRD) showed that the putty was mainly composed of calcite (CaCO3), while pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) analysis indicated that tung oil was used in making the putty. In addition, plant fibers inside the putty were identified as jute by the means of polarizing microscope and scanning electron microscope (SEM) analysis. These findings confirmed the putty as the so-called chu-nam putty, which was a traditional sealing material used in ancient shipbuilding. Moreover, the surface morphology of the putty was obtained by SEM, and pore size distribution was measured by gas adsorption-desorption analysis. The analytical results suggested that the putty was quite compact, which could perform well in sealing huge wooden ships. This research revealed the shipbuilding skills of the Baochuanchang Shipyard. It may provide reference for studying Zheng He's vessels and make further a contribution to the conservation and restoration of ancient wooden ships of the Ming Dynasty.

Gottardi, R., Adams, L.M., Borrok, D., Teixeira, B., 2019. Hydrocarbon source rock characterization, burial history, and thermal maturity of the Steele, Niobrara and Mowry Formations at Teapot Dome, Wyoming. Marine and Petroleum Geology 100, 326-340.


Teapot Dome oilfield near the town of Midwest, Wyoming, has been the testing site of numerous drilling and production techniques since the early 1900's. The structure is a doubly plunging basement-cored anticline that formed during the Laramide orogeny, with sediments ranging from Cambrian to Quaternary. The Steele, Niobrara, and Mowry formations are potential source rocks in the area. In this study, we combine geochemical analyses with one-dimensional modeling of burial history, thermal maturity, and timing of petroleum generation to evaluate the potential of the field for unconventional exploration. Rock Eval™ pyrolysis and oxidation results show a mixture of Type II and Type III kerogen in the Niobrara and Mowry formations, and no hydrocarbon generation potential for the Steele Formation. These geochemical results, combined with regional tectonics, stratigraphy, and sedimentological conditions, were implemented into burial history and maturation models. Results from the modeling show that the Niobrara and Mowry formations are in the early oil generation window. The Mowry is the most mature of the three formations, but only 10% of the kerogen has been converted to oil. The study area did not reach the thermal maturity required to generate the significant amount of oil and gas produced to date from the structure. The results and method of this study can easily be extrapolated to better constrain the basin evolution of nearby

fields. This study is significant for further exploration in other established Laramide basins with similar formations.

Grieman, M.M., Aydin, M., McConnell, J.R., Saltzman, E.S., 2018. Burning-derived vanillic acid in an Arctic ice core from Tunu, northeastern Greenland. Climate of the Past 14, 1625-1637.

https://doi.org/10.5194/cp-14-1625-2018

In this study, vanillic acid was measured in the Tunu ice core from northeastern Greenland in samples covering the past 1700 years. Vanillic acid is an aerosol-borne aromatic methoxy acid, produced by the combustion of lignin during biomass burning. Air mass trajectory analysis indicates that North American boreal forests are likely the major source region for biomass burning aerosols deposited to the ice core site. Vanillic acid levels in the Tunu ice core range from < 0.005 to 0.08ppb. Tunu vanillic acid exhibits centennial-scale variability in pre-industrial ice, with elevated levels during the warm climates of the Roman Warm Period and Medieval Climate Anomaly, and lower levels during the cooler climates of the Late Antique Little Ice Age and the Little Ice Age. Analysis using a peak detection method revealed a positive correlation between vanillic acid in the Tunu ice core and both ammonium and black carbon in the North Greenland Eemian Ice Drilling (NEEM) project ice core from 600 to 1200CE. The data provide multiproxy evidence of centennial-scale variability in North American high-latitude fire during this time period.

Grohmann, S., Fietz, S.W., Littke, R., Daher, S.B., Romero-Sarmiento, M.F., Nader, F.H., Baudin, F., 2018. Source rock characterization of Mesozoic to Cenozoic organic matter rich marls and shales of the Eratosthenes Seamount, Eastern Mediterranean Sea. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 49.


Several significant hydrocarbon accumulations were discovered over the past decade in the Levant Basin, Eastern Mediterranean Sea. Onshore studies have investigated potential source rock intervals to the east and south of the Levant Basin, whereas its offshore western margin is still relatively underexplored. Only a few cores were recovered from four boreholes offshore southern Cyprus by the Ocean Drilling Program (ODP) during the drilling campaign Leg 160 in 1995. These wells transect the Eratosthenes Seamount, a drowned bathymetric high, and recovered a thick sequence of both pre- and post-Messinian sedimentary rocks, containing mainly marine marls and shales. In this study, 122 core samples of Late Cretaceous to Messinian age were analyzed in order to identify organic-matter-rich intervals and to determine their depositional environment as well as their source rock potential and thermal maturity. Both Total Organic and Inorganic Carbon (TOC, TIC) analyses as well as Rock-Eval pyrolysis were firstly performed for the complete set of samples whereas Total Sulfur (TS) analysis was only carried out on samples containing significant amount of organic matter (>0.3 wt.% TOC). Based on the Rock-Eval results, eight samples were selected for organic petrographic investigations and twelve samples for analysis of major aliphatic hydrocarbon compounds. The organic content is highly variable in the analyzed samples (0–9.3 wt.%). TS/TOC as well as several biomarker ratios (e.g. Pr/Ph < 2) indicate a deposition under dysoxic conditions for the organic matter-rich sections, which were probably reached during sporadically active upwelling periods. Results prove potential oil prone Type II kerogen source rock intervals of fair to very good quality being present in Turonian to Coniacian (average: TOC = 0.93 wt.%, HI = 319 mg HC/g TOC) and in Bartonian to Priabonian (average: TOC = 4.8 wt.%, HI = 469 mg HC/g TOC) intervals. A precise determination of the actual source rock thickness is prevented by low core recovery rates for the respective intervals. All analyzed samples are immature to early mature. However, the presence of

deeper buried, thermally mature source rocks and hydrocarbon migration is indicated by the observation of solid bitumen impregnation in one Upper Cretaceous and in one Lower Eocene sample.

Gros, J., Dissanayake, A.L., Daniels, M.M., Barker, C.H., Lehr, W., Socolofsky, S.A., 2018. Oil spill modeling in deep waters: Estimation of pseudo-component properties for cubic equations of state from distillation data. Marine Pollution Bulletin 137, 627-637.


Deep-water oil spills represent a major, localized threat to marine ecosystems. Multi-purpose computer models have been developed to predict the fate of spilled oil. These models include databases of pseudo-components from distillation cut analysis for hundreds of oils, and have been used for guiding response action, damage assessment, and contingency planning for marine oil spills. However, these models are unable to simulate the details of deep-water, high-pressure chemistry. We present a new procedure to calculate the chemical properties necessary for such simulations that we validate with 614 oils from the ADIOS oil library. The calculated properties agree within 20.4% with average values obtained from data for measured compounds, for 90% of the chemical properties. This enables equation-of-state calculations of dead oil density, viscosity, and interfacial tension. This procedure enables development of comprehensive oil spill models to predict the behavior of petroleum fluids in the deep sea.

Grossman, A., Wilfred, V., 2019. Lignin-based polymers and nanomaterials. Current Opinion in Biotechnology 56, 112-120.


Approximately 50 million tons of lignin are currently produced annually as a by-product of the pulp- and paper industry, and this amount is likely to double in the future with the anticipated production of renewable fuels and chemicals from lignocellulosic biomass, as a sustainable alternative to petroleum. The latter process can be expedited by valorizing lignin, which entails making products from lignin that generate additional revenues for biorefineries so that the production of biofuels becomes more competitive with gasoline. Industrially produced lignin is considered a low-value material that is used as a boiler fuel to generate heat and electricity, and as an ingredient of adhesives, cement, and drilling fluids for underwater oil wells. The aromatic nature of lignin, its ability to participate in radical-mediated cross-linking reactions, the many functional groups available for derivatization or chemical reactions, and its amenability to existing procedures for making thermoplastics, make it attractive as an additive to polymers to enhance UV-tolerance and/or other physico-chemical properties. Lignin can also be used as the basis for various nanomaterials, either per se or in combination with other polymers. This review summarizes recent developments in the synthesis of lignin-containing polymers and nanomaterials, whereby inherent variation in lignin subunit composition and structure, as a function of plant species and lignin extraction method, offer unique opportunities for fine-tuning material properties (e.g. tensile strength, hardness, elasticity) to match specific applications.

Guan, H., Birgel, D., Peckmann, J., Liang, Q., Feng, D., Yang, S., Liang, J., Tao, J., Wu, N., Chen, D., 2018. Lipid biomarker patterns of authigenic carbonates reveal fluid composition and seepage intensity at Haima cold seeps, South China Sea. Journal of Asian Earth Sciences 168, 163-172.


Authigenic carbonates retrieved from sites ROV1 and ROV2 of the Haima hydrocarbon seeps of the South China Sea at approximately 1390 m water depth were studied using lipid biomarker analyses. Abundant molecular fossils of anaerobic methane oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) with strong 13C-depletions (δ13C values as low as −126‰), in combination with low δ13Ccarbonate values (−42.7‰ to −36.8‰), provide evidence that anaerobic oxidation of methane (AOM) was the major process driving the precipitation of the studied seep carbonates. The extremely low δ13C values of archaeal biomarkers confirm that biogenic methane was the main carbon source, but the seepage of accessory crude oil is also suggested by the presence of unresolved complex mixtures in the hydrocarbon fractions. A suite of 13C-depleted biomarkers indicate the predominance of ANME-1/DSS consortia at both sites, which indicates that the studied carbonates formed during low to medium methane flux. Somewhat higher contents of archaeal biomarkers and their stronger 13C-depletion at site ROV2 probably reflect at least temporarily higher seepage intensities than at site ROV1. Abundant bacterial dialkyl glycerol diethers (DAGEs), revealing a large offset of their δ13C values compared to SRB-derived terminally branched fatty acids, were possibly produced by distinct SRB species other than members of the DSS cluster. The encountered hopanoids are attributed to aerobic methanotrophic bacteria based on their moderate 13C-depletion. The application of molecular fossils in combination with their compound-specific isotope signatures is an efficient tool to reconstruct the composition of seepage fluids and seepage intensities.

Guan, H., Chen, L., Luo, M., Liu, L., Mao, S., Ge, H., Zhang, M., Fang, J., Chen, D., 2019. Composition and origin of lipid biomarkers in the surface sediments from the southern Challenger Deep, Mariana Trench. Geoscience Frontiers 10, 351-360.


The surface sediments collected from the southern Mariana Trench at water depths between ca. 4900 m and 7068 m were studied using lipid biomarker analyses to reveal the origin and distribution of organic matters. For all samples, an unresolved complex mixture (UCM) was present in the hydrocarbon fractions, wherein resistant component tricyclic terpanes were detected but C27–C29

regular steranes and hopanes indicative of a higher molecular weight range of petroleum were almost absent. This biomarker distribution patterns suggested that the UCM and tricyclic terpanes may be introduced by contamination of diesel fuels or shipping activities and oil seepage elsewhere. The well-developed faults and strike-slip faults in the Mariana subduction zone may serve as passages for the petroleum hydrocarbons. In addition, the relative high contents of even n-alkanes and low Carbon Preference Indices indicated that the n-alkanes were mainly derived from bacteria or algae. For GDGTs, the predominance of GDGT-0 and crenarchaeol, together with low GDGT-0/Crenarchaeol ratios (ranging from 0.86 to 1.64), suggests that the GDGTs in samples from the southern Mariana Trench were mainly derived from planktic Thaumarchaeota. However, the high GDGT-0/crenarchaeol ratio (10.5) in sample BC07 suggests that the GDGTs probably were introduced by methanogens in a more anoxic environment. Furthermore, the n-alkanes C19–C22 and the n-fatty acids C20:0–C22:0 were depleted in 13C by 3‰ compared to n-alkanes C16–C18 and the n-fatty acids C14:0–C18:0, respectively, which was interpreted to result from the preferential reaction of fatty acid fragments with carbon “lighter” terminal carboxyl groups during carbon chain elongation from the precursors to products. The abundance of total alkanes, carboxylic acids, alcohols and total lipids were generally increased along the down-going seaward plate, suggesting the lateral organic matter inputs play an important role in organic matter accumulation in hadal trenches. The extremely high contents of biomarkers in sample BC11 were most likely related to trench topography and current dynamics, since the lower steepness caused by graben texture and proximity to the trench axis may result in higher sedimentation rate. This paper, for the first time, showed the biomarker patterns in

surface sediments of the Mariana Trench and shed light on biogeochemistry of the hardly reached trench environment.

Guan, W., Zhang, X., Xi, C., Wang, X., Yang, F., Shi, X., Li, Q., 2018. Displacement and development characteristics of fire flooding of vertical wells in old heavy oil areas. Petroleum Research 3, 165-179.


As the vertical-well fire flooding technology is industrially applied in the steam-injection old heavy oil areas of Xinjiang and Liaohe oilfields, its enhanced oil recovery potential is gradually clear. According to laboratory experiment, field test and reservoir engineering, the displacement characteristics of vertical-well fire flooding in the steam-injection old heavy oil areas are systematically investigated. Laboratory experiments and core data show that the vertical-well fire flooding has significantly high flooding efficiency, no residual oil are remained in the firing front sweeping zone, and the lateral sweep efficiency and ultimate recovery can be achieved. The vertical-well fire flooding is a strategic replacement technology to enhance the recovery greatly. Development characteristics and advantages of areal and linear fire flooding are well investigated, and research results are applied in the design of industrial test plan of fire flooding in the Hongqian block, Xinjiang. The research shows that the linear well pattern has advantages of easy construction of ground facilities and management, less well of stage management, simple matching technology and easy achievement of purposeful control for fire front; the areal well pattern has advantages in reducing the air/oil ratio during the fire flooding period, increasing the total recovery rate of reservoirs and reducing the geological and reservoir management risks. To select well patterns of fire flooding, some factors such as geology, reservoir, fluid properties, oil price, and reservoir development degree should be mainly considered. In the Hongqian block, an improved linear well pattern with a combination of new wells and old wells is applied, this not only absorb experiences of linear well pattern pilot test, but also use advantages of areal well pattern.

Guijas, C., Siuzdak, G., 2018. Reply to Comment on METLIN: A technology platform for identifying knowns and unknowns. Analytical Chemistry 90, 13128-13129.


Original Article: Guijas, C.; Montenegro-Burke, J. R.; Domingo-Almenara, X.; Palermo, A.; Warth, B.; Hermann, G.; Koellensperger, G.; Huan, T.; Uritboonthai, W.; Aisporna, A. E., et al. METLIN: A Technology Platform for Identifying Knowns and Unknowns. Anal. Chem. 2018, 90, 3156– 3164.

Replying to: Kite, G.C., 2018. Comment on METLIN: A technology platform for identifying knowns and unknowns. Analytical Chemistry, 2018, 90, 13126-13127

We agree with the comment, additional data acquisition parameters would be beneficial for the community as a whole. However, we are currently in the process of a major METLIN data generation effort. This effort has allowed us to expand METLIN(1) from 14 000 (in 2017) to now over 150 000 molecular standards each containing MS/MS data at multiple collision energies in both positive and negative ionization modes (see Figure 1). We have explored the idea of broadening the acquisition parameters, including adding more collision energies. Unfortunately, these additional parameters did not have a significant positive effect on the data. Empirical data quality and maintaining high throughput have been of utmost importance in our decision process, a goal we try to sustain while maintaining a successful acquisition rate as determined by manual curation. Therefore, we have made

the strategic decision to acquire data at parameters that will provide the most useful data without sacrificing quality or throughput.

Given the success and throughput of our platform, we welcome the donation of verified standards, especially from the plant community, and we encourage feedback on MS/MS spectral data quality. We understand this data is crucial for both the identification of known molecules via comparison with experimental data,(1,2) characterizing active metabolites,(3) as well as for the identification of unknowns via development of more effective bioinformatic tools based on the newly added data. In fact, we could potentially create a specialized parameter set to analyze selected classes of compounds at higher collision energies to facilitate the identification of molecules that do not readily dissociate at the standard collision energies. Higher collision energies also aid in the generation of pseudo-MS3 spectra for structural elucidation and isomer characterization of some molecules. A particularly interesting example of the utility of such an approach was the case of 9-PAHSA, a class of lipids with antidiabetic and anti-inflammatory properties, where it was possible to assign the positional isomers fragmenting at high collision energies.(5)

Gumulya, Y., Baek, J.-M., Wun, S.-J., Thomson, R.E.S., Harris, K.L., Hunter, D.J.B., Behrendorff, J.B.Y.H., Kulig, J., Zheng, S., Wu, X., Wu, B., Stok, J.E., De Voss, J.J., Schenk, G., Jurva, U., Andersson, S., Isin, E.M., Bodén, M., Guddat, L., Gillam, E.M.J., 2018. Engineering highly functional thermostable proteins using ancestral sequence reconstruction. Nature Catalysis 1, 878-888.

https://doi.org/10.1038/s41929-018-0159-5

Commercial biocatalysis requires robust enzymes that can withstand elevated temperatures and long incubations. Ancestral reconstruction has shown that pre-Cambrian enzymes were often much more thermostable than extant forms. Here, we resurrect ancestral enzymes that withstand ~30 °C higher temperatures and ≥100 times longer incubations than their extant forms. This is demonstrated on animal cytochromes P450 that stereo- and regioselectively functionalize unactivated C–H bonds for the synthesis of valuable chemicals, and bacterial ketol-acid reductoisomerases that are used to make butanol-based biofuels. The vertebrate CYP3 P450 ancestor showed a 60T50 of 66 °C and enhanced solvent tolerance compared with the human drug-metabolizing CYP3A4, yet comparable activity towards a similarly broad range of substrates. The ancestral ketol-acid reductoisomerase showed an eight-fold higher specific activity than the cognate Escherichia coli form at 25 °C, which increased 3.5-fold at 50 °C. Thus, thermostable proteins can be devised using sequence data alone from even recent ancestors.

Guo, W., Dai, S., Nechaev, V.P., Nechaeva, E.V., Wei, G., Finkelman, R.B., Spiro, B.F., 2019. Geochemistry of Palaeogene coals from the Fuqiang Mine, Hunchun Coalfield, northeastern China: Composition, provenance, and relation to the adjacent polymetallic deposits. Journal of Geochemical Exploration 196, 192-207.


This paper describes the geochemistry of the two Palaeogene coal seams (FQ-23 and FQ-26) from the Fuqiang mine, Hunchun Coalfield, Jilin Province, northeastern China. The samples investigated consist of coal, parting, and roof and floor strata. The two Fuqiang coals are lignite/subbituminous rank and have low sulfur contents (0.13% and 0.16% on average, respectively). In comparison with the average values for common global low-rank coals, the Fuqiang coals are richer in W, Cs, Sb, Pb, Li, V, Ga, and Zr.

The terrigenous components in the Fuqiang coals were derived from the Mesozoic (mostly Lower Cretaceous) and Paleozoic igneous and metamorphic rocks, which are abundant in areas surrounding the Hunchun coal basin. The elevated concentrations of trace elements are attributed to two processes: (1) Contribution of clastic materials derived from mineralized Paleozoic rocks, which also host economical ore deposits of these elements; and (2) Mobilisation and redeposition of these elements by acidic waters, which circulated within the coal basin. The latter is evidenced by enrichment in medium rare earth elements, distinct positive Gd anomalies, and high concentrations of boron in the coals. The overall similarity of the geochemical signatures of the Fuqiang coals and the adjacent Au, Cu and W deposits hosted by the Paleozoic igneous and metamorphic rocks underlying and bordering the Hunchun Basin, indicate that they are genetically linked.

Hackley, P.C., Lünsdorf, N.K., 2018. Application of Raman spectroscopy as thermal maturity probe in shale petroleum systems: Insights from natural and artificial maturation series. Energy & Fuels 32, 11190-11202.


Raman spectroscopy was studied as a thermal maturity probe in a series of Upper Devonian Ohio Shale samples from the Appalachian Basin spanning from immature to dry gas conditions. Raman spectroscopy also was applied to samples spanning a similar thermal range created from 72-h hydrous pyrolysis (HP) experiments of the Ohio Shale at temperatures from 300 to 360 °C and isothermal HP experiments lasting up to 100 days of similar Devonian–Mississippian New Albany Shale. Raman spectra were treated by automated evaluation software based on iterative and simultaneous modeling of signal and baseline functions to decrease subjectivity. Spectra show robust correlation to measured solid bitumen reflectance (BRo) values and were therefore used to construct logarithmic regression relationships for calculation of BRo equivalent values. Raman spectra show considerable differences between natural samples and HP residues with similar measured BRo values, indicating as-yet undetermined differences in carbon chemistry. We speculate this result may be due to differences in the sampling interactions of Raman vs reflectance measurements, and the incomplete nature of maturation reactions in the time-limited hydrous pyrolysis residues. Samples used in this study are similar in organic assemblage (dominantly solid bitumen) to other commonly exploited North American shale petroleum systems, i.e., Bakken, Barnett, Duvernay, Fayetteville, and Woodford shales. Therefore, results presented herein may be broadly applicable to other important shale plays. However, caution is suggested and Raman spectroscopy as a thermal probe may need individual calibration in each shale play due to differences in solid bitumen carbon chemistry.


https://doi.org/10.1029/2018PA003362

The atmospheric concentration of the greenhouse gas carbon dioxide, CO2, is intimately coupled to the carbon chemistry of seawater, such that the radiative climate forcing from CO2 can be changed by an array of physical, geochemical, and biological ocean processes. For instance, biological carbon sequestration, seawater cooling, and net CaCO3 dissolution are commonly invoked as the primary drivers of CO2 change that amplify the orbitally paced ice age cycles of the late Pleistocene. Based on first‐principle arguments with regard to ocean chemistry, we demonstrate that seawater pH change (ΔpH) is the dominant control that effectively sets CO2 radiative forcing (ΔF) on orbital timescales, as is evident from independent late Pleistocene reconstructions of pH and CO2. In short, all processes relevant for CO2on orbital timescales, including temperature change, cause pH to change to bring

about fractional CO2 change so as to yield a linear relationship of ΔpH to CO2 climate forcing. Further, we show that ΔpH and CO2 climate forcing can be reconstructed using the boron isotope pH proxy more accurately than absolute pH or CO2, even if seawater boron isotope composition is poorly constrained and without information on a second carbonate system parameter. Thus, our formalism relaxes otherwise necessary assumptions to allow the accurate determination of orbital timescale CO2 radiative forcing from boron isotope pH reconstructions alone, thereby eliminating a major limitation of current methods to estimate our planet's climate sensitivity from the geologic record.

Háková, M., Chocholoušová Havlíková, L., Solich, P., Švec, F., Šatínský, D., 2019. Electrospun nanofiber polymers as extraction phases in analytical chemistry – The advances of the last decade. TrAC Trends in Analytical Chemistry 110, 81-96.


Nanofiber polymers are known to offer many attractive properties in various areas of research, industry, medicine, environmental protection, and biotechnologies. These outstanding characteristics also make them promising candidates as the extraction sorbents for sample clean-up before analysis in different areas of analytical chemistry. As sorbents in modern extraction techniques, they provide almost unlimited number of opportunities because of the large number of polymeric materials available and their continuing rapid innovations. While searching for novel extraction sorbents in analytical field is like running a marathon, in case of nanofiber polymers it is rather like a sprint. This review summarizes current advancement in application of nanofiber polymers used as sorbents for extraction and sample pretreatment in analytical techniques. New approaches are included that concern polymer modifications for different extraction and microextraction techniques published during the last decade.

Han, H., Pang, P., Li, Z.-l., Shi, P.-t., Guo, C., Liu, Y., Chen, S.-j., Lu, J.-g., Gao, Y., 2019. Controls of organic and inorganic compositions on pore structure of lacustrine shales of Chang 7 member from Triassic Yanchang Formation in the Ordos Basin, China. Marine and Petroleum Geology 100, 270-284.


To quantify the contributions of organic and inorganic compositions to pore volumes of Chang 7 shales, sub-critical gas adsorption experiments were performed on a suite of shale and organic matter samples. The parameters of pore structure were then calculated from the gas adsorption data. The grain densities of the studied samples were also measured. Based on the total organic carbon (TOC) contents and pore volumes of shale and organic matter samples, the contributions of organic matter and inorganic compositions to pore volumes were estimated. The results showed that the adsorbed gas volumes, pore volumes, surface areas and pore size distribution lines of organic matter samples were all higher than those of shale samples. It indicated that organic matter was more porous than other fractions in the studied samples. The average contributions of organic matter to the volumes of micropore, mesopore and macropore are 45.98%, 27.20% and 33.27%, respectively. The contributions of organic matter to pore volume increased with the maturity, which can be attributed to the formation of organic matter pores during maturation. The contributions of organic matter to mesopore and macropore volumes correlated positively with TOC content, which suggested that TOC content is another controlling factor of the contributions of organic matter to pore volume.

Han, W., He, P., Shao, L., Lü, F., 2018. Metabolic interactions of a chain elongation microbiome. Applied and Environmental Microbiology 84, Article e01614-18.


Abstract: Carbon chain elongation (CCE), a reaction within the carboxylate platform that elongates short-chain to medium-chain carboxylates by mixed culture, has attracted worldwide interest. The present study provides insights into the microbial diversity and predictive microbial metabolic pathways of a mixed-culture CCE microbiome on the basis of a comparative analysis of the metagenome and metatranscriptome. We found that the microbial structure of an acclimated chain elongation microbiome was a highly similar to that of the original inoculating biogas reactor culture; however, the metabolic activities were completely different, demonstrating the high stability of the microbial structure and flexibility of its functions. Additionally, the fatty acid biosynthesis (FAB) pathway, rather than the well-known reverse β-oxidation (RBO) pathway for CCE, was more active and pivotal, though the FAB pathway had more steps and consumed more ATP, a phenomenon that has rarely been observed in previous CCE studies. A total of 91 draft genomes were reconstructed from the metagenomic reads, of which three were near completion (completeness, >97%) and were assigned to unknown strains of Methanolinea tarda, Bordetella avium, and Planctomycetaceae. The last two strains are likely new-found active participators of CCE in the mixed culture. Finally, a conceptual framework of CCE, including both pathways and the potential participators, was proposed.

Importance: Carbon chain elongation means the conversion of short-chain volatile fatty acids to medium-chain carboxylates, such as n-caproate and n-caprylate with electron donors under anaerobic condition. This bio-reaction can both expand the resource of valuable biochemicals and broaden the utilization of low-grade organic residues in a sustainable biorefinery context. Clostridium kluyveri is conventionally considered model microbe for carbon chain elongation which uses the reverse β-oxidation pathway. However, little is known about the detailed microbial structure and function of other abundant microorganism in a mixed culture (or open culture) of chain elongation. We conducted the comparative metagenomic and metatranscriptomic analysis of a chain elongation microbiome to throw light on the underlying functional microbes and alternative pathways.

Han, X., Liu, J., Wang, B., Du, A., Xu, L., Wu, B., 2018. Synthesis and chromatographic applications of polysiloxane-based stationary phase containing nitrogen heterocyclic system. Journal of Chromatography A 1578, 76-82.


In this work, a novel kind of stationary phase called 2,5-diphenyl-3,4-bis(pyridin-2-yl) phenyl grafted polysiloxane (DPPP, containing 16.0% 2,5-diphenyl-3,4-bis(pyridin-2-yl) phenyl group) was synthesized and statically coated inside fused-silica capillary column. The thermo-stability of DPPP was evaluated by thermogravimetric analysis (TGA) and the result indicated that DPPP did not decompose slightly until 380 °C. The chromatogram of the polyethylene pyrolysis products showed that the upper working temperature of the DPPP column was about 370 °C. The column efficiency of the DPPP column was 3500–3800 plates/m. McReynolds contants of the DPPP revealed that its polarity was moderate. Abraham system contants revealed that H-bond basicity was the major interaction of DPPP, followed by dipole-induced dipole interaction and dispersion force. In particular, compared to DB-17 column, the DPPP showed superiority on separating pyridine derivatives, aromatic aldehydes, and fatty alcohols.

Hanafy, S., Farhood, K., Mahmoud, S.E., Nimmagadda, S., Mabrouk, W.M., 2018. Geological and geophysical analyses of the different reasons for DHI failure case in the Nile Delta Pliocene section. Journal of Petroleum Exploration and Production Technology 8, 969-981.

https://doi.org/10.1007/s13202-018-0445-4

The shallow clastic section in the Nile Delta is characterized by mild velocity variations. The relationship between the expected velocity reduction in the gas reservoir rocks and the encompassing shale is responsible for acoustic impedance contrast, predictable to a particular AVO-class. In class-3AVO, the bright spot is a result of great reduction in velocity increase due to differences between high-velocity encompassing shale and relatively low-velocity reservoir sand. The class-3AVO characterizes a strong seismic amplitude appearance in the full stack section and with similar characteristic view of AVO analysis and interpretation. In addition to the strong amplitude, there are different DHI features related to the gas occurrence. These DHI features are analyzed to achieve and deliver a successful exploratory well. The DHI analysis of one of the unsuccessful cases using recent 3-D seismic data clarifies the importance of the workflow that works for exploring types of anomalies in the Nile Delta. The anomaly is drilled mainly based on an explicit high-amplitude anomaly with local flat spot, but without taking into consideration the extent of DHI characteristics, inherent to gas occurrence in the Nile Delta. Authors investigate all the features related to this unproven case in the form of a postmortem and compare it with proven existing discoveries, to know the possible reason of unsuccessful DHI anomalies in the Nile Delta.

Hang, L., Xu, Z., Yin, Z., Hang, W., 2018. Approaching standardless quantitative elemental analysis of solids: Microsecond pulsed glow discharge and buffer-gas-assisted laser ionization time-of-flight mass spectrometry. Analytical Chemistry 90, 13222-13228.


Headspace (HS) extraction and preconcentration of volatiles by solid-phase microextraction (SPME) can improve the sensitivity and selectivity of ambient ionization-mass spectrometry approaches like direct analysis in real time (DART), but previous approaches to HS-SPME-DART-MS have been challenging to automate. This report describes the production of inexpensive, reusable solid-phase mesh-enhanced sorption from headspace (SPMESH) sheets by laser-etching mesh patterns into poly(dimethylsiloxane) (PDMS) sheets. Parallel headspace extraction of volatiles from multiple samples can be achieved by positioning the SPMESH sheets over multiwell plates and then attaching to a positioning stage for automated DART-MS quantitation. Using three representative odorants (3-isobutyl-2-methoxypyrazine, linalool, and methyl anthranilate), we achieved μg/L–ng/L detection limits with SPMESH-DART-MS, with the DART-MS step requiring only 17 min for 24 samples. Acceptable repeatability (24% or less day-to-day variation) and excellent recovery from a grape matrix (99–106%) could be achieved. Through use of a Teflon gasket and stainless steel spacers, cross-contamination between the headspaces of adjacent wells could be limited to roughly 1%. Optimum SPMESH extraction and desorption parameters were determined by response surface methodology. In summary, sheet-based SPMESH provides a sensitive, readily automated approach for coupling with DART-MS and achieving high-throughput trace-level volatile analyses.

Hantsoo, K.G., Kaufman, A.J., Cui, H., Plummer, R.E., Narbonne, G.M., 2018. Effects of bioturbation on carbon and sulfur cycling across the Ediacaran–Cambrian transition at the GSSP in Newfoundland, Canada. Canadian Journal of Earth Sciences 55, 1240-1252.


The initiation of widespread penetrative bioturbation in the earliest Phanerozoic is regarded as such a significant geobiological event that the boundary between Ediacaran and Cambrian strata is defined by the appearance of diagnostic trace fossils. While ichnofabric analyses have yielded differing interpretations of the impact of Fortunian bioturbation, the disruption of sediments previously sealed by microbial mats is likely to have effected at least local changes in carbon and sulfur cycling. To assess the geochemical effects of penetrative bioturbation, we conducted a high resolution chemostratigraphic analysis of the siliciclastic-dominated basal Cambrian Global Stratotype Section and Point (GSSP; Chapel Island Formation, Newfoundland, Canada). A positive δ13C excursion in organic matter starts at the Ediacaran–Cambrian boundary and returns to stably depleted values near the top of member 2, while the δ13C of carbonate carbon increases from strongly depleted values toward seawater values beginning near the top of member 2. Pyrite sulfur coincidently undergoes significant 34S depletion at the Ediacaran–Cambrian boundary. These isotope anomalies most likely reflect progressive ventilation and oxygenation of shallow sediments as a consequence of bioturbation. In this interpretation, sediment ventilation in the earliest Cambrian may have spurred a temporary increase in microbial sulfate reduction and benthic sulfur cycling under low-oxygen conditions. In the late Fortunian, local carbon cycling appears to have stabilized as reductants were depleted and more oxygenated conditions predominated in the shallow substrate. Overall, these data attest to the geochemical significance of the initiation of sediment ventilation by animals at the dawn of the Phanerozoic.



Based on organic petrology, organic geochemistry and SEM method, type, formation period and source of bitumens in the Cambrian Longwangmiao Formation in the central Sichuan Basin were well investigated, and combined with fluid inclusions and tectonic evolution characteristics, the hydrocarbon accumulation history of the gas reservoir of the Longwangmiao Formation in the Anyue gasfield was also studied. The result shows that all bitumens in the Longwangmiao Formation was from the Lower Cambrian source rocks, it had multiple genetic types which was dominated by the pyrolysis genetic type; the bitumens were formed into three stages, i.e., the bitumen of the oxidized water-washing type in the first stage, the bitumen of the precipitated type in the second stage, and the bitumen of the pyrolyzed type in the third stage; the gas reservoir in the Anyue gasfield experienced five stages of hydrocarbon charging, including two stages of liquid hydrocarbon charging, charging of the kerogen pyrolysis gas in the Late Triassic-Early Jurassic, charging of the crude oil pyrolysis gas in the Late Jurassic-Early Cretaceous and charging of the dry gas charging in the Himalayan trap reformation and adjustment process.


https://www.frontiersin.org/article/10.3389/feart.2018.00180

Batch experiments between solid materials including komatiite, peridotite and basalt with an H2O-CO2 atmosphere were performed at temperatures from 200°C to 500°C to simulate the interaction between the new rocky crust formed after the magma ocean stage and the concurrent proto-atmosphere of the early Earth. Electron microscopic observations show that clay mineral flakes were

generated in all experiments. In komatiite/peridotite reaction systems, fibrous actinolite was generated in experiments conducted at higher temperatures (>400°C). Different carbonate species were produced in experiments conducted at temperatures no higher than 400°C. Formation of these carbonates and their diverse crystal habits may indicate varied extraction rates of calcium, magnesium and SiO2 from the original ultramafic rocks resulted from different experimental temperatures. Our results imply that clay minerals and carbonates could probably be formed extensively in the early Hadean by the intense interaction between the ultramafic rocky crust and the H2O-CO2 atmosphere before the formation of the earliest ocean. Rapid sequestration of the atmospheric CO2 caused by the massive precipitation of carbonates might have led to the rapid cooling of the Earth’s atmosphere and the formation of the earliest oceans.

Hargitai, H.I., Gulick, V.C., Glines, N.H., 2018. Paleolakes of northeast Hellas: Precipitation, groundwater-fed, and fluvial lakes in the Navua–Hadriacus–Ausonia Region, Mars. Astrobiology 18, 1435-1459.

https://doi.org/10.1089/ast.2018.1816

The slopes of northeastern Hellas Basin, Mars exhibit a wide variety of fluvial landforms. In addition to the Dao–Niger–Harmakhis–Reull Valles outflow channels, many smaller channels and valleys cut into this terrain, several of which include discontinuous sections. We have mapped these channels and channel-associated depressions to investigate potential paleolakes from the Navua Valles in the West, through the Hadriacus Mons volcano in the center, to the Ausonia Montes in the East. We have identified three groups of candidate paleolakes at the source regions of major drainages and a fourth paleolake type scattered along the lower reaches of these drainages. Each paleolake group has a distinct character, determined by different formative processes, including precipitation and groundwater for lakes at the channel sources, and fluvially transported water at the lower channel reaches. Only one of these 34 basins had been cataloged previously in paleolake basin databases. Several of these sites are at proximity to the Hadriacus volcanic center, where active dikes during the Hesperian could have produced hydrothermal systems and habitable environments. Deposits within these paleolake depressions and at the termini of channels connected to these candidate paleolakes contain the geological and potentially biological record of these environments.

Hasanvand, M.Z., Feyzi, F., Behbahani, R.M., Dehghani, S.A.M., 2018. Detection of solid asphaltene phase separation via viscosity monitoring at high pressure high temperature conditions. International Journal of Oil, Gas and Coal Technology 19, 458-476.

http://dx.doi.org/10.1504/IJOGCT.2018.095986

In this study, the viscosimetry method is used for detection of onset of asphaltene precipitation at HPHT conditions. The results are compared to other common methods (HPHT filtration, high pressure microscopy and light refraction). Five different live field oil samples are examined over a pressure and temperature range of 34.72 MPa to 65.90 MPa and 368.4 K to 408.4 K, respectively. A modified version of the Krieger (1972) equation is proposed and used for calculating the amount of precipitation based on viscosity measurements. The results show that the viscosimetry method is an accurate method for determining asphaltene content of crude oils with a gravity range of 18 to 40 American Petroleum Institute (API) degrees in a vast pressure and temperature range from reservoir to atmospheric conditions. The measured phase separation pressure at constant reservoir temperature for light to heavy oil samples ranged from 42.74 to 24.13 MPa, respectively.



Microbes have been isolated previously from bentonite materials that may be used as barriers for the disposal of radioactive waste. Actively respiring microbes in such barrier materials, within a repository environment, have the potential to adversely affect waste container corrosion rates. Additionally, they could potentially alter the properties of the bentonite barrier itself. This is of significance, since the integrity of the waste container and properties of the bentonite barrier are required to fulfil defined safety functions. To help identify the critical factors that affect microbial activity in bentonite materials, this study examines the impact of a range of parameters that could affect microbial metabolism in a geodisposal environment. Several bentonites from different sources (bentonite mined from locations in Spain and the USA, along with commercially-sourced bentonite) were subjected to increased pressure (74 MPa, 30 s), heat (90 °C, 24 h), and irradiation (1000 Gy, 24.17 Gy min−1), before incubation in growth media selective for sulfate-reducing bacteria (SRB) or iron-reducing bacteria (IRB). The amount of SRB, and IRB were counted using the most probable number method and identified by 16S rRNA gene sequencing. The bentonites initially contained 660–6600 SRB cells g−1, and the number of SRB was correlated with the initial water content of the bentonite. A similar number of IRB was also present (400–4000 cells g−1), and the number of IRB was correlated with the ratio of bioavailable Fe(II)/Fe(III) present in the bentonite. The bentonites hosted sulfate-reducing species from two bacterial genera, with Desulfotomaculum dominating the SRB communities in the Spanish bentonite used in the Full-scale Engineered Barriers Experiment (FEBEX), while the other communities contained Desulfosporosinus species. The nature of the SRB community played a significant role in the microbial community response to different stresses, with the FEBEX material producing high SRB cell counts in response to pressure and irradiation but yielding low numbers in response to heat. Initially, the IRB communities contained a mixture of Gram-negative bacteria such as Geobacter, and Gram-positive spore-forming bacteria such as Bacillus and Desulfosporosinus, with an increase in the number of Gram-positive spore-formers in response to stress. The ability of Gram-positive spore-formers to grow, despite exposure to pressure, heat and irradiation, highlights the need to generate a swelling pressure sufficient to minimise microbial activity. In addition, we suggest that the microbial communities naturally present in the bentonite should be considered as part of the selection process for buffer materials in a geological disposal facility for radioactive waste.

He, C., Ji, L., Su, A., Wu, Y., Zhang, M., Zhou, S., Li, J., Hao, L., Ma, Y., 2019. Source-rock evaluation and depositional environment of black shales in the Triassic Yanchang Formation, southern Ordos Basin, north-central China. Journal of Petroleum Science and Engineering 173, 899-911.


A recent drilling operation in the Triassic Yanchang Formation (Tongchuan District of the Ordos Basin, north-central China) reached a black shale bed with an average in-situ gas content of 1.11 g/ml. Subsequent total organic carbon (TOC) content measurements and rock-eval analysis showed that the black shale section was generally classified as excellent source rock, with TOC contents commonly over 12% and an average genetic potential reaching 90 mg HC/g rock. The black shale samples of the Yanchang Formation contain kerogen of types I and II1, indicating the presence of oil source rocks, and the Tmax values range from 438 to 442 °C, which indicate a maturity stage in the early oil window. To reconstruct the depositional environment of the black shales with high TOC contents, various geochemical elements and their ratios were analyzed, yielding a number of interesting results: (i) the paleoclimate indexes CIA, CIW and C-values range from 50 to 72 (mean

65), 56 to 85 (mean 75), and 0.8 to 2.6 (mean 1.5), respectively, indicating humid conditions during the sedimentation period of the black shales; (ii) the redox conditions during the sedimentation of the black shales were dysoxic to anoxic as evidenced by the cross-plot of V/Cr vs. V/(V + Ni); (iii) the water column environment was a deep, fresh-water lake, further confirming the moist paleoclimate and reducing environment; and (iv) the high TOC contents of the black shales are attributed to inputs from hydrothermal fluids as evidenced by the samples falling into or near to the hydrothermal area of the Ni/Cr vs. Ti plot and the Ti vs. V plot.

He, H., Fu, J., Zhao, H., Yuan, F., Guo, L., Li, Z., Wang, X., Peng, H., 2018. Synergistic mechanism of hydrolyzed polyacrylamide enhanced branched-preformed particle gel for enhanced oil recovery in mature oilfields. Energy & Fuels 32, 11093-11104.


Branched-preformed particle gel (B-PPG) is a novel agent for EOR application in mature reservoirs. To improve the enhanced oil recovery (EOR) performance of B-PPG, the heterogeneous combination flooding system composed of B-PPG, hydrolyzed polyacrylamide (HPAM), and surfactant was proposed. However, the synergistic mechanism of B-PPG and HPAM still remains unclear. Here, a series of experiments were performed to study the viscosities of HPAM, B-PPG, and mixture of HPAM and B-PPG, evaluate the suspension stability of B-PPG and mixture of HPAM and B-PPG, to investigate the propagation behavior of HPAM, B-PPG, and a mixture of HPAM and B-PPG through porous media, and to study the EOR performance of HPAM, B-PPG, and a mixture of HPAM and B-PPG in heterogeneous reservoirs by performing parallel sand pack flooding experiments. Results show that the suspension stability of B-PPG can be improved by adding polymer due to the increase in viscosity. The higher the HPAM concentration is, the higher viscosity of mixture of HPAM and B-PPG suspension and the better the suspension stability is. Due to the lubrication and increased viscosity effect of the polymer, compared with the B-PPG suspension, the HPAM enhanced B-PPG suspension can be more easily injected into the porous media and can propagate through porous media. The propagation behavior of HPAM enhanced B-PPG through porous media is achieved by blocking, deforming, and passing through the pore throat. EOR performance results in a heterogeneous reservoir demonstrate that HPAM enhanced B-PPG flooding shows better sweep efficiency improvement ability and recovers more remaining oil left unswept in the low permeability zones.



Defatted cottonseed meal is a N-rich biomass that deserves valorized recycling. In this work, slow pyrolysis was applied to produce pyrolytic bio-oil from this biomass. Both the upper oily and lower aqueous fractions were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, and ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) with both negative and positive electrospray ionization modes. The contents of C and S were much higher in the oily fraction than in the aqueous fraction. Furthermore, the composition and molecular formulas of the organic compounds in the oily fraction were much more complex and diverse. From the mass spectral analysis, 9 and 14 different oxygen heteroatom classes were detected in the aqueous and oily fractions, respectively. While CHON compounds were found in both

fractions, CHONS compounds were detected only in the oily fraction. The van Krevelen diagrams from the FT-ICR-MS data showed the presence of lipid-, peptide-, and lignin-like components in both fractions. However, carbohydrate-like components were found only in the oily fraction. Furthermore, the diagrams revealed more N species in the oily fraction that mostly clustered with O/C < 0.2 in the unsaturated hydrocarbon-like region. On the other hand, there were less N species in the aqueous fraction, and they were present mostly in the lipid-like region. This information is useful for both chemical fingerprinting of cottonseed meal/cake-based bio-oils and guiding the effective uses of these N-rich types of products as a bioenergy resource and as an industrial feedstock.

Henard, C.A., Franklin, T.G., Youhenna, B., But, S., Alexander, D., Kalyuzhnaya, M.G., Guarnieri, M.T., 2018. Biogas biocatalysis: Methanotrophic bacterial cultivation, metabolite profiling, and bioconversion to lactic acid. Frontiers in Microbiology 9, 2610. doi: 10.3389/fmicb.2018.02610.


Anaerobic digestion (AD) of waste substrates, and renewable biomass and crop residues offers a means to generate energy-rich biogas. However, at present, AD-derived biogas is primarily flared or used for combined heat and power (CHP), in part due to inefficient gas-to-liquid conversion technologies. Methanotrophic bacteria are capable of utilizing methane as a sole carbon and energy source, offering promising potential for biological gas-to-liquid conversion of AD-derived biogas. Here, we report cultivation of three phylogenetically diverse methanotrophic bacteria on biogas streams derived from AD of a series of energy crop residues. Strains maintained comparable central metabolic activity and displayed minimal growth inhibition when cultivated under batch configuration on AD biogas streams relative to pure methane, although metabolite analysis suggested biogas streams increase cellular oxidative stress. In contrast to batch cultivation, growth arrest was observed under continuous cultivation configuration, concurrent with increased biosynthesis and excretion of lactate. We examined the potential for enhanced lactate production via the employ of a pyruvate dehydrogenase mutant strain, ultimately achieving 0.027 g lactate/g DCW/h, the highest reported lactate specific productivity from biogas to date.

Hennius, A., 2018. Viking Age tar production and outland exploitation. Antiquity 92, 1349-1361.

https://doi.org/10.15184/aqy.2018.22

The use of tar and resinous substances dates back far into Scandinavian prehistory. How it was produced, however, was unknown until recent excavations in eastern Sweden revealed funnel-shaped features—now identified as structures for producing tar. A new way of organising tar production appeared in the eighth century AD, leading to large-scale manufacture within outland forests. Intensified Viking Age maritime activities probably increased the demand for tar, which also became an important trade commodity. The transition to intensive tar manufacturing implies new ways of organising production, labour, forest management and transportation, which influenced the structure of Scandinavian society and connected forested outlands with the world economy.



Reconstruction of sea surface temperatures from the oxygen isotope composition (δ18O) of calcite biominerals synthesised in the mesopelagic zone of the oceans requires knowledge of the δ18O of

seawater and constraints on the magnitude of biological 18O∕16O fractionation (the so-called vital effect). In the palaeoceanography community, seawater δ18O and salinity are unduly treated as a common parameter owing to their strong covariation both geographically and in the geological register. If the former parameter has arguably no notable influence on the biogeochemistry of marine calcifiers, salinity potentially does. However, how salinity per se and the effect of osmotic adjustment can modulate the biogeochemistry, and in turn, the expression of the vital effect in calcite biomineral such as the coccoliths remains undocumented. In this culture-based study of coccolithophores (Haptophyta) belonging to the Noelaerhabdaceae family, we kept temperature and seawater δ18O constant, and measured basic physiological parameters (growth rate and cell size), and the isotope composition (18O∕16O and 13C∕12C) of coccoliths grown under a range of salinity, between 29 and 39. Ultimately, the overarching aim of this biogeochemical study is to refine the accuracy of palaeotemperature estimates using fossil coccoliths. We found that despite significant physiological changes in the coccolithophores, varying salinity does not modulate biological fractionation of oxygen isotopes. This observation contrasts with previous in vitro manipulations of temperature and carbonate chemistry that led to substantial changes in the expression of the vital effect. As such, salinity does not affect temperature estimation from coccolith-bearing pelagic sequences deposited during periods of change in ice volume, especially at the highest latitudes, or in coastal regions. By contrast, the carbon isotope composition of the coccoliths is influenced by a growth rate mediated control of salinity with implications for deriving productivity indices from pelagic carbonate.

Hernandez-Soriano, M.C., Dalal, R.C., Warren, F.J., Wang, P., Green, K., Tobin, M.J., Menzies, N.W., Kopittke, P.M., 2018. Soil organic carbon stabilization: Mapping carbon speciation from intact microaggregates. Environmental Science & Technology 52, 12275-12284.


The clearing of land for agricultural production depletes soil organic carbon (OC) reservoirs, yet despite their importance, the mechanisms by which C is stabilized in soils remain unclear. Using synchrotron-based infrared microspectroscopy, we have for the first time obtained in situ, laterally resolved data regarding the speciation of C within sections taken from intact free microaggregates from two contrasting soils (Vertisol and Oxisol, 0–20 cm depth) impacted upon by long-term (up to 79 y) agricultural production. There was no apparent gradient in the C concentration from the aggregate surface to the interior for any of the three forms of C examined (aliphatic C, aromatic C, and polysaccharide C). Rather, organo-mineral interactions were of critical importance in influencing overall C stability, particularly for aliphatic C, supporting the hypothesis that microaggregates form through organo-mineral interactions. However, long-term cropping substantially decreased the magnitude of the organo-mineral interactions for all three forms of C. Thus, although organo-mineral interactions are important for OC stability, C forms associated with the mineral phases are not entirely resistant to degradation. These results provide important insights into the underlying mechanisms by which microaggregates form and the factors influencing the persistence of OC in soils.

Hershey, O.S., Kallmeyer, J., Wallace, A., Barton, M.D., Barton, H.A., 2018. High microbial diversity despite extremely low biomass in a deep karst aquifer. Frontiers in Microbiology 9, 2823. doi: 10.3389/fmicb.2018.02823.


Despite the importance of karst aquifers as a source of drinking water, little is known about the role of microorganisms in maintaining the quality of this water. One of the limitations in exploring the

microbiology of these environments is access, which is usually limited to wells and surface springs. In this study, we compared the microbiology of the Madison karst aquifer sampled via the potentiometric lakes of Wind Cave with surface sampling wells and a spring. Our data indicated that only the Streeter Well (STR), which is drilled into the same hydrogeologic domain as the Wind Cave Lakes (WCL), allowed access to water with the same low biomass (1.56–9.25 × 103 cells mL-1). Filtration of ∼300 L of water from both of these sites through a 0.2 μm filter allowed the collection of sufficient cells for DNA extraction, PCR amplification of 16S rRNA gene sequences, and identification through pyrosequencing. The results indicated that bacteria (with limited archaea and no detectable eukaryotic organisms) dominated both water samples; however, there were significant taxonomic differences in the bacterial populations of the samples. The STR sample was dominated by a single phylotype within the Gammaproteobacteria (Order Acidithiobacillales), which dramatically reduced the overall diversity and species richness of the population. In WCL, despite less organic carbon, the bacterial population was significantly more diverse, including significant contributions from the Gammaproteobacteria, Firmicutes, Chloroflexi, Actinobacteria, Planctomycetes, Fusobacter, and Omnitrophica phyla. Comparisons with similar oligotrophic environments suggest that karst aquifers have a greater species richness than comparable surface environs. These data also demonstrate that Wind Cave provides a unique opportunity to sample a deep, subterranean aquifer directly, and that the microbiology of such aquifers may be more complex than previously anticipated.

Hewaidy, A.G.A., Makled, W.A., El Garhy, M.M., Baioumi, A.H., Mostafa, T.F., 2019. Aspects of palyno-organic facies analysis: Comprehensive evaluation of the source rocks and age of some subsurface Lower Cretaceous core materials in the north Western Desert, Egypt. Marine and Petroleum Geology 99, 498-525.


The palyno-organic facies aspects of the subsurface Lower Cretaceous core samples are extensively investigated in three wells in the northern part of the Western Desert of Egypt. These wells are Burg El Arab-1 and Mamura-1, Mersa Matruh-1 (BAX-1, MAX-1 and MMX-1 respectively). The study is based on the palynofacies and organic geochemical analyses. The palynofacies examination includes a statistical analysis of the different classes of organic particles by cluster analysis and principal component analysis (PCA). This analysis leads to identify 4 palynofacies types (A, B, C1 and C2) which are dominated by various levels of terrestrial floral materials. The paleoenvironmental settings that are attributed to these palynofacies types are the distal suboxic-oxic, proximal oxic, transitional oxic and highly distal oxic. The principal component analysis (PCA) differentiates between these palynofacies types mathematically by the biplot of components 1 and 2. The component 1 corresponds to distance from the terrestrial floral sources. The identification of quantity, type, quality and thermal maturity of organic matter is discussed depending on the palynofacies and organic geochemical analyses. The thermal maturity is assessed digitally by measuring the RGB color channels in the spore images and their corresponding thermal alteration index (TAI incorporated with values of Tmax). These measures are integrated in burial history models with geothermal gradient and depositional history. The study reveals that most of the core samples represent generally fair to good enriched sources of gas prone type III kerogen and less mixed gas-oil type II/III kerogen. Additionally, some occasional high levels of organic conversions are recorded. The burial history models indicate that oil expulsion window initiated in the Cretaceous. The examinations indicate mature oil sources in the Alam El Bueib Formation in MMX-1 well. The organic geochemical parameters are correlated versus the component 1 and sum of all components of PCA. The correlation coefficients (R2) pointed to good correlation between the oxygen index (OI), TOC and S2 and lower correlation with hydrogen index (HI).



Due to excellent separation capacity for complex mixtures of chemicals, comprehensive two-dimensional gas chromatography (GC × GC) is being utilized with increasing frequency for metabolomics analyses. This review describes recent advances in GC × GC method development for metabolomics, organismal sampling techniques compatible with GC × GC, metabolomic discoveries made using GC × GC, and recommendations and best practices for collecting and reporting GC × GC metabolomics data.

Hirose, H., Tsiamantas, C., Katoh, T., Suga, H., 2019. In vitro expression of genetically encoded non-standard peptides consisting of exotic amino acid building blocks. Current Opinion in Biotechnology 58, 28-36.


Ribosomal incorporation of non-proteinogenic amino acids (NPaa) into peptides have made significant progress in recent years. These non-standard peptides have been utilized for a plethora of applications in the fields of chemical biology and therapeutics. Here we comprehensively review recent advances for the incorporation of exotic NPaa into peptide chain using custom-made in vitro translation system under reprogrammed genetic code. Such approaches allow us to express non-standard peptides containing various amino acid building blocks in the mRNA-encoding manner, leading to the discovery of therapeutically useful macrocyclic molecules with molecular weight of less than 2500 Da.

Hoffman, C.L., Stutz, K., Vasilopoulos, T., 2018. An examination of adult women’s sleep quality and sleep routines in relation to pet ownership and bedsharing. Anthrozoös 31, 711-725.

https://doi.org/10.1080/08927936.2018.1529354

People in many parts of the world commonly share their beds not only with human partners but also with dogs and cats. Self-report and actigraphy data have shown that sleeping with an adult human partner has both positive and negative impacts on human sleep, but there has been little exploration of the impacts that pets have on human sleep quality. We collected survey data online from 962 adult women living in the United States to investigate relationships between pet ownership and human sleep. Fifty-five percent of participants shared their bed with at least one dog and 31% with at least one cat. In addition, 57% of participants shared their bed with a human partner. Our findings did not show a strong relationship between pet ownership status or bedsharing conditions and sleep quality as assessed by the Pittsburgh Sleep Quality Index (PSQI), although according to this measure, a high percentage of study participants did experience sleep quality deficits. It is possible that pet ownership contributed to the high global PSQI scores we observed, especially since all but 7% of participants resided with dogs and/or cats. Other measures included in this study indicate that dogs and cats, and where they sleep, may indeed affect sleep habits and perceptions of sleep quality. Dog owners had earlier bedtimes and wake times than individuals who had cats but no dogs. Compared with human bed partners, dogs who slept in the owner?s bed were perceived to disturb sleep less and were associated with stronger feelings of comfort and security. Conversely, cats who slept in their owner?s

bed were reported to be equally as disruptive as human partners, and were associated with weaker feelings of comfort and security than both human and dog bed partners. Follow-up research is necessary to determine if pet owners? perceptions of pets? impacts on their sleep align with objective measures of sleep quality.

Horinouchi, M., Koshino, H., Malon, M., Hirota, H., Hayashi, T., 2018. Steroid degradation in Comamonas testosteroni TA441: Identification oF metabolites and the genes involved in the reactions necessary before D-ring cleavage. Applied and Environmental Microbiology 84, Article e01324-18.


Abstract: Bacterial steroid degradation has been studied mainly with Rhodococcus equi (Nocardia restrictus) and Comamonas testosteroni as representative steroid degradation bacteria for more than 50 years. The primary purpose was to obtain materials for steroid drugs, but recent studies showed that many genera of bacteria (Mycobacterium, Rhodococcus, Pseudomonas, etc.) degrade steroids and that steroid-degrading bacteria are globally distributed and found particularly in wastewater treatment plants, the soil, plant rhizospheres, and the marine environment. The role of bacterial steroid degradation in the environment is, however, yet to be revealed. To uncover the whole steroid degradation process in a representative steroid-degrading bacterium, C. testosteroni, to provide basic information for further studies on the role of bacterial steroid degradation, we elucidated the two indispensable oxidative reactions and hydration before D-ring cleavage in C. testosteroni TA441. In bacterial oxidative steroid degradation, A- and B-rings of steroids are cleaved to produce 2-hydroxyhexa-2,4-dienoic acid and 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid. The latter compound was revealed to be degraded to the coenzyme A (CoA) ester of 9α-hydroxy-17-oxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid, which is converted to the CoA ester of 9,17-dioxo-1,2,3,4,5,6,10,19-octanorandrostan-7-oic acid by ORF31-encoded hydroxylacyl dehydrogenase (ScdG), followed by conversion to the CoA ester of 9,17-dioxo-1,2,3,4,5,6,10,19-octanorandrost-8(14)-en-7-oic acid by ORF4-encoded acyl-CoA dehydrogenase (ScdK). Then, a water molecule is added by the ORF5-encoded enoyl-CoA hydratase (ScdY), which leads to the cleavage of the D-ring. The conversion by ScdG is presumed to be a reversible reaction. The elucidated pathway in C. testosteroni TA441 is different from the corresponding pathways in Mycobacterium tuberculosis H37Rv.

Importance: Studies on representative steroid degradation bacteria Rhodococcus equi (Nocardia restrictus) and Comamonas testosteroni were initiated more than 50 years ago primarily to obtain materials for steroid drugs. A recent study showed that steroid-degrading bacteria are globally distributed and found particularly in wastewater treatment plants, the soil, plant rhizospheres, and the marine environment, but the role of bacterial steroid degradation in the environment is yet to be revealed. This study aimed to uncover the whole steroid degradation process in C. testosteroni TA441, in which major enzymes for steroidal A- and B-ring cleavage were elucidated, to provide basic information for further studies on bacterial steroid degradation. C. testosteroni is suitable for exploring the degradation pathway because the involvement of degradation-related genes can be determined by gene disruption. We elucidated the two indispensable oxidative reactions and hydration before D-ring cleavage, which appeared to differ from those present in Mycobacterium tuberculosis H37Rv.

Hou, N., Xia, Y., Wang, X., Liu, H., Liu, H., Xun, L., 2018. H2S biotreatment with sulfide-oxidizing heterotrophic bacteria. Biodegradation 29, 511-524.

https://doi.org/10.1007/s10532-018-9849-6

Many industrial activities produce H2S, which is toxic at high levels and odorous at even very low levels. Chemolithotrophic sulfur-oxidizing bacteria are often used in its remediation. Recently, we have reported that many heterotrophic bacteria can use sulfide:quinone oxidoreductase and persulfide dioxygenase to oxidize H2S to thiosulfate and sulfite. These bacteria may also potentially be used in H2S biotreatment. Here we report how various heterotrophic bacteria with these enzymes were cultured with organic compounds and the cells were able to rapidly oxidize H2S to zero-valence sulfur and thiosulfate, causing no apparent acidification. Some also converted the produced thiosulfate to tetrathionate. The rates of sulfide oxidation by some of the tested bacteria in suspension, ranging from 8 to 50 µmol min−1 g−1 of cell dry weight at pH 7.4, sufficient for H2S biotreatment. The immobilized bacteria removed H2S as efficiently as the bacteria in suspension, and the inclusion of Fe3O4 nanoparticles during immobilization resulted in increased efficiency for sulfide removal, in part due to chemical oxidation H2S by Fe3O4. Thus, heterotrophic bacteria may be used for H2S biotreatment under aerobic conditions.

Hu, F., Liu, Z., Meng, Q., Wang, J., Song, Q., Xie, W., 2018. Biomarker characterization of various oil shale grades in the Upper Cretaceous Qingshankou Formation, southeastern Songliao Basin, NE China. Oil Shale 35, 304–326.

https://doi.org/10.3176/oil.2018.4.02

In the Songliao Basin, northeastern China, the oil shale-bearing succession in the Upper Cretaceous Qingshankou Formation contains excellent source rocks. Oil shales with different total organic carbon (TOC) contents and oil yields developed in the lower member of the formation (K2qn1). In this study, we apply gas chromatography-mass spectrometry (GC-MS) to determine the geochemical characteristics, organic matter (OM) sources and depositional environments of various grades of oil shale. Rock-Eval pyrolysis indicates that type I kerogen is the predominant organic matter in the K2qn1 oil shale, though variability in n-alkanes, steranes and hopanoids contents implies that organic matter from a variety of sources is present. High-quality oil shales are dominated by phytoplanktonic/algal and bacterial organic matter, while lower-quality oil shales are dominated by planktonic kerogen with a minor contribution from land plants. Organic matter types can indicate a high shale oil conversion rate, and increased prospects for oil shale utilization. Oxygen-deficient bottom water conditions, related to salinity stratification, are evidenced by biomarker ratios (Pr/Ph, gammacerane index (GI)). We propose that the highest-quality oil shales were deposited under anoxic conditions, with strong salinity stratification of the water column. OM sources, redox conditions and water column salinity stratification were the key factors controlling the accumulation of high-quality oil shale in the southeastern Songliao Basin.

Hu, G., Sun, C., Huang, J., Xu, G., Zhu, J., 2018. Evolution of shale microstructure under microwave irradiation stimulation. Energy & Fuels 32, 11467-11476.


As the low permeability of shale gas reservoirs limit its large-scale commercial development, the microwave irradiation stimulation is proposed as a new approach to increase the shale gas reservoir’s production. In this study, in order to investigate the microwave’s effect on shale pore structure, experiments were performed using nuclear magnetic resonance to compare the pore size distribution of shale samples before and after microwave treatment. The results showed that the numbers as well as sizes of mesopores and macropores in shale samples increased, while the number of micropores decreased after the microwave irradiation. This is benefit to enhance shale gas flow in reservoirs. In addition, the moisture within the shale samples increased its ability to absorb microwave energy,

leading to a positive effect on the increase of breathable pores and microfractures. When the accompanying thermal stress and vapor pressure generated inside the shale is larger than the cementation strength between the shale mineral particles, the shale cracks and forms microcracks until it is destroyed. The experimental results demonstrated that the microwave stimulation is effective in expanding breathable pores and inducing fissures in shale samples; it may therefore have applications in enhancing shale gas reservoirs.

Hu, W., Wang, X., Zhu, D., You, D., Wu, H., 2018. An overview of types and characterization of hot fluids associated with reservoir formation in petroliferous basins. Energy Exploration & Exploitation 36, 1359-1375.

https://doi.org/10.1177/0144598718763895

Increasing petroleum explorations indicate that the formation of many reservoirs is in close association with deep hot fluids, which can be subdivided into three groups including crust-derived hot fluid, hydrocarbon-related hot fluid, and mantle-derived hot fluid. The crust-derived hot fluid mainly originates from deep old rocks or crystalline basement. It usually has higher temperature than the surrounding rocks and is characterized by hydrothermal mineral assemblages (e.g. fluorite, hydrothermal dolomite, and barite), positive Eu anomaly, low δ18O value, and high 87Sr/86Sr ratio. Cambrian and Ordovician carbonate reservoirs in the central Tarim Basin, northwestern China serve as typical examples. The hydrocarbon-related hot fluid is rich in acidic components formed during the generation of hydrocarbons, such as organic acid and CO2, and has strong ability to dissolve alkaline minerals (e.g. calcite, dolomite, and alkaline feldspar). Extremely 13C-depleted carbonate cements are indicative of the activities of such fluids. The activities of hydrocarbon-related hot fluids are distinct in the Eocene Wilcox Group of the Texas Gulf Coast, and the Permian Lucaogou Formation of the Jimusaer Sag and the Triassic Baikouquan Formation of the Mahu Sag in the Junggar Basin. The mantle-derived hot fluid comes from the upper mantle. The activities of mantle-derived hot fluids are common in the rift basins in eastern China, showing a close spatial relationship with deep faults. This type of hot fluid is characterized by high CO2 content, unique gas compositions, and distinct noble gas isotopic signatures. In the Huangqiao gas field of eastern China, mantle-derived CO2-rich hot fluids have created more pore spaces in the Permian sandstone reservoirs adjacent to deep faults.



Methane of various origins is widespread in the sediments of continental margins, representing a key component of the carbon cycle in the ocean. Its occurrence in shallow marine sediments can be linked to the gas hydrate reservoir in the deep sedimentary column. However, this type of methane is difficult to track due to complex reactions occurred during its long distance migration. Porewater geochemical analyses of two ∼7 m piston cores (D17-15 and W01-16) combined with a reaction-transport model were applied to quantify methane-related biogeochemical processes and to explore the linkage of shallow methane to gas hydrate reservoir in the hydrate drilling areas of Shenhu and Dongsha in the South China Sea (SCS). The model results revealed that anaerobic oxidation of methane (AOM) is the predominant biogeochemical process in both cores, consuming approximately 85% and 74% of sulfate in the modeled domain, respectively. The crossplot of dissolve inorganic carbon (DIC) accumulation versus sulfate depletion of the system suggests that methane consumed during the AOM is mainly originated from external methane sources rather than local

methanogenesis. Using a δ13CDIC mass balance calculation together with model-derived fractions of different DIC sources, we estimated that the δ13C value of the external methane in core D17-15 is −66.6‰, which is in accordance with the previous reported δ13C values of hydrate-bound methane in the area. These results suggest that methane consumed in shallow sediments in the hydrate drilling areas of the SCS is mainly originated from local gas hydrate reservoir. The proposed approach has the potential to be used to differentiate the sources of methane, which will provide constraints on dynamics of methane in gas hydrate-bearing marine sediments.

Huang, C., Zhang, J., Hua, W., Yue, J., Lu, Y., 2018. Sedimentology and lithofacies of lacustrine shale: A case study from the Dongpu sag, Bohai Bay Basin, Eastern China. Journal of Natural Gas Science and Engineering 60, 174-189.


This paper analyzes the sedimentology and lithofacies of the lacustrine shale from the third member of the Eocene Shahejie Formation (Es3) in the Dongpu sag, Bohai bay basin, eastern China. The results show that lacustrine shale is heterogeneous in its sedimentary structure, lithology, mineralogy, lithofacies, and oil content. From the margin of the lake to its center, the depositional environment progresses from delta front to prodelta to deep water lake, and the primary sedimentary lithologies changes from interbedded mudstone and sandstone to mudstone with siltstone to mudstone with evaporite and carbonate rocks. The major deep water deposits are laminated shales. From the lake margin to the center, felsic mineral content decreases gradually, and clay mineral and pyrite content increases gradually. Felsic mineral content is the highest in the delta front shale, and clay mineral and pyrite content is highest in the deep water lake. Shale lithofacies also change with the depositional environment. The lithofacies of the delta front shale are primarily felsic-rich lithofacies: clay-rich carbonate-poor felsic shale (S-4) and a clay-rich, carbonate-poor felsic-rich mixed shale (MS-2). The lithofacies of the prodelta shale are primarily a carbonate-poor felsic-rich muddy shale (M-2), S-4, and MS-2. The lithofacies of deep water lake shales are primarily clay mineral-rich lithofacies: M-2, MS-2, and the clay-rich, carbonate-rich, felsic-rich mixed shale (MS-3). The TOC and the types of organic matter also change with the depositional environment in the Dongpu sag. The results of this study show the sedimentary structures, lithology, mineral content, lithofacies, and spatial distribution of the lacustrine shale was not only controlled by the macro depositional environment and the local depositional environment, but also controlled by the source and transport (or the sediment transport path), water depth, and accommodation space.

Huang, L., Tang, J., Chen, M., Liu, X., Zhou, S., 2018. Two modes of riboflavin-mediated extracellular electron transfer in Geobacter uraniireducens. Frontiers in Microbiology 9, 2886. doi: 10.3389/fmicb.2018.02886.


Anaerobes respire extracellular electron acceptors by extracellular electron transfer (EET). It is widely recognized that flavins can act as electron shuttles to facilitate this process. Flavin synthesis genes are widely distributed in Geobacter species. However, the functions of flavins in the EET of Geobacter species are unclear. Here, we demonstrate that G. uraniireducens can secrete abundant riboflavin (up to 270 nM) to facilitate EET. When an electrode was used as the electron acceptor, the quick recovery of anodizing current after anolyte replacement and the electrochemical behavior of the G. uraniireducens biofilm characterized by differential pulse voltammetry suggest that the self-secreted riboflavin promoted EET by serving as bound redox cofactors for cytochromes. On the contrary, when Fe(III) oxide was the electron acceptor, free riboflavin acted as electron shuttle to

mediate the reduction of Fe(III) oxide. The results demonstrate the flexibility of flavins in EET, suggesting that the properties of electron acceptors can affect the binding mode of extracellular flavins, and broaden the knowledge of the EET of Geobacter species.



Two oilfield-produced wastewater (OPW) plants, one grown through two-stage aerobic (O1/O2) activated sludge process in North-China Oilfield (NCO) and the other through anaerobic/aerobic/aerobic (An/O1/O2) biofilm process in Liao–He Oilfield (LHO), were used for the analysis of the distribution of bacterial communities systematically by high-throughput sequencing. A large number of halotolerant, thermotolerant, and petrol-degrading microbes, Firmicute, Chloroflexi, Thermotogae, Chlorobi, and SBR1093, were detected in each plant because of high OPW temperature (43 °C–54 °C) and salinity (6.5–12 g L−1 of Cl−). However, the Shannon and Chao 1 indexes of LHO were higher than that of NCO, indicating greater microbial diversity and richness in biofilm process than in the activated sludge system. The microbiota structures of the two plants also differed, and such difference was significantly induced by various raw wastewater petroleum hydrocarbon constituents and treatment processes. The distance-based redundancy analysis showed that the temperature, DO, Cl−, and organic components in OPW were closely related to bacteria distribution. Interestingly, two same-genus strains, NC(X-6) and LH(X-9), were isolated from NCO and LHO, respectively. Both strains were identified as Bacillus licheniformis, but showed different colony colors, transparencies, cell surface hydrophobicities, dehydrogenase activities, and biodegradabilities of organic matter, which was probably due to the different gene expression levels caused by environmental change.

Hug, L.A., 2018. Sizing up the uncultured microbial majority. mSystems 3, Article e00185-18.

http://msystems.asm.org/content/3/5/e00185-18.abstract

Predicting the total number of microbial cells on Earth and exploring the full diversity of life are fundamental research concepts that have undergone paradigm shifts in the genomic era. In this issue, Lloyd and colleagues (K. G. Lloyd, A. D. Steen, J. L. Ladau, J. Yin, and L. Crosby, mSystems 3:e00055-18, https://doi.org/10.1128/mSystems.00055-18, 2018) present results that combine these two concepts by estimating the total diversity of all cells from Earth’s environments. Leveraging publicly available amplicon, metagenomic, and metatranscriptomic datasets, they determined that nearly all environments are dominated by uncultured lineages, with the exception of humans and human-associated habitats. They define a new concept: phylogenetically diverse noncultured cells (PDNC). Unlike viable but nonculturable cells (VBNC), PDNC are microorganisms for which traditional isolation techniques may never succeed. Lloyd et al. estimate that the majority of microorganisms in Earth’s ecosystems may be PDNC and conclude that culture-independent methods combined with innovative culturing techniques may be required to understand the ecology and physiology of these abundant and divergent microorganisms.The views expressed in this article do not necessarily reflect the views of the journal or of ASM.

Idowu, I., Johnson, W., Francisco, O., Obal, T., Marvin, C., Thomas, P.J., Sandau, C.D., Stetefeld, J., Tomy, G.T., 2018. Comprehensive two-dimensional gas chromatography high-resolution mass

spectrometry for the analysis of substituted and unsubstituted polycyclic aromatic compounds in environmental samples. Journal of Chromatography A 1579, 106-114.


Polycyclic aromatic compounds (PACs) consists of multiple compounds and the number of theoretically possible isomers can reach into the thousands. Currently each PAC group is quantified collectively as a single group of compounds. However, individual PACs can reveal important information on how the PACs were formed and this information may be used to determine sources of PACs in environmental samples, It is hypothesized that many of the limitations with characterizing alkylated PACs with one dimensional gas-chromatography (1D GC) can be circumvented using GC × GC (two dimensional gas chromatography). Here we apply comprehensive GCxGC coupled to high-resolution time of flight mass spectrometry (GC × GC-HFTOF-MS) to aid in the separation, identification and quantitation of APACs in three environmental matrices: mussel tissue (Mytilus edulis), lubricating oil and coal. In the absence of authentic analytical standards, differences in the mass spectral fragmentation pattern of isomers were used to confirm the identity of isomers within a PAC group. The method was validated according to the EURACHEM guidelines and used to quantify a biological standard reference material (SRM 2974a). The method met all the standard method performance requirements such as trueness, precision and measurement of uncertainty and is fit for quantifying these compounds in biota. Furthermore, the method was used to identify and quantify additional PAC compounds in the SRM 2974a material which to date have not been certified. With appropriate statistical analytical tools, the described GC × GC method can be used as a tool for more robust source fingerprinting and source apportionment of PACs in the environment.

Ilyinskaya, E., Mobbs, S., Burton, R., Burton, M., Pardini, F., Pfeffer, M.A., Purvis, R., Lee, J., Bauguitte, S., Brooks, B., Colfescu, I., Petersen, G.N., Wellpott, A., Bergsson, B., 2018. Globally significant CO2 emissions from Katla, a subglacial volcano in Iceland. Geophysical Research Letters 45, 10,332-10,341.

https://doi.org/10.1029/2018GL079096

Abstract: Volcanoes are a key natural source of CO2, but global estimates of volcanic CO2 flux are predominantly based on measurements from a fraction of world's actively degassing volcanoes. We combine high‐precision airborne measurements from 2016 and 2017 with atmospheric dispersion modeling to quantify CO2 emissions from Katla, a major subglacial volcanic caldera in Iceland that last erupted 100 years ago but has been undergoing significant unrest in recent decades. Katla's sustained CO2 flux, 12–24 kt/d, is up to an order of magnitude greater than previous estimates of total CO2 release from Iceland's natural sources. Katla is one of the largest volcanic sources of CO2 on the planet, contributing up to 4% of global emissions from nonerupting volcanoes. Further measurements on subglacial volcanoes worldwide are urgently required to establish if Katla is exceptional, or if there is a significant previously unrecognized contribution to global CO2 emissions from natural sources.

Plain Language Summary: We discovered that Katla volcano in Iceland is a globally important source of atmospheric carbon dioxide (CO2) in spite of being previously assumed to be a minor gas emitter. Volcanoes are a key natural source of atmospheric CO2, but estimates of the total global amount of CO2 that volcanoes emit are based on only a small number of active volcanoes. Very few volcanoes that are covered by glacial ice have been measured for gas emissions, probably because they tend to be difficult to access and often do not have obvious degassing vents. Through high‐precision airborne measurements and atmospheric dispersion modeling, we show that Katla, a highly hazardous subglacial volcano that last erupted 100 years ago, is one of the largest volcanic sources of CO2 on

Earth, releasing up to 4% of total global volcanic emissions. This is significant in a context of a growing awareness that natural CO2 sources have to be more accurately quantified in climate assessments, and we recommend urgent investigations of other subglacial volcanoes worldwide.


http://dx.doi.org/10.1093/femsec/fiy198

Seasonal changes of microbial abundance and associated extracellular enzymatic activity in marine snow and in seawater were studied in the northern Adriatic during a three-year period. Marine snow was present during the entire period of investigation, although in higher concentrations during summer than during winter. Microorganisms densely colonized marine snow and aggregate-associated enzymatic activity was substantially higher (up to 105 times) than in seawater. Alkaline phosphatase activity (APA) and aminopeptidase activity in marine snow showed seasonal variations with higher values in late spring–summer than in autumn–winter, probably in response to changes in the quantity and quality of organic matter. The highest cell-specific bacterial activity was found for phosphatase, followed by peptidase, and the lowest was for glucosidases. Differential hydrolysis of marine snow-derived organic matter points to the well-known phosphorus limitation of the northern Adriatic and indicates preferential utilization of phosphorus- and nitrogen-rich organic compounds by microbes, while hydrolysis of polysaccharides seemed to be less important. In oligotrophic conditions during summer, organic matter released from marine snow might represent a significant source of substrate for free-living bacteria in seawater. For the first time microorganisms producing APA in marine snow were identified, revealing that dense populations of bacteria expressed APA, while cyanobacteria did not. Cyanobacteria proliferating in marine snow could benefit from phosphorus release by bacteria and nanoflagellates.

Jagadeesh, M.K., Roszkowska, M., Kaczmarek, Ł., 2018. Tardigrade indexing approach on exoplanets. Life Sciences in Space Research 19, 13-16.


Finding life on other worlds is a fascinating area of astrobiology and planetary sciences. Presently, over 3800 exoplanets, representing a very wide range of physical and chemical environments, are known. Scientists are not only looking for traces of life outside Earth, but they are also trying to find out which of Earth's known organisms (ex: tardigrades (water bears)) would be able to survive on other planets. In our study, we have established a metric tool for distinguishing the potential survivability of active and cryptobiotic tardigrades on rocky-water and water-gas planets in our solar system and exoplanets, taking into consideration the geometrical means of six physical parameters such as radius, density, escape velocity, revolution period, surface temperature, and surface pressure of the considered planets. More than 3800 exoplanets are available as the main sample from Planetary Habitable Laboratory – Exoplanet Catalog (PHL-EC), from which we have chosen 57 exoplanets in our study including Earth and Mars, with water composition as reference. The Active Tardigrade Index (ATI) and Cryptobiotic Tardigrade Index (CTI) are two metric indices with minimum value 0 (= tardigrades cannot survive) and maximum 1 (= tardigrades will survive in their respective state). Values between 0 and 1 indicate a percentage chance of the active or cryptobiotic tardigrades surviving on a given exoplanet. Among known planets some of the exoplanets are tabulated as ATI and CTI indices for sample representation like: Kepler-100d, Kepler-48d, Kepler-289b, TRAPPIST-1

f and Kepler-106e. The results with Mars as the threshold indicates that Mars could be the only rock-water composition planet that could be more suitable for tardigrades than other considered exoplanets.

Jakubowicz, M., Dopieralska, J., Kaim, A., Skupien, P., Kiel, S., Belka, Z., 2019. Nd isotope composition of seep carbonates: Towards a new approach for constraining subseafloor fluid circulation at hydrocarbon seeps. Chemical Geology 503, 40-51.


The carbonates forming at deep-sea hydrocarbon seeps provide an archive for the source and migration pathways of the seeping fluids. Interpretation of the archived isotopic and elemental signatures is, however, not straightforward because of mixing between the signals of fluids and ambient seawater, limited understanding of subseafloor fluid circulation, and effects of diagenetic alteration. The Nd isotope system is among the most widely used tracers of circulation patterns in modern and past oceans, but to date Nd isotopes have been rarely used in investigations of fluid migration pathways at hydrocarbon seeps. To test the sensitivity of Nd isotope signals of seep carbonates to record past interactions between the seeping fluids and 143Nd-enriched, volcanic-derived mineral components, we performed Nd, Sr and stable isotope analyses of the Lower Cretaceous (Barremian) seep carbonates found in Baška (Czech Carpathians). These seep deposits are directly underlain by a complex of mafic igneous rocks, which the methane-charged fluids must have passed through on their way to the seafloor. The εNd(t) values measured in the seep carbonates are significantly more radiogenic than the inferred signal of contemporaneous local seawater, and shifted towards the composition typical of the underlying basaltoids. This is in agreement with the 87Sr/86Sr ratios, which are markedly lower that the coeval seawater signature. Consistent co-variance trends are observed among the measured εNd(t), 87Sr/86Sr and δ13C values, attesting increasing role of the volcanic-derived fluid component with increasing contribution of methane-derived carbon. The results of the present approach reveal the potential of Nd isotopes to fingerprint exotic fluid end-members present in plumbing systems of both fossil and modern methane discharges. The method can be of particular use in studies of seeps associated with plate margins, where 143Nd-enriched igneous materials are commonly encountered in the basement or in the sediment column.

Jamieson, A.J., 2018. A contemporary perspective on hadal science. Deep Sea Research Part II: Topical Studies in Oceanography 155, 4-10.


The hadal zone (6000–~ 11,000m deep) arguably represents the last great frontier in marine science. Although scientific endeavour in these deepest ecosystems has been slow relative to other more accessible environments, progress is steadily being made, particularly in the last 10 years. This paper details the latest developments in technology and sampling effort at full ocean depth, scientific literature, representation in international conferences and symposia, the recent acquisition of large ecological data sets, conservation, the potential for biodiscovery and describes some key strategic sampling approaches to ensure recent progress is sustained effectively. The timing of this article is indeed to reflect on recent sampling efforts and resulting publications to provide perspectives on where the scientific community is with regards to hadal science and where it might lead in the immediate future.

Jeffery, J.E., Storrs, G.W., Holland, T., Tabin, C.J., Ahlberg, P.E., 2018. Unique pelvic fin in a tetrapod-like fossil fish, and the evolution of limb patterning. Proceedings of the National Academy of Sciences 115, 12005-12010.


Significance: The fossil fish Rhizodus hibberti, a member of the tetrapod stem group, shows a unique skeletal pattern in the pelvic fin. Rather than the highly conserved one-to-two pattern of a femur, tibia, and fibula (seen in all known tetrapods, including the extinct, fishlike members of the group), the fin of Rhizodus comprises a femur articulating distally with three bones, each with a distinct morphology. This reveals an early stage in the evolution of limb development, in which the processes patterning the proximal parts of the embryonic fin/limb (the stylopod and zeugopod) were not constrained in the way seen in living tetrapods and could produce more varied skeletal patterns in the adult.

Abstract: All living tetrapods have a one-to-two branching pattern in the embryonic proximal limb skeleton, with a single element at the base of the limb (the humerus or femur) that articulates distally with two parallel radials (the ulna and radius or the tibia and fibula). This pattern is also seen in the fossilized remains of stem-tetrapods, including the fishlike members of the group, in which despite the absence of digits, the proximal parts of the fin skeleton clearly resemble those of later tetrapods. However, little is known about the developmental mechanisms that establish and canalize this highly conserved pattern. We describe the well-preserved pelvic fin skeleton of Rhizodus hibberti, a Carboniferous sarcopterygian (lobe-finned) fish, and member of the tetrapod stem group. In this specimen, three parallel radials, each robust with a distinct morphology, articulate with the femur. We review this unexpected morphology in a phylogenetic and developmental context. It implies that the developmental patterning mechanisms seen in living tetrapods, now highly constrained, evolved from mechanisms flexible enough to accommodate variation in the zeugopod (even between pectoral and pelvic fins), while also allowing each element to have a unique morphology.

Jegede, T.O., Adekola, S.A., Akinlua, A., 2018. Trace element geochemistry of kerogens from the central Niger Delta. Journal of Petroleum Exploration and Production Technology 8, 999-1007.

https://doi.org/10.1007/s13202-018-0448-1

Trace elements in kerogens isolated from shale samples obtained from oil wells in the central Niger Delta were determined using atomic absorption spectrometry, with the aim to determine the depositional environment and source of the organic matter. The results showed that the concentrations of the elements in the kerogens ranged from 1.50 to 6470.00 ppm and 3.50 to 7946.00 ppm for Wells X and Y, respectively. In both wells, Fe was the most abundant element, while cobalt had the least concentration. Nickel had an enhanced concentration over vanadium in Well X, while the reversed was the case in Well Y. The distribution patterns of the trace elements indicate that most of the kerogens from the two wells have similar origin. The geochemical ratios calculated from the concentrations of the trace elements revealed kerogens from Well X have terrestrial organic matter input, while kerogens from Well Y have both mixed marine/terrestrial organic matter and terrestrial inputs. The concentrations of the trace elements also revealed that the organic materials of samples from Well X were deposited under oxic conditions, while those from Well Y were deposited under oxic–suboxic conditions.

Jensen, S., Högström, A.E.S., Høyberget, M., Meinhold, G., McIlroy, D., Ebbestad, J.O.R., Taylor, W.L., Agić, H., Palacios, T., 2018. New occurrences of Palaeopascichnus from the Stáhpogieddi

Formation, Arctic Norway, and their bearing on the age of the Varanger Ice Age. Canadian Journal of Earth Sciences 55, 1253-1261.


We report on new occurrences of the late Ediacaran problematicum Palaeopascichnus (Protista?) from the Stáhpogieddi Formation, Arctic Norway. The stratigraphically lowest occurrences are in beds transitional between the Lillevannet and Indreelva members: the highest in the second cycle of the Manndrapselva Member, stratigraphically close to the lowest occurrences of Cambrian-type trace fossils. This establishes a long stratigraphical range of Palaeopascichnus on the Digermulen Peninsula, as has been previously documented from Newfoundland, South Australia, and elsewhere in Baltica. The age range of Palaeopascichnus in Avalonia and Baltica is from ∼565 to 541 Ma. Since the transition from the Mortensnes Formation to the Stáhpogieddi Formation is without a major break in sedimentation, this supports the inference that the underlying glacigenic Mortensnes Formation is ca. 580 Ma, and therefore Gaskiers-equivalent, or younger.

Ji, Y., Hou, Y., Ren, S., Yao, C., Wu, W., 2019. Separation of phenolic compounds from oil mixtures using environmentally benign biological reagents based on Brønsted acid-Lewis base interaction. Fuel 239, 926-934.


Phenolic compounds, which are widely used in producing synthetic fibers, engineering plastics, and other industrial organic chemicals, can be obtained from oil mixtures before further processing or applications by separation. Based on Lewis/Brønsted acid-base theory, we proposed the separation of phenolic compounds from oil mixtures using some environmentally benign biological reagents (BRs, including 1,3-dimethylxanthine-DMX, isonicotinamide-INA, and L-lysine-LYS). The effects of stirring time, temperature, initial phenol concentration, and BR:phenol mole ratio on phenol removal were studied in detail. LYS, INA and DMX show phenol removal efficiencies of 98.4%, 82.2%, and 66.6% from toluene at BR:phenol mole ratios of 1.6, 1.4, and 0.4, respectively, and those of 99.1%, 91.8%, and 74.6% from n-hexane at BR:phenol mole ratios of 2.20, 1.60, and 0.80, respectively, at room temperature. The BRs were regenerated with an anti-extraction method for four cycles without significant changes in separation efficiency and their properties. In addition, it is found that there is little toluene entrained in the biological reagents, which is as low as 2.3 wt% of separated phenol, indicating high purities of products. These BRs show the advantages of easy biodegradation, no corrosion to the equipment and containers, and no pollution to the environment.

Jia, R., Unsal, T., Xu, D., Lekbach, Y., Gu, T., 2019. Microbiologically influenced corrosion and current mitigation strategies: A state of the art review. International Biodeterioration & Biodegradation 137, 42-58.


In nature, microbes tend to form synergistic biofilms on a wide range of materials using extracellular polymeric substances to embed sessile cells. Problematic biofilms provide environments conducive to the occurrence of microbiologically influenced corrosion (MIC) in many industries. MIC includes corrosion caused by microbes as well as corrosion by another pre-existing corrosion agent that is accelerated by microbes. There are several distinct types of MIC mechanisms associated with different microbial species and metabolism types. Biofilms employ different defense mechanisms to protect themselves from environmental hazards. This makes sessile cells in biofilms much more

resistant to treatment than planktonic cells. Biofilms are often treated with biocides together with physical scrubbing. Various approaches have been developed to boost biocide efficacy. New emerging technologies such as bacterial phages, quorum sensing inhibitors, and special chemicals to enhance biocides have been proposed in recent years. This review evaluates these different treatment methods and various techniques used to assess biocide treatment outcome including microbiology, molecular biology, corrosion testing and electrochemical methods.

Jian, K., Chen, G., Guo, C., Ma, G., Ru, Z., 2019. Biogenic gas simulation of low-rank coal and its structure evolution. Journal of Petroleum Science and Engineering 173, 1284-1288.


For this paper, low-rank coals with Ro,max of 0.53% were selected to carry out the simulation on the degradation of coal by the microbial action. The bacterial solution of biogenic gas simulation was derived from coal mine water containing the methanogenic bacteria. The results show that the origin of produced gas is biogenic, and its formation pathway is dominated by acetic acid fermentation, and the composition of produced gas is mainly CH4 and CO2. Changes in CH4 and CO2 content show a regularity of synchronization in the stabilization period of gas-producing, and the carbon isotopic composition of CH4 is lighter than that of CO2. Due to the inherited isotope fractionation effects, the light carbon isotopes of produced gas are fractionated into CH4 while the heavy carbon isotopes of that are fractionated into CO2. In addition, a significant negative correlation exists between δ13CCH4 and δ13CCO2,. The lighter the δ13CCH4, the heavier the δ13CCO2. The enriched tendency of light carbon isotopes of CH4 is significant in the process of biogenic gas simulation. During the 90 days of simulation, both the absorption peak strength of aliphatic -CH2- stretching and that of aliphatic -CH2- and -CH3 deformation show the trend of increasing first and then decreasing. Besides, the microbial action do not only affects the aliphatic structure, but also affects the aromatic structure. It is speculated that the microbes derived from coal mine water may have the ability to make the insoluble structure of coal soluble in part. These research results have a theoretical significance for enriching the formation mechanisms of coalbed methane in low-rank coal reservoirs.

Jiang, J., Yang, W., Cheng, Y., Liu, Z., Zhang, Q., Zhao, K., 2019. Molecular structure characterization of middle-high rank coal via XRD, Raman and FTIR spectroscopy: Implications for coalification. Fuel 239, 559-572.


In recent years, the major coal producing areas in China have entered the period of deep mining, with coal rank changing from low-rank coal (LRC) to middle-high rank coal (MHRC). Even though material properties of MHRC, such as pore size and shape, have attracted increasing attentions, its molecular structures still remains unclear. This study probes molecular structural properties of five MHRC samples using X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy. Test results show that with the deepening of coalification, the aromatic rings of MHRC increase gradually. The aliphatic side chains between the aromatic rings continuously fall off. The ordered structure of coal continues to enhance, resulting in an increase in the degree of graphitization of coal. The average lateral sizes (La), stacking heights (Lc) and interlayer spacing (d002) of the crystallite structures of MHRC samples derived from the XRD range from 20.65 to 31.68, 10.62 to 19.21 and 3.42 to 3.66 Å, respectively. The La values derived from the Raman spectra using the classical linear relationship between 1/La and the ID1/IG band ratio are higher (36.36–59.91 Å) than the values obtained from XRD. The FTIR spectra reveals that MHRC samples contain aliphatic functional groups such as CH2 and CH3, aromatic functional groups such as CC and aromatic ring

CH, and oxygen-containing functional groups such as OH, CO and CO. The aromaticity (fa) of the coal samples determined by FTIR ranges from 0.66 to 0.98, and compared with the fa valued from XRD (0.63 to 0.93), which shows that the MHRC contains abundant of aliphatic components. On the basis of these results, the structural parameters obtained by different spectral techniques are also used to comparatively study the effects of coalification on the molecular structure of coals. The structural parameters of coal derived by these methods reflect the coalification jumps at Ro = 0.5, 0.7–0.9, 1.2, 2.6, 3.3, 3.5–4.0 and 4.2–4.8%. Among them, the jump at Ro = 4.2–4.8% is unreported in previous studies and should be further studied in subsequent research. The application range of structure parameters used to evaluate the coal rank such as d002, La (XRD), fa and G-D1 should be considered because of coalification jumps. The parameters such as 'C', ID1/IG and La (Raman) are better choices for evaluating coal rank for their better correlation with Ro. It is worth pointing out that these parameters have implications for coalification and should be concerned in further study.

Jiang, W., Zhang, Q., Zeng, F., 2019. Metamorphic degree of coal dependence of content and genesis of coal-bed methane in China. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 378-388.

https://doi.org/10.1080/15567036.2018.1518356

Aiming to investigate the coal metamorphic degree dependences of both the distribution characteristics of the content of CBM and the output characteristics of CBM, the thermal simulation experiments were adopted in this study. The results confirm that the content of CBM shows a unimodal relationship with the elevated coal metamorphic degree. The CBM in high-rank coal-bed mainly falls into the category of thermogenic CBM. The thermogenic CBM is generated after the thermal stability of coal metamorphism. The output characteristic of thermogenic CBM is the dominant factor determining the relationship between content of CBM and coal metamorphism degree. Both the amount of thermogenic CBM and the content of CBM increase with the coal metamorphism degree with Ro max ≤ 3.5%; however, the opposite trend is found for Ro max ≥ 3.5%.

Jiang, Y., Chekuri, S., Fang, R.H., Zhang, L., 2019. Engineering biological interactions on the nanoscale. Current Opinion in Biotechnology 58, 1-8.


Nanoparticulate platforms have contributed significantly to the field of biomedical research, demonstrating advantages over traditional modalities in areas such as drug delivery, detoxification, and vaccination. When it comes to the design of nanoparticles, biomimetic strategies have become increasingly popular as a means of promoting effective interactions with biological systems. A recently developed cell membrane-coated nanoparticle platform can leverage the natural interactions that cells engage in with other cells, the extracellular matrix, and biomolecules in order to reduce undesirable nonspecific interactions, while increasing target-specific interactions. Here, we discuss the current state of these biomimetic nanoparticles and highlight how they can be used for various biomedical applications.

Jiang, Y., Zhou, H., Chen, L., Yuan, Y., Fang, H., Luan, L., Chen, Y., Wang, X., Liu, M., Li, H., Peng, X., Sun, B., 2018. Nematodes and microorganisms interactively stimulate soil organic carbon turnover in the macroaggregates. Frontiers in Microbiology 9, 2803. doi: 10.3389/fmicb.2018.02803.


The intra-aggregate architecture of soil macroaggregates provides suitable microhabitats for nematodes to graze on microorganisms. However, it is not fully disentangled how nematodes and microbial communities interactively mediate soil organic carbon (SOC) turnover. Here, we aimed to illustrate the relationships between nematodes, microbial community, and SOC turnover in the macroaggregates of a red soil receiving long-term manure application. Soil macroaggregates (> 2 mm) were sampled from an 11-year field experiment including four manure treatments: no manure (M0), low manure rate (M1), high manure rate (M2), and high manure rate with lime (M3). The abundances of nematodes and microbial communities were substantially increased under manure treatments. Bacterivores dominated under the M2 and M3 treatments, while plant parasites were enriched under the M1 treatment. Phospholipid fatty acid analysis indicated that the ratio of bacteria to fungi significantly increased but the ratio of Gram-positive bacteria to Gram-negative bacteria declined with the increasing manure addition. Random forest modelling showed that soil porosity had a primary effect on the nematode assemblages, while pH and SOC contributed profoundly to the microbial community structure and carbon metabolic capacity. Structural equation modelling suggested that nematode grazing promoted carbon metabolic activities predominantly due to increased microbial biomass. Taken together, the mechanistic understanding of nematode-microorganism interactions may have important implications for improving soil fertility by nematode-mediated microbial processes.

Jiao, N., Liang, Y., Zhang, Y., Liu, J., Zhang, Y., Zhang, R., Zhao, M., Dai, M., Zhai, W., Gao, K., Song, J., Yuan, D., Li, C., Lin, G., Huang, X., Yan, H., Hu, L., Zhang, Z., Wang, L., Cao, C., Luo, Y., Luo, T., Wang, N., Dang, H., Wang, D., Zhang, S., 2018. Carbon pools and fluxes in the China Seas and adjacent oceans. Science China Earth Sciences 61, 1535-1563.

https://doi.org/10.1007/s11430-018-9190-x

The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semi-closed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea, Yellow Sea, East China Sea, and South China Sea, including different interfaces (land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems (mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO2 sources, releasing about 0.22 and 13.86–33.60 Tg C yr−1 into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr−1 of atmospheric CO2, respectively. Overall, if only the CO2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO2, with a net release of 6.01–9.33 Tg C yr−1, mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C

yr−1, respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr−1, significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr−1, respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr−1, respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr−1, with a dissolved organic carbon (DOC) output from seagrass beds of up to 0.59 Tg C yr−1. Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr−1 and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr−1, respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr−1. The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr−1. The DOC efflux from the South China Sea is 31.39 Tg C yr−1. Although the marginal China Seas seem to be a source of atmospheric CO2 based on the CO2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export, and microbial carbon pump (DOC conversion and output) indicate that the China Seas represent an important carbon storage area.



Relatively high abundance of 17α (H)-diahopane has been detected in source rock extracts in the Yabulai Basin, a lacustrine basin in northwest China. Gas chromatography-mass spectrometry (GC-MS), X-ray diffraction (XRD) and Field emission environment scanning electron microscope imaging (FE-ESEM) were used in combination with conventional geochemical parameters to unravel the enrichment mechanisms. Significant variations of 17α (H)-diahopane concentrations detected in the Xinhe Formation with similar maturity inferred that thermal evolution is not the unique factor inducing the compound generating. The sedimentation of samples rich in 17α (H)-diahopane usually occur under suboxic conditions. Results of mineralogy analysis suggested that samples with high content of 17α (H)-diahopane are rich in carbonate minerals (about 20 wt %), which might deposit in brackish-saline water depositional environment. Relatively high content of gammacerane is also consistent with the experimental results of XRD. Based on the viewpoint of Moldowan et al. (1991), the regular hopanes may be the precursor of the rearranged hopanes, with the Wagner-Meerwein rearrangement as the mechanism. In this reaction, the critical factor of methyl migration is the production of carbocation starting with dehydroxylation. We suggested a general scheme for the generation of 17α (H)-diahopane in this study. In lacustrine sediments, suboxic and brackish environment could catalyze the methyl migration accompanied by carbonate deposit. Its geochemical implication can be used to reconstruct lacustrine paleoenvironment and contribute to a better understanding on oil-oil correlation, oil-source rock correlation and petroleum system study.

Jing, H., Zhu, W., Liu, H., Zheng, L., Zhang, Y., 2018. Particle-attached and free-living archaeal communities in the benthic boundary layer of the Mariana Trench. Frontiers in Microbiology 9, 2821. doi: 10.3389/fmicb.2018.02821.


The benthic boundary layer (BBL) is the part of the water column that is situated near to the sediment surface, where active oceanic biogeochemical cycling occurs. Archaea play an important role in

mediating this cycling, however, their composition and diversity in the BBL remain largely unknown. We investigated the community composition and abundance of both particle-attached (PA) and free-living (FL) archaea in the BBL on the slopes of the Mariana Trench using Illumina sequencing and quantitative PCR (qPCR), at both the DNA and RNA levels. Our results showed that Thaumarchaeota (>90%) and Woesearchaeota (1–10%) dominated in all the BBL samples, and that the former was composed mainly of Marine Group I (MGI). A clear separation of PA and FL samples was observed, and they showed a high level of similarity to the subsurface sediments and the water column, respectively. No significant differences were detected in the archaeal communities located in the southern and northern slopes of the Mariana Trench, or between the levels of DNA and RNA. However, lower RNA/DNA ratios (estimated by qPCR) were found in the PA samples than in the FL samples, indicating higher transcriptional activities in the FL fractions. A distinct archaeal community structure was found in the middle of the trench when compared with samples collected at the same depth at other stations along the trench slopes. This indicates that a dynamic deep current might affect the distribution of organic matter on the slopes. Our study provides direct information regarding the archaeal communities in the BBL of the Mariana Trench. We suggest that this might promote further exploration of the ecological roles and microbial processes of such communities located in deep-sea ecosystems.

Jing, Z., Rodrigues, S., Strounina, E., Li, M., Wood, B., Underschultz, J.R., Esterle, J.S., Steel, K.M., 2019. Use of FTIR, XPS, NMR to characterize oxidative effects of NaClO on coal molecular structures. International Journal of Coal Geology 201, 1-13.


Oxidant stimulation using Sodium Hypochlorite (NaClO) is proposed for enhancing coal seam permeability. To understand the effect of NaClO on different coal types, a subbituminous coal (Coal S) and a bituminous coal (Coal B) collected from the Surat Basin and Bowen Basin, Australia, respectively, were studied. The molecular structures of the two coals and their oxidised residues (Coal So and Coal Bo) were examined using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), X-ray Photoelectron Spectroscopy (XPS) and solid state 13C Nuclear Magnetic Resonance Spectroscopy (13C NMR). Based on the results, the molecular structure schematic models of the samples were established.

Results illustrate that Coal S is less aromatic with longer aliphatic chains and more oxygen content, while Coal B has larger average aromatic clusters, as expected given its higher rank. NaClO prefers to oxidise aliphatic chains, particularly those with oxygen functional groups. NaClO tends to oxidise small aromatic rings first, evidenced by the loss of smaller clusters in coal S, leaving the larger aromatic clusters. NaClO then attacks the larger aromatic clusters, confirmed by the average cluster size decrease for Coal B. The oxidised Coal B (Coal Bo) has a similar molecular structure to raw Coal S.

After oxidation, both coal residues exhibit lower aromaticity, longer aliphatic chains and more oxygen content. The decreased aromaticity suggests reaction between NaClO and benzene rings. The breakage of aromatic rings is further suggested to give rise to longer aliphatic chains. NaClO oxidation products enriches the coals in C–O and O-C=O for both coals. These findings observed fill a gap in knowledge on coal oxidation by NaClO and contribute to the decision of selecting the most suitable oxidant stimulation targets for enhancing coal permeability.

Jones, C.G., Martynowycz, M.W., Hattne, J., Fulton, T.J., Stoltz, B.M., Rodriguez, J.A., Nelson, H.M., Gonen, T., 2018. The CryoEM method MicroED as a powerful tool for small molecule structure determination. ACS Central Science 4, 1587-1592.

https://doi.org/10.1021/acscentsci.8b00760

In the many scientific endeavors that are driven by organic chemistry, unambiguous identification of small molecules is of paramount importance. Over the past 50 years, NMR and other powerful spectroscopic techniques have been developed to address this challenge. While almost all of these techniques rely on inference of connectivity, the unambiguous determination of a small molecule’s structure requires X-ray and/or neutron diffraction studies. In practice, however, X-ray crystallography is rarely applied in routine organic chemistry due to intrinsic limitations of both the analytes and the technique. Here we report the use of the electron cryo-microscopy (cryoEM) method microcrystal electron diffraction (MicroED) to provide routine and unambiguous structural determination of small organic molecules. From simple powders, with minimal sample preparation, we could collect high-quality MicroED data from nanocrystals (∼100 nm, ∼10–15 g) resulting in atomic resolution (<1 Å) crystal structures in minutes.

Jones, J., Higham, T.F.G., Chivall, D., Bianucci, R., Kay, G.L., Pallen, M.J., Oldfield, R., Ugliano, F., Buckley, S.A., 2018. A prehistoric Egyptian mummy: Evidence for an ‘embalming recipe’ and the evolution of early formative funerary treatments. Journal of Archaeological Science 100, 191-200.


Interdisciplinary scientific investigations utilising chemical analysis, shotgun metagenomics, textile analysis and radiocarbon dating have been applied to the study of an intact prehistoric Egyptian mummy, allowing insights into when this individual lived and died, and the funerary treatments employed in the preparation of the body. Here we present the first evidence for an extant prehistoric mummy that has undergone treatment with notably similar formative complex ‘balms’ that would later constitute the classic embalming recipes employed at the height of pharaonic mummification some 2500 years later. Making the informed assumption that the provenance of the Turin body was Gebelein, Qena or Luxor (Thebes), the findings offer the first indication that this type of funerary recipe was likely to have been employed over a wider geographical area at a time when the concept of a pan-Egyptian identity was supposedly still developing.

Jordan, T.A., Martin, C., Ferraccioli, F., Matsuoka, K., Corr, H., Forsberg, R., Olesen, A., Siegert, M., 2018. Anomalously high geothermal flux near the South Pole. Scientific Reports 8, Article 16785.

https://doi.org/10.1038/s41598-018-35182-0

Melting at the base of the Antarctic Ice Sheet influences ice dynamics and our ability to recover ancient climatic records from deep ice cores. Basal melt rates are affected by geothermal flux, one of the least constrained properties of the Antarctic continent. Estimates of Antarctic geothermal flux are typically regional in nature, derived from geological, magnetic or seismic data, or from sparse point measurements at ice core sites. We analyse ice-penetrating radar data upstream of South Pole revealing a ~100 km long and 50 km wide area where internal ice sheet layers converge with the bed. Ice sheet modelling shows that this englacial layer configuration requires basal melting of up to 6 ± 1 mm a−1 and a geothermal flux of 120 ± 20 mW m−2, more than double the values expected for this cratonic sector of East Antarctica. We suggest high heat producing Precambrian basement rocks and hydrothermal circulation along a major fault system cause this anomaly. We conclude that local

geothermal flux anomalies could be more widespread in East Antarctica. Assessing their influence on subglacial hydrology and ice sheet dynamics requires new detailed geophysical observations, especially in candidate areas for deep ice core drilling and at the onset of major ice streams.

Juntunen, H.L., Leinen, L.J., Pitts, B.K., O’Hanlon, S.M., Theiling, B.P., Barge, L.M., Videau, P., Gaylor, M.O., 2018. Investigating the kinetics of montmorillonite clay-catalyzed conversion of anthracene to 9,10-anthraquinone in the context of prebiotic chemistry. Origins of Life and Evolution of Biospheres 48, 321-330.

https://doi.org/10.1007/s11084-018-9562-9

Carbonaceous meteorites contributed polycyclic aromatic hydrocarbons (PAHs) to the organic inventory of the primordial Earth where they may have reacted on catalytic clay mineral surfaces to produce quinones capable of functioning as redox species in emergent biomolecular systems. To address the feasibility of this hypothesis, we assessed the kinetics of anthracene (1) conversion to 9,10-anthraquinone (2) in the presence of montmorillonite clay (MONT) over the temperature range 25 to 250 °C. Apparent rates of conversion were concentration independent and displayed a sigmoidal relationship with temperature, and conversion efficiencies ranged from 0.027 to 0.066%. Conversion was not detectable in the absence of MONT or a sufficiently high oxidation potential (in this case, molecular oxygen (O2)). These results suggest a scenario in which meteoritic 1 and MONT interactions could yield biologically important quinones in prebiotic planetary environments.

Kaiser, D., Schulz-Bull, D.E., Waniek, J.J., 2018. Polycyclic and organochlorine hydrocarbons in sediments of the northern South China Sea. Marine Pollution Bulletin 137, 668-676.


We investigated the concentration distribution and composition of organic pollutants in sediments of the shelf and the deep northern South China Sea (NSCS). Concentrations of polycyclic aromatic hydrocarbons (Σ15PAH; 10.69–66.45 ng g−1), Dichlorodiphenyltrichloroethane (Σ4DDT; 0–0.82 ng g−1), and polychlorinated biphenyls (Σ24PCB; 0–0.12 ng g−1) are below established sediment quality guidelines, suggesting no environmental risk. Surprisingly, concentrations increase from the shelf to the deep NSCS, and are higher in the east of the study area. The organic pollutant composition indicates PAH mainly derived from pyrogenic sources, and mostly degraded DDT and PCB. However, in the deep NSCS, considerable contribution of petrogenic PAH, low chlorinated PCB and p,p′-DDT suggest more recent input from different sources compared to the shelf. From these results we infer that organic pollution in the NSCS does not originate from the Pearl River Estuary but from the NE SCS, SW of Taiwan.

Kamel, A., Alomair, O., Elsharkawy, A., 2019. Measurements and predictions of Middle Eastern heavy crude oil viscosity using compositional data. Journal of Petroleum Science and Engineering 173, 990-1004.


Determining the viscosity of heavy crude oil is important in the field of petroleum science, and reservoir simulators are routinely used to achieve this goal. In this study, a new empirical model for predicting heavy-oil viscosity is presented. The model was developed using the compositional data of 28 heavy crude oil samples from the Middle East. Viscosity measurements from 196 data points in the 20–80 °C temperature range were used during model development, and another 47 viscosity

measurements were used to validate the model. The compositional and viscosity measurements were also used to evaluate the accuracy of previously published methods for predicting heavy-oil viscosities. These methods include corresponding-states models, residual viscosity models, and equations-of-state-based models. The study reveals that none of the previously published methods adequately predict the viscosities of heavy crude oils. On the other hand, it shows that the new empirical model is able to predict the viscosities of heavy oils with an average relative error of 3.8%. The proposed model is much simpler and easier to use than existing methods.

Kandasamy, S., Lin, B., Lou, J.-Y., Kao, S.-J., Chen, C.-T.A., Mayer, L.M., 2018. Estimation of marine versus terrigenous organic carbon in sediments off southwestern Taiwan using the bromine to total organic carbon ratio as a proxy. Journal of Geophysical Research: Biogeosciences 123, 3387-3402.

https://doi.org/10.1029/2018JG004674

Abstract: We measured bromine to total organic carbon (Br:TOC) ratios as an organic source indicator in terrestrial and marine settings of Taiwan, a tectonically active margin that differs from previously studied, passive margins. Terrestrial lake sediments, soils, and river bed and suspended sediments showed Br:TOC ratios ranging from 0.02 to 2.8 mg‐Br/g‐TOC. In ocean margin sediments, Br:TOC ratios ranged from terrigenous values up to 7.6 mg‐Br/g‐TOC. A two‐component Br:TOC mixing model for ocean margin sediments indicates roughly equal proportions of terrigenous and marine organic matter (FT and FM, respectively). Terrestrial δ13C values varied from −31.5 to −24.7‰, a range which is twice the difference between the isotopic terrigenous and marine end‐members used to calculate these proportions. FT and FM based on δ13C were similar to those using Br:TOC if averaged across all marine sediments but often differed at the level of individual samples. Depth profiles of amounts of these two forms of organic matter (OCterr and OCmar) using Br:TOC ratios show that OCmar burial is relatively constant while OCterr and hence TOC vary more strongly; this pattern suggests either episodic terrigenous carbon inputs or winnowing before burial. Variations in TOC:TN and δ13C are consistent with this control of TOC by terrigenous carbon. This study validates Br:TOC as a source indicator for terrigenous versus marine‐derived organic matter in sediments derived from mountainous areas in Oceania. As a single parameter source indicator it should have less error than δ13C due to less uncertainty of the terrestrial end‐member.

Plain Language Summary: Ocean margins account for most burial of organic matter in Earth's sediments. This burial affects global cycles such as carbon, nitrogen, and oxygen. Both land and sea contribute organic matter to these margin sediments, varying in extent in different places and times. Here we explore the use of bromine as an indicator of land versus sea contribution in Taiwan—representing the sediment‐rich, southwest Pacific region of Oceania. We compare the use of bromine with the more commonly used stable carbon isotope approach, finding that each provides 50:50 estimates of land versus sea sources at the scale of averages. Nevertheless, there is less agreement at the scale of individual samples, probably due to wide ranges of carbon isotope compositions in terrestrial end‐members.


http://www.pnas.org/content/115/48/12130.abstract

Significance: Fire is crucial to maintaining modern subtropical grasslands, yet the geologic and ecological history of this association is not well constrained. Here, we test the role of fire during the expansion of C4 grassland ecosystems in the Mio-Pliocene through innovative molecular proxies from

ancient soils in Pakistan. We produce a synoptic terrestrial record of fire and vegetation change in this region, which indicates that increased fire occurrence accompanied two stages of landscape opening. Proxy data confirm that a pronounced fire–grassland feedback was a critical component of grassland ecosystems since their origination and fostered the rise of C4-dominated grasslands. The approach presented here can be used to examine landscape-scale interactions between paleofire and vegetation for other geographic regions and climatic transitions.

Abstract: That fire facilitated the late Miocene C4 grassland expansion is widely suspected but poorly documented. Fire potentially tied global climate to this profound biosphere transition by serving as a regional-to-local driver of vegetation change. In modern environments, seasonal extremes in moisture amplify the occurrence of fire, disturbing forest ecosystems to create niche space for flammable grasses, which in turn provide fuel for frequent fires. On the Indian subcontinent, C4 expansion was accompanied by increased seasonal extremes in rainfall (evidenced by δ18Ocarbonate), which set the stage for fuel accumulation and fire-linked clearance during wet-to-dry seasonal transitions. Here, we test the role of fire directly by examining the abundance and distribution patterns of fire-derived polycyclic aromatic hydrocarbons (PAHs) and terrestrial vegetation signatures in n-alkane carbon isotopes from paleosol samples of the Siwalik Group (Pakistan). Two million years before the C4 grassland transition, fire-derived PAH concentrations increased as conifer vegetation declined, as indicated by a decrease in retene. This early increase in molecular fire signatures suggests a transition to more fire-prone vegetation such as a C3 grassland and/or dry deciduous woodland. Between 8.0 and 6.0 million years ago, fire, precipitation seasonality, and C4-grass dominance increased simultaneously (within resolution) as marked by sharp increases in fire-derived PAHs, δ18Ocarbonate, and 13C enrichment in n-alkanes diagnostic of C4 grasses. The strong association of evidence for fire occurrence, vegetation change, and landscape opening indicates that a dynamic fire–grassland feedback system was both a necessary precondition and a driver for grassland ecology during the first emergence of C4 grasslands.

Kars, M., Musgrave, R.J., Hoshino, T., Jonas, A.-S., Bauersachs, T., Inagaki, F., Kodama, K., 2018. Magnetic mineral diagenesis in a high temperature and deep methanic zone in Izu Rear Arc marine sediments, Northwest Pacific Ocean. Journal of Geophysical Research: Solid Earth 123, 8331-8348.

https://doi.org/10.1029/2018JB015861

Abstract Magnetic mineral diagenesis is an important process in sediments that is responsible for the partial or total destruction of records of Earth's magnetic field variations and also plays an important part in iron and sulfur cycling. A rock magnetic study has been carried out at International Ocean Discovery Program Expedition 350 Site U1437 in the Izu Bonin rear arc to investigate magnetic mineral diagenesis in deeply buried sediments from ~775 to ~1,002 m below sea floor (mbsf) with burial temperatures ranging from ~67 to 85 °C. Nonsteady state geochemical environments occur within an unusual deep methanic zone (below 850 mbsf) because of a release of sulfate below the shallow sulfate reduction zone. A drastic decline in magnetic susceptibility and remanence is observed at ~850 mbsf due to a decrease in ferrimagnetic iron oxide contents. Reduction of (titano)-magnetite and pyritization occur at this inferred deep sulfate-methane transition zone. Below ~850 mbsf, lower magnetic mineral contents coincide with further methane release. Geochemical analyses support a change in redox conditions and secondary precipitation of iron sulfides and carbonates in the methane-rich zone. Magnetic mineral alteration is enhanced in zones where methane accumulates underneath low porosity intervals that act as seals. Although geochemical processes due to methane occurrence are likely dominant, more than one mechanism, possibly involving microbial activity, is probably responsible for the observed magnetic mineral assemblage changes.

Kato, H., Amekawa, S., Kano, A., Mori, T., Kuwahara, Y., Quade, J., 2019. Seasonal temperature changes obtained from carbonate clumped isotopes of annually laminated tufas from Japan: Discrepancy between natural and synthetic calcites. Geochimica et Cosmochimica Acta 244, 548-564.


Carbonate clumped isotopes provide a novel paleo-thermometer that does not require knowledge of the isotopic compositions of environmental water. Despite considerable effort, there are substantial inter-laboratory disagreements in empirical calibrations between the abundance anomaly of the clumped isotopes (Δ47) and absolute temperature, and discrepancies in paleo-temperature estimates from natural samples. In this study, clumped isotopes using two types of 17O corrections were analyzed for two sample sets of synthetic calcites and tufas collected monthly from two sites in southwest Japan with known δ18O values and temperatures of parent water. These measurements form the basis for two new temperature calibrations of carbonate clumped isotopes, the first from our Kyushu University laboratory in Japan. The calcites synthesized at four different temperatures (2.9–61.0°C) yield a temperature-Δ47 relationship of Δ47=0.0354±0.0013×106/T2+0.290±0.015 (R2 = 0.986), which is indistinguishable from the calibrations of other recent studies based on acid digestion experiments at high temperature (70–100°C).

The Δ47 thermometry for the natural tufa samples display the seasonal pattern of water temperature better than the δ18O thermometry. However, the Δ47 values of the tufa samples deposited at temperatures ranging from 5.6 to 16.0°C were lower than the values expected from the calibration using synthetic calcites, thus providing another temperature calibration of Δ47=0.0336±0.0036×106/T2+0.301±0.048 (R2 = 0.735). Therefore, our results clearly identify a detectable, but fairly uniform, discrepancy in Δ47-temperature calibration between synthetic calcite and natural samples (tufas). The amplitude of Δ47 offset between the tufa and synthetic samples appears to be independent of the seasonal change in water temperature and the chemical properties of water, including pH, pCO2, and precipitation rate of calcite. The lower Δ47 values have been previously reported from other tufas and travertines, and therefore appear to be associated with processes inherent to tufas and travertines, such as CO2 degassing. We also find that our results are insignificantly influenced by types of 17O corrections and almost independent with bulk isotopic composition.

Kawamura, K., Konagaya, N., Maruoka, Y., 2018. Enhancement and inhibitory activities of minerals for alanine oligopeptide elongation under hydrothermal conditions. Astrobiology 18, 1403-1413.

https://doi.org/10.1089/ast.2017.1732

In a previous study, we have showed that the elongation of an alanine oligopeptide [L-alanyl-L-alanyl-L-alanyl-L-alanine ((Ala)4)] to higher oligopeptides is enhanced by calcite and dolomite at 275°C, using a mineral-mediated hydrothermal flow reactor system. However, a problem during the use of hydrothermal flow reactor system was that some of the minerals, such as clay, could not be tested due to their clogging in the reactor. In this article, we attempted to analyze the scope of enhancement for the formation of L-alanyl-L-alanyl-L-alanyl-L-alanyl-L-alanine ((Ala)5) and higher oligopeptides with different minerals including clay minerals for the elongation of alanine oligopeptide at 175°C. First, carbonate minerals and some clay minerals showed an enhancement of the formation of (Ala)5 from (Ala)4. On the contrary, volcanic products showed strong inhibitory activities. According to the pH dependence on the (Ala)4 elongations, we confirmed that most enhancement and inhibitory activities are due to the pH influence on the elongation of (Ala)4. However, the enhancement of montmorillonite (Tsukinuno), sphalerite, apatite, tourmaline, calcite

(Nitto Funka), and the inhibitory activities by volcanic ash (Shinmoedake), volcanic ash (Sakurajima), dickite, and pyrophillite are not simply due to the pH change in the presence of these minerals. The difference found between the previous and present studies suggests that the interaction kinetics of the aqueous phase with the mineral phase is also an important factor for the elongation of (Ala)4. These data imply that the environments with pH near neutral to weak alkaline and with minerals might have been useful for the accumulation of oligopeptides in hydrothermal conditions.

Kazak, A., Chugunov, S., Chashkov, A., 2018. Integration of large-area scanning-electron-microscopy imaging and automated mineralogy/petrography data for selection of nanoscale pore-space characterization sites. SPE Reservoir Evaluation & Engineering 21, 821-836.

https://doi.org/10.2118/191369-PA

The task of reliable characterization of complex reservoirs is tightly coupled to studying their microstructure at a variety of scales, which requires a departure from traditional petrophysical approaches and delving into the world of nanoscale. A promising method of representatively retaining a large volume of a rock sample while achieving nanoscale resolution is based on multiscale digital rock technology. The smallest scale of this approach is often realized in the form of working with several 3D focused-ion-beam–scanning-electron-microscopy (FIB-SEM) models, registration of these models to a greater volume of rock sample, and estimation and scaling up of model local properties to the volume of the entire sample. However, a justified and automated selection of representative regions for building FIB-SEM models poses a big challenge to a researcher. In this work, our objective was to integrate modern SEM and mineral-mapping technologies to drive a justified decision on location of representative zones for FIB-SEM analysis of a rock sample. The procedure is based on two experimental methods. The first method is automated mapping of sample surface area with the use of backscattered electrons (BSEs) and secondary electrons (SEs); this method has resolution down to nanometers and spatial coverage up to centimeters, also referred to as large-area high-resolution SEM imaging. The second method is automated quantitative mineralogy and petrography scanning that allows covering sample’s cross section with a mineral map, with resolution down to 1 µm/pixel. Data gathered with both methods on millimeter-sized cross sections of rock samples were registered and integrated in the paradigm of joint-data interpretation, augmented with computer-based image-processing techniques, to provide a reliable classification of nanoscale and microscale features on sample cross sections. The superimposed SEM and mineral-map images were combined with physics-based selection criteria for reasonable selection of FIB-SEM candidates out of a great number of potential sites. In the result, a semiautomated work flow was developed and tested. Demonstration of the work flow is made on one of Russia’s most promising tight gas formations, where the characteristic dimension of void-space objects spans from a single nanometer to millimeters. An example of an optimized site selection for FIB-SEM operations is discussed.

Kershaw, S., Munnecke, A., Jarochowska, E., 2018. Understanding Palaeozoic stromatoporoid growth. Earth-Science Reviews 187, 53-76.


Stromatoporoids were abundant components of reefs, reef complexes and associated facies for ca. 100 million years between Middle Ordovician and end-Devonian time. A lot of environmental information stored in their skeletons may be used to develop: a) understanding of stromatoporoid growth controls; and b) interpretations of sedimentary environments in which they lived. General patterns of stromatoporoid distribution are well known, but knowledge of detailed interactions between stromatoporoids and their environments is poorly developed and under-used, potentially of

great value in analysis of facies and palaeoecology. From a pool of several thousand specimens examined over four decades, this study identifies four key attributes of stromatoporoids that may be applied to enhance broad-scale knowledge of these fossils and their environments: 1) Substrates: Most stromatoporoids grew directly on wackestone to packstone substrates comprising micrite, clay and bioclasts. Evidence from the relationship between stromatoporoids and sediments demonstrates they were able to grow on soft substrates, but also leads to interpretation of partial lithification of the sea floor (and/or stabilisation by microbial filaments that may not be preserved) in mid-Palaeozoic carbonate facies, with potential implications for models of oceanic carbonate cycling. 2) Growth interruption: Almost all stromatoporoids examined show growth interruption, mostly caused by sedimentation and movement. Stromatoporoids normally recovered quickly and completely from interruption, thus were resilient to interruption events; 3) Associated organisms: Stromatoporoids have abundant associated organisms in two groups: (i) epibiotic encrusters and borers; and (ii) endobiotic organisms embedded in their structure, alive as the stromatoporoids grew. Epibionts used stromatoporoid surfaces that are presumed dead in almost all cases; some are associated with interruption events, but in most cases those were overgrown by successive stromatoporoid growth. Endobionts (mostly corals, plus spirorbids and others) are common to abundant in many stromatoporoid taxa. Stromatoporoid growth was little affected by presence of endobionts but in many cases (commonly restricted to certain stromatoporoid taxa) there was a complex biological interaction valuable in understanding controls on stromatoporoid development. 4) Growth form and taxonomy: Stromatoporoid assemblages are low diversity in almost all cases, regardless of age and facies, with two or three taxa much more abundant than the others. Some stromatoporoid taxa are limited to certain growth forms, thus taxonomic information is very important for facies analysis and palaeobiological interpretations. Stromatoporoids occur commonly with rugose and tabulate corals, both of which could also live on unconsolidated fine-grained substrates, therefore sediment-tolerance cannot be the only reason for stromatoporoid ability to outgrow corals in reefs. Arguments in the literature for photosymbiosis in both stromatoporoids and Palaeozoic corals are currently inconclusive for both fossil groups. Nevertheless, the sum of evidence indicates stromatoporoids were fast-growing, resilient and flexible benthic organisms, in a range of water depths, capable of dealing with soft substrates and largely unaffected by presence of endobionts. These characteristics are interpreted to have made stromatoporoids successful during mid-Palaeozoic time and valuable as tools in facies analysis. Recognition of the four key attributes which encompass all aspects of stromatoporoid growth controls makes palaeobiological study of stromatoporoids, in palaeoenvironmental reconstructions where they occur, readily accessible to researchers.

Keshmiri, K., Huang, H., Nazemifard, N., 2019. Microfluidic platform to evaluate asphaltene deposition during solvent-based extraction of bitumen. Fuel 239, 841-851.


Viscosity reduction is necessary for economical heavy oil production. Dilution of heavy oil with light hydrocarbons is one of the extraction methods as an alternative to the thermal processes. However, in-situ upgrading of heavy oil leads to asphaltene deposition, which causes pore clogging and prevents diluted oil to drain in the direction of production well. Understanding the asphaltene precipitation and deposition mechanism on hydrophilic and hydrophobic porous media improves the efficiency of the solvent-based extraction methods and accuracy of solvent selection in both experiment and simulation. In this work, two different patterns of microfluidic platforms were used to study asphaltene deposition in porous media. Porous media were treated with a silane to evaluate the effect of wettability alteration on asphaltene deposition. Quantitative analysis of the detection point of asphaltene deposition showed faster precipitation from n-pentane in comparison with n-decane as heavier solvent. Helium Ion Microscopy (HIM) analysis was performed on precipitated asphaltene to

evaluate the effect of different solvents on the structure of asphaltene precipitates. Moreover, a high-resolution Total Internal Reflection Fluorescence (TIRF) microscopy was used to identify the morphology of precipitated asphaltenes and results compared with HIM analysis. It was found that precipitated asphaltene with n-decane had larger asphaltene particles but fine precipitates from n-pentane led to higher aggregation and flocculation. Formation damage and pore blockage of deposited asphaltene from n-pentane was noticeably higher than n-decane.

Khadka, R., Clothier, L., Wang, L., Lim, C.K., Klotz, M.G., Dunfield, P.F., 2018. Evolutionary history of copper membrane monooxygenases. Frontiers in Microbiology 9, 2493. doi: 10.3389/fmicb.2018.02493.


Copper membrane monooxygenases (CuMMOs) oxidize ammonia, methane and some short-chain alkanes and alkenes. They are encoded by three genes, usually in an operon of xmoCAB. We aligned xmo operons from 66 microbial genomes, including members of the Alpha-, Beta-, and Gamma-proteobacteria, Verrucomicrobia, Actinobacteria, Thaumarchaeota and the candidate phylum NC10. Phylogenetic and compositional analyses were used to reconstruct the evolutionary history of the enzyme and detect potential lateral gene transfer (LGT) events. The phylogenetic analyses showed at least 10 clusters corresponding to a combination of substrate specificity and bacterial taxonomy, but with no overriding structure based on either function or taxonomy alone. Adaptation of the enzyme to preferentially oxidize either ammonia or methane has occurred more than once. Individual phylogenies of all three genes, xmoA, xmoB and xmoC, closely matched, indicating that this operon evolved or was consistently transferred as a unit, with the possible exception of the methane monooxygenase operons in Verrucomicrobia, where the pmoB gene has a distinct phylogeny from pmoA and pmoC. Compositional analyses indicated that some clusters of xmoCAB operons (for example, the pmoCAB in gammaproteobacterial methanotrophs and the amoCAB in betaproteobacterial nitrifiers) were compositionally very different from their genomes, possibly indicating recent lateral transfer of these operons. The combined phylogenetic and compositional analyses support the hypothesis that an ancestor of the nitrifying bacterium Nitrosococcus was the donor of methane monooxygenase (pMMO) to both the alphaproteobacterial and gammaproteobacterial methanotrophs, but that before this event the gammaproteobacterial methanotrophs originally possessed another CuMMO (Pxm), which has since been lost in many species.



Aggregation onsets of seven different asphaltenes dissolved in model oils, due to the effects of misciblized compressed air or nitrogen injections, were studied through molecular dynamics simulation. Natures of aggregations, cumulative coordination numbers, and interaction energies were investigated. Onset of aggregation processes were highly affected by injected gas concentration. In more cases little differences were observed between using air and pure nitrogen. However, asphaltene aggregation onset was highly affected by its molecular architecture. Asphaltenes with long aliphatic chains and archipelago structure showed low aggregation affinities.

Khamehchi, E., Shakiba, M., Ardakani, M.S., 2018. A novel approach to oil production optimization considering asphaltene precipitation: a case study on one of the Iranian south oil wells. Journal of Petroleum Exploration and Production Technology 8, 1303-1317.

https://doi.org/10.1007/s13202-017-0409-0

Nowadays, the significance of hydrocarbon reservoirs as the main supply of world energy is being increased more than before. Hence, a safe and continuous production process of oil and gas wells is one of the most important criteria in the oil industry. In this regard, some issues such as deposition of heavy organic materials, especially asphaltene in the tubing, and surface pipelines can cause considerable damages to the production unit. Asphaltene precipitation occurs due to change in thermodynamic conditions, such as the composition of crude oil, temperature and pressure, which can disturb the thermodynamic equilibrium and result in asphaltene deposition. These particles would result in obstruction of the tubing and surface pipelines. In this study, the distribution profile of asphaltene precipitation in a well of one of the Iranian south oil reservoirs has been developed using an integrated thermodynamic modeling. The impacts of hydrodynamic parameters on asphaltene precipitation have also been investigated, and some sensitivity analyses have been made on them in order to optimize well completion and production conditions. Optimization operation can obviate shortcomings associated with the asphaltene deposition, and as a result, it would decrease costs and subsequently lead to more benefit. If there is an optimized integrated model for tubing and surface facilities, it can not only be used for investigating the fluid flow behavior but also it can prolong the lifetime of the entire production unit. In this case study, one of the most important intelligent optimization algorithms (i.e., the particle swarm optimization algorithm) has been used to solve the problem. The results showed that cumulative oil production and thickness of asphaltene deposition under optimum conditions are 5.6 million barrels and 0.33 inches, respectively. According to the outcomes of optimization operation, tubing size and surface choke bean size are 4.25 and 47.9 inches, respectively. In addition, the oil production rate has been determined as 5972 STB/day. At these conditions, well head pressure and temperature should be considered as 1336 psi and 160 °F, respectively.

Kiani, A., Sakurovs, R., Grigore, M., Sokolova, A., 2018. Gas sorption capacity, gas sorption rates and nanoporosity in coals. International Journal of Coal Geology 200, 77-86.


Bituminous coals from a wide range of sources (including Australia, New Zealand, Europe, China, South America, Canada, the US and South Africa) were characterised by their capacity for gas sorption, rate of gas sorption of CO2 and CH4, and their nanoporosity (pore size distribution less than 50 nm radius) in order to identify the relationships between them. The following new relationships were established:

The rate of gas sorption was unrelated to the capacity for gas sorption. The rate of gas sorption for CH4 and CO2 increased exponentially with the amount of total and accessible porosity in the size range 8–50 nm (with no influence of coal origin on the relationship being discerned), suggesting that the extent of porosity of coals in this size range controls the rates of gas sorption in coals. In contrast, the capacity for gas sorption was only weakly related to pore numbers in this size range, which shows that the number of 8–50 nm pores do not control capacity for gas sorption. Moreover, this difference in relationship shows the number of pores of the size where gas is sorbed predominantly (<5 nm) does not correlate strongly with the number of larger pores.

Both the number of pores and rates of gas sorption tended to increase with inertinite content but the relationship with inertinite content differed for coals from different sources. The inertinite-rich coals from Australia (except those from the Illawarra region) had both the greatest porosity and gas penetration rates, whereas in coals sourced from other regions, although the gas penetration rate increased with inertinite content, the effect was not so strong. The rates of sorption in the inertinite-rich coals also tended to decrease with increasing rank below 0.9% Rv,max. In contrast to the results obtained with kinetic studies, we found no overall trend of capacity for gas sorption with maceral composition, though the Australian bituminous coals generally had greater capacity than the other bituminous coals examined. This suggests that not only the number of 8–50 nm pores in coals sourced from Australia (not those from the Illawarra region) and elsewhere are different, the number density of accessible <5 nm pores (not directly measurable in coals by SANS) may also be systematically different between these coals.

The relationships developed in this study have important implications in predicting coal structure, fundamental understanding of gas transport through coal beds, and explaining the variation of coking properties of coals sourced from Australia and elsewhere.

Kiddell, C.B., Cloutis, E.A., Dagdick, B.R., Stromberg, J.M., Applin, D.M., Mann, J.P., 2018. Spectral reflectance of powder coatings on carbonaceous chondrite slabs: Implications for asteroid regolith observations. Journal of Geophysical Research: Planets 123, 2803-2840.

https://doi.org/10.1029/2018JE005600

Abstract. Carbonaceous chondrite meteorites (CCs) are among the most primitive materials in the solar system and provide important insights into solar system history and evolution. A number of planetary spacecraft missions will visit asteroids that are thought to compositionally resemble these meteorites. To better assist sample acquisition in terms of how the physical properties of CCs affect their reflectance spectra, we investigated the spectral reflectance properties of solid and powdered CCs and powder coatings on slabs of a number of CCs, including CB, CH, CK, CM, CO, CR, and CV classes. We found that decreasing grain size leads to increasing reflectance across the ~500‐ to 2,500‐nm range and steeper spectral slope, regardless of CC type. Powdered CC reflectance spectra are brighter beyond ~500 nm and redder than bare roughened slabs. For powders sprinkled on slabs, as the powder coating gets thicker, spectral slopes get redder. Optically thick fine‐grained powders are brighter beyond ~500 nm and are as red or redder than slabs covered with airfall dust (for dust thicknesses up to a few hundred microns). Diagnostic absorption features of CC minerals, particularly those in the 1,000‐nm region attributable to Fe‐bearing silicates, are ubiquitous regardless of physical properties. Reflectance spectra of terrestrially weathered (i.e., rusty) CCs are strongly modified below ~700 nm and in the 900‐ and 1,900‐nm regions by these Fe oxyhydroxides. Their effects can be mitigated through chemical treatment, but this may also affect preterrestrial ferric iron‐bearing phases. Some spectral characteristics, such as hydrous and anhydrous silicate absorption bands in CC spectra, are present regardless of physical properties (fine‐grained dust, powders, slabs, and dust on slabs). Other spectral characteristics (such as albedo and spectral slope) vary as a function of physical properties, indicating that reflectance spectroscopy could be used to ascribe spectral variations across an asteroid's surface to either physical or compositional causes. This information can, in turn, be used to inform site selection for asteroid sample return missions, where both composition and physical properties are important drivers. When searching for fine‐grained areas on an asteroid to sample, the best indication would be the brightest‐ and reddest‐sloped spectra.

Plain Language Summary. Carbonaceous chondrites are a group of meteorites that are important for understanding the evolution of life on Earth because they contain various organic compounds that may have seeded the Earth with the essential building blocks of life. Because of their scientific

importance, a number of planetary spacecraft missions will visit asteroids that are thought to be the sources of these meteorites. Primarily to assist these asteroid sample return missions to successfully acquire a sample to bring back to the Earth, we have studied how spectrometers on board these spacecraft may be able to distinguish regions that can be sampled from those that cannot (each mission has unique needs in terms of the kinds of surfaces they can best sample). Specifically, we looked at how solid surfaces can be distinguished from powdered and rubbly surfaces. We found that different kinds of surfaces can be distinguished by how they reflect sunlight, in terms of properties such as brightness, how brightness changes at different wavelengths, and how the intensity of mineral‐specific absorption bands vary.

Kim, T.-Y., Kim, M.G., Lee, J.-H., Hur, H.-G., 2018. Biosynthesis of nanomaterials by Shewanella species for application in lithium ion batteries. Frontiers in Microbiology 9, 2817. doi: 10.3389/fmicb.2018.02817.


Nanomaterials exhibit extraordinary properties based on their size, shape, chemical composition, and crystal structure. Owing to their unique properties nanomaterials are preferred over their bulk counterparts for a number of applications. Although conventional physical and chemical routes were established for the massive production of nanomaterials, there are some drawbacks such as environmental burden and high cost that cannot be disregarded. Recently, there has been great interest toward the green synthesis of inorganic nanomaterials. It has been reported that dissimilatory metal reduction by microorganisms is a cost-effective process to remediate toxic organic and inorganic compounds under anaerobic conditions. Particularly, members of the Shewanella genus have been utilized to produce various biogenic nanomaterials with unique micro/nanostructured morphologies through redox transformations as well as to remove harmful metals and metalloids in eco-efficient and environment-friendly methods under ambient conditions. In the present mini-review, we specifically address the active utilization of microbial respiration processes for the synthesis of novel functional biogenic nanomaterials by the members of the Shewanella genus. This biosynthetic method may provide alternative approaches to produce electrode materials for sustainable energy storage applications.

Kimble, J.C., Winter, A.S., Spilde, M.N., Sinsabaugh, R.L., Northup, D.E., 2018. A potential central role of Thaumarchaeota in N-Cycling in a semi-arid environment, Fort Stanton Cave, Snowy River passage, New Mexico, USA. FEMS Microbiology Ecology 94, Article fiy173.


Low biomass and productivity of arid-land caves with limited availability of nitrogen (N) raises the question of how microbes acquire and cycle this essential element. Caves are ideal environments for investigating microbial functional capabilities, as they lack phototrophic activity and have near constant temperatures and high relative humidity. From the walls of Fort Stanton Cave (FSC), multicolored secondary mineral deposits of soil-like material low in fixed N, known as ferromanganese deposits (FMD), were collected. We hypothesized that within FMD samples we would find the presence of microbial N cycling genes and taxonomy related to N cycling microorganisms. Community DNA were sequenced using Illumina shotgun metagenomics and 16S rRNA gene sequencing. Results suggest a diverse N cycle encompassing several energetic pathways including nitrification, dissimilatory nitrate reduction and denitrification. N cycling genes associated with assimilatory nitrate reduction were also identified. Functional gene sequences and taxonomic findings suggest several bacterial and archaeal phyla potentially play a role in nitrification pathways

in FSC and FMD. Thaumarchaeota, a deep-branching archaeal division, likely play an essential and possibly dominant role in the oxidation of ammonia. Our results provide genomic evidence for understanding how microbes are potentially able to acquire and cycle N in a low-nutrient subterranean environment.

King, E.K., Pett-Ridge, J.C., 2018. Reassessing the dissolved molybdenum isotopic composition of ocean inputs: The effect of chemical weathering and groundwater. Geology 46, 955-958.

http://dx.doi.org/10.1130/G45124.1

The abundance and isotopic composition of molybdenum (Mo) in marine sediments has been used to reconstruct the evolution of the ocean’s oxidation-reduction (redox) potential. However, the utility of Mo as a redox tracer relies on quantifying the flux and isotopic composition of Mo delivered to the ocean, and understanding how these parameters may change as a function of the extent of chemical weathering in the terrestrial environment. Here we present Mo data from groundwater and river samples across the Hawaiian Islands where the duration of chemical weathering is well defined, and a complementary data set from rivers draining a variety of sedimentary, metamorphic, and igneous lithologies. Groundwater flow dominates Mo transport at the earliest stage of weathering, and there is little Mo isotopic fractionation from bedrock. As the duration of chemical weathering increases, rivers draining shallower flow paths become the main vector for water transport to the oceans. Molybdenum concentrations in these rivers are two orders of magnitude lower than in groundwater and show greater isotopic fractionation relative to bedrock. Data from rivers draining diverse sedimentary, metamorphic, and igneous lithologies show highly variable Mo isotopic signatures but consistently small Mo fluxes. We find that both groundwater and rivers with high Mo fluxes are isotopically similar to the average continental crust, suggesting that the range of Mo isotopic compositions delivered to the oceans is likely to be limited to a narrow range close to average crustal values.

Kinloch, I.A., Suhr, J., Lou, J., Young, R.J., Ajayan, P.M., 2018. Composites with carbon nanotubes and graphene: An outlook. Science 362, 547-553.


Composite materials with carbon nanotube and graphene additives have long been considered as exciting prospects among nanotechnology applications. However, after nearly two decades of work in the area, questions remain about the practical impact of nanotube and graphene composites. This uncertainty stems from factors that include poor load transfer, interfacial engineering, dispersion, and viscosity-related issues that lead to processing challenges in such nanocomposites. Moreover, there has been little effort to identify selection rules for the use of nanotubes or graphene in composite matrices for specific applications. This review is a critical look at the status of composites for developing high-strength, low-density, high-conductivity materials with nanotubes or graphene. An outlook of the different approaches that can lead to practically useful nanotube and graphene composites is presented, pointing out the challenges and opportunities that exist in the field.

Kirschbaum, M.U.F., Zeng, G., Ximenes, F., Giltrap, D.L., Zeldis, J.R., 2018. Towards a more complete quantification of the global carbon cycle. Biogeosciences Discussions 2018, 1-31.

https://doi.org/10.5194/bg-2018-436

The main components of global carbon budget calculations are the emissions from burning fossil fuels, cement production, and net land-use change, partly balanced by ocean CO2 uptake and CO2 increase in the atmosphere. The remaining difference between these terms is referred to as the residual sink, assumed to correspond to increasing carbon storage in the terrestrial biosphere (ΔB). It is often used to constrain carbon exchange in global earth-system models. More broadly, it guides expectations of autonomous changes in global carbon stocks in response to climatic changes, including increasing CO2, that may add to, or subtract from, anthropogenic CO2 emissions.

However, a budget with only these terms omits some important additional fluxes that are important for correctly inferring ΔB. They are cement carbonation and fluxes into increasing pools of plastic, bitumen, harvested-wood products, and landfill deposition after disposal of these products, and carbon fluxes to the oceans via wind erosion and non-CO2 fluxes of the intermediate break-down products of methane and other volatile organic compounds. While the global budget includes river transport of dissolved inorganic carbon it omits river transport of dissolved and particulate organic carbon, and the deposition of carbon in inland water bodies.

Each one of these terms is relatively small, but together they can constitute important additional fluxes that would significantly reduce the size of the inferred ΔB. We estimate here that inclusion of these fluxes would reduce ΔB from the currently reported 3.6 down to only about 2.1GtCyr−1 (excluding losses from land-use change). The implicit reduction in the size of ΔB has important implications for the inferred magnitude of current-day biospheric net carbon uptake and the consequent potential of future biospheric feedbacks to amplify or negate net anthropogenic CO2 emissions.

Kite, G.C., 2018. Comment on METLIN: A technology platform for identifying knowns and unknowns. Analytical Chemistry 90, 13126-13127.


Refers to: Guijas, C.; Montenegro-Burke, J. R.; Domingo-Almenara, X.; Palermo, A.; Warth, B.; Hermann, G.; Koellensperger, G.; Huan, T.; Uritboonthai, W.; Aisporna, A. E., et al. METLIN: A Technology Platform for Identifying Knowns and Unknowns. Anal. Chem. 2018, 90, 3156– 3164

Reply to comment: Guijas, C., Siuzdak, G., 2018. Reply to Comment on METLIN: A Technology Platform for Identifying Knowns and Unknowns. Analytical Chemistry 2018, 90, 13128-13129.

The METLIN tandem mass spectrometry database is undoubtedly a significant resource for the annotation (identification) of small molecules in biological extracts following analysis by liquid chromatography–tandem mass spectrometry (LC–MS/MS).(1) The need for such libraries of tandem MS/MS spectra has been driven in part by the rising use of metabolomics methods in biomarker discovery.(2). Most frequently this involves the analysis of small molecules in mammalian, often human, blood and urine resulting in platforms such as the Human Metabolome Database specifically supporting such research.(3). Plant metabolomics, often focusing on secondary metabolites, has generally used the workflows and resources developed for primary metabolites(4,5) with comparatively few additional plant-specific resources having been created(6,7) even though the analysis of plant secondary metabolites presents particular and different challenges.

My comment on METLIN is whether the parameters used to acquire MS/MS spectra for this resource require revision to accommodate the needs of plant metabolomics. Many plant small molecules can be considered as “multiunit” compounds; for example, glycosides such as flavonoid glycosides, terpenoid glycosides (saponins) and phenylethanoid glycosides. To annotate such compounds to a

high degree of confidence by tandem MS/MS is perhaps beyond current expectations, given the number of possible positional isomers and isomeric subunits, but the annotation of certain subunits of these plant metabolites, such as the aglycone of a flavonoid O-glycoside, should be achievable by reference to tandem MS/MS libraries.

METLIN records tandem MS/MS spectra at low, medium and high collision energies, as is typical in untargeted metabolomics, with the goal of achieving maximum fragment coverage. Specifically, METLIN uses energies of 10, 20 and 40 eV on their platform, and this works very well for many small molecules but possibly not for larger multiunit plant secondary metabolites. For example, in the tandem MS/MS spectra of [M + H]+ (at m/z 611) of rutin, a diglycoside of quercetin and one of the most frequently encountered plant flavonoid O-glycosides, the aglycone ion (at m/z 303, protonated quercetin) is hardly fragmented even in the high energy (40 eV) spectrum. Fragments detected below m/z 303 appear to be from the attached sugars, not the fragments of quercetin. Such a spectrum could only be used to support an annotation as a quercetin O-glycoside from the exact mass of the aglycone, since there is no confirmation from the diagnostic A- and B-ring aglycone fragments ions at m/z 153 and 137.(8) In the high-energy METLIN spectrum of querctirin, a monoglycoside of quercetin, these A- and B-ring aglycone fragments are evident, albeit at low relative abundance. This suggests that for flavonoid O-glycosides having two or more sugar units, the collision energy in the high energy spectrum used by METLIN and other libraries such as WEIZMASS,(7) which uses a 10–30 eV ramp, is not high enough.

This could be a particular problem when distinguishing glycosides of the two most frequently encountered isomeric flavonoid aglycones, luteolin and kaempferol. Experimental spectra for diglycosides of luteolin and kaempferol were not evident on METLIN so spectra of luteolin 3′,7-O-diglucoside and kaempferol 3-O-rutinoside were recorded using the “HCD” MS/MS capability of a Thermo Scientific LTQ-Orbitrap XL mass spectrometer. On this instrument, a normalized collision energy of 30% applied to protonated rutin reproduced METLIN’s high energy spectrum for rutin; i.e., fragments of the aglycone were lacking (Figure 1C). When this collision energy was applied to the diglycosides of luteolin and kaempferol there was also no fragmention of either of the protonated aglycones, both at m/z 287 (Figure 1A,B). Luteolin 3′,7-O-diglucoside has the same molecular mass as rutin (M = 610 Da) and kaempferol 3-O-rutinoside (M = 594 Da) is only 16 Da less, so the effects of collision energy normalization were nullified in this experiment. Using a much increased normalized collision energy of 70% did generate diagnostic A- and B-ring aglycone fragments at m/z 153 and 135, respectively, for luteolin 3′,7-O-diglucoside and at m/z 153 and 121 for kaempferol 3-O-rutinoside (Figure 1D,E). Diagnostic A- and B-ring quercetin fragments at m/z 153 and 137 were also generated in the spectrum of rutin at 70% normalized energy (Figure 1F), and this spectrum was in accordance with the HCD MS/MS spectra for protonated rutin lodged on mzCloud.(9) These higher energy spectra of flavonoid O-glycosides, with the diagnostic A- and B-ring fragments, would therefore have more value in library search or denovo annotation workflows.

As the number of plant metabolites on METLIN increases, there is an argument for “triaging” multiunit plant molecules at collision energies higher than 40 eV to determine whether any further fragments generated are of sufficient diagnostic value to merit adding a higher energy spectrum to the METLIN resource. Such an approach could further increase the value of METLIN in plant metabolomics.

Kivisaar, M., 2018. The effect of cellular redox status on the evolvability of new catabolic pathways. mBio 9, Article e01981-18.

http://mbio.asm.org/content/9/5/e01981-18.abstract

Oxidation of aromatic compounds can be mutagenic due to the accumulation of reactive oxygen species (ROS) in bacterial cells and thereby facilitate evolution of corresponding catabolic pathways. To examine the effect of the background biochemical network on the evolvability of environmental bacteria hosting a new catabolic pathway, Akkaya and colleagues (mBio 9:e01512-18, 2018, https://doi.org/10.1128/mBio.01512-18) introduced the still-evolving 2,4-dinitrotoluene (2,4-DNT) pathway genes from the original environmental Burkholderia sp. isolate into the genome of Pseudomonas putida KT2440. They show that the mutagenic effect of 2,4-DNT oxidation, which is associated with the accumulation of ROS and oxidative damage on DNA, can be avoided by preserving high NADPH levels in P. putida. The observations of this study highlight the impact of the cellular redox status of bacteria on the evolvability of new metabolic pathways.

Kjær, K.H., Larsen, N.K., Binder, T., Bjørk, A.A., Eisen, O., Fahnestock, M.A., Funder, S., Garde, A.A., Haack, H., Helm, V., Houmark-Nielsen, M., Kjeldsen, K.K., Khan, S.A., Machguth, H., McDonald, I., Morlighem, M., Mouginot, J., Paden, J.D., Waight, T.E., Weikusat, C., Willerslev, E., MacGregor, J.A., 2018. A large impact crater beneath Hiawatha Glacier in northwest Greenland. Science Advances 4, Article eaar8173.

http://advances.sciencemag.org/content/4/11/eaar8173.abstract

We report the discovery of a large impact crater beneath Hiawatha Glacier in northwest Greenland. From airborne radar surveys, we identify a 31-kilometer-wide, circular bedrock depression beneath up to a kilometer of ice. This depression has an elevated rim that cross-cuts tributary subglacial channels and a subdued central uplift that appears to be actively eroding. From ground investigations of the deglaciated foreland, we identify overprinted structures within Precambrian bedrock along the ice margin that strike tangent to the subglacial rim. Glaciofluvial sediment from the largest river draining the crater contains shocked quartz and other impact-related grains. Geochemical analysis of this sediment indicates that the impactor was a fractionated iron asteroid, which must have been more than a kilometer wide to produce the identified crater. Radiostratigraphy of the ice in the crater shows that the Holocene ice is continuous and conformable, but all deeper and older ice appears to be debris rich or heavily disturbed. The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet.

Klaebe, R.M., Smith, M.P., Fairchild, I.J., Fleming, E.J., Kennedy, M.J., 2018. Facies-dependent δ13C variation and diagenetic overprinting at the onset of the Sturtian glaciation in North-East Greenland. Precambrian Research 319, 96-113.


Time-significant surfaces are used to construct a stratigraphic test of the intrabasinal reproducibility of a 16‰ Neoproterozoic carbon-isotope (δ13C) anomaly in the NE Greenland Caledonides. The δ13C excursion from +6‰ to −10‰ occurs in the carbonate-dominated Andrée Land Group and lies below glacial diamictites of the Tillite Group commonly correlated as Sturtian in age (∼720 Ma) and has been widely interpreted to record a global isotopic event reflecting a perturbation in the carbon cycle preceding the initiation of the snowball ice age. δ13C stratigraphic patterns were determined in two strike sections with relatively shallow platform deposits at Kap Weber and slope deposits on Ella Ø preserved directly below the first evidence for glaciation. The top and bottom of the δ13C profile was bounded by contiguous chronostratigraphic surfaces including an unconformity (sequence boundary) at the base recognisable in both sections and a subaerial exposure surface with a basinal correlative conformity at the top. The δ13C profile at Kap Weber shows δ13C values of +6‰ that drop to −8‰ in

fine-grained slope deposits before returning to +6‰ in platform carbonates at the base of the glacial diamictite. The slope section on Ella Ø shows similar values for platformal carbonates of +6‰ with a similar drop to ∼−10‰ in slope deposits, but this section lacks the return to platform deposits evident at Kap Weber beneath the diamictite as well as a return to positive δ13C values. The absence of the platformal sediments and positive δ13C values on Ella Ø cannot be attributed to erosional truncation because the contact in this section shows a conformable, interbedded transition into the glacial deposits indicating that a continuous record is preserved. This disparity in δ13C values below the base of the Tillite Group suggests that the most negative δ13C values recorded in slope mudstone facies (−10‰) occur near synchronously with values of +6‰ on the platform. Elemental mapping of the mudstone facies indicates that carbonate is largely pore-filling and authigenic, representing a secondary phase that is unlikely to record a seawater value. Elevated δ13C values in shallow inner-ramp carbonate intervals may record locally modified seawater enriched in 13C by photosynthesis and evaporation. The excursion in δ13C values in the upper Andrée Land Group is therefore interpreted to result from a shift in facies from platform carbonates to carbonate cemented and diagenetically overprinted mudstone and does not record the secular change in seawater δ13C used for correlation or interpretation of biogeochemical events preceding the snowball ice age.

Kletetschka, G., Vondrák, D., Hruba, J., Prochazka, V., Nabelek, L., Svitavská-Svobodová, H., Bobek, P., Horicka, Z., Kadlec, J., Takac, M., Stuchlik, E., 2018. Cosmic-impact event in lake sediments from Central Europe postdates the Laacher See eruption and marks onset of the Younger Dryas. The Journal of Geology 126, 561-575.

https://doi.org/10.1086/699869

The Younger Dryas (YD) climate episode (∼12,850–11,650 calendar years before present [cal BP]) is an event recorded widely across the Northern Hemisphere. We conducted multiple analyses at high resolution of a YD-age sedimentary sequence from Stara Jimka, a paleolake in the Bohemian Forest, Czech Republic. Age-depth modeling indicates that a central European warming trend was interrupted at ∼13,020±110 ∼13,020±110 cal BP by the sudden onset of cooling (<20 y) known as the Gerzensee climate oscillation and marked by the deposition of fine-grained sediment at this location. That cooling episode ended at ∼13,001±66 ∼13,001±66 cal BP and was followed by a ∼121-y-long warming trend. After that, the Laacher See tephra depositional event, dating to ∼12,820±20 ∼12,820±20 cal BP, continued an overall warming trend. The composition of Laacher See volcanic tephra in this section likely corresponds to the middle eruption sequence. Finally, the deposition of glassy microspherules marked the onset of the YD climate change at 12,755±92 12,755±92 cal BP. The sequence across the YD onset is marked by (1) a peak in glassy microspherules (>17,000/kg), (2) a peak in framboidal spherules (>4,000/kg), (3) significant changes in the lake’s weathering proxies, and (4) major changes in fauna and flora, showing a shift to unfavorable environmental conditions (decrease in temperature and lake trophy status). Collectively, this evidence is consistent with the YD impact hypothesis and evidence of one or more cosmic airburst events occurring at this time.

Knackstedt, K.A., Moffett, B.F., Hartmann, S., Wex, H., Hill, T.C.J., Glasgo, E.D., Reitz, L.A., Augustin-Bauditz, S., Beall, B.F.N., Bullerjahn, G.S., Fröhlich-Nowoisky, J., Grawe, S., Lubitz, J., Stratmann, F., McKay, R.M.L., 2018. Terrestrial origin for abundant riverine nanoscale ice-nucleating particles. Environmental Science & Technology 52, 12358-12367.


Ice-nucleating particles (INPs) associated with fresh waters are a neglected, but integral component of the water cycle. Abundant INPs were identified from surface waters of both the Maumee River and Lake Erie with ice nucleus spectra spanning a temperature range from −3 to −15 °C. The majority of river INPs were submicron in size and attributed to biogenic macromolecules, inferred from the denaturation of ice-nucleation activity by heat. In a watershed dominated by row-crop agriculture, higher concentrations of INPs were found in river samples compared to lake samples. Further, ice-nucleating temperatures differed between river and lake samples, which indicated different populations of INPs. Seasonal analysis of INPs that were active at warmer temperatures (≥−10 °C; INP–10) showed their concentration to correlate with river discharge, suggesting a watershed origin of these INPs. A terrestrial origin for INPs in the Maumee River was further supported by a correspondence between the ice-nucleation signatures of river INPs and INPs derived from the soil fungus Mortierella alpina. Aerosols derived from turbulence features in the river carry INP–10, although their potential influence on regional weather is unclear. INP–10 contained within aerosols generated from a weir spanning the river, ranged in concentration from 1 to 11 INP m–3, which represented a fold-change of 3.2 over average INP–10 concentrations sampled from aerosols at control locations.

Koehler, M.C., Buick, R., Barley, M.E., 2019. Nitrogen isotope evidence for anoxic deep marine environments from the Mesoarchean Mosquito Creek Formation, Australia. Precambrian Research 320, 281-290.


Current evidence for oxygenated environments in the Mesoarchean is limited to the shallowest marine and fluvio-lacustrine settings. It is not until the Neoarchean that signs of oxygenated surface waters above outer shelf and basinal depositional environments become evident. In order to further explore the Mesoarchean redox landscape for signs of basinward surface water oxygenation, we present nitrogen and carbon isotope ratios from the turbiditic Mosquito Creek Formation of the Nullagine Group (∼2.9 Ga). The δ15N and δ13Corg values are invariant around −1.8‰ and −32‰ respectively throughout a 70 m section of drill-core, suggesting an ecosystem dominated by nitrogen fixers (anaerobic nitrogen cycling) and CO2 fixation by the Calvin Cycle. When compared with other Archean isotopic data, these results (i) provide further evidence that the Mosquito Creek Formation was deposited in a marine basin, and (ii) contain δ15N values that highlight the prevalence of nitrogen fixation by Mo-nitrogenase and the dearth of aerobic nitrogen metabolisms in the Mesoarchean.

Kolosov, P.N., Sofroneeva, L.S., 2018. New Vendian saarinid microorganisms from the Siberian Platform. Paleontological Journal 52, 589-592.

https://doi.org/10.1134/S0031030118060060

Vendian (Ediacaran) tubiform organic-walled segmented microfossils from the East Siberian Platform, with no biological interpretation, were previously assigned to the Incertae sedis genus Kursovia Kolosov et Rudavskaja, 1984 and identified as Kursovia sp. 4. The re-examination of these fossils showed that these are new saarinid microorganisms that resemble Saarina juliae in the tubiform shape, segmented structure, presence of crenulae on free (upper) edge of segments and in the prominence of these features, but are smaller by one–two orders of magnitude. They are herein assigned to a new genus and species Saarinomorpha infundibularis Kolosov et Sofroneeva, gen. et sp. nov. in the family Saarinidae Sokolov, 1965.

Kong, W., Tu, D., Wan, Y., Zhao, Y., Zang, X., 2018. Organic geochemistry and depositional architecture of Jimusaer oil shale, Junggar Basin, NC China. Oil Shale 35, 291–303.

https://doi.org/10.3176/oil.2018.4.01

The Jimusaer oil shale (JOS) of the Upper Permian Lucaogou Formation in the southeastern margin of the Junggar Basin, Northwest China has retained a close relationship with the Bogda orogeny. JOS samples were studied for organic geochemistry, and samples of other rocks collected from between the oil shale layers (sandstone, mudstone shale, dolostone, limestone) were investigated for mineral characteristics. The results showed JOS samples to have a high total organic carbon (TOC) content, 5.35–21.45%, and a high oil yield, 3.67–10.3%. Dolomite, clay minerals, quartz, tuffaceous matrix, tuff debris, calcite, ferruginous debris, siliceous debris and anorthose could be found in the samples of other rocks. The Jimusaer oil shale was characterized by fine grain size, dark color and horizontal bedding. Depositional architecture and symbiotic rocks indicated that JOS was mainly deposited in a semi-deep to deep water environment under reducing conditions. The oil shale developed in the highstand systems tract (HST) and was enriched in organic matter.

Kopprio, G.A., Dutto, M.S., Garzón Cardona, J.E., Gärdes, A., Lara, R.J., Graeve, M., 2018. Biogeochemical markers across a pollution gradient in a Patagonian estuary: A multidimensional approach of fatty acids and stable isotopes. Marine Pollution Bulletin 137, 617-626.


A combined approach merging stable isotopes and fatty acids was applied to study anthropogenic pollution in the Río Negro estuary. Fatty acid markers of vegetal detritus indicated considerable allochthonous inputs at freshwater sites. Correlative evidence of diatom fatty acids, δ13C, chlorophyll and particulate organic matter suggested the importance of diatoms for the autochthonous organic matter production at the river mouth. Low δ15N values (~0‰) and high fatty acid 18:1(n-7) concentrations in the suspended particulate matter, in combination with the peaks of coliforms and ammonium, indicated a strong impact of untreated sewage discharge. The 15N depletion was related to oxygen-limited ammonification processes and incorporation of 15N depleted ammonium to microorganisms. This work demonstrates that the combined use of lipid and isotopic markers can greatly increase our understanding of biogeochemical factors and pollutants influencing estuaries, and our findings highlight the urgent need for water management actions to reduce eutrophication.

Krickov, I.V., Lim, A.G., Manasypov, R.M., Loiko, S.V., Shirokova, L.S., Kirpotin, S.N., Karlsson, J., Pokrovsky, O.S., 2018. Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across a 1700 km latitudinal transect. Biogeosciences 15, 6867-6884.


In contrast to numerous studies on the dynamics of dissolved ( < 0.45µm) elements in permafrost-affected high-latitude rivers, very little is known of the behavior of river suspended ( > 0.45µm) matter (RSM) in these regions. In order to test the effect of climate, permafrost and physio-geographical landscape parameters (bogs, forest and lake coverage of the watershed) on RSM and particulate C, N and P concentrations in river water, we sampled 33 small and medium-sized rivers (10–100000km2 watershed) along a 1700km N–S transect including both permafrost-affected and permafrost-free zones of the Western Siberian Lowland (WSL). The concentrations of C and N in RSM decreased with the increase in river watershed size, illustrating (i) the importance of organic debris in small rivers which drain peatlands and (ii) the role of mineral matter from bank abrasion in

larger rivers. The presence of lakes in the watershed increased C and N but decreased P concentrations in the RSM. The C : N ratio in the RSM reflected the source from the deep soil horizon rather than surface soil horizon, similar to that of other Arctic rivers. This suggests the export of peat and mineral particles through suprapermafrost flow occurring at the base of the active layer. There was a maximum of both particulate C and N concentrations and export fluxes at the beginning of permafrost appearance, in the sporadic and discontinuous zone (62–64°N). This presumably reflected the organic matter mobilization from newly thawed organic horizons in soils at the active latitudinal thawing front. The results suggest that a northward shift of permafrost boundaries and an increase in active layer thickness may increase particulate C and N export by WSL rivers to the Arctic Ocean by a factor of 2, while P export may remain unchanged. In contrast, within a long-term climate warming scenario, the disappearance of permafrost in the north, the drainage of lakes and transformation of bogs to forest may decrease C and N concentrations in RSM by 2 to 3 times.

Kueh, B., Kapsi, M., Veziri, C.M., Athanasekou, C., Pilatos, G., Reddy, K.S.K., Raj, A., Karanikolos, G.N., 2018. Asphaltene-derived activated carbon and carbon nanotube membranes for CO2 separation. Energy & Fuels 32, 11718-11730.


Due to large energy requirements of the traditional gas separation processes, novel and less energy-intensive technologies, such as adsorption- and membrane-based ones, are anticipated to play major role in future industrial separations. Thus, finding new means for economical fabrication of materials related to these processes is of significant importance to facilitate their implementation in large-scale operations. In this work, we synthesized high-quality activated porous carbons (AC) and carbon nanotube (CNT) membranes using asphaltene, an abundant waste of the petroleum industry. The resulting materials were tested for CO2 separation in adsorption and membrane modes. Among the various porous carbons produced, AC from raw asphaltene reached a CO2 sorption capacity of 7.56 mmol/g at 4 bar and 25 °C with a relatively low heat of adsorption (up to 23 kJ/mol) implying low energy requirement for regeneration. The versatility of the asphaltene precursors in the formation of carbon nanomaterials was also demonstrated by growing, for the first time, CNT membranes via template-based, catalyst-free carbonization of asphaltene inside the pores of anodized alumina. The resulting CNT membranes attained a promising separation performance with permeability ratios exceeding the respective Knudsen values for H2/CO2, N2/CO2, N2/CH4, and H2/CH4 gas pairs.

Kueter, N., Schmidt, M.W., Lilley, M.D., Bernasconi, S.M., 2019. Experimental determination of equilibrium CH4–CO2–CO carbon isotope fractionation factors (300–1200°C). Earth and Planetary Science Letters 506, 64-75.


We show that chemical and isotopic equilibrium among gas species is obtained when applying a nickel catalyst for CO2/CH4, CH4/CO, and CO2/CO at ≤600 °C or without a catalyzing agent for CO2/CO at ≥800 °C. The experiments define carbon isotope fractionation factors for the CO2/CH4, CO2/CO and CH4/CO pairs as

(i)103ln αCO2/CH4=8.9(±0.6)⋅105⋅(1/T2)0.825(±0.005) (200–1200°C)

(ii)103ln αCO2/CO=1.07(±0.05)⋅106⋅(1/T2)0.830(±0.003) (300–1200°C)

(iii)103ln αCH4/CO=1.1(±0.2)⋅103⋅(1/T2)0.462(±0.001) (300–1200°C),

which reproduce the experimental values within 0.2‰ for CO2/CH4 and CO2/CO and within 0.12‰ for CH4/CO (T in K, 1σ fit uncertainties in brackets, CO2/CH4 includes the ≤600 °C experimental data of Horita, 2001). Carbon isotope fractionation factors at 1000 °C are still large for CO2/CH4 and CO2/CO (6.6 and 7.5‰, respectively) but only 1.5‰ for CH4/CO.

Elemental carbon precipitated through thermal decomposition of the organic starting materials yields δ13C values that depend on the X(O) = O/(O + H) of the organic starting material, i.e. the initial oxidation state of carbon in the organics. We further observe a catalytic effect of the quartz walls on chemical and isotopic exchange in the CO2/CO system, probably due to the activation of the silicate surface by H+ and OH− ions at >650 °C. Our experimental results yield improved calibrations of the CO2/CH4 equilibria and the first experimental calibration of CO2/CO and CH4/CO carbon isotope fractionation. Applications are in the tracing of magmatic hydrothermal gas emissions, in carbon-precipitating COH-fluids, and in monitoring of coal-seam fires, but our results may also be applied for quality control during steel-making processes.

Kumar, L.R., Yellapu, S.K., Zhang, X., Tyagi, R.D., 2019. Energy balance for biodiesel production processes using microbial oil and scum. Bioresource Technology 272, 379-388.


Biodiesel production using microbial oil is a promising technology. The main aim of this study is to check practical feasibility (in terms of energy balance) of different biodiesel production processes. Mass and energy balance of biodiesel production have been performed for 3 separate processes: (1) microbial lipid production from T. oleaginosus using waste substrates followed by INRS downstream process (2) microbial lipid production from pure substrate using R. toruloides followed by traditional and INRS downstream process and 3) oil extraction from scum and conversion to biodiesel. It was found that employing waste substrates like crude glycerol and municipal sludge in fermentation reduced the energy input by 50%. While employing biodegradable surfactants and petroleum-diesel as solvent (PD) for lipid extraction and recovery significantly reduced the energy input at cell wall disruption step. Biodiesel production from scum is a two-step process which is fast and energetically favorable.

Lai, J.C.Y., Pearce, B.K.D., Pudritz, R.E., Lee, D., 2019. Meteoritic abundances of fatty acids and potential reaction pathways in planetesimals. Icarus 319, 685-700.


The origin of fatty acids on the prebiotic Earth is important as they likely formed the encapsulating membranes of the first protocells. Carbon-rich meteorites (i.e., carbonaceous chondrites) such as Murchison and Tagish Lake are well known to contain these molecules, and their delivery to the early planet by intense early meteorite bombardments constitutes a key prebiotic source. We collect the fatty acid abundances measured in various carbonaceous chondrites from the literature and analyze them for patterns and correlations. Fatty acids in meteorites include straight-chain and branched-chain monocarboxylic and dicarboxylic acids up to 12 carbons in length—fatty acids with at least 8 carbons are required to form vesicles, and modern cell membranes employ lipids with  ∼ 12–20 carbons. To understand the origin of meteoritic fatty acids, we search the literature for abiotic fatty acid reaction pathways and create a candidate list of 11 reactions that could potentially produce these fatty acids in meteorite parent bodies. Straight-chain monocarboxylic acids (SCMA) are the dominant fatty acids in meteorites, followed by branched-chain monocarboxylic acids (BCMA). SCMA are most abundant in CM2 and Tagish Lake (ungrouped) meteorites, ranging on average from 102 ppb to 4  ×  105 ppb, and

104 ppb to 5  ×  106 ppb, respectively. In CM, CV, and Tagish Lake meteorites, SCMA abundances generally decrease with increasing carbon chain length. Conversely, SCMA abundances in CR meteorites peak at 5 and 6 carbons in length, and decrease on either side of this peak. This unique CR fatty acid distribution may hint at terrestrial contamination, or that certain fatty acid reactions mechanisms are active in different meteorite parent bodies (planetesimals). We identify Fischer-Tropsch-type synthesis as the most promising pathway for further analysis in the production of fatty acids in planetesimals.

Lajoinie, M.F., Ballivián Justiniano, C.A., Salvioli, M.A., Ruiz, R., Recio, C., Sial, A.N., Etcheverry, R.O., Curci, M.V., de la Cal, H.G., Lanfranchini, M.E., 2019. Significance of graphite inclusion occurrence in the minerals of the San Miguel skarn for the Palaeoproterozoic basement of Tandilia Belt (Argentina) and for the Río de la Plata Craton. Journal of South American Earth Sciences 89, 118-139.


Graphite in Archaean-Palaeoproterozoic rocks has been a subject of interest since it could represent an evidence of early life on Earth. In the Palaeoproterozoic basement of the Tandilia Belt, graphite was found both in fluid inclusions (FI) hosted in the San Miguel skarn calc-silicate minerals, and as solid inclusions in calcite crystals from the protolithic marble (a13C enriched carbonate from the “Lomagundi-Jatuli event”). FI microthermometry and oxygen stable isotope ratios indicated the skarn minerals formation within the range of 630–650 °C (at ∼5 kbars) and ∼642–654 °C, respectively. Also, the characterisation of the metasomatic fluid (of a low salinity <7 wt% NaCl eq. NaCl-H2O/NaCl-KCl-H2O aqueous system) pointed out that the zonal crystallisation pattern shown by the skarn minerals (wollastonite-vesuvianite, grossular-diopside-calcite and diopside-calcite zones in the exoskarn, and grossular-diopside and diopside-calcic plagioclase zones in the endoskarn) responds to the increase of the involved cation activity gradients (Ca2+-Si4+-Mg2+-Fe2+/3+-Al3+) and not to significant changes in the temperature or concentration of CO2 in the system. Variation in the crystallinity degree of the graphite hosted in the skarn minerals and in marble calcite, shown by Raman spectroscopy, would indicate that the graphite could have been formed from the ripening of organic matter present in the sedimentary rocks during the metamorphic-metasomatic event (Transamazonian Orogeny). In this sense, the increase of the organic carbon productivity in the oceans during the Palaeoproterozoic, represented by the “Lomagundi-Jatuli event”, would support this graphite origin and also the possible existence of a marine sedimentary basin in the previous stages of the Río de la Plata amalgamation (Siderian-Rhyacian), in the San Miguel area of the Tandilia Belt.

Lan, P., Tan, M., Zhang, Y., Niu, S., Chen, J., Shi, S., Qiu, S., Wang, X., Peng, X., Cai, G., Cheng, H., Wu, J., Li, G., Lei, M., 2018. Structural insight into precursor tRNA processing by yeast ribonuclease P. Science 362, eaat6678 DOI: 10.1126/science.aat6678 http://science.sciencemag.org/content/362/6415/eaat6678.abstract

Editor's summay - Structures of eukaryotic ribonuclease P: Ribonuclease P (RNase P) is a ribozyme that processes transfer RNA (tRNA) precursors and is found in all three kingdoms of life. Now, Lan et al. report the structures of yeast RNase P (see the Perspective by Scott and Nagai). The aporibozyme structure reveals how the protein components stabilize the RNA and explains how the structural roles of bacterial RNA elements have been delegated to the protein components in RNase P of higher organisms during evolution. The structure of yeast RNase P in complex with its natural substrate, a tRNA precursor, demonstrates the structural basis for substrate recognition and provides insights into its catalytic mechanism.

Structured Abstract

Introduction: Ribonuclease P (RNase P), a universal ribozyme that has been found in organisms from all three domains of life, processes the 5′ end of transfer RNA (tRNA). RNase P is a ribonucleoprotein complex, composed of a single catalytic RNA component and a variable number of proteins. Unlike bacterial RNase P, which contains only one small protein cofactor, archaeal and eukaryotic nuclear RNase Ps have evolved considerably more complex protein subunits: five in archaea and 9 to 10 in eukarya. The pre-tRNA processing reaction can be described by a kinetic mechanism that includes four distinct events: (i) rapid and irreversible binding of RNase P (E) to pre-tRNA (S) to form the initial RNase P-pre-tRNA complex (ES); (ii) a conformational change isomerizing the ES complex to a catalytically competent conformer (ES*) in a magnesium ion (Mg2+)–dependent manner; (iii) the cleavage of the phosphodiester bond; and (iv) rapid dissociation of the 5′ leader and slow, rate-limiting release of the mature tRNA (see the figure, right).

Rationale: Despite extensive biochemical and genetic studies, however, the role of protein components and the reason for the increased complexity of the protein moieties in eukaryotic nuclear RNase P are still poorly understood. It is still enigmatic how the pre-tRNA substrate, especially the 5′-leader, is recognized by eukaryotic RNase P; how the catalytically important metal ions are coordinated in the active site; and what the chemical mechanism is of pre-tRNA 5′ cleavage. High-resolution structures of eukaryotic RNase Ps are required to answer these key questions.

Results: Here, we report the 3.5-Å cryo–electron microscopy structures of Saccharomyces cerevisiae RNase P holoenzyme alone and in complex with pre-tRNAPhe. The yeast RNase P holoenzyme consists of one catalytic RNA Rpr1 and nine protein components. The Rpr1 RNA adopts an extended single-layered conformation that maintains a central helical core but lacks most of the long-range RNA-RNA interactions that are essential for structural stability in bacterial RNase P. The protein components form an interconnected hook-shaped architecture that tightly wraps around the RNA and stabilizes yeast RNase P into a “measuring device,” with two fixed anchors that recognize the L-shaped structure rather than specific sequences of pre-tRNA substrates (see the figure, left). This “measuring device” mediates the initial engagement with pre-tRNA to form the low-affinity ES complex. The recognition of the 5′-leader of pre-tRNA involves both the Rpr1 RNA and the protein subunit Pop5. Two catalytically important Mg2+ ions are coordinated in the catalytic center by highly conserved uridine U93 and the phosphate backbone of Rpr1, together with the scissile phosphate and the O3′ leaving group of pre-tRNA (see the figure, right). The configuration of this RNA-based catalytic center is universally conserved in all RNase Ps, from bacteria to eukarya. Pre-tRNA binding induces a dramatic conformational change in the catalytic center, corresponding to the isomerization step to the ES* state. Moreover, our simulation analysis visualized the mechanistic details of phosphodiester bond hydrolysis of pre-tRNA, which is a two-Mg2+-ion–mediated SN2 reaction (see the figure, right).

Conclusion: The structures presented here represent a major step forward for mechanistic understanding of the function of eukaryotic RNase P. Our data support that all RNase P ribozymes share an RNA-based, substrate-induced catalytic mechanism of pre-RNA processing. Whereas bacterial RNase P RNA is catalytically active by itself, eukaryotic RNase P is a protein-controlled ribozyme; its protein components not only directly participate in substrate recognition but also stabilize the catalytic RNA in a conformation optimal for pre-tRNA binding and cleavage reaction.

Lan, Y., Yang, Z., Wang, P., Yan, Y., Zhang, L., Ran, J., 2019. A review of microscopic seepage mechanism for shale gas extracted by supercritical CO2 flooding. Fuel 238, 412-424.


Shale gas exploitation with supercritical CO2 is a promising technology that not only improve gas recovery but also achieve geological storage of CO2. This paper presents the research status of shale gas seepage mechanism under supercritical CO2 conditions from several aspects including the adsorption and desorption of gas, the competitive adsorption of CO2 and CH4, the multi-scale spatial gas mass transfer process and the shale gas seepage mechanism under multi-field coupling. Adsorption potential theory provides a method for predicting the real shale reservoir adsorption capacity under supercritical conditions. The desorption model needs to be considered simultaneously due to the existence of hysteresis. The adsorption selectivity of CO2 /CH4 is always greater than 1, and there is an optimal selectivity coefficient to optimize the in-situ process conditions. For the competitive adsorption mechanism, the reason why CO2 adsorption capacity of shale is stronger than that of CH4 is explained in terms of kinetic diameter, critical temperature, molecular polarity and diffusion rate. The interaction between CO2 and CH4 will make the shale gas seepage mechanism more complex, so further research is needed on the mass transfer process involving multi-component gas. The changes in reservoir physical properties after supercritical CO2 fracturing, the mathematical model of multi-field fully coupled gas microscopic seepage and the universal stress-sensitive model are the focus of future research.

Lan, Z., Sano, Y., Yahagi, T., Tanaka, K., Shirai, K., Papineau, D., Sawaki, Y., Ohno, T., Abe, M., Yang, H., Liu, H., Jiang, T., Wang, T., 2019. An integrated chemostratigraphic (δ13C-δ18O-87Sr/86Sr-δ15N) study of the Doushantuo Formation in western Hubei Province, South China. Precambrian Research 320, 232-252.


High-resolution isotopic analyses were conducted on core samples from the Ediacaran Doushantuo Formation at the Wangjiapeng section, western Hubei Province in South China, whereby two laterally traceable, negative δ13Ccarb excursions (EN1 and EN3) were recognized. The magnitude and duration of these excursions permit intra-basinal and inter-basinal correlation, which indicates that they probably represent a global change in seawater composition. The occurrence of decoupled δ13Ccar-δ13Corg with almost invariable δ13Corg values at Wangjiapeng, Zhongling, Yangjiaping sections is consistent with remineralization of a dissolved organic carbon (DOC) pool by means of sulfate reduction, as recorded in EN3. The synchronous presence of EN3, a shift to higher 87Sr/86Sr and decrease of Mn and Fe contents and δ15N values together points to a glacial influence whereby oxygenation and remineralization of reduced carbon produced 13C-depleted DIC. Glaciations cause a drop in sea level, which itself leads to increased continental shelf area to be exposed to surface weathering, and ultimately to enhanced delivery of radiogenic 87Sr. The increase of 87Sr/86Sr ratios, sulfate and phosphate are consequences of surface runoff into oceanic environments and such perturbations induce biogeochemical changes.

Landis, M.S., Studabaker, W.B., Pancras, J.P., Graney, J.R., Puckett, K., White, E.M., Edgerton, E.S., 2019. Source apportionment of an epiphytic lichen biomonitor to elucidate the sources and spatial distribution of polycyclic aromatic hydrocarbons in the Athabasca Oil Sands Region, Alberta, Canada. Science of The Total Environment 654, 1241-1257.


The sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) atmospheric deposition in the boreal forests surrounding bitumen production operations in the Athabasca Oil Sands Region (AOSR), Alberta, Canada were investigated as part of a 2014 passive in-situ bioindicator source apportionment study. Epiphytic lichen species Hypogymnia physodes samples

(n = 127) were collected within a 150 km radius of the main surface oil sand production operations and analyzed for total sulfur, total nitrogen, forty-three elements, twenty-two PAHs, ten groups of C1-C2-alkyl PAHs and dibenzothiophenes (polycyclic aromatic compounds; PACs), five C1- and C2-alkyldibenzothiophenes, and retene. The ΣPAH + PAC in H. physodes ranged from 54 to 2778 ng g−1 with a median concentration of 317 ng g−1. Source apportionment modeling found an eight-factor solution that explained 99% of the measured ΣPAH + PAC lichen concentrations from four anthropogenic oil sands production sources (Petroleum Coke, Haul Road Dust, Stack Emissions, Raw Oil Sand), two local/regional sources (Biomass Combustion, Mobile Source), and two lichen biogeochemical factors. Petroleum Coke and Raw Oil Sand dust were identified as the major contributing sources of ΣPAH + PAC in the AOSR. These two sources accounted for 63% (43.2 μg g−1) of ΣPAH + PAC deposition to the entire study domain. Of this overall 43.2 μg g−1 contribution, approximately 90% (39.9 μg g−1) ΣPAH + PAC was deposited within 25 km of the closest oil sand production facility. Regional sources (Biomass Combustion and Mobile Sources) accounted for 19% of ΣPAH + PAC deposition to the entire study domain, of which 46% was deposited near-field to oil sand production operations. Source identification was improved over a prior lichen-based study in the AOSR through incorporation of PAH and PAC analytes in addition to inorganic analytes.

Lauretano, V., Zachos, J.C., Lourens, L.J., 2018. Orbitally paced carbon and deep-sea temperature changes at the peak of the Early Eocene climatic optimum. Paleoceanography and Paleoclimatology 33, 1050-1065.

https://doi.org/10.1029/2018PA003422

The late Paleocene to early Eocene warming trend was punctuated by a series of orbitally paced transient warming events, associated with the release of isotopically light carbon into the ocean-atmosphere system. These events occurred throughout the early Eocene, critically persisting during onset, peak, and termination of the early Eocene climatic optimum (EECO) and the onset of the middle Eocene cooling. Here we present a ~5.2-Myr-long high-resolution benthic foraminiferal stable-isotope record spanning the peak of the early Eocene ?hothouse? from Ocean Drilling Program Leg 208 Site 1263. Our new oxygen isotope record confirms the presence of short-term warming events during the peak and termination of the EECO, previously described in coeval bulk carbonate records. The degree of change between deep-sea temperature and concurrent carbon release during these events is consistent with previous findings for Eocene thermal maximum 2 to 3, suggesting that the orbitally forced processes that triggered these perturbations in the exogenic carbon pool were similar. Additionally, the long-term background carbon isotope signature reveals a rapid enrichment of up to ~1.0? across the peak warmth of the EECO, ~51.6 Ma, without a corresponding shift in the oxygen record, suggesting a decoupling from climate. We speculate that this carbon shift reflects a non-recurrent adjustment in the mean (steady) state of the deep-ocean carbon reservoir due to a significant change in carbon source/sink, the biological pump, and/or ocean circulation during the extreme greenhouse conditions of the EECO.

Lawler, A., 2018. Migrants and trade spiced up Canaanite metropolis. Science 362, 980-981.


Looming over a strategic spot on Israel's northern coastal plain, the ancient city of Megiddo was often a battleground, befitting its biblical name Armageddon. But in two Bronze Age tombs, archaeologists are finding signs that, nearly 3500 years ago, Megiddo was also a surprisingly cosmopolitan place. It

drew immigrants from what is now Armenia, imported exotic spices from tropical climes, and boasted a state-of-the-art health care system—at least for the elite.

At last week's annual meeting of the American Schools of Oriental Research here, Israeli and U.S. researchers laid out the first results from the tombs, which were discovered in 2016 and date from when Megiddo was a major metropolis of the Canaanites, the ancient inhabitants of present-day Israel and Lebanon. The finds add to growing evidence of international trade long before the rise of the Assyrian, Persian, and Roman empires. The people of the Bronze Age Middle East “had much more contact with distant places than we give them credit for,” says Eric Cline, an archaeologist at George Washington University in Washington, D.C., and a former member of the project, known as the Megiddo Expedition.

One tomb, dated to about 1600 B.C.E. by radiocarbon and ceramic studies, was a cramped but unusually elaborate vaulted chamber containing nine individuals, including a man between 45 and 60 years old wearing a gold headband, as well as a gold bracelet and other jewelry. Nearby lay a woman aged 25 to 40 with a gold brooch and an elegant silver pin shaped like a duck head. A third skeleton was a child under the age of 10 with similar gold jewelry and two silver rings.

“This seems to be a family grave, given the matching grave goods,” says Melissa Cradic, an archaeologist at the University of California (UC), Berkeley, who led the examination of the tomb. She speculates that the three may represent an elite, if not royal, family that died at about the same time from disease. Analysis of their genetic makeup, which could confirm their family ties, is underway, along with isotopic and other studies that could reveal their diet and health.

The tomb's biggest surprise emerged when three small jugs were tested for residues. Chromatography and mass spectrometry analysis detected chemical components of vanilla. “This was a shock,” says Vanessa Linares from Tel Aviv University in Israel, who led the team conducting the work. Botanist Pesach Lubinsky of UC Riverside, a vanilla expert who was not involved in the Megiddo research, says the finding is at odds with current thinking on vanilla's origins. Vanilla is found in tropical orchids on every continent except Antarctica and Australia. Only in Mesoamerica, however, is there evidence of its early domestication, and it was long thought to be unknown in the Old World until the Spanish brought it back from Mexico in the 16th century C.E.

All aromatic vanilla orchids contain a mixture of compounds, including vanilla, 4-hydroxybenzaldehyde, and vanillic acid. The best matches to the residues found in the jugs grow in Mesoamerica, Indonesia, Kenya, and India, Linares says. Ruling out the first two sources because of distance, she speculates that the vanilla may have arrived in Megiddo from Africa, via Egypt, or from India, through trade across the Persian Gulf.

“India is the most likely source,” says Cline, who notes the robust trade linking nearby Mesopotamia with India in the Bronze Age. The vanilla may have been traded from southern India through the vestiges of the earlier Indus civilization in the subcontinent's northwest. But Dorian Fuller, an archaeobotanist at University College London, says he “would be cautious in attributing origins, given the lack of much ethnobotanical evidence for the use of native vanilla.”

The find, if it proves accurate, would support hints of an early and far-flung spice trade in the ancient Middle East. Peppercorns that likely came from Sri Lanka were stuffed into the nose of Egypt's mummified King Ramses II in 1213 B.C.E., and evidence of cinnamon from Sri Lanka or southern India appears in the Middle East a couple of centuries later.

Investigators also found hints of a grimmer import in a burial pit directly on top of the Megiddo tomb, dating to a century or so later. The pit holds the remains of two men who may have been in their

twenties at death. “These were children of misfortune,” says Rachel Kalisher, a Brown University archaeologist who examined the remains. Both men's bones were pitted, and one had broken his nose and pinky toes, conditions Kalisher says might be due to leprosy. That disease is thought to have spread from Africa to India by 4000 years ago; trade may then have carried it to the Middle East. Genetic testing is underway to determine whether Kalisher's hunch is correct.

“Their illness left them debilitated, and they needed help to survive,” she adds. Both appear to have been carefully tended. Their teeth lacked the wear typical for men of their age, a sign that they may have been fed a special nonabrasive diet designed for weakened jaws. “There was a societal mechanism of health care—they were not ostracized and clearly were given considerable respect,” Kalisher adds.

At the end of his life, the more debilitated of the two men underwent a drastic treatment: A physician was called in to cut a window into his skull—a practice called trepanation, often used to treat physical, mental, and spiritual disorders in ancient times. “This was done with fine precision and great expertise,” says Kalisher, although the man died within less than a month of the procedure.

Preliminary DNA studies by geneticists Liran Carmel of Hebrew University in Jerusalem and David Reich of Harvard University show the men were brothers. Additional genetic studies may reveal more about their origins and whether they were related to the occupants of the older tomb below.

DNA studies also revealed the far-flung connections of three occupants of another tomb. At the meeting, Carmel said genetic analysis suggests they were recent immigrants from today's Armenia in the Caucasus, some 1300 kilometers to the north. Unlike the vaulted tomb, which lay near Megiddo's palace, this tomb was surrounded by humbler houses and graves. If the results hold up, they hint that long-distance travel was not confined to the elite.

Dozens of ancient DNA samples from the region, including many from Megiddo, are now being analyzed, and may soon shed more light on the genetic makeup of the city's inhabitants, Carmel added.

Glenn Schwartz, an archaeologist at Johns Hopkins University in Baltimore, Maryland, who is not involved with the dig, says the burst of data from Megiddo, rich in genetic and chemical detail, doesn't just provide fresh insight into this important Bronze Age center. The findings also “illustrate the numerous new techniques derived from the natural sciences that archaeologists are now using to identify the source and identity of the humans, animals, plants, and other materials found in the archaeological record.”

Lee, S., Suh, J., Choi, Y., 2018. Review of smartphone applications for geoscience: current status, limitations, and future perspectives. Earth Science Informatics 11, 463-486.

https://doi.org/10.1007/s12145-018-0343-9

Smartphones can be utilized in the field of geosciences for various purposes due to their multifaceted abilities that combine both hard- and software features. The unique abilities of smartphones allow new methodologies for the collection and visualization of data that rarely become available in traditional computing platforms. In this study, commercially available smartphone applications (apps) that have been released in geoscience (e.g., geology/soil, minerals and rocks, petroleum and gas) so far were investigated. The apps were categorized based on the extent of smartphone feature usage into (a) basic, standard-feature apps; (b) calculator and referencing apps; and (c) sensing and communication apps. Furthermore, each of these categories was divided into several app groups based on specific features. Representative apps of each specific app group were selected and their

characteristics and applicability were examined. Lastly, major limitations regarding smartphone app development and implementation in geoscience and implications for future improvements were discussed.



A native microbial consortium for the bioremediation of soil contaminated with diesel fuel in Korea was constructed and its biodegradation ability was assessed. Microbial strains isolated from Korean terrestrial environments, with the potential to biodegrade aliphatic hydrocarbons, PAHs, and resins, were investigated and among them, eventually seven microbial strains, Acinetobacter oleivorans DR1, Corynebacterium sp. KSS-2, Pseudomonas sp. AS1, Pseudomonas sp. Neph5, Rhodococcus sp. KOS-1, Micrococcus sp. KSS-8, and Yarrowia sp. KSS-1 were selected for the construction of a microbial consortium based on their biodegradation ability, hydrophobicity, and emulsifying activity. Laboratory- and bulk-scale biodegradation tests showed that in diesel fuel-contaminated soil supplemented with nutrients (nitrogen and phosphorus), the microbial consortium clearly improved the biodegradation of total petroleum hydrocarbons, and all microbial strains constituting the microbial consortium, except for Yarrowia survived and grew well, which suggests that the microbial consortium can be used for the bioremediation of diesel fuel-contaminated soil in Korea.

Lemaitre, N., Planchon, F., Planquette, H., Dehairs, F., Fonseca-Batista, D., Roukaerts, A., Deman, F., Tang, Y., Mariez, C., Sarthou, G., 2018. High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes. Biogeosciences 15, 6417-6437.

https://doi.org/10.5194/bg-15-6417-2018

In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May–June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 (234Th) with the ratio of POC to 234Th of sinking particles at the depth of export. Particles were collected in two size classes ( > 53 and 1–53µm) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4mmolm−2d−1 in the Irminger basin, where the bloom was close to its maximum, to 12mmolm−2d−1 near the Iberian Margin, where the bloom had already declined. In addition to the state of progress of the bloom, variations of the POC export fluxes were also related to the phytoplankton size and community structure. In line with previous studies, the presence of coccolithophorids and diatoms appeared to enhance the POC export flux, while the dominance of picophytoplankton cells, such as cyanobacteria, resulted in lower fluxes. The ratio of POC export to primary production (PP) strongly varied regionally and was generally low ( ≤ 14%), except at two stations located near the Iberian Margin (35%) and within the Labrador basin (38%), which were characterized by unusual low in situ PP. We thus conclude that during the GEOVIDE cruise, the North Atlantic was not as efficient in exporting carbon from the surface, as reported earlier by others. Finally, we also estimated the POC export at 100m below the surface export depth to investigate the POC transfer efficiencies. This parameter was also highly variable amongst regions, with the highest transfer efficiency at sites where coccolithophorids dominated.



Biological samples are inherently heterogeneous and complex. Tackling this complexity requires innovative technological and analytical solutions. Recent advances in high-throughput single-cell isolation and nucleic acid barcoding methods are rapidly changing the technological landscape of biological sciences and now make it possible to measure the (epi)genomic, transcriptomic, or proteomic state of individual cells. In addition, few experimental approaches enable multi-omics measurements of the same cell. However, merging-omics data collected from different experiments remains a considerable challenge. Although several strategies for merging transcriptomics datasets have recently been introduced, cell-to-cell variability and heterogeneity remains one of the confounding factors limiting data fusion and integration. Here, we focus our discussion on the latest single-cell technological and analytical solutions to achieve high data dimensionality and resolution. Obtaining datasets with a wealth of multi-omics information will undoubtedly provide new avenues for researchers to unravel the complexity of biological samples encountered in modern biological research and molecular diagnostics.

Lepot, K., Williford, K.H., Philippot, P., Thomazo, C., Ushikubo, T., Kitajima, K., Mostefaoui, S., Valley, J.W., 2019. Extreme 13C-depletions and organic sulfur content argue for S-fueled anaerobic methane oxidation in 2.72 Ga old stromatolites. Geochimica et Cosmochimica Acta 244, 522-547.


The extreme 13C-depletions recorded in Neoarchean organic matter (OM) have commonly been interpreted as markers of methanotrophy. This methane oxidation metabolism could have been performed using oxidants such as dioxygen, sulfate, nitrite/nitrate, and/or Fe3+- and Mn4+-minerals. Acetogenesis using acetyl-CoA metabolism may produce similar 13C-depletions. We investigated δ13C and S/C values of OM in 2.72 Ga old lacustrine stromatolites of the Tumbiana Formation (Australia) using Secondary Ion Mass Spectrometry (SIMS), coupled with X-ray spectroscopy. Type-A OM is embedded in quartz and/or chlorite. We show that mixtures of chlorite bias negatively the δ13Corg of associated OM measured by SIMS, likely through recombination of hydrogen from chlorite with carbon from OM during analysis. Type-A OM, associated with quartz or interleaved with chlorites (but remote enough to avoid H-recombination), displays δ13Corg between −56.1 and −50.6‰ VPDB (mean: −53.5‰, SD ± 1.8‰). The intimate association of Type-A OM with Fe-rich chlorite and its main occurrence in pyritic layers coupled with 13C-depletions is most parsimoniously interpreted as anaerobic methanotrophy using Fe3+-minerals and/or oxidized S. Type-B OM comprises <2-µm organic globules embedded in calcite. A mass balance correction using the δ13C values measured on Type-B globules mixed with calcite and those measured on pure calcite yielded corrected δ13C∗org values for the globules ranging between −65.2 and −52.5‰ (mean −58.8‰, SD ± 3.6‰). In a context where Fe and S reduction could outcompete acetogenesis for a fraction of any available H2, these extremely low δ13Corg values are difficult to explain with chemoautotrophic acetogenesis. Atomic S/C ratios in Type-B globules reach up to 0.042, i.e. up to tenfold the values (0.003–0.004) in Type A-OM. These organic S concentrations, combined with the extremely low δ13C∗org values, support anaerobic oxidation of methane coupled to sulfur oxidation. Finally, Type-C OM, interpreted as migrated pyrobitumen nodules, displays δ13Corg of −48 to −39.1‰. The most extreme low-δ13Corg values of the Precambrian are thus best interpreted as the result of lacustrine methanotrophy fueled by oxidized S and/or Fe species, which likely derived from oxygenic and/or anoxygenic photosynthesis. Photosynthesis, followed by methanogenesis and methanotrophy may have been important in lakes at

a time of supercontinent growth and eruption of large subaerial igneous provinces. In this context, anaerobic methanotrophy could have played a part in regulating atmospheric methane.

Li, C., Ou, C., 2018. Modes of shale-gas enrichment controlled by tectonic evolution. Acta Geologica Sinica - English Edition 92, 1934-1947.

https://doi.org/10.1111/1755-6724.13686

The typical characteristics of shale gas and the enrichment differences show that some shale gases are insufficiently explained by the existing continuous enrichment mode. These shale gases include the Wufeng–Longmaxi shale gas in the Jiaoshiba and Youyang Blocks, the Lewis shale gas in the San Juan Basin. Further analysis reveals three static subsystems (hydrocarbon source rock, gas reservoirs and seal formations) and four dynamic subsystems (tectonic evolution, sedimentary sequence, diagenetic evolution and hydrocarbon‐generation history) in shale‐ gas enrichment systems. Tectonic evolution drives the dynamic operation of the whole shale‐gas enrichment system. The shale‐gas enrichment modes controlled by tectonic evolution are classifiable into three groups and six subgroups. Group I modes are characterized by tectonically controlled hydrocarbon source rock, and include continuous in‐situ biogenic shale gas (I1) and continuous in‐situ thermogenic shale gas (I2). Group II modes are characterized by tectonically controlled gas reservoirs, and include anticline‐controlled reservoir enrichment (II1) and fracture‐controlled reservoir enrichment (II2). Group III modes possess tectonically controlled seal formations, and include faulted leakage enrichment (III1) and eroded residual enrichment (III2). In terms of quantity and exploitation potential, I1 and I2 are the best shale‐gas enrichment modes, followed by II1 and II2. The least effective modes are III1 and III2. The categorization provides a different perspective for deep shale‐gas exploration.

Li, F., Gong, Q., Burne, R.V., Tang, H., Su, C., Zeng, K., Zhang, Y., Tan, X., 2019. Ooid factories operating under hothouse conditions in the earliest Triassic of South China. Global and Planetary Change 172, 336-354.


The concept of “Carbonate Factory” was introduced to describe areas of carbonate production and accumulation. In this paper, the “Ooid Factories” is used to analyze extensive Griesbachian (Triassic) oolite deposits in South China that, along with microbialites and lime-mud deposits from different carbonate depositional environments. Late Permian tropical shallow-water skeletal factories (dominant by calcareous algae, sponge, and other associated organisms) collapsed in pace with the most severe mass extinction event, and were rapidly replaced by mud-mound factories (microbialite and lime-mud deposits) and subsequent ooid factories in shallow-water circumstances of Griesbachian. Meantime, temporal nutrient-rich and high-temperature conditions probably delayed re-establishment of tropical shallow-water skeletal factories. As an elementary unit of ooid factories, Lower Triassic oolites have diagnostic characteristics of ooid fabrics (alternatively dark- and light-colored laminae), size ranges (1–5 mm), and grain compositions (pure ooids, and only a few gastropod and bivalve fragments). Continuous aggradational and progradational oolite sequences caused extensive oolite accumulations that significantly contribute to the development of platform architecture with the collaboration of mud-mound factories (mainly line-mud deposits) in South China, through the evolution of low-angle or homoclinal ramps in the early Griesbachian to distally steepened ramps or flat-topped shelves in the late Griesbachian. Moreover, ooid factories also developed in Western Tethyan, Cimmerian, and Arabian carbonate platforms within low latitudes of the Tethyan Ocean during the Griesbachian. It is suggested that extreme hothouse climate with (seasonal) dry conditions in low latitudes significantly facilitated the extensive carbonate production

of ooid factories at that time due to the strong linear relationship between surface seawater temperature and carbonate saturation state.

Li, J., He, Y., Tan, L., Zhang, P., Peng, X., Oruganti, A., Yang, G., Abe, H., Wang, Y., Tsubaki, N., 2018. Integrated tuneable synthesis of liquid fuels via Fischer–Tropsch technology. Nature Catalysis 1, 787-793.

https://doi.org/10.1038/s41929-018-0144-z

To tune the product selectivity by controlling the complicated reaction path is a big challenge in Fischer–Tropsch synthesis. Here, we report an integrated catalytic process for the direct conversion of syngas (CO/H2) into different types of liquid fuels without subsequent hydrorefining post-treatments of Fischer–Tropsch waxes. Outstanding selectivities for gasoline, jet fuel and diesel fuel as high as 74, 72 and 58% are achieved, respectively, by only using mesoporous Y-type zeolites in combination with cobalt nanoparticles. The types of liquid fuels can be readily tuned by controlling the porosity and acid properties of the zeolites. We further build a new product-distribution model for the bifunctional catalysts, which do not obey the traditional Anderson–Schulz–Flory (ASF) distribution. The present work offers a simple and effective method for the direct synthesis of different types of liquid fuels.



Polysaccharides are secreted by many marine bacteria as a strategy for growth, binding trace metals, adhering to solid surfaces, and to survive adverse conditions. Therefore, they have attracted extensive research interest due to their biological roles as well as potential industrial application. Many works have been carried out to study the growth dynamics of polysaccharides producing bacteria. Average polysaccharide production per cell during growth were usually studied in the past. However, most previous works were carried out at the population level, and the research at a single cell level was rare. Atomic force microscopy (AFM) is a powerful tool in studying single microorganisms and their extracellular polysaccharides. Here we investigated the growth dynamics and capsular polysaccharide (CPS) production of a CPS producing bacterium Zunongwangia profunda SM-A87 isolated from deep-sea sediments with AFM. Z. profunda SM-A87 exhibited slow growth rates at 10°C, which was lower than at optimum growth temperature (30°C). But the CPS production at 10°C was much higher than that at 30°C. Single cell imaging with AFM revealed rod like cell morphology at both temperatures, but filamentous bacteria could sometimes be noticed at 10°C. The CPSs surrounding bacterial cells were observed, and the fibrils of polysaccharides entangled into networks. The diameter of the capsules and the length of the polysaccharides fibrils increased as cultivation time increased. The average volume of the bacterial cells and capsular polysaccharides surrounding each cell at both temperatures were calculated. The average volume of a single bacterial cell was 0.2–0.3µm3, and it increased in exponential phase and slightly decreased in stationary phase, but the average volume of CPS produced by single cells increased during bacterial growth. CPS production increased to 0.097 ± 0.051µm3 per cell at 10°C in stationary phase, which is larger than that produced at 30°C (0.055 ± 0.013µm3 per cell). We report a novel method of estimating the average bacterial polysaccharide production with AFM. Since polysaccharides-producing bacteria are abundant in

marine sediments, this method is potentially useful for studying the biological and ecological role of polysaccharides-producing bacteria from the deep sea in the future.

Li, N., Liu, Y., Liu, Y., Lou, Y., Zhao, X., 2019. Effect of oil spill on compound-specific stable carbon isotope composition of amino acid in Nitzschia closterium and Heterosigma akashiwo. Science of The Total Environment 653, 1095-1104.


Marine microalgae, the most important primary producers in marine ecosystems, are susceptible to toxicants and usually selected as the promising organisms for chemical risk testing. The stable carbon isotope ratios (δ13C) of amino acids (AAs) were measured to determine if compound-specific stable isotope analysis could be used to provide insight into the toxic effects of oil spill on the marine microalgae. The water accommodated fractions (WAF) of #180 fuel oil were selected as the toxic targets with different concentrations in acute (96 h) toxic tests. Naphthalene, phenanthrene, anthracene, and fluoranthene were detected as the predominant congeners of polycyclic aromatic hydrocarbons in the WAF, and may be the main toxic components. At the same WAF concentration, the δ13C values of leucine in Nitzschia closterium increased with the culture time, whereas decreased in Heterosigma akashiwo. However, with the increasing WAF concentrations, the δ13C values of glutamic acid exhibited the increasing trend in both of the two kinds of microalgae at the same culture time. The similar phenomenon was also observed for histidine in H. akashiwo, while opposite in N. closterium, but both enriching in δ13C compared to the controlled experiments without the WAF. Under the different culture times and WAF concentrations, the δ13C values of alanine and methionine showed unexpected trend. These findings indicated that the synthesis pathways of AA in microalgae cells were affected by the WAF, thus leading to the carbon isotopic fractionation in AAs. The present study provide a novel approach to explore the toxicity mechanism of primary producers under oil spill stress, and monitor and evaluate the marine ecological risk of oil spill pollution.

Li, N., Yang, X., Peng, J., Zhou, Q., Chen, D., 2018. Paleo-cold seep activity in the southern South China Sea: Evidence from the geochemical and geophysical records of sediments. Journal of Asian Earth Sciences 168, 106-111.


Over the past decade more than 30 cold seep sites have been reported along the continental slope of the South China Sea (SCS). These seep sites have all been located in the northern SCS, and no methane seepage has been discovered in the southern SCS. Here, we report on the analysis results of the geochemical and geophysical of the marine core sediments (58S) collected from the southern continental slope of the SCS. We suggest that the sedimentary total sulfur (TS), total inorganic carbon (TIC), δ34SCRS values of chromium reducible sulfur (CRS) and carbonate δ13CTIC values of the bulk sediments, coupled with the ratio of (NRMAF60mT-NRMAF80mT)/NRM can be used to trace the methane release events in a methane-rich environment. At least two methane release events were identified at depths of 5.5–6.2 m and 6.8–7.2 m. Moreover, according to the characteristic of the TS/TOC and (NRMAF60mT-NRMAF80mT)/NRM ratio of sediments, we suggest the methane flux has changed episodically. This inference is supported by the occurrence of the strongly negative carbonate δ13CTIC values of bulk sediments and the positive δ34SCRS values, which indicate the occurrence of anaerobic oxidation of methane (AOM) and the location of a past or present sulfate methane transition zone (SMTZ), respectively. Ultimately, these new data suggest that the combined geochemical and geophysical study of marine sediments provides a valuable tool with which to infer the temporal variations in methane seepage in a marine environment.



Analysis and characterization of micro/nano-sized pore structure are critical issues in shale geology and engineering. Scanning electron microscopy (SEM) imaging is one of the most widespread methods for the analysis of the micro/nano-sized pores in shale, but precise identification of the ultrafine pore structure in shale is still a big challenge because shale is so complex that some components may have overlap with pores based on the simple discrimination of gray scale under SEM microscopy. Here, Fe3O4/Au nanocomposite with magnetic properties is synthesized, characterized, and introduced as a novel pore-marker to improve SEM identification and quantitation of micro/nano-sized pores in shale. Due to the superparamagnetic property, the nanomarker is conveniently controlled by an external magnetic field to fill into pores and offers a sharp contrast imaging between matrix of shale (various gray) and pores (bright), which makes the identification of micro/nano-sized pores in shale much more straightforward and reliable. Furthermore, because gold, as a noble metal, is particularly rare in shale, energy-dispersive X-ray spectroscopy mapping of Au is delicately used to precisely calculate area porosity in shale. Combining with the aforementioned merits of the nanomarker, a precise and practical technique is proposed to promote characterization of micro/nano-sized pores in shale.

Li, Q., Wang, Y., Wang, X., Yu, H., Li, Q., Wang, F., Bai, H., Kobina, F., 2019. An application of thickener to increase viscosity of liquid CO2 and the assessment of the reservoir geological damage and CO2 utilization. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 368-377.

https://www.tandfonline.com/doi/abs/10.1080/15567036.2018.1518355

In comparison to hydraulic fracturing, CO2 fracturing technology is more efficient and effective in solving environmental problems caused by the fracturing process. However, the low viscosity caused by pure CO2 under high pressure hinders the development of the entire fracturing technology. Given that, a siloxane that can significantly improve the liquid CO2 viscosity is prepared and the excellent performance to thicken CO2 by silicone polymer is shown. Polymerization that occurs under water conditions presents a trend and is more likely to trigger reaction than ring-opening polymerization under anhydrous conditions. The thickening performance test is conducted by capillary viscometer self-designed at 35°C and 10 MPa. Moreover, a rising trend in viscosity is demonstrated with increase in thickener concentration. Smaller damages and chemical residue exists in the stratum after CO2 fracturing. In addition, there are no changes that occur in the quality of crude oil. A fine conclusion for thickening performance provides a basis for the synthesis of the polymer to thicken CO2.

Li, S., Zhao, S., Liu, X., Cao, H., Yu, S., Li, X., Somerville, I., Yu, S., Suo, Y., 2018. Closure of the Proto-Tethys Ocean and Early Paleozoic amalgamation of microcontinental blocks in East Asia. Earth-Science Reviews 186, 37-75.


As a complex paleo-ocean located between the Tarim-North China and the Sibumasu/Baoshan blocks, the Proto-Tethys Ocean was opened from the rifting of the Supercontinent Rodinia and

mainly closed at the end of the Early Paleozoic. The known studies suggest that there were many continents and/or micro-continents in the Proto-Tethys Ocean. During closure of the Proto-Tethys Ocean and assembly of these continents/micro-continents, some Early Paleozoic ophiolites and HP-UHP metamorphic rocks developed in East Asia similar to those Early Paleozoic orogens in Gondwana. However, some academic debates still remain on the boundaries of the Proto-Tethys Ocean and the nature, relationships and assembly processes of these continents/micro-continents to the Tarim-North China Continent to the north. These problems are important for revealing and reconstructing tectonic processes before the closure of the Proto-Tethys Ocean and the initial assembly of the Supercontinent Pangea. Not surprisingly, the Proto-Tethys tectonic domain is characterized by complex ocean-continent configurations, assemblies and dispersals of continents, from the rifting and drifting of the Supercontinent Rodinia to the assembly of the Supercontinent Pangea. Therefore, this paper mainly focuses on summarizing and discussing the northern part of the Proto-Tethys tectonic domain based on field geology, structural geology, magmatism, sedimentary formations, geochemical records, geochronology and tomography, in order to reveal three key aspects: 1) identifying the southern and northern boundaries of the Proto-Tethys Ocean; 2) establishing affinities of continents/micro-continents within the Proto-Tethys Ocean and its ocean-continent configuration; and 3) clarifying the temporal sequence and styles of micro-continental assembly and the closure of the Proto-Tethys Ocean. Integrated analysis results show that to the north the region is bounded by the paleo-Luonan-Luanchuan Suture (or Kuanping Suture) and its extension to West Kunlun; the southern boundary is marked by the Longmu Co-Shuanghu-Changning-Menglian Suture. The Tarim-Alax-North China Block to the north of the Proto-Tethys Ocean had a southward subduction polarity and collided with Gondwana along the northern margin of Gondwana in the Early Devonian. The southern branch of the Proto-Tethys Ocean may be closed, making the Greater South China Block, including the northern Qiangtang, Ruoergai, Yangtze and Cathaysia, Bureya-Jiamusi and Indochina blocks, southward subduction and accretion to the northern margin of Gondwana in the Early Devonian. The results also show that the North China Block had no clear affinity to Gondwana, whereas the other continental/micro-continental blocks, such as the Yangtze, Cathaysia, Tarim, Qaidam, Alax, North Qinling, Qilian, Oulongbuluke, South Qiangtang, Lhasa, Lanping-Simao and Indochina all have an affinity to Gondwana in the earlier part of the Early Paleozoic. During the interval 480–400Ma these series of continental blocks/micro-continental blocks experienced gradual southward subduction and accretion to the eastern segment of the northern margin of Gondwana, resulting in the closure of the Proto-Tethys Ocean and formation of the supercontinent called Proto-Pangea. The Greater South China Block and the Tarim-North China Block separated and drifted from Greater Gondwana of the Supercontinent Proto-Pangea since 380Ma, resulting in the formation of the Paleo-Tethys and the Mianlue oceanic crusts. After this minor adjustment and until 240–220Ma, they assembled northward gradually to develop Laurasia, which in turn resulted in the final formation of the Supercontinent Pangea.

Li, Y., Shao, L., Yan, Z., Hou, H., Tang, Y., Large, D.J., 2018. Net primary productivity and its control of the Middle Jurassic peatlands: An example from the southern Junggar coalfield. Science China Earth Sciences 61, 1633-1643.

https://doi.org/10.1007/s11430-017-9263-4

The Jurassic is an important period of global coal formation, including the development of several large coalfields in central Asia and northern China. Individual seams within these peatlands represent sustained periods of terrestrial carbon accumulation and a key environmental indicator attributed to this record is the rate of carbon accumulation. Determining the rate of carbon accumulation requires a measure of time contained within the coal and this study aimed at determining the rate via the identification of Milankovitch orbital cycles using spectral analysis. Spectral analyses of geophysical

data from two thick coal seams, No. 43 (35.9 m) and No. 3 (13.2 m), of the Middle Jurassic of the southern Junggar coalfield were conducted to identify significant signals of variations in ash content. The results showed that the variations in ash content of the coal showed spatial cycles at 0.2, 0.7 and 1.1 m−1, which were interpreted to represent 123 ka (eccentricity), 37.1 ka (obliquity), and 21.2 ka (precession) orbital periodicities, respectively. Using this timeframe, the depositional time of the No. 43 and No. 3 coal seams were calculated to be 876–970 and 322–357 ka, respectively. In combination with an understanding of carbon loss during coalification, the carbon accumulation rates of these Middle Jurassic peatlands were calculated to be 58.6–64.9 and 60.3–66.8 g C m−2 a−1 for the No. 43 and No. 3 coal seams, respectively. Given that the net primary productivity (NPP) was 4.3 times the value of the carbon accumulation in a mid-latitude region of 40°–45°N, an NPP of 251.8–279.1 and 259.1–287.1 g C m−2 a−1 was calculated for the No. 43 and No. 3 coal seams, respectively. In the context of the same paleolatitude (40°–45°N) and peat type, the NPP values of the Middle Jurassic strata in the study area were higher than those of the peatlands of the Holocene and Permian, and were similar to the NPP values of Early Cretaceous peatlands. Considering the NPP of a peatland is predominantly controlled by atmospheric CO2 and O2 levels and temperature, the lower content of CO2 and an excessive O2 level in the temporal atmosphere would lead to a decrease in peatland NPP. Therefore, it is inferred that the CO2 level during the Middle Jurassic was higher than that of the icehouse Permian and Holocene periods, and it was similar to the CO2 level of the greenhouse Cretaceous period. The results are consistent with the global CO2 variation curve of Berner. In conclusion, Milankovitch orbital cycles calculated from geophysical logs can be used to infer the NPP of temporal peatlands during different geological periods, based on which the deep-time paleoclimates can be analyzed.



Shallow-water hydrothermal vent ecosystems are distinctly different from deep-sea vents, as other than geothermal, sunlight is one of their primary sources of energy, so their resulting microbial communities differ to some extent. Yet compared with deep-sea systems, less is known about the active microbial community in shallow-water ecosystems. Thus, we studied the community compositions, their metabolic pathways, and possible coupling of microbially driven biogeochemical cycles in a shallow-water hydrothermal vent system off Kueishantao Islet, Taiwan, using high-throughput 16S rRNA sequences and metatranscriptome analyses. Gammaproteobacteria and Epsilonbacteraeota were the major active bacterial groups in the 16S rRNA libraries and the metatranscriptomes, and involved in the carbon, sulfur, and nitrogen metabolic pathways. As core players, Thiomicrospira, Thiomicrorhabdus, Thiothrix, Sulfurovum, and Arcobacter derived energy from the oxidation of reduced sulfur compounds and fixed dissolved inorganic carbon (DIC) by the Calvin-Benson-Bassham (CBB) or reverse tricarboxylic acid cycles. Sox-dependent and reverse sulfate reduction were the main pathways of energy generation, and probably coupled to denitrification by providing electrons to nitrate and nitrite. Sulfur-reducing Nautiliaceae members, accounting for a small proportion in the community, obtained energy by the oxidation of hydrogen, which also supplies metabolic energy for some sulfur-oxidizing bacteria. In addition, ammonia and nitrite oxidation is another type of energy generation in this hydrothermal system, with marker gene sequences belonging to Thaumarchaeota/Crenarchaeota and Nitrospina, respectively, and ammonia and nitrite oxidation was likely coupled to denitrification by providing substrate for nitrate and nitrite reduction to nitric oxide. Moreover, unlike the deep-sea systems, cyanobacteria may also actively

participate in major metabolic pathways. This study helps us to better understand biogeochemical processes mediated by microorganisms and possible coupling of the carbon, sulfur, and nitrogen cycles in these unique ecosystems.

Li Yung Lung, J.Y.S., Tank, S.E., Spence, C., Yang, D., Bonsal, B., McClelland, J.W., Holmes, R.M., 2018. Seasonal and geographic variation in dissolved carbon biogeochemistry of rivers draining to the Canadian Arctic Ocean and Hudson Bay. Journal of Geophysical Research: Biogeosciences 123, 3371-3386.

https://doi.org/10.1029/2018JG004659

The chemical composition of river water can be used to diagnose change on land, while playing a determining role in the ecology and biogeochemistry of riverine-influenced ocean waters. Despite this, little is known about the seasonal and geographic variability of riverine chemistry throughout much of the Canadian north. Here we assess the chemical composition of a broad suite of rivers draining to the Canadian Arctic Ocean and Hudson Bay using previously unpublished government data. We focus on inorganic and organic carbon (alkalinity and dissolved organic carbon), using paired chemistry and discharge measurements to assess constituent flux. Concentrations and area-normalized yields vary substantially across the northern Canadian landscape, with dissolved organic carbon typically highest in rivers draining the Hudson Bay Lowland, alkalinity highest in rivers draining Cordillera and Plains terrains, and the ratio of organic to inorganic species highest in rivers draining the Canadian Shield. Yields of major weathering ions show that carbonate weathering - a notable proportion of which may be driven by sulfide oxidation - dominates inorganic carbon delivery from the rivers we assess. Despite the reasonably diverse coverage of the data set, we find that clear gaps exist, including a lack of data through to the present day for many rivers, and a dearth of measurements from the Arctic Archipelago and eastern shores of Hudson Bay. We therefore use a modeling approach to extrapolate fluxes to the full Canadian Arctic drainage basin. Region-specific differences between our results and previous models reinforce the need for targeted river water chemistry measures throughout the Canadian Arctic domain.

Li, Z., Lyu, R., Tower, J., 2018. Models of replicator proliferation involving differential replicator subunit stability. Origins of Life and Evolution of Biospheres 48, 331-342.

https://doi.org/10.1007/s11084-018-9561-x

Several models for the origin of life involve molecules that are capable of self-replication, such as self-replicating polymers composed of RNA or DNA or amino acids. Here we consider a hypothetical replicator (AB) composed of two subunits, A and B. Programs written in Python and C programming languages were used to model AB replicator abundance as a function of cycles of replication (iterations), under specified hypothetical conditions. Two non-exclusive models describe how a reduced stability for B relative to A can have an advantage for replicator activity and/or evolution by generating free A subunits. In model 1, free A subunits associate with AB replicators to create AAB replicators with greater activity. In simulations, reduced stability of B was beneficial when the replication activity of AAB was greater than two times the replication activity of AB. In model 2, the free A subunit is inactive for some number of iterations before it re-creates the B subunit. A re-creates the B subunit with an equal chance of creating B or B′, where B′ is a mutant that increases AB’ replicator activity relative to AB. In simulations, at moderate number of iterations (< 15), a shorter survival time for B is beneficial when the stability of B is greater than the inactive time of A. The results are consistent with the hypothesis that reduced stability for a replicator subunit can be advantageous under appropriate conditions.

Liang, B., Du, M., Yanez, P.P., 2019. Subsurface well spacing optimization in the Permian Basin. Journal of Petroleum Science and Engineering 174, 235-243.


Optimum subsurface well spacing is key to developing unconventional reservoirs. From a field application perspective, this paper presents our systematic study on subsurface well spacing in the Permian Basin for unconventional reservoirs which consisted of four main components, i.e., numerical modeling, well interference quantification through simulation and regression, field pilot analogs, and economic evaluation. In this paper, field pilot wells are actual wells in the field to test different well spacing and completion designs.

To capture upsized and downsized completions, a wide range of fracture designs in combination with different well spacing scenarios are conducted for both hydraulic fracture modeling and reservoir simulation. At the section level (1 mile by 1 mile, 640 acres), multiple wells are simulated to better capture well interactions and reservoir property variations. A complex fracture network is generated by considering interactions between natural fracture and hydraulic fracture. Well interference, which is determined by estimating ultimate recovery (EUR) difference between a single well and a middle well from multiple wells, is analyzed for general trend regressions and validated through field test results. At the section level, economics is done to evaluate capital efficiency of various scenarios.

Results from both modeling work and pilots indicate that larger hydraulic fracture size without an increase in subsurface well spacing does not necessarily improve section EUR and there is a point of diminishing returns. Larger subsurface well spacing with bigger fracture size is thereby a preferable combination.



Distributions of branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are sensitive to environmental parameters, which enables their use in paleoenvironmental studies. In particular, the degree of methylation of brGDGTs (MBT and MBT′) and the cyclization ratio of brGDGTs (CBT) are often used to estimate changes in temperature in paleoclimate studies. Application of these proxies requires reliable and precise calibrations to temperature. However, available calibrations of brGDGT proxies to temperature have large calibration errors in arid areas which suggests that other environmental variables influence brGDGT distributions in these areas. Here we analyze brGDGT distributions in soils from the Tibetan Plateau, an arid/semi-arid region with gradients in vegetation cover (forest, grassland, and desert) to examine: (1) the applicability of MBT′/CBT calibrations to reconstruct mean annual air temperature (MAAT); and (2) the effects of vegetation cover on temperature calibrations. We show that temperatures reconstructed using the global soil MBT′/CBT calibrations are warmer than instrumentally observed temperature, and that the calibrations are significantly influenced by the presence or absence of vegetation. Excluding sample sites without vegetation (bare soil) from temperature calibrations substantially improves the correlation between observed and reconstructed temperatures. Within the vegetated soils, we reanalyzed published global soil calibration datasets, including results of analyses that either did or did not separate 5- and 6-methyl brGDGT isomers, and find that the correlation between MBT′5Me and MBT′ and temperature

varies for different vegetation types (grass and forest) and that the error of temperature calibrations is reduced if calibrations are separated by the type of vegetative cover (grass or forest). We test these new calibrations in sequences from the Lantian and Mangshan loess of the Chinese Loess Plateau and find that reconstructed temperatures from both modern and Last Glacial Maximum sediments are more consistent with other reconstructions and climate model simulations when vegetation-specific calibrations are applied to the brGDGT data. The results indicate that changes in vegetation should be taken into consideration when applying brGDGT proxies to reconstruct past changes in climate.

Liden, T., Carlton, D.D., Miyazaki, S., Otoyo, T., Schug, K.A., 2019. Forward osmosis remediation of high salinity Permian Basin produced water from unconventional oil and gas development. Science of The Total Environment 653, 82-90.


Unconventional oil and gas operations are on the rise, and they are an integral component to meeting the nation's energy needs. Produced water is the primary by-product of oil and gas operations, and it has proven challenging to treat to date. The aim of this study was to evaluate the feasibility of using forward osmosis with thin-film composite hollow fiber membranes as a remediation option for produced water with high total dissolved solids levels from the Permian Basin. Trials consisted of a series of 5 experiments in order to evaluate the performance of the membrane. Three PW samples, each from different locations, were used to conduct the series of experiments and compare the performance of the membranes on samples with TDS levels ranging from 16,000 to 210,000 mg/L. It was concluded that forward osmosis can be used to extract water from high salinity oil field brines and PW. Flux decreased over the course of the trials due to a combination of membrane fouling, concentration polarization, and temperature fluctuations. The flux of the PW was similar to the flux measured for the PW mimic with small difference due to the influence of activity on the osmotic pressure. The flux was also influenced by temperature and the linear velocity of the feed solution and draw solution.

Lin, P., Fleming, L.T., Nizkorodov, S.A., Laskin, J., Laskin, A., 2018. Comprehensive molecular characterization of atmospheric brown carbon by high resolution mass spectrometry with electrospray and atmospheric pressure photoionization. Analytical Chemistry 90, 12493-12502.


Light-absorbing components of atmospheric organic aerosols, which are collectively termed “brown carbon” (BrC), are ubiquitous in the atmosphere. They affect absorption of solar radiation by aerosols in the atmosphere and human health as some of them have been identified as potential toxins. Understanding the sources, formation, atmospheric evolution, and environmental effects of BrC requires molecular identification and characterization of light-absorption properties of BrC chromophores. Identification of BrC components is challenging due to the complexity of atmospheric aerosols. In this study, we employ two complementary ionization techniques, atmospheric pressure photo ionization (APPI) and electrospray ionization (ESI), to obtain broad coverage of both polar and nonpolar BrC components using high-resolution mass spectrometry (HRMS). These techniques are combined with chromatographic separation of BrC compounds with high performance liquid chromatography (HPLC), characterization of their light absorption with a photodiode array (PDA) detector, and chemical composition with HRMS. We demonstrate that this approach enables more comprehensive characterization of BrC in biomass burning organic aerosols (BBOAs) emitted from test burns of sage brush biofuel. In particular, we found that nonpolar BrC chromophores such as PAHs are only detected using positive mode APPI. Meanwhile, negative mode ESI results in

detection of polar compounds such as nitroaromatics, aromatic acids, and phenols. For the BrC material examined in this study, over 40% of the solvent-extractable BrC light absorption is attributed to water insoluble, nonpolar to semipolar compounds such as PAHs and their derivatives, which require APPI for their identification. In contrast, the polar, water-soluble BrC compounds, which are detected in ESI, account for less than 30% of light absorption by BrC.



Mud volcanoes provide an accessible channel through which deep subsurface environments can be observed. The manner in which deeply sourced materials shape biogeochemical processes and microbial communities in such geological features remains largely unknown. This study characterized redox transitions, biogeochemical fluxes and microbial communities for samples collected from a methane-rich mud volcano in southwestern Taiwan. Our results indicated that oxygen penetration was confined within the upper 4 mm of fluids/muds and counteracted by the oxidation of pyrite, dissolved sulfide, methane and organic matter at various degrees. Beneath the oxic zone, anaerobic sulfur oxidation, sulfate reduction, anaerobic methanotrophy and methanogenesis were compartmentalized into different depths in the pool periphery, forming a metabolic network that efficiently cycles methane and sulfur. Community members affiliated with various Proteobacteria capable of aerobic oxidation of sulfur, methane and methyl compounds were more abundant in the anoxic zone with diminished sulfate and high methane. These findings suggest either the requirement of alternative electron acceptors or a persistent population that once flourished in the oxic zone. Overall, this study demonstrates the distribution pattern for a suite of oxidative and reductive metabolic reactions along a steep redox gradient imposed by deep fluids in a mud volcano ecosystem.



Authigenic pyrite is a common mineral in seepage areas, where it is mainly derived from sulfate-driven anaerobic oxidation of methane (SO4-AOM). However, reports on the iron isotopic composition of SO4-AOM generated pyrite are limited, and the mechanisms controlling the fractionation of iron isotopes are insufficiently understood. Here, we present new iron isotope data for pyrite and iron oxides from sediments of the Taixinan seepage and gas hydrate-bearing area (sites HD109 and GMGS2-16) and revisit published data for pyrite from the Shenhu area to unravel the impact of SO4-AOM on the iron isotope composition of pyrite. The δ56Fe values (relative to average igneous rock) of pyrite were found to vary from −0.86 to −0.56‰ for site HD109, and from −1.57 to −0.25‰ for site GMGS2-16. In contrast, the iron isotopic compositions of iron oxides from site GMGS2-16 reveal positive values throughout the core, spanning from +0.52‰ to +0.74‰. In addition, the extent of pyritization (Fepy/FeHR) of the sediment was investigated, revealing a variability between 0.01 and 0.29 for HD109, and between 0.00 and 0.36 for GMGS2-16. A previous study on the Shenhu seepage area recognized an enrichment of 56Fe in pyrite at (paleo-)sulfate-methane transition zones (SMTZ), which was regarded as a consequence of pronounced SO4-AOM. However, peaks in δ56Fepy values are not observed at (paleo-)SMTZs at sites HD109 and GMGS2-16 in this study. The negative δ56Fepy values are likely to reflect the dominance of dissimilatory iron reduction

(DIR) during diagenesis in this area. In addition, for all samples of the Taixinan and Shenhu areas, their δ56Fepy values, and the extent of pyritization, a clear positive correlation becomes apparent, where both δ56Fepy values and Fepy/FeHR ratios from the Taixinan area are lower. Hence, it can be inferred that the availability of sulfide is among the key factors that affect the iron isotopic composition of pyrite. With respect to the Taixinan area, the low degree of pyritization was apparently insufficient to alter the iron isotopic composition of the iron sources (i.e., iron oxides) to a significant degree.

Littlefair, C.A., Tank, S.E., 2018. Biodegradability of thermokarst carbon in a till-associated, glacial margin landscape: The case of the Peel Plateau, NWT, Canada. Journal of Geophysical Research: Biogeosciences 123, 3293-3307.

https://doi.org/10.1029/2018JG004461

The Peel Plateau is a characteristic glacial margin landscape, with permafrost comprised of thick, ice‐rich glacial tills deposited at the end of the Last Glacial Maximum. Unmodified tills at depth are overlain by a paleo‐active layer, created when early Holocene warming deepened regional active layers, enabling organic matter incorporation into now‐frozen soils. Ice‐rich permafrost encourages retrogressive thaw slumps, which mobilize variable proportions of modern active layer, paleo‐active layer, and Pleistocene tills to downstream systems. Here we investigate the biolability of thaw‐released dissolved organic carbon (DOC) on the Peel Plateau and compare our results to previous studies from nontill‐dominated landscapes. Similar to other Arctic regions, biolability was significantly greater for slump‐derived DOC (retrogressive thaw slump runoff) than for DOC from paired, unimpacted locations. However, runoff source was an important control on biolability. Lability was greater for slumps releasing water with a Holocene‐like δ18O signature than for slumps with a more Pleistocene‐like signature, while a small slump, with runoff δ18O similar to the modern active layer, showed no biolability increase. Similar to other Arctic regions, biolability was strongly related to DOC aromaticity and molecular weight. However, lability also increased significantly with increasing nutrients, which has not been shown universally. Previous work has shown that DOC concentration dynamics differ sharply on the Peel Plateau when compared to other permafrost thaw landscapes. This work indicates that the lability of permafrost DOC may be relatively uniform across variable Arctic regions, although some factors—such as the importance of nutrient status—may need further exploration.

Liu, H., Guo, P., Du, J., Ou, H., Wang, Z., Yang, L., Jiang, X., Wang, C., 2019. Investigating the influence of CO2 injection and reservoir cores on the phase behavior of two low-permeability crude oils: Experimental verification and thermodynamic model development. Fuel 239, 701-708.


CO2 flooding can be used to increase oil recovery and also achieve CO2 sequestration. Knowledge of the phase behavior of CO2-crude oil mixtures in reservoir cores during CO2 sequestration is important for predicting reservoir performance and future processing needs. In this work, a new experimental system for measuring the bubble point pressures of oils in low permeability reservoir cores was built. The saturation pressures and gas-oil volume ratios of two crude oil samples with different amounts of CO2 injection (13 mol%, 18 mol%, 26 mol%, 34 mol%, 41 mol%, 49 mol%) in both a PVT cell and three low permeability reservoir cores with different permeabilities (3.4 mD, 1.0 mD, 0.5 mD) were measured. The experimental results show that the dissolution of CO2 substantially increased both the saturation pressure and gas-oil volume ratio of the oils. There was only a slight decrease (ΔP ∼ 0.87 bar) of saturation pressure for the oil 1 + 13 mol% CO2 sample in the 3.4 mD core than in

the PVT cell. Increasing the amount of CO2 dissolution in the oil resulted in ΔP quickly increasing. Meanwhile, ΔP increased quickly with the decrease of the core permeability. For the oil 1 + 34 mol% CO2 sample in the 0.5 mD core, ΔP reached ∼22.85 bar. For the first time, tests showed the dissolution of CO2 substantially increased the influence of reservoir cores on the phase equilibrium of oils. A new thermodynamic model based on the PT equation of state (EOS) was further developed to describe the phase behavior of oils in both the PVT cell and reservoir cores. To model the saturation pressures of oils in reservoir cores, considering the influence of core pores on the phase behavior of oils, a new idea of adding the ratio between the molecular diameter of oil components with the mean pore diameter of the core to the α(T) function of the PT EOS was proposed. The calculated results are consistent with the experimental data.

Liu, J., An, Z., 2018. A hierarchical framework for disentangling different controls on leaf wax δDn-alkane values in terrestrial higher plants. Quaternary Science Reviews 201, 409-417.


Leaf wax δDn-alkane values have been widely utilized in terrestrial paleoenvironmental research, and numerous studies have reported that leaf wax δDn-alkane values were affected by a lot of factors. However, the current knowledge regarding the constructive relationships among these factors is still unclear. Based upon a limited compilation of available δDn-alkane records from published literature across the world, we proposed a hierarchical framework of three-level controls on leaf wax δDn-alkane values by using an Interpretive Structural Modeling (ISM). Precipitation δD, plant types and evapotranspiration are the first-level controls that serve as direct co-controls on leaf wax δDn-alkane values in higher plants, on average contributing 47 ± 22%, 20 ± 9.8% and 33%, respectively. The proportions of different controls on leaf wax δDn-alkane values vary significantly over the world, probably responsible for the across-site substantial variability of isotopic fractionation (εapp) between leaf wax δDn-alkane values and precipitation δD. Moreover, extra factors (e.g., salinity, seasonality etc.) and climate parameters (e.g., temperature, relative humidity, light intensity etc.) execute the second-level and third-level controls on leaf wax δDn-alkane values, respectively. They play indirect controls, through affecting the first-level controls, and thus are translated into leaf wax δDn-alkane values. To quantitatively disentangle these controls on leaf wax δDn-alkane values is important for better understanding the spatial-temporal variability of sedimentary δDn-alkane values.


https://doi.org/10.5194/bg-15-6329-2018

Phosphorus is often invoked as the ultimate limiting nutrient, modulating primary productivity on geological timescales. Consequently, along with nitrogen, phosphorus bioavailability exerts a fundamental control on organic carbon production, linking all the biogeochemical cycles across the Earth system. Unlike nitrogen that can be microbially fixed from an essentially infinite atmospheric reservoir, phosphorus availability is dictated by the interplay between its sources and sinks. While authigenic apatite formation has received considerable attention as the dominant sedimentary phosphorus sink, the quantitative importance of reduced iron-phosphate minerals, such as vivianite, has only recently been acknowledged, and their importance remains underexplored. Combining microscopic and spectroscopic analyses of handpicked mineral aggregates with sediment geochemical profiles, we characterize the distribution and mineralogy of iron-phosphate minerals present in methane-rich sediments recovered from the northern South China Sea. Here, we demonstrate that vivianite authigenesis is pervasive in the iron-oxide-rich sediments below the sulfate–methane

transition zone (SMTZ). We hypothesize that the downward migration of the SMTZ concentrated vivianite formation below the current SMTZ. Our observations support recent findings from non-steady-state post-glacial sedimentary successions, suggesting that iron reduction below the SMTZ, probably driven by iron-mediated anaerobic oxidation of methane (Fe-AOM), is coupled to phosphorus cycling on a much greater spatial scale than previously assumed. Calculations reveal that vivianite acts as an important burial phase for both iron and phosphorus below the SMTZ, sequestering approximately half of the total reactive iron pool. By extension, sedimentary vivianite formation could serve as a mineralogical marker of Fe-AOM, signalling low-sulfate availability against methanogenic and ferruginous backdrop. Given that similar conditions were likely present throughout vast swathes of Earth's history, it is possible that Fe-AOM and vivianite authigenesis may have modulated methane and phosphorus availability on the early Earth, as well as during later periods of expanded marine oxygen deficiency. A better understanding of vivianite authigenesis, therefore, is fundamental to test long-standing hypotheses linking climate, atmospheric chemistry and the evolution of the biosphere.



Pores with sizes ranging from nanometers to micrometers are widely distributed in shale gas and shale oil formations. These pores are the sites for hydrocarbon accumulation and provide the flow paths for hydrocarbons during production. The Middle Bakken member is the main production zone of the Bakken Formation in North Dakota. In order to reveal the pore structures of the Middle Bakken, we employed field emission scanning electron microscopy (FE-SEM). After segmentation of the SEM images, we calculated the surface area and shape of the pores using image analysis and then quantified the complexity and heterogeneity of the pore structures by applying both fractal and multifractal analyses. Finally, we employed the fractal permeability model to estimate the permeability of the samples. The results showed that different pore types, such as interparticle and intraparticle pores exist in the Middle Bakken samples. Even under the same scale of the same sample, the pore parameters could be different. Sample 2 has the largest average porosity, followed by Sample 1 and Sample 3. The mean pore size of these samples is less than 31 nm indicating that the pores in Middle Bakken samples are very small. The pore structures in the Middle Bakken exhibited fractal and multifractal behavior. The fractal dimension from the entire size range of pores is the largest compared with the fractal dimension of the subdivided groups. The pore size distribution in Sample 2 is the most heterogeneous.

Liu, L., Wang, Y., Chen, Y., Shen, B., Gao, X., 2018. Gas occurrence and accumulation characteristics of Cambrian–Ordovician shales in the Tarim Basin, northwest China. Acta Geologica Sinica - English Edition 92, 1948-1958.

https://doi.org/10.1111/1755-6724.13687

The Tarim Basin is located in northwestern China and is the biggest basin in China with huge oil and gas resources. Especially the Lower to Middle Cambrian and Middle to Upper Ordovician possess the major marine source rocks in the Tarim Basin and have large shale gas resource potential. The Cambrian–Ordovician shales were mainly deposited in basin–slope facies with thicknesses between 30–180 m. For shales buried shallower than 4500 m, there is high organic matter abundance with TOC (total organic carbon) mainly between 1.0% and 6.0%, favorable organic matter of Type I and Type II, and high thermal maturity with RoE as 1.3%–2.75%. The mineral composition of these

Cambrian–Ordovician shale samples is mainly quartz and carbonate minerals while the clay minerals content is mostly lower than 30%, because these samples include siliceous and calcareous shale and marlstone. The Cambrian and Ordovician shales are compacted with mean porosity of 4% and 3%, permeability of 0.0003×10–3–0.09×10–3 μm2 and 0.0002×10–3–0.11×10–3 μm2, and density of 2.30 g/m3

and 2.55 g/m3, respectively. The pores in the shale samples show good connectivity and are mainly mesopore in size. Different genetic types of pores can be observed such as intercrystal, intergranular, dissolved, organic matter and shrinkage joint. The reservoir bed properties are controlled by mineral composition and diagenesis. The maximum adsorption amount to methane of these shales is 1.15–7.36 cm3/g, with main affecting factors being organic matter abundance, porosity and thermal maturity. The accumulation characteristics of natural gas within these shales are jointly controlled by sedimentation, diagenesis, hydrocarbon generation conditions, reservoir bed properties and the occurrence process of natural gas. The natural gas underwent short‐distance migration and accumulation, in‐place accumulation in the early stage, and adjustment and modification in the later stage. Finally, the Yulin (well Y1) and Tazhong (well T1) areas are identified as the targets for shale gas exploration in the Tarim Basin.

Liu, M., Chen, D., Zhou, X., Yuan, W., Jiang, M., Liu, L., 2019. Climatic and oceanic changes during the Middle-Late Ordovician transition in the Tarim Basin, NW China and implications for the Great Ordovician Biodiversification Event. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 522-535.


The Middle-Late Ordovician transition (Darriwilian to Sandbian Age) witnessed a major pulse of the Great Ordovician Biodiversification Event (GOBE) and distinctive oceanic geochemical fluctuations, such as coeval negative C and Sr isotope excursions. In this study, investigations into geochemical variations, notably the Hg abundance (or Hg/TOC), have been carried upon the organic-rich black shale of the Middle-Upper Ordovician Saergan Formation to unravel the causes of this pulse. Based on these data, three phases were identified. Phase 1 (0 to 3 m) is characterized by rising Hg/TOC (up to 138 ppb/wt%) and Ti/Al values as well as high CIAcorr (corrected chemical index of alteration) values (68.9–72.3) with negligible enrichment of redox sensitive elements (RSE) and nutrient elements (e.g. U ≤ 5.2 ppm, V ≤ 153 ppm, Mo ≤ 1.8 ppm, P2O5 ≤ 0.2%), suggesting intensified volcanism, which could have emitted significant amounts of greenhouse gases, thereby leading to climate warming. In contrast, Phase 2 (3 to 11 m) is characterized by decreasing Hg/TOC and Ti/Al ratios, relatively low though slightly fluctuating CIAcorr values, generally depleted in RSE (except moderately enriched U up to 14.6 ppm) and increased P/Al and Ba/Al ratios, implying weakening volcanic activity and subsequent climate cooling and the potential for improved seawater ventilation as a result of oceanic upwelling. Phase 3 (Sandbian Age: 11–13 m) witnessed continuous decrease in Hg/TOC ratio, an increase in Ti/Al and CIAcorr values, fairly low values of RSE enrichment and P/Al and Ba/Al ratios, indicating recurrent climate warming, and the potential for slowed oceanic circulation and attenuated upwelling of nutrient-rich deep waters onto the shallow shelf. These changes could have diminished bioproductivity and organic output onto the seafloor. This study offers insights into volcanic-climatic-oceanic interactions during a major pulse of the GOBE around the Middle-Late Ordovician transition while black shales were extensively deposited.

Liu, Q., Guo, X., Yin, Z., Zhou, K., Roberts, E.G., Dai, M., 2018. Carbon fluxes in the China Seas: An overview and perspective. Science China Earth Sciences 61, 1564-1582.

https://doi.org/10.1007/s11430-017-9267-4

This paper aims to provide an overview of regional carbon fluxes and budgets in the marginal seas adjacent to China. The “China Seas” includes primarily the South China Sea, East China Sea, Yellow Sea, and the Bohai Sea. Emphasis is given to CO2 fluxes across the air-sea interface and their controls. The net flux of CO2 degassing from the China Seas is estimated to be 9.5±53 Tg C yr−1. The total riverine carbon flux through estuaries to the China Seas is estimated as 59.6±6.4 Tg C yr−1. Chinese estuaries annually emit 0.74±0.02 Tg C as CO2 to the atmosphere. Additionally, there is a very large net carbon influx from the Western Pacific to the China Seas, amounting to ∼2.5 Pg C yr−1. As a first-order estimate, the total export flux of particulate organic carbon from the upper ocean of the China Seas is 240±80 Tg C yr−1. This review also attempts to examine current knowledge gaps to promote a better understanding of the carbon cycle in this important region.

Liu, Q., Kämpf, H., Bussert, R., Krauze, P., Horn, F., Nickschick, T., Plessen, B., Wagner, D., Alawi, M., 2018. Influence of CO2 degassing on the microbial community in a dry mofette field in Hartoušov, Czech Republic (Western Eger Rift). Frontiers in Microbiology 9, 2787. doi: 10.3389/fmicb.2018.02787.


The Cheb Basin (CZ) is a shallow Neogene intracontinental basin filled with fluvial and lacustrine sediments that is located in the western part of the Eger Rift. The basin is situated in a seismically active area and is characterized by diffuse degassing of mantle-derived CO2 in mofette fields. The Hartoušov mofette field shows a daily CO2 flux of 23–97 tons of CO2 released over an area of 0.35 km2 and a soil gas concentration of up to 100% CO2. The present study aims to explore the geo–bio interactions provoked by the influence of elevated CO2 concentrations on the geochemistry and microbial community of soils and sediments. To sample the strata, two 3-m cores were recovered. One core stems from the center of the degassing structure, whereas the other core was taken 8 m from the ENE and served as an undisturbed reference site. The sites were compared regarding their geochemical features, microbial abundances, and microbial community structures. The mofette site is characterized by a low pH and high TOC/sulfate contents. Striking differences in the microbial community highlight the substantial impact of elevated CO2 concentrations and their associated side effects on microbial processes. The abundance of microbes did not show a typical decrease with depth, indicating that the uprising CO2-rich fluid provides sufficient substrate for chemolithoautotrophic anaerobic microorganisms. Illumina MiSeq sequencing of the 16S rRNA genes and multivariate statistics reveals that the pH strongly influences microbial composition and explains around 38.7% of the variance at the mofette site and 22.4% of the variance between the mofette site and the undisturbed reference site. Accordingly, acidophilic microorganisms (e.g., OTUs assigned to Acidobacteriaceae and Acidithiobacillus) displayed a much higher relative abundance at the mofette site than at the reference site. The microbial community at the mofette site is characterized by a high relative abundance of methanogens and taxa involved in sulfur cycling. The present study provides intriguing insights into microbial life and geo–bio interactions in an active seismic region dominated by emanating mantle-derived CO2-rich fluids, and thereby builds the basis for further studies, e.g., focusing on the functional repertoire of the communities. However, it remains open if the observed patterns can be generalized for different time-points or sites.

Liu, S., Sang, S., Wang, T., Du, Y., Jia, J., Fang, H., 2018. The effects of CO2 on organic groups in bituminous coal and high-rank coal via Fourier transform infrared spectroscopy. Energy Exploration & Exploitation 36, 1566-1592.

https://doi.org/10.1177/0144598718764752

The interactions between supercritical CO2 and coal and their effects on changes in the coal pore structure and organic groups play a critical role in the CO2 geological storage-enhanced coalbed methane recovery. To investigate the effects of supercritical CO2 on organic groups in coals of different ranks and its mechanisms under different temperature and pressure conditions, CO2 sequestration processes in bituminous coals and high-rank coals were replicated using a high-pressure reactor. Four coal samples of different ranks were exposed to supercritical CO2 and water under three temperatures and pressures for 240 h. Fourier transform infrared spectroscopy was used to provide semiquantitative ratios and Fourier transform infrared spectra of coal samples before and after the supercritical CO2–H2O treatment. The results show that interactions between supercritical CO2 and coal were controlled by the coal macromolecular structure, and semianthracite is the inflection point of interaction characteristics for coal samples of different ranks. Bituminous coal, including high- and low-volatility bituminous coal, has a low degree of condensation of its aromatic structure, and its aromatic nuclei can facilitate addition reactions. Swellings primarily break cross-links between aromatic nuclei in the same aromatic layer. These characteristics favor the polymerization addition of aliphatic side chains of aromatic nuclei, causing an increase in the degree of condensation of the aromatic structures in bituminous coal. High-rank coals including semianthracite and anthracite have a high degree of condensation of their aromatic structures, and the aromatic nuclei favor substitution reactions. Swellings primarily break cross-links connecting different aromatic layers, and bond dissociation reactions and sulfuration reactions are more significant for high-rank coal. These characteristics cause a decrease in the degree of condensation of the aromatic structure in high-rank coal. Temperature and pressure have a great impact on interactions between supercritical CO2 and coal and are controlled by the reaction types of the organic groups. With the increase in experimental temperature and pressure, the changes in the organic group content can be classified as the descending type, the rising type, the lower opening parabola type, and the upper opening parabola type. 45.0°C and 10 MPa is the inflection point of the changes in the organic group content. Descending- and rising-type changes favor addition, bond dissociation, and sulfuration reactions, which are endothermic. The reaction rate of supercritical CO2 and the organic groups increases, and the effects caused by temperature and pressure decrease as the temperature and pressure increase. Lower opening parabola- and upper opening parabola-type changes favor substitution, oxidation, and addition polymerization reactions, which are exothermic. These changes were significantly affected by a variety of reactions and were suppressed by high temperature and pressure. When the temperature is ≤45.0°C and the pressure is ≤10 MPa, supercritical CO2 has remarkable effects on alkyl and hydroxy groups and has a stronger effect on bituminous coal. When the temperature is >45.0°C and the pressure is >10 MPa, supercritical CO2 has remarkable effects on oxygen- and sulfur-containing groups and has a greater effect on high-rank coals.

Liu, Y.-M., Dong, Y., Rui, Z.-H., Lu, X.-S., Zhou, X.-M., Wei, L.-C., 2018. Origin, migration, and accumulation of carbon dioxide in the East Changde Gas Field, Songliao Basin, northeastern China. Petroleum Science 15, 695-708.

https://doi.org/10.1007/s12182-018-0259-5

CO2 reservoirs are widely distributed within the Yingcheng Formation in the Songliao Basin, but the extreme horizontal heterogeneity of CO2 content causes difficulties in the exploration and exploitation of methane. Former studies have fully covered the lithology, structure, and distribution of the reservoirs high in CO2 content, but few are reported about migration and accumulation of CO2. Using the East Changde Gas Field as an example, we studied the accumulation mechanisms of CO2 gas. Two original types of accumulation model are proposed in this study. The fault-controlled accumulation model refers to gas accumulation in the reservoir body that is cut by a basement fault (the West Xu Fault), allowing the hydrocarbon gas generated in the lower formation to migrate into

the reservoir body through the fault, which results in a relatively lower CO2 content. The volcanic conduit-controlled accumulation model refers to a reservoir body that is not cut by the basement fault, which prevents the hydrocarbon gas from being mixed in and leads to higher CO2 contents. This conclusion provides useful theories for prediction of CO2 distribution in similar basins and reservoirs.

Liu, Y., Kaszuba, J., Oakey, J., 2019. Microfluidic investigations of crude oil-brine interface elasticity modifications via brine chemistry to enhance oil recovery. Fuel 239, 338-346.


Waterflooding has been widely adopted as an improved oil recovery technique since water is, in general, inexpensive and readily available. More recently, low salinity waterflooding (LSW) has been applied to oil production. LSW has successfully demonstrated higher recovery efficiencies than conventional water flooding, yet the underlying mechanism is still quite unclear. Extensive research has focused upon rock-fluid interactions under low salinity conditions, however very little work has considered interactions between oil and brine and how fluid-fluid interfacial properties are influenced by brine salinity and composition. To fill this gap, we have developed a microfluidic device for multiphase interfacial testing with length scales comparable to the pore scale of oil reservoir rocks. Unlike conventional core flooding tests, fluid-fluid phenomena can be easily visualized within microfluidic devices via optical microscopy. Oil snap-off, a phenomenon that represents a major dispersion mechanism, occurs when crude oil flows through porous media in the reservoir and induces trapping hysteresis, can be investigated within a well-controlled microfluidic flow-focusing geometry. The size of formed droplets is examined as a measure of the resistance to snap-off. It has been previously demonstrated that snap-off events are influenced by brine chemistry, oil composition, and the interaction time between crude oil and brine. Here, we show that asphaltenes in the oil phase contribute directly to the development of the elasticitic film. We also propose the reduction of interfacial elasticity by other polar components, such as naphthenic acids, which counteract asphaltene behavior over different time scales. The contribution of these effects on interfacial elasticity is shown to be mediated by both the composition and concentration of brine and oil.

Liu, Y., Liu, J., Yao, P., Ge, T., Qiao, Y., Zhao, M., Zhang, X.-H., 2018. Distribution patterns of ammonia-oxidizing archaea and bacteria in sediments of the eastern China marginal seas. Systematic and Applied Microbiology 41, 658-668.


Ammonia-oxidizing archaea (AOA) and bacteria (AOB) vary in their contribution to nitrification in different environments. The eastern China marginal seas (ECMS) are featured by complex river runoffs and ocean currents, forming different sediment patches. Here, via quantitative PCR and clone library analysis of the amoA genes, we showed that AOB were more abundant than AOA in ECMS sediments. The abundance, diversity and richness of AOA, but not AOB, were higher in the East China Sea (ECS) than in the Yellow Sea (YS) and Bohai Sea (BS). Nitrosopumilus (AOA) and Nitrosospira (AOB) were predominant lineages, but their abundances varied significantly between ECS, and BS and YS. This was mainly attributed to salinity and dissolved oxygen of the bottom water. The discovery of a high abundance of Nitrosophaera at estuarine sites suggested strong terrigenous influence exerted on the AOA community. In contrast, variations in ocean conditions played more important roles in structuring the AOB community, which was separated by bottom water dissolved oxygen into two groups: the south YS, and the north YS and BS. This study provides a comprehensive insight into the spatial distribution pattern of ammonia-oxidizing prokaryotes in ECMS sediments, laying a foundation for understanding their relative roles in nitrification.

Liu, Y., Tang, D., Xu, H., Tao, S., Li, S., 2019. Quantitative characterization of middle-high ranked coal reservoirs in the Hancheng Block, eastern margin, Ordos Basin, China: implications for permeability evolution with the coal macrolithotypes. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 201-215.

https://doi.org/10.1080/15567036.2018.1512684

Macrolithotypes control the pore-fracture distribution heterogeneity in coal impacting the coalbed methane (CBM) production from the reservoir. However, few studies have focused on the characteristics of macrolithotypes. Here, the macrolithotype samples from the three continuous seams (No. 3, 5 and 11) in the Hancheng Block, Ordos Basin, China were quantitatively characterized by multiple length scales. The results indicate that the bright coal has the best development of micro-fracture than those of the other macrolithotypes, which with good openness and connectivity under the optical microscopy; N2 adsorption/desorption results reflect that the adsorption pores of the semi-dull and dull coal are more developed than the bright coal and semi-bright coal, and are dominated by plate-like and ink-bottle pores. The characteristics of the mercury intrusion/extrusion curves were determined by the mercury injection (MIP). From bright to dull coal the pore connectivity being worse, and the uniformity of pore and throats distribution becomes lower. The pore type that divided by NMR are recovered to be seepage type (the bright), comprehensive type (the semi-bright and semi-dull), and the type of adsorption (the dull). The behavioral differences would impact the porosity and permeability in coal. Thus, by the well logging evaluation approach, the relationship between coal macrolithotypes and select logging parameters were determined for coal macrolithotype identification, and with the petrel software included, the porosity-permeability models were built to investigate the permeability evolution with the coal macrolithotypes. Macrolithotypes are closely related to the permeability of coal reservoirs in this area. The greater contribution of permeability is typically from of the bright and semi-bright coal, and followed by semi-dull and dull coal, the better development of bright coal, the better permeability of the reservoir and vice versa.



In order to investigate pore characteristics and formation mechanism in the high-maturity organic-rich shale of Lower Cambrian Jiumenchong Formation in southern Guizhou, the pore structure, pore type and storage properties are well studied through the rock thin section, total rock X-ray diffraction, low-temperature nitrogen adsorption, high pressure mercury injection-adsorption test, helium porosity test, argon ion polishing-scanning electron microscope, thermal evolution and pore evolution history reconstruction, and based on the diagenesis and compaction as well as thermal evolution process, a microscopic pore formation and evolution model of high-maturity organic-rich shale are established. The result shows that the high-maturity organic-rich shale of Jiumenchong Formation has the average total specific surface area of 12.66 m2/g and the total pore volume of 11.54 × 10−3 cm3/g, and the total specific surface area have a positive correlation with total pore volume; the total specific surface area and the total pore volume are slightly lower compared with the Lower Silurian shale. The pores are dominated by micropores and mesopores, while macropores are very rare. The pores of the organic-rich shale mainly are organic pores with small diameter usually less than 30 nm, and the pore boundary form is irregular, the inorganic mineral pores are not developed. Compared with the Silurian shale, the shale has poorer reservoir property, the average porosity is only 2.80%; the

horizontal permeability is 1–3 times of the vertical permeability, indicating the horizontal lamellations are not developed. The formation and evolution of pores in high-maturity organic-rich shale is jointly influenced by the evolutionary process of intergranular pores of inorganic mineral under the control of the diagenesis and compaction, the organic pore formation process in the hydrocarbon generation-oil formation-oil and gas transformation sequence under the control of thermal evolution, and the natural gas loss-supply equilibration process under the condition of later pore preservation.

Lloyd, K.G., Steen, A.D., Ladau, J., Yin, J., Crosby, L., 2018. Phylogenetically novel uncultured microbial cells dominate Earth microbiomes. mSystems 3, Article e00055-18.


Abstract: To describe a microbe’s physiology, including its metabolism, environmental roles, and growth characteristics, it must be grown in a laboratory culture. Unfortunately, many phylogenetically novel groups have never been cultured, so their physiologies have only been inferred from genomics and environmental characteristics. Although the diversity, or number of different taxonomic groups, of uncultured clades has been studied well, their global abundances, or numbers of cells in any given environment, have not been assessed. We quantified the degree of similarity of 16S rRNA gene sequences from diverse environments in publicly available metagenome and metatranscriptome databases, which we show have far less of the culture bias present in primer-amplified 16S rRNA gene surveys, to those of their nearest cultured relatives. Whether normalized to scaffold read depths or not, the highest abundances of metagenomic 16S rRNA gene sequences belong to phylogenetically novel uncultured groups in seawater, freshwater, terrestrial subsurface, soil, hypersaline environments, marine sediment, hot springs, hydrothermal vents, nonhuman hosts, snow, and bioreactors (22% to 87% uncultured genera to classes and 0% to 64% uncultured phyla). The exceptions were human and human-associated environments, which were dominated by cultured genera (45% to 97%). We estimate that uncultured genera and phyla could comprise 7.3 × 1029 (81%) and 2.2 × 1029 (25%) of microbial cells, respectively. Uncultured phyla were overrepresented in metatranscriptomes relative to metagenomes (46% to 84% of sequences in a given environment), suggesting that they are viable. Therefore, uncultured microbes, often from deeply phylogenetically divergent groups, dominate nonhuman environments on Earth, and their undiscovered physiologies may matter for Earth systems.

Importance: In the past few decades, it has become apparent that most of the microbial diversity on Earth has never been characterized in laboratory cultures. We show that these unknown microbes, sometimes called “microbial dark matter,” are numerically dominant in all major environments on Earth, with the exception of the human body, where most of the microbes have been cultured. We also estimate that about one-quarter of the population of microbial cells on Earth belong to phyla with no cultured relatives, suggesting that these never-before-studied organisms may be important for ecosystem functions.

Long, D.G.F., 2019. Archean fluvial deposits: A review. Earth-Science Reviews 188, 148-175.


The recognition of Archean fluvial deposits is complicated in many cases by post depositional deformation and metamorphism. Most surviving deposits can be categorized as deposits of alluvial fans with and without debris flows, and sand and gravel-bed braided rivers. Examples of possible intermediate to high sinuosity meandering systems have been tentatively identified in Africa,

Australia and India: all lack clear evidence of lateral migration and can be reinterpreted in terms of esturine deposition, shallow tide-influenced marine, and deep-water mass-flow deposits respectively. Mudstone intervals in Archean fluvial strata are rare, and where present, are typically of silt grade. These may represent ponds developed within channel thalwegs, or where more extensive may be of lacustrine rather than floodplain origin. Prior to 3.2 Ga preserved fluvial deposits appear to be largely confined to the flanks of volcanic cones or plateau, perhaps reflecting globally high sea level combined with the small-scale of cratonic nuclei. The onset of modern style plate tectonics in the early Mesoarchean allowed for more extensive generation and preservation of fluvial strata: most of these are first cycle deposits, preserved in rift, strike-slip, and foreland basins, with rare examples accumulating in forearc and syn-tectonic piggy-back basins.

Lopez-Fernandez, M., Åström, M., Bertilsson, S., Dopson, M., 2018. Depth and dissolved organic carbon shape microbial communities in surface influenced but not ancient saline terrestrial aquifers. Frontiers in Microbiology 9, 2880. doi: 10.3389/fmicb.2018.02880.


The continental deep biosphere is suggested to contain a substantial fraction of the earth’s total biomass and microorganisms inhabiting this environment likely have a substantial impact on biogeochemical cycles. However, the deep microbial community is still largely unknown and can be influenced by parameters such as temperature, pressure, water residence times, and chemistry of the waters. In this study, twenty-one boreholes representing a range of deep continental groundwaters from the Äspö Hard Rock Laboratory were subjected to high throughput 16S rRNA gene sequencing to characterize how the different water types influence the microbial communities. Geochemical parameters showed the stability of the waters and allowed their classification into three groups. These were (i) waters influenced by infiltration from the Baltic Sea with a ‘modern marine’ signature, (ii) a ‘thoroughly mixed’ water containing groundwaters of several origins, and (iii) deep ‘old saline’ waters. Decreasing microbial cell numbers positively correlated with depth. In addition, there was a stronger positive correlation between increased cell numbers and dissolved organic carbon for the modern marine compared to the old saline waters. This supported that the modern marine waters depend on organic carbon infiltration from the Baltic Sea while the ancient saline waters were fed by ‘geogases’ such as carbon dioxide and hydrogen. The 16S rRNA gene relative abundance of the studied groundwaters revealed different microbial community compositions. Interestingly, the thoroughly mixed water showed the highest dissimilarity compared to the other two water types, potentially due to the several contrasting water types contributing to this groundwater. The main identified microbial phyla in the groundwaters were Gammaproteobacteria, unclassified sequences, Campylobacterota (formerly Epsilonproteobacteria), Patescibacteria, Deltaproteobacteria, and Alphaproteobacteria. Many of these taxa are suggested to mediate ferric iron and nitrate reduction, especially in the modern marine waters. This indicated that nitrate reduction may be a neglected but important process in the deep continental biosphere. In addition to the high number of unclassified sequences, almost 50% of the identified phyla were archaeal or bacterial candidate phyla. The percentage of unknown and candidate phyla increased with depth, pointing to the importance and necessity of further studies to characterize deep biosphere microbial populations.

López-López, J.A., Mendiguchía, C., Pinto, J.J., Moreno, C., 2019. Application of solvent-bar micro-extraction for the determination of organic and inorganic compounds. TrAC Trends in Analytical Chemistry 110, 57-65.


Solvent bar micro-extraction (SBME) was introduced to improve some aspects of hollow fiber liquid phase micro-extraction. It has rapidly evolved and gained increasing interest. In SBME the fiber can be left freely tumbling in the sample during extraction. Consequently, the procedure is simplified, portability of the micro-extraction system is improved and mass transfer from the sample to the fiber lumen is enhanced, reducing extraction times and allowing the simultaneous extraction of several samples. We present an overview on the evolution and applications of SBME for sample preparation. It has been applied in the analysis of polar and non-polar organic compounds in water, slurry, food, and biological samples. In the case of inorganic analysis, main applications have been directed to their determination and speciation in plants and marine water samples. In conclusion, SBME is a simple, accurate and affordable methodology for sample preparation in environmental, medical and food analytical chemistry.

Lotfiyar, A., Chehrazi, A., Swennen, R., Ghasemi Siani, M., 2018. Geochemical, geological, and petrophysical evaluation of Garau Formation in Lurestan basin (west of Iran) as a shale gas prospect. Arabian Journal of Geosciences 11, 653.

https://doi.org/10.1007/s12517-018-3954-z

The Garau Formation in western Iran is a potential shale gas play. To evaluate its gas potential, a geochemical, geological, and petrophysical study was conducted on samples from the Baba Ghir 1 well drilled in Lurestan District (W Iran). Organic matter analysis of Garau Formation shows that total organic carbon (TOC) ranges between 0.42 and 2.43 wt% and this formation possesses kerogen type III with a high degree of maturity, reflecting gas window conditions. Mineralogical analyses show that the lithology of Garau Formation in this well is carbonate-dominated and the clay mineral content is less than 4%, and displays several characteristics that are similar to the Eagle Ford shale. Based on the relationship among quartz, carbonate, and clay minerals, the brittleness index is about 25%, a value of importance to select the best stimulation fluid. Petrophysical evaluation shows a porosity of about 5–15%. Estimation of the amount of free gas reserves possesses a good correlation with the reserves that were estimated based on petrophysical interpretation. Because of absence of underground contour maps, calculation of adsorbed gas volumes was not possible but estimates of gas storage capacity (GC) shows an increase with depth. All data indicate that the Garau Formation can be considered as a promising gas shale play.

Loydell, D.K., Large, R.R., 2019. Biotic, geochemical and environmental changes through the early Sheinwoodian (Wenlock, Silurian) carbon isotope excursion (ESCIE), Buttington Quarry, Wales. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 305-325.


Palaeontological, sedimentological and geochemical data (particularly from LA-ICPMS analyses of pyrite) from a 12.4 m section through the lower Sheinwoodian Trewern Brook Mudstone Formation of Buttington Quarry, Wales are combined to reveal the environmental changes taking place during the early Wenlock Epoch of the Silurian, during the early part of the ESCIE (early Sheinwoodian carbon isotope excursion). The uppermost Cyrtograptus murchisoni through to lower Monograptus riccartonensis biozones show increased nutrient levels and peaks in palynomorph and graptolite abundance. At this time graptolite diversity globally was declining dramatically, possibly associated with metal (particularly zinc) concentrations attaining toxic levels and probably with the base of the euphotic zone being higher in the water column (resulting from blooms of phytoplankton) causing those graptolites that specialized in feeding on phytoplankton that were outcompeted in this diminished volume of illuminated surface waters to decline in numbers and eventually become

extinct. Correlation of the graptolite and conodont biozonations enables the levels of the main stratigraphically higher Ireviken Event Datum Points to be proposed for the Buttington section and this in turn allows events recognised elsewhere (intervals of malformed palynomorphs and re-organization of polychaete faunas, together with an oceanic anoxic event) to be correlated with the lower part of the studied Buttington section. The commencement of the OAE, identified on Gotland at Ireviken Event Datum Point 4, appears to correlate rather well with a rapid transition, marking the top of the Butterley Mudstone Member at Buttington, from heavily bioturbated mudstones to laminated graptolitic mudstones. Surprisingly, the most rapid change in δ13Ccarb values within the Buttington section (from 0.6‰ at 8.19–8.25 m to 2.09‰ at 8.50–8.55 m) is not associated with any major faunal, palynological abundance or geochemical changes – these are all coincident with the initial rise in δ13Ccarb values, up to about the 5 m level in the Buttington section. Another unexplained feature of the graptolite record is a sudden change from Monograptus-dominated to Pristiograptus-dominated assemblages about half way through the studied section.

Lu, H., Wang, W., Li, F., Zhu, L., 2019. Mixed-surfactant-enhanced phytoremediation of PAHs in soil: Bioavailability of PAHs and responses of microbial community structure. Science of The Total Environment 653, 658-666.


The present study was conducted to explore the mechanisms of surfactant-enhanced phytoremediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs), focusing on the bioavailability of PAHs and microbial diversity. We investigated the remediation efficiencies of phenanthrene and pyrene after the addition of mixed surfactants (sodium dodecyl benzene sulfonate (SDBS) and Tween 80) of different ratios (1:1, 1:2, and 2:1) at the concentration of 100 mg/kg to soils cultured with ryegrass (Lolium multiflorum L.). The fractions of phenanthrene and pyrene were determined using a sequential extraction method, and the microbial diversity was evaluated using 16S rRNA gene high-throughput sequencing. The results showed that mixed surfactants could enhance the remediation efficiencies of PAHs, and mainly occurred in the initial 21 days. Mixed surfactants at the ratio of 1:1 (HM1) showed the best remediation efficiency in enhancing the dissipation of pyrene in 21 days. Mixed surfactants showed little effects on the removal of phenanthrene. In general, HM1 significantly decreased the bioavailable, bound and residual fractions of pyrene; additionally, higher abundances of PAH-degradation bacteria and degradation-related genes were observed. Pearson correlation analysis among PAH degraders, degradation-related genes and bioavailable fraction of PAHs was performed. Our results indicated that mixed surfactants could promote the transformation of pyrene from the bound and residual fractions to bioavailable fractions and enhance the abundances of PAH degradation bacteria and PAH degradation-related genes, thereby enhancing the degradation of pyrene.


https://doi.org/10.1007/s11430-017-9180-y

The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump (BP) and the microbial carbon pump (MCP); the latter is scarcely simulated and quantified in the China seas. In this study, we developed a coupled physical-ecosystem model with major MCP processes in the South China Sea (SCS). The model estimated a SCS-averaged MCP rate of 1.55 mg C m−2 d−1, with an MCP-to-BP ratio of 1:6.08 when considering the BP at a depth of 1000 m. Moreover, the ecosystem responses were projected in two representative global warming scenarios

where the sea surface temperature increased by 2 and 4°C. The projection suggested a declined productivity associated with the increased near-surface stratification and decreased nutrient supply, which leads to a reduction in diatom biomass and consequently the suppression of the BP. However, the relative ratio of picophytoplankton increased, inducing a higher microbial activity and a nonlinear response of MCP to the increase in temperature. On average, the ratio of MCP-to-BP at a 1000-m depth increased to 1:5.95 with surface warming of 4°C, indicating the higher impact of MCP in future ocean carbon sequestration.

Lu, Z., Chen, S., He, Q., Li, Y., Zhang, J., Wu, Q., 2018. Relationship between methylphenanthrene distribution and organic matter maturity: a case study of Yangchang Formation Chang 7 source rocks, Erdos Basin, China. Petroleum Science and Technology 36, 1718-1724.

https://doi.org/10.1080/10916466.2018.1506808

The methylphenanthrene component of Chang 7 source rocks in the Ordos Basin was analyzed using gas chromatograph-mass method. The relationship between methylphenanthrene index (MPI), methylphenanthrene distribution fraction (MPDF) and vitrinite reflectance (Ro) was established. The comparative analysis results showed that the MPDF and Ro were positively correlated and the correlation coefficient was high. Therefore, it was more accurate that the Chang 7 source rocks were determined by MPDF. Based on the established relational expression, the maturity of Chang 7 lacustrine source rocks in the Ordos Basin was calculated. The obtained results were consistent with actual geological background.

Luo, M., Algeo, T.J., Tong, H., Gieskes, J., Chen, L., Shi, X., Chen, D., 2018. More reducing bottom-water redox conditions during the Last Glacial Maximum in the southern Challenger Deep (Mariana Trench, western Pacific) driven by enhanced productivity. Deep Sea Research Part II: Topical Studies in Oceanography 155, 70-82.


The modern southern Mariana Trench is characterized by oligotrophic surface waters, resulting in low primary productivity and well-oxygenated bottom waters. This study investigates changes in the redox conditions of bottom waters in the southern Mariana Trench during the Last Glacial Maximum (LGM) and their potential causes. We measured major, trace, and rare earth elements (REE) in three gravity cores (GC03, GC04, and GC05) and one box core (BC11) retrieved from the southern Challenger Deep at water depths from 5289 to 7118 m. The upper sediment layers of both GC05 and BC11 are dominated by valve fragments of the giant diatom Ethmodiscus rex, forming laminated diatom mats (LDMs). 14C-AMS dates of bulk organic matter show that the LDMs accumulated between 18.4 and 21.8 kyr B.P., corresponding to the LGM. Modest enrichments of U and Mo along with weak or absent Ce anomalies in the LDM point to suboxic conditions during the LGM. In contrast, non-LDM samples exhibit little to no enrichment of redox-sensitive elements as well as negative Ce anomalies, indicating deposition under oxic bottom-water conditions. The Ce anomalies are considered valid proxies for bottom-water redox conditions because REE signatures were acquired in the early diagenetic environment, as indicated by strong P-REE correlations and middle-REE enrichment associated with early diagenetic cycling of Fe-Mn oxyhydroxides in the sediment column followed by capture of the REE signal by biogenic and/or authigenic apatite. We postulate that the more reducing bottom-water conditions during the LGM were linked to increased primary productivity induced by enhanced Asian dust input. As shown in earlier studies, the increased primary productivity associated with Ethmodiscus rex blooms in the eastern Philippine Sea played a significant role in capturing atmospheric CO2 during the LGM. Consequently, the magnitude of

atmospheric CO2 sequestration by giant diatom blooms during the LGM may have been greater than previously envisaged.

Luo, S., Lutkenhaus, J.L., Nasrabadi, H., 2018. Multiscale fluid-phase-behavior simulation in shale reservoirs using a pore-size-dependent equation of state. SPE Reservoir Evaluation & Engineering 21, 806-820.

https://doi.org/10.2118/187422-PA

The phase behavior of reservoir fluids plays a fundamental role in predicting well performance and ultimate recovery. The uncertainty in phase behavior is currently one of the greatest challenges in developing unconventional shale resources. The complex phase behavior is attributed to the broad range of pore sizes in shale. In macroscale geometries such as fractures and macropores, the fluid behavior is bulk-like; in nanoscale pores, the fluid behavior is significantly altered by confinement effects. The overall phase behavior of fluids in porous media of mixed pore sizes is yet to be understood.

In this paper, we present a study on the effect of pore-size distribution on the phase behavior of shale-reservoir fluids in a multiscale-pore system. The global fluid-phase equilibria among different sizes of pores are simulated. A pore-size-dependent equation of state (EOS) is used to describe the fluid by the confining pore diameter. The EOS confinement parameters for fluid/pore-wall surface interaction are determined by experimental results from differential-scanning calorimetry (DSC) and isothermal adsorption of species C1–14. The multiscale phase equilibria are simulated by directly minimizing the total Helmholtz free energy. A modified Eagle Ford oil is used for the case study. Constant-composition expansions (CCEs) of dual-scale (bulk and 15 nm) and triple-scale (bulk, 15 nm, and 5 nm) systems are simulated. The first bubble emerges from the bulk region at a lightly suppressed “apparent” bubblepoint pressure. Below the bubblepoint, the liquid saturation in the bulk region drops sharply, but the fluids in the nanopores are undersaturated throughout the multistage expansions. In the end, large amounts of intermediate-to-heavy hydrocarbons are retained in nanopores, implying a significant oil-recovery loss in shale. The confinement effect also leads to near-critical phase behavior in small-scale nanopores (<5 nm).

Lupien, R.L., Russell, J.M., Feibel, C., Beck, C., Castãneda, I., Deino, A., Cohen, A.S., 2018. Reply to comments by Nutz and Schuster (2018) on “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya”. Quaternary Science Reviews 201, 508-510.


Reply to: Alexis Nutz, Mathieu Schuster, Comments on: “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya” by Lupien et al. [Quat. Sci. Rev. 186 (2018), 225–235]. Quaternary Science Reviews 201, 505-507.

Original Article: R.L. Lupien, J.M. Russell, C. Feibel, C. Beck, I. Castañeda, A. Deino, A.S. Cohen. A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya. Quaternary Science Reviews 186, 225-235.

We thank Nutz and Schuster (2018) for their constructive comments on our publication, Lupien et al. (2018), and for pointing out their 2017 paper, Orbitally-driven evolution of Lake Turkana (Turkana Depression, Kenya, EARS) between 1.95 and 1.72 Ma: A sequence stratigraphy perspective (Nutz et al., 2017), of which we were not aware at the time of our publication. We fully agree with the authors that comparisons between outcrops and drill cores provide valuable insight into paleohydroclimatic

conditions and paleoenvironments. We note that the two records exhibit substantial agreement (Nutz et al., 2017), but also disagreement, and at times Nutz and Schuster (2018) misinterpret our interpretations of paleoclimate in the Turkana Basin.

Nutz et al. (2017) present sedimentary facies and sequence stratigraphic reconstructions of Turkana water levels between 1.95 and 1.72 Ma from outcrops. Much of their record overlaps with our paleoclimate reconstruction based upon δDwax measurements from a drill core from West Turkana (WTK13) spanning ∼1.87 to ∼1.4 Ma. In comparing these records one must remember that each proxy senses different aspects of hydroclimate: δDwax is generally interpreted to reflect variations in precipitation amount in East Africa (Caley et al., 2018; Feakins, 2013; Levin et al., 2009; Liddy et al., 2016; Schefuß et al., 2005, 2011; Tierney & deMenocal, 2013, Tierney et al., 2017; Tierney et al., 2008), and records a variety of atmospheric processes associated with rainfall and the water cycle (Dansgaard, 1964; Rozanski et al., 1993; Tierney et al., 2008; Vuille et al., 2005b). Lake levels are also sensitive to precipitation amount, and can additionally reflect tectonically-driven changes in basin configuration, subsidence, sill depth, and other processes that can modify the relationship between lake levels and rainfall. Modern observations indicate that changes in the δD of precipitation, which is the principal control on δDwax, exhibit a fairly linear relationship with precipitation amount over relatively large precipitation gradients (Rozanski et al., 1993; Vuille et al., 2005a), whereas lake levels and sedimentary facies often do not (Lepre, 2014). For instance, lake levels cannot rise above basin sill depth despite increasing precipitation amount. Additionally, lake level can be controlled by upstream (and downstream) complexities in hydrology (i.e. drainage diversions), which may or may not be in synchrony with local precipitation (e.g. Felton et al., 2007). Because Lake Lorenyang, which occupied the Turkana Basin from ∼2.1 to 1.4 Ma, was fundamentally different from modern Lake Turkana (Feibel, 2011), it is not an exact analog for characteristics such as bathymetry, hydrology, or sedimentary facies....

Indeed, as suggested by Nutz and Schuster (2018), comparison of sedimentary lake level records against independent climate records can provide considerable insight into the impacts of climate processes on paleoenvironments. We further suggest such comparisons can reveal not only the impacts of climate, but the Earth surface processes that shaped paleo-basins and paleo-landscapes in East Africa, the timing and nature of which represent a major uncertainty in paleoclimatology and paleoanthropology (c.f. Maslin et al., 2014).

Lastly, we agree that the WTK13 core location in our Fig. 1 was misplaced and include a revised figure in this reply. The outline of Lake Lorenyang is based upon data presented in Brown and Feibel (1991).

Ma, P., Li, Y., Wang, C., Zheng, L., Lv, D., Zou, Y., Li, S., 2018. Oligocene-Miocene source rocks of the Zhongcang Basin: Implications for hydrocarbon potential differentiation between lake basins in Central Tibet. International Journal of Coal Geology 199, 124-137.


The Oligocene-Miocene Dingqinghu Formation is widely distributed in lake basins of the Bangong-Nujiang suture zone (BNSZ), central Tibet and has been reported as an important source rock layer. However, limited works have been conducted in the Zhongcang Basin. To gain knowledge on hydrocarbon potential of this area and further investigate the organic matter (OM) accumulation mechanisms of source rocks in the BNSZ basins, samples collected along two measured sections from the Zhongcang Basin were subjected to sedimentological, organic geochemical and petrographic analyses. Sedimentological analyses indicate that all samples were deposited in prodeltic to deep lake environments. Total organic carbon (TOC) values and pyrolysis data suggest a poor to fair

hydrocarbon source potential of the middle Dingqinghu Formation, with the exception of OM-rich samples locate in a marker bed of the upper part. Vitrinite reflectance (Ro) values of the upper part and middle-lower part samples range from 0.41 to 0.50 and 0.52 to 0.61, indicating immature and marginal mature stages, respectively. These maturity levels were also supported by specific maturity indices of sample extracts, such as ratios of C31 22S/(22S + 22R) homohopanes and C29 ββ/(αα + ββ) steranes. Bulk geochemistry, maceral composition of kerogen, and extract biomarkers demonstrate that OM-rich samples were deposited in fresh to brackish waters with type II-III kerogen mainly derived from algae and higher plants; while poor to fair samples have less higher plant contribution, but relatively high bacterial content that probably originated from more saline environments. The paleoclimate-induced environmental reorganization is likely responsible for the differential OM accumulation in the Zhongcang Basin; relatively wet climates would facilitate primary productivity of the lake as well as development of swamps on the delta, resulting in deposition of mixed terrestrial and aquatic OM with higher TOC, whilst dry conditions would restrict the development of river systems and promote the establishment of saline environments, causing decreased total OM input but increased proportion of halophilic bacterial OM. In addition, we summarized published data of the Dingqinghu Formation in the BNSZ basins and preliminarily reconstructed paleogeography of central Tibet. Two types of drainage patterns were confirmed in this area. A long-lived hierarchical drainage system is developed in the Lunpola area, while single lake systems were prevalent in other basins, including the Zhongcang Basin. The hierarchical drainage pattern could minimize clastic dilution effects during tectonic active and/or relatively wet periods, and prevent the establishment of hypersaline environments during the dry period. The drainage center in this kind of hierarchical system has lower sedimentation accumulation rate and could receive much more aquatic OM at any climatic conditions. We argue that tectonic-induced drainage organization primarily controlled the hydrocarbon potential differentiation between lake basins of central Tibet.

Ma, Q., Zhang, X., Qu, Y., 2018. Biodegradation and biotransformation of indole: Advances and perspectives. Frontiers in Microbiology 9, 2625. doi: 10.3389/fmicb.2018.02625.


Indole is long regarded as a typical N-heterocyclic aromatic pollutant in industrial and agricultural wastewater, and recently it has been identified as a versatile signaling molecule with wide environmental distributions. An exponentially growing number of researches have been reported on indole due to its significant roles in bacterial physiology, pathogenesis, animal behavior and human diseases. From the viewpoint of both environmental bioremediation and biological studies, the researches on metabolism and fates of indole are important to realize environmental treatment and illuminate its biological function. Indole can be produced from tryptophan by tryptophanase in many bacterial species. Meanwhile, various bacterial strains have obtained the ability to transform and degrade indole. The characteristics and pathways for indole degradation have been investigated for a century, and the functional genes for indole aerobic degradation have also been uncovered recently. Interestingly, many oxygenases have proven to be able to oxidize indole to indigo, and this historic and motivating case for biological applications has attracted intensive attention for decades. Herein, the bacteria, enzymes and pathways for indole production, biodegradation and biotransformation are systematically summarized, and the future researches on indole-microbe interactions are also prospected.



Mixing should be optimized in anaerobic digestion (AD) systems to achieve excellent biomaterials production in the sewage sludge (SS) management in wastewater treatment plant. AD depends on the coordinated activity of hydrolysis, acidification and methanogenesis. However, the effect of mixing intensity on characteristics of hydrolysis and acidification in AD of SS is still poorly understood. This study focused on the mixing intensity (30, 60, 90 and 120 rpm) effect on the characteristics of dissolved organic matter (DOM) and the key microorganisms in the hydrolysis and acidification of SS. Results showed that enhanced hydrolysis and acidification efficiency was obtained at mixing of 90 and 120 rpm (p<0.05), while the maximum acetic acid (388 ± 21 mg/L) was produced at 90 rpm. Mixing at 90 rpm enhanced the release of protein and polysaccharide as well as humic acid. Further analyses of DOM molecular features revealed that 90 rpm led to the highest molecular diversity and easily biodegradable molecules (lipid and proteins/amino sugars), which contributed to the maximum hydrolysis and acidification efficiency. Firmicutes and Actinobacteria significantly increased with mixing intensity (p<0.05), and Chloroflexi and Fusobacteria were enriched at mixing of 90 rpm, which favored the hydrolysis of SS. The enrichment of Clostridium XI and Clostridium sensu stricto contributed to the acidification of DOM at 90 and 120 rpm. The results of this study can advance our knowledge about mixing intensity effects on the AD systems of SS. This research also showed how increasing mixing intensity to a relatively high speed can enhance the hydrolysis and acidification efficiency of SS.


https://doi.org/10.3176/oil.2018.4.06

Currently there are two different industrial shale oil production processes utilized in Estonia called Galoter and Kiviter. It is known that the composition of pyrolytic water from these processes is different. The most emphasized difference lies in the concentration of phenols. However, the general composition of the water has not been very deeply investigated. Therefore, the purpose of this paper was to study the pyrolytic water from solid heat carrier technology (SHC). The pyrolytic water from the SHC process was subjected to headspace gas chromatography-mass spectrometry (GC-MS) analysis for the identification of organic compounds and to inductively coupled plasma mass spectrometry (ICP-MS) analysis for the identification of trace elements. The parameters generally used to describe wastewater – biochemical oxygen demand (BOD7), chemical oxygen demand (CODCr), suspended solids, dry residue, total organic carbon (TOC), pH, oil products, conductivity, amounts of phosphorus, nitrogen and sulphur –, were also measured. The analysed water contained surprisingly high amounts of sulphur and nitrogen, 0.03% and 0.24%, respectively. It was found that the water did not contain any significant amounts of toxic metals and it exhibited good biodegradability.



Wet-based regions of glaciers and ice sheets are now recognized to host unique and diverse microbial communities capable of influencing global biogeochemical cycles. However, the isolated nature of subglacial environments poses limitations upon the supply of protons for chemical weathering and

energy sources (electron donors/acceptors) to support in situ microbial communities. A less well recognized source of these substrates is the release of gases from mineral structures, pore spaces or fluid inclusions and the generation of gases from the breakage of mineral bonds during the mechanical breakdown of rocks by moving ice. Here, we investigate the potential release of H2, CO2, CO, and short chain hydrocarbons, particularly CH4, by glacial erosion at rates relevant to chemical weathering and microbial activity beneath glaciers. A wide range of magmatic, metamorphic, and sedimentary rocks, and subglacial sediments from glaciated catchments in Greenland, Norway and Canada were ground in the laboratory to varying grain sizes and the release of gases was measured. The volume of gas released increased as the grain size of the ground sediments decreased. The results of these laboratory experiments were used to estimate rates of catchment-scale gas release based upon estimates of long term abrasion rates at each glacier. H2 generation was calculated to be sufficient to potentially support previously estimated rates of methanogenesis in the upper centimeters of subglacial sediment at a gneissic catchment in Greenland and a sedimentary catchment in Canada. Sufficient CO2 could be released by grinding to drive as much as 20% of subglacial chemical weathering at a metamorphic catchment in Svalbard, with potential implications for the inferred quantity of CO2 drawn-down from the atmosphere by glacial weathering. Rates of CH4 generation from grinding bedrock has the potential to be greater than subglacial microbial generation in a sedimentary catchment in Canada with carbon rich bedrock, suggesting a potentially important source of CH4 for methanotrophic microorganisms. We conclude that mechanical erosion beneath a range of glaciers generates significant quantities of gases which have the potential to enhance chemical weathering and/or support subglacial microbial communities in the deep icy biosphere.

MacLagan, E.A., Walton, E.L., Herd, C.D.K., Dence, M., 2018. Investigation of impact melt in allochthonous crater-fill deposits of the Steen River impact structure, Alberta, Canada. Meteoritics & Planetary Science 53, 2285-2305.


The Steen River impact structure (SRIS) formed in mixed target rocks, with Devonian carbonates, shales, and evaporites overlying granitic basement rocks of the Canadian Shield. A detailed study of impact melt phases within a continuous sequence of polymict impact breccia, as intersected by drill core, evaluated the relationship of impact melt to the breccia, identified the target rocks that contributed to the melt, and calculated the amount of melt within the breccia. Impact melt in the SRIS breccia occurs in three main forms (1) as individual matrix-supported clasts, (2) as rims enveloping granitic clasts, and (3) as layers of agglomerated melt. Major and minor element abundances of large impact melt clasts (>1 mm) are similar to granitic basement, aside from elevated CaO and K2O wt% oxides in these melt clasts from incorporation of carbonates and calcareous shales. In contrast, submillimeter-sized impact melt clasts have a composition derived almost exclusively from melting of shales. The small size of the shale-derived melt clasts is attributed to increased fragmentation and a wider dispersion due to the volatile-rich nature of the shale protolith. The wide compositional range of impact-melted target lithologies documented at the SRIS contradicts breccia clast formation by impact melts that merged into larger bodies but were subsequently disrupted. Our observations are consistent with disruption of impact melt early in its formation history, and the volatile-rich nature of the target materials likely contributed to this disruption. Bimodal thin section scans provide an estimate of the proportion of impact melt phases in the SRIS breccias (~19 vol%). When compared to similarly sized, mixed-target impact structures, our results are consistent with the estimated volume of impact melt clasts from Ries, Germany (21 vol%), but are roughly twice that observed at Haughton, Canada (<10 vol%).

Madani, M., Zargar, G., Takassi, M.A., Daryasafar, A., Wood, D.A., Zhang, Z., 2019. Fundamental investigation of an environmentally-friendly surfactant agent for chemical enhanced oil recovery. Fuel 238, 186-197.


Surfactant injection is an important chemical enhanced oil recovery (EOR) technique with beneficial impacts for oil recovery from subsurface reservoirs due to interfacial tension (IFT) reduction and wettability alteration. However, most of the available or proposed synthetic surfactants have negative environmental impacts. Here, a novel synthesis procedure of an amino-acid based (non-toxic; easily biodegradable) surfactant is described and its application for chemical EOR is rigorously tested using IFT, wettability and coreflooding experimental tests. The effect of salinity on the IFT reduction highlights the potential impact of injection water salt concentration on its performance. Two sets of carbonate and sandstone rock samples are used for wettability alteration tests. Two displacement tests quantitatively assess the performance of the proposed surfactant during injection as part of secondary and tertiary recovery schemes. The synthesized amino-acid based surfactant demonstrates good synergy with appropriate injection water salt concentrations. The wettability test results suggest that both sandstone and carbonate reservoir rocks would potentially benefit when subjected to chemical EOR using this surfactant. Comparisons between secondary and tertiary surfactant flooding schemes suggest that the surfactant is potentially more effective during secondary injection.

Malard, L.A., Pearce, D.A., 2018. Microbial diversity and biogeography in Arctic soils. Environmental Microbiology Reports 10, 611-625.

https://doi.org/10.1111/1758-2229.12680

Microorganisms dominate terrestrial environments in the polar regions and Arctic soils are known to harbour significant microbial diversity, far more diverse and numerous in the region than was once thought. Furthermore, the geographic distribution and structure of Arctic microbial communities remains elusive, despite their important roles in both biogeochemical cycling and in the generation and decomposition of climate active gases. Critically, Arctic soils are estimated to store over 1500 Pg of carbon and, thus, have the potential to generate positive feedback within the climate system. As the Arctic region is currently undergoing rapid change, the likelihood of faster release of greenhouse gases such as CO2, CH4 and N2O is increasing. Understanding the microbial communities in the region, in terms of their diversity, abundance and functional activity, is key to producing accurate models of greenhouse gas release. This review brings together existing data to determine what we know about microbial diversity and biogeography in Arctic soils.

Malkin, A.Y., Zuev, K.V., Arinina, M.P., Kulichikhin, V.G., 2018. Modifying the viscosity of heavy crude oil using surfactants and polymer additives. Energy & Fuels 32, 11991-11999.


A systematic study of the influence of surfactant and stabilizing polymer additives on the rheological properties of heavy oil was carried out. The aim was to optimize the recipe for the most effective reduction in the oil viscosity. A total of 41 versions of the emulsion were prepared using different protocols. Creation of the emulsions with different recipes and modes of mixing led to a regulation of their morphologies, which determined the rheological properties of the final products. In all cases, emulsification resulted in a transformation of the oil from Newtonian behavior to a viscoplastic medium with a blurred yield stress. Dependent upon the composition, the yield stress was decreased

up to 0.6 Pa and the viscosity at high shear obtained a value up to 50 mPa s, which is lower than the viscosity of crude oil by 34 times. The efficiency of the viscosity reduction increased with a decreasing temperature.

Mann, A., 2018. Inner workings: Hunting for microbial life throughout the solar system. Proceedings of the National Academy of Sciences 115, 11348.


A robotic lander surveys a frosty landscape near the northern pole of Mars sometime in the 2020s. Revving up a powerful 1-meter drill, it bores into the polar subsurface, extracts a sample, and runs it through a battery of cleverly designed instruments. Maybe, just maybe, it uncovers the chemical residues of living organisms.Jupiter’s icy moon Europa, seen here in enhanced color based on images from the 1990s Galileo mission, is among the candidates for harboring microbial life. Image courtesy of NASA/JPL-Caltech/SETI Institute.This is the proposed Icebreaker Life mission, a couch-sized lander that would till through the same frozen soil visited by NASA’s Phoenix spacecraft in 2008 to find evidence of ancient microbes (1). Icebreaker is not alone. Within the astrobiological community, there is a growing consensus that it’s time to directly hunt for life elsewhere in the solar system. No such experiment has been attempted since the 1976 twin Viking landers’ life-detection instruments turned up inconclusive results on Mars (2). But this year, NASA put out a call to develop technology to go to another world and look for signatures of microbial life, the first such solicitation in more than 40 years. “We’ve got places that are so intriguing that it’s becoming much more compelling to look for life,” says atmospheric scientist Hunter Waite of the Southwest Research Institute in San Antonio, TX. And in October, the National Academies of Sciences, Engineering, and Medicine released a detailed report, titled An Astrobiology Strategy for the Search for Life in the Universe, urging NASA to make astrobiology an integral part of a broad range of future missions (3).Mars is the nearest target. Two discoveries over the summer reinforced its potential for hosting life—a possible reservoir of briny water that lies beneath its ice cap and organic material …

Mann, A., 2018. Large galaxy found lurking on the Milky Way's far side. Science 362, 737.


Circling our galaxy is a stealthy giant. Astronomers have discovered a dwarf galaxy, called Antlia 2, that is one-third the size of the Milky Way itself. As big as the Large Magellanic Cloud, the galaxy's largest companion, Antlia 2 eluded detection until now because it is 10,000 times fainter. Such a strange beast challenges models of galaxy formation and dark matter, the unseen stuff that helps pull galaxies together.

“It's a very odd object and kind of exciting because we don't know yet how to interpret all of its properties,” says Andrey Kravtsov of The University of Chicago in Illinois, who was not involved in the work.

The galaxy was discovered with data from the European Space Agency's Gaia satellite, a space telescope measuring the motions and properties of more than 1 billion stars in and around the Milky Way. Gabriel Torrealba, an astronomy postdoc at the Academia Sinica in Taipei, decided to sift the data for RR Lyrae stars. These old stars, often found in dwarf galaxies, shine with a throbbing blue light that pulses at a rate signaling their inherent brightness, allowing researchers to pin down their distance.

“RR Lyrae are so rare at these distances that even if you see two, you question why they are together,” says Vasily Belokurov, an astronomer at the University of Cambridge in the United Kingdom and a collaborator on the discovery. When the team found three, some 420,000 light-years away, it was “an overwhelming signal” of a large cluster of stars in that location, Belokurov says. But because the RR Lyrae stars lie on the far side of the disk of the Milky Way and its obscuring veils of stars and gas, finding their companions was not easy.

Gaia data helped the team see past the foreground stars. Objects in the Milky Way's disk are close enough for Gaia to measure their parallax: a shift in their apparent position as Earth moves around the sun. More distant stars appear fixed in one spot. After removing the parallax-bearing stars, the researchers homed in on more than 100 red giant stars moving together in the constellation Antlia, they report in a paper posted to the preprint server arXiv this week. The giants mark out a sprawling companion galaxy 100 times less massive than anything of similar size, with far fewer stars.

To explain such a diffuse galaxy, Belokurov suggests that early in Antlia 2's history, many young stars exploded as violent supernovae. This would have blown gas and dust out of the galaxy, weakening its gravity so that it puffed up. An abundance of the heavy elements that are strewn from the guts of exploding stars adds credibility to this idea, says Shea Garrison-Kimmel, an astrophysicist at the California Institute of Technology in Pasadena. Antlia 2 could also have lost matter as stars were tugged away by gravitational tidal forces as it orbited around the larger Milky Way.

Even so, its large size is hard to explain. Galaxies are thought to have formed when the gravity of enormous clumps of dark matter drew in enough ordinary matter to fuel the birth of stars. The team speculates that Antlia 2 might have been born from a fluffier, faster-moving type of dark matter than current models hypothesize.

To Garrison-Kimmel, one example isn't enough to say the dark matter in Antlia 2 is different from that in the Milky Way and its other satellites. “There's nothing in this one galaxy that screams to me that we need to rethink dark matter,” he says. “But if there are a lot of these, then we might need to take a step back and ask what's going on.”

That could happen now that astronomers know how to find these big, elusive companions. “I think this object is a harbinger,” Kravtsov says. “A taste of things to come.”

Marlot, L., Batteau, M., De Beer, D., Faure, K., 2018. In silico screening of comprehensive two-dimensional centrifugal partition chromatography × liquid chromatography for multiple compound isolation. Analytical Chemistry.


Isolation of unknown compounds for structural identification and the collection of target molecules to generate unavailable standards remain a challenge when dealing with complex samples. While tedious multistep purification is commonly used, it is not appropriate for a limited amount of sample or when a full recovery of expensive molecules is required. Two-dimensional preparative chromatography in a comprehensive mode provides an effective means to collect a large number of molecules in such a case. However, there is currently a lack of metrics to estimate preparative performances with a minimal number of experiments. An in silico comparative study of various pairs of chromatographic systems is proposed, focusing on the occupation rate and the homogeneity of peak spreading in the 2D separation space. Off-line combination of centrifugal partition chromatography (CPC) with liquid chromatography (LC) exhibits numerous advantages for 2D preparative separation. Our in silico approach was illustrated through the isolation of eight bioactive

compounds with very similar structures from Cyclopia genistoides plant by CPC×LC. The column screening was performed considering predictive 2D plots in light of the preparative performance descriptors and compared to real 2D preparative separations.



South-East Asia is home to one of the world's largest stores of tropical peatland and accounts for roughly 10% of the global land-to-sea dissolved organic carbon (DOC) flux. We present the first ever seasonally resolved measurements of DOC concentration and chromophoric dissolved organic matter (CDOM) spectra for six peatland-draining rivers and coastal waters in Sarawak, north-western Borneo. The rivers differed substantially in DOC concentration, ranging from 120–250µmolL−1 (Rajang River) to 3100–4400µmolL−1 (Maludam River). All rivers carried high CDOM concentrations, with a350 in the four blackwater rivers between 70 and 210m−1 and 4 and 12m−1 in the other two rivers. DOC and CDOM showed conservative mixing with seawater except in the largest river (the Rajang), where DOC concentrations in the estuary were elevated, most likely due to inputs from the extensive peatlands within the Rajang Delta. Seasonal variation was moderate and inconsistent between rivers. However, during the rainier north-east monsoon, all marine stations in the western part of our study area had higher DOC concentrations and lower CDOM spectral slopes, indicating a greater proportion of terrigenous DOM in coastal waters. Photodegradation experiments revealed that riverine DOC and CDOM in Sarawak are photolabile: up to 25% of riverine DOC was lost within 5 days of exposure to natural sunlight, and the spectral slopes of photo-bleached CDOM resembled those of our marine samples. We conclude that coastal waters of Sarawak receive large inputs of terrigenous DOC that is only minimally altered during estuarine transport and that any biogeochemical processing must therefore occur mostly at sea. It is likely that photodegradation plays an important role in the degradation of terrigenous DOC in these waters.



Branched dialkyl glycerol tetraethers (brGDGTs) are increasingly used as a paleotemperature proxy, yet the microbial producers of these compounds and the way they respond to environmental perturbations remain poorly understood. In this work, we used mesocosms to track the evolution of brGDGTs over several months, as well as an array of microcosms to study microbial brGDGT response to oxygen availability and carbon source. Overall our results confirm that brGDGTs are produced in the water column and respond to environmental perturbation. brGDGT concentrations increase in response to low oxygen, in agreement with empirical observations, but respond to added carbon only when ambient nutrients are low. Slow adjustment to temperature changes from the field to the laboratory appears to have influenced the relative methylation and isomerization of brGDGTs in the mesocosms. Overall our work is consistent with the inference that the producers are facultative aerobic heterotrophic organisms. Our results demonstrate that the use of micro- and mesocosms is a viable option to study brGDGTs in real time and help better understand this biomarker as a paleoproxy.

Mazel, F., Davis, K.M., Loudon, A., Kwong, W.K., Groussin, M., Parfrey, L.W., 2018. Is host filtering the main driver of phylosymbiosis across the tree of Life? mSystems 3, Article e00097-18.


Abstract::Host-associated microbiota composition can be conserved over evolutionary time scales. Indeed, closely related species often host similar microbiota; i.e., the composition of their microbiota harbors a phylogenetic signal, a pattern sometimes referred to as “phylosymbiosis.” Elucidating the origins of this pattern is important to better understand microbiota ecology and evolution. However, this is hampered by our lack of theoretical expectations and a comprehensive overview of phylosymbiosis prevalence in nature. Here, we use simulations to provide a simple expectation for when we should expect this pattern to occur and then review the literature to document the prevalence and strength of phylosymbiosis across the host tree of life. We demonstrate that phylosymbiosis can readily emerge from a simple ecological filtering process, whereby a given host trait (e.g., gut pH) that varies with host phylogeny (i.e., harbors a phylogenetic signal) filters preadapted microbes. We found marked differences between methods used to detect phylosymbiosis, so we proposed a series of practical recommendations based on using multiple best-performing approaches. Importantly, we found that, while the prevalence of phylosymbiosis is mixed in nature, it appears to be stronger for microbiotas living in internal host compartments (e.g., the gut) than those living in external compartments (e.g., the rhizosphere). We show that phylosymbiosis can theoretically emerge without any intimate, long-term coevolutionary mechanisms and that most phylosymbiosis patterns observed in nature are compatible with a simple ecological process. Deviations from baseline ecological expectations might be used to further explore more complex hypotheses, such as codiversification.

Importance: Phylosymbiosis is a pattern defined as the tendency of closely related species to host microbiota whose compositions resemble each other more than host species drawn at random from the same tree. Understanding the mechanisms behind phylosymbiosis is important because it can shed light on rules governing the assembly of host-associated microbiotas and, potentially, their coevolutionary dynamics with hosts. For example, is phylosymbiosis a result of coevolution, or can it be generated by simple ecological filtering processes? Beyond qualitative theoretical models, quantitative theoretical expectations can provide new insights. For example, deviations from a simple baseline of ecological filtering may be used to test more-complex hypotheses (e.g., coevolution). Here, we use simulations to provide evidence that simple host-related ecological filtering can readily generate phylosymbiosis, and we contrast these predictions with real-world data. We find that while phylosymbiosis is widespread in nature, phylosymbiosis patterns are compatible with a simple ecological model in the majority of taxa. Internal compartments of hosts, such as the animal gut, often display stronger phylosymbiosis than expected from a purely ecological filtering process, suggesting that other mechanisms are also involved.

McGuire, B., Olsen, B., Bemis, K.E., Orantes, D., 2018. Urine marking in male domestic dogs: honest or dishonest? Journal of Zoology 306, 163-170.

https://doi.org/10.1111/jzo.12603

Abstract Scent marking is a common mode of communication in mammals. Such marking is thought to communicate information about the signaler's size and corresponding competitive ability and accurately reflect the signaler's attributes (i.e., an honest signal). However, new data suggest that scent marking can be dishonest in certain circumstances. Via two studies, we tested the hypothesis that urine marking is a dishonest signal in adult male domestic dogs, which raise a hindlimb when marking vertical objects. In Study 1, we tested whether raised-leg angle (i.e., during a urination, the angle between a dog's raised leg and the axis normal to the ground) is a proxy for urine mark height

(n = 15 dogs) and, in Study 2, we tested whether small dogs exhibit larger raised-leg angles than large dogs (n = 45 dogs). We videotaped urinations of adult male dogs and, afterwards, measured height of urine marks (Study 1) and degree of raised-leg angles (Studies 1 and 2). In Study 1, we found significant positive relationships between both raised-leg angle and height of urine mark and body size (using either body mass or height at withers) and height of urine mark; raised-leg angle was a stronger predictor than either measure of body size. In Study 2, we found a significant negative relationship between body size (using either body mass or height at withers) and average raised-leg angle. Our findings support raised-leg angle as a proxy for urine mark height and provide additional evidence that scent marking can be dishonest. Assuming body size is a proxy for competitive ability, small adult male dogs may place urine marks higher, relative to their own body size, than larger adult male dogs to exaggerate their competitive ability. We did not control for over marking, which also may explain our findings.

McGuire, J.T., Cozzarelli, I.M., Bekins, B.A., Link, H., Martinović-Weigelt, D., 2018. Toxicity assessment of groundwater contaminated by petroleum hydrocarbons at a well-characterized, aged, crude oil release site. Environmental Science & Technology 52, 12172-12178.


Management of petroleum-impacted waters by monitored natural attenuation requires an understanding of the toxicology of both the original compounds released and the transformation products formed during natural breakdown. Here, we report data from a groundwater plume consisting of a mixture of crude oil compounds and transformation products in an effort to bridge the gap between groundwater quality information and potential biological effects of human exposures. Groundwater samples were characterized for redox processes, concentrations of nonvolatile dissolved organic carbon (NVDOC) and total petroleum hydrocarbons in the diesel range, as well as for activation of human nuclear receptors (hNR) and toxicologically relevant transcriptional pathways. Results show upregulation of several biological pathways, including peroxisome proliferator-activated receptor gamma and alpha, estrogen receptor alpha, and pregnane X receptor (PXR) with higher levels of hNR activity observed in more contaminated samples. Our study of affected groundwater contaminated by a crude-oil release 39 years ago shows these types of waters may have the potential to cause adverse impacts on development, endocrine, and liver functioning in exposed populations. Additionally, positive trends in activation of some of the molecular targets (e.g., PXR) with increasing NVDOC concentrations (including polar transformation products) demonstrate the importance of improving our understanding of the toxicity associated with the unknown transformation products present in hydrocarbon-impacted waters. Our results begin to provide insight into the potential toxicity of petroleum-impacted waters, which is particularly timely given the ubiquitous nature of waters impacted by petroleum contamination not only recently but also in the past and the need to protect drinking-water quality.



Significance: Endosymbiotic theory suggests that mitochondria evolved from free-living prokaryotes which entered the host cell and were retained as endosymbionts. Here, we model this earliest stage of the endosymbiotic theory of mitochondrial evolution by engineering endosymbiosis between two genetically tractable model organisms, Escherichia coli and Saccharomyces cerevisiae. In this model

system, we engineered E. coli strains to survive in the yeast cytosol and provide ATP to a respiration-deficient yeast mutant. In a reciprocal fashion, yeast provided thiamin to an endosymbiotic E. coli thiamin auxotroph. This readily manipulated chimeric system was stable for more than 40 doublings and should allow us to investigate various aspects of the endosymbiotic theory of mitochondrial evolution.

Abstract: It has been hypothesized that mitochondria evolved from a bacterial ancestor that initially became established in an archaeal host cell as an endosymbiont. Here we model this first stage of mitochondrial evolution by engineering endosymbiosis between Escherichia coli and Saccharomyces cerevisiae. An ADP/ATP translocase-expressing E. coli provided ATP to a respiration-deficient cox2 yeast mutant and enabled growth of a yeast–E. coli chimera on a nonfermentable carbon source. In a reciprocal fashion, yeast provided thiamin to an endosymbiotic E. coli thiamin auxotroph. Expression of several SNARE-like proteins in E. coli was also required, likely to block lysosomal degradation of intracellular bacteria. This chimeric system was stable for more than 40 doublings, and GFP-expressing E. coli endosymbionts could be observed in the yeast by fluorescence microscopy and X-ray tomography. This readily manipulated system should allow experimental delineation of host–endosymbiont adaptations that occurred during evolution of the current, highly reduced mitochondrial genome.



Solvent-based recovery processes have gained some advantage over thermal recovery processes under specific reservoir conditions. Solvent–bitumen mass transfer is a diffusion dominated process. The calculation of diffusion coefficients is fundamental for the design of solvent-based recovery processes as it allows us to understand the performance of the process. In a recent work, Babak et al.(1) developed a new slopes and intercept method which was demonstrated to be very robust for the calculation of diffusion coefficients of binary systems. In this paper, the diffusion coefficients of dimethyl ether (DME), pentane, and toluene into two different bitumen systems are calculated using this method as a function of concentration. X-ray computed tomography (CT) is used to obtain the concentration profiles of the bitumen–solvent systems. Furthermore, a new modification of Vignes’ equation is introduced to predict concentration-dependent diffusion coefficients. This new modification includes the acceleration and deceleration parameter associated with the solvent and bitumen mass transfer behavior. The developed equation successfully predicts the diffusion coefficients of the studied systems.

Miller, D.R., Habicht, M.H., Keisling, B.A., Castañeda, I.S., Bradley, R.S., 2018. A 900-year New England temperature reconstruction from in situ seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs). Climate of the Past 14, 1653-1667.

https://doi.org/10.5194/cp-14-1653-2018

Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleolimnology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. Here, we report seasonally resolved measurements of brGDGT production in the water column, in catchment soils, and in a sediment core from Basin Pond, a small, deep inland lake in Maine, USA. We find

similar brGDGT distributions in both water column and lake sediment samples but the catchment soils have distinct brGDGT distributions suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the down-core sedimentary signal. Seasonally, depth-resolved measurements indicate that most brGDGT production occurs in late fall, and at intermediate depths (18–30m) in the water column. We utilize these observations to help interpret a Basin Pond brGDGT-based temperature reconstruction spanning the past 900 years. This record exhibits trends similar to a pollen record from the same site and also to regional and global syntheses of terrestrial temperatures over the last millennium. However, the Basin Pond temperature record shows higher-frequency variability than has previously been captured by such an archive in the northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic or solar activity. This first brGDGT-based multi-centennial paleoreconstruction from this region contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.



The present contribution aims for a characterization of microstructure and pore-space distribution of upper Visean Rudov beds, considered the main source rock for conventional oil deposits in the Ukrainian Dneiper–Donets Basin and a prospect for unconventional hydrocarbon production in recent years. Broad ion beam–scanning electron microscopy (SEM) mapping revealed a remarkably heterogeneous microstructure controlled by diagenetic precipitates (Fe/Mg carbonates, albite). Formation of these precipitates is likely triggered by organic matter decomposition and represents an important influencing factor for overall porosity and permeability. Furthermore, shale diagenesis also influences mechanical properties, as suggested by nanoindentation tests. The SEM-visible organic matter porosity is restricted to solid bitumen; although pores less than 2–3 nm in vitrinites of overmature samples are indicated by focused ion beam–SEM results, they cannot be resolved clearly by this method. Pore generation in solid bitumen that likely formed in situ in primary amorphous organic matter already starts at the early oil window in samples from the basinal oil-prone organofacies, whereas most porous solid bitumen at peak oil maturity was interpreted as relicts of primary oil migration, representing an earlier oil phase that predominantly accumulated in quartz-rich layers and became nanoporous during secondary cracking. In the terrestrially dominated transitional to marginal organofacies, pore generation in pyrobitumen resulting from gas generation occurs significantly later and is less intense. Formation of authigenic clay and carbonate minerals within pyrobitumen is likely related to organic acids formed during bitumen decomposition and implies the presence of an aqueous phase even in pores that are apparently filled exclusively with solid bitumen.



The present study investigated the feasibility of domestic sewage wastewater (DSW) as an alternate to fresh-water microalgae growth media towards high-value bioenergy feedstock production. Eight native microalgal strains were screened from DSW and the effect of raw DSW (RDSW), and autoclaved DSW (ADSW) on growth and bioremediation potential were evaluated and compared

with control BG11 medium. The study confirmed RDSW as a potential growth medium while Monoraphidium sp. KMC4 showed superior biomass (1.47 ± 0.08 g L−1) and lipid yield (436.01 ± 0.06 mg L−1). The corresponding values for bioremediation of ammonia, nitrate, phosphate, as well as COD remained within 88–100%. CHNS, biochemical, TGA, FTIR, FAME analysis of KMC4 confirmed it’s potential as bioenergy feedstock. Additionally, a comprehensive characterization of lipid-extracted microalgae biomass (LEMB) was carried out which suggested that LEMB can be used as a growth promoter as well as feedstock for biogas, bioethanol, and bio-oil production.


https://www.biogeosciences-discuss.net/bg-2018-477/

The kinetics of urea hydrolysis (ureolysis) and induced calcium carbonate (CaCO3) precipitation for engineering use in the subsurface was investigated under aerobic conditions using Sporosarcina pasteurii (ATCC strain 11859) as well as Bacillus sphaericus strains 21776 and 21787. All bacterial strains showed ureolytic activity inducing CaCO3 precipitation aerobically. Rate constants not normalized to biomass demonstrated slightly higher rate coefficients for both ureolysis (kurea) and CaCO3 precipitation (kprecip) for B. sphaericus 21776 (kurea = 0.10 ± 0.03h−1, kprecip = 0.60 ± 0.34h−1) compared to S. pasteurii (kurea = 0.07 ± 0.02h−1, kprecip = 0.25 ± 0.02h−1). B. sphaericus 21787 showed little ureolytic activity but was still capable of inducing some CaCO3 precipitation. Cell growth appeared to be inhibited during the period of CaCO3 precipitation. TEM images suggest this is due to the encasement of cells and was reflected in lower kurea values observed in the presence of dissolved Ca. However, biomass re-growth could be observed after CaCO3 precipitation ceased, which suggests that ureolysis-induced CaCO3 precipitation is not necessarily lethal for the entire population. The kinetics of ureolysis and CaCO3 precipitation with S. pasteurii were further analyzed under anaerobic conditions. Rate coefficients obtained in anaerobic environments were comparable to those under aerobic conditions, however no cell growth was observed under anaerobic conditions with NO3

−, SO4

2− and Fe3+ as potential terminal electron acceptors. These data suggest that the initial rates of ureolysis and ureolysis-induced CaCO3 precipitation are not significantly affected by the absence of oxygen but that long-term ureolytic activity might require the addition of suitable electron acceptors. Such variations in the ureolytic capabilities and associated rates of CaCO3 precipitation between strains must be fully considered in subsurface engineering strategies that utilize microbial amendments.

Mitchell, E.G., Kenchington, C.G., Harris, S., Wilby, P.R., 2018. Revealing rangeomorph species characters using spatial analyses. Canadian Journal of Earth Sciences 55, 1262-1270.


Rangeomorphs dominate the Ediacaran Avalonian macrofossil assemblages of Charnwood Forest, UK (∼562 Ma). However, their unfamiliar fractal architecture makes distinguishing phylogenetically reliable characters from intraspecific features difficult. Fortunately, spatial analysis of large in-situ populations offers an independent means of assessing their taxonomy. Populations of a single biological species are likely to exhibit similar spatial distributions due to their shared responses to the biological and ecological processes acting upon them. As such, spatial analyses can be used to interrogate which are the most taxonomically deductive characters in similar species. We used random labelling analyses to investigate the presence or absence of characters of Primocandelabrum

boyntoni, P. aethelfalaedia, and P. aelfwynnia on the Bed ‘B’. The resultant spatial distributions were compared to observed characters using goodness-of-fit tests to determine which characters were associated with unique populations, and which were found across multiple populations. We found that P. boyntoni and P. aelfwynnia had statistically indistinguishable character distributions, suggesting that they represent a single biological species, and that they exhibited significantly different distributions to P. aethelfalaedia, suggesting that there are two (rather than three) species of Primocandelabrum present on the B surface. Furthermore, we found that the distribution of concealed versus unconcealed 1st order branches across all specimens exhibited significantly different density-dependant behaviour, with unconcealed branching occurring in areas of higher density populations and concealed branching occurring in the lower density areas of Primocandelabrum. We speculate that unconcealed branches may have been a response to the reduced availability of resources in higher density areas, implying rangeomorphs were capable of ecophenotypic responses.

Mohamadi-Baghmolaei, M., Hajizadeh, A., Azin, R., Izadpanah, A.A., 2018. Assessing thermodynamic models and introducing novel method for prediction of methane hydrate formation. Journal of Petroleum Exploration and Production Technology 8, 1401-1412.

https://doi.org/10.1007/s13202-017-0415-2

Transmission of natural gas with methane as the main constituent has been a subject of interest to industrial companies. Predicting hydrate formation conditions is important to prevent formation of methane hydrate in gas pipeline. Also, attention has been taken to account for capture and storage of pure methane. In this paper, a comprehensive comparison is performed between empirical correlations and different equation of state in van der Waals Platteeuw (VdW-P) thermodynamic model to determine the most accurate method of hydrate formation condition of methane. In addition, a novel, simple and accurate correlation is developed to predict methane hydrate formation temperature using genetic programming. Error analysis on a wide range of experimental data indicates that the new proposed correlation is superior over existing correlations and all VdW-P models with R2 = 0.999.

Mohammadzadeh, O., Sedaghat, M.H., Kord, S., Zendehboudi, S., Giesy, J.P., 2019. Pore-level visual analysis of heavy oil recovery using chemical-assisted waterflooding process – Use of a new chemical agent. Fuel 239, 202-218.


Chemical-assisted waterflooding enhances the ultimate recovery of a conventional waterflooding process through several mechanisms such as reducing interfacial tension between water and oil, formation of in-situ emulsions, treatment of adverse mobility ratio, and wettability modification. Application of chemical-assisted waterflooding for recovery of heavy oil is still an active research topic. A new chemical technology (i.e. IPC Technology as referred to in this paper) has been developed. A proprietary mixture of surfactants is used in several techniques associated with surface extraction as well as in-situ recovery of heavy oil and bitumen. This formulation of solvents and surfactants is reusable, low foaming, non-flammable, not acutely toxic, and non-carcinogenic. The efficacy of using IPC as an additive for waterflooding was presented earlier through a systematic coreflooding study, which showed increased ultimate recovery of different types of oils when compared with commercial surfactant and alkali flooding. In order to investigate the mechanisms behind the enhanced macro-scale oil recovery, a series of pore-scale tests were designed and conducted in this study. Glass micromodel type of porous media was used in the presence of brines with different ion compositions. The pore-scale chemical-assisted waterflooding tests were carried

out in four consecutive stages: brine flooding, chemical flooding, soaking period, and extended brine flooding. High quality pore-scale images were captured for qualitative and quantitative analysis of the IPC-assisted waterflooding at the pore-level. IPC intensified water wettability of grain particles in the presence of NaCl; however in the presence of MgCl2, use of IPC makes solid surfaces oil-wet. The phenomenon of water-in-oil and oil-in-water emulsification was observed when IPC was used along with different brine compositions. This phenomenon is weakened for lighter oils. When the acid number of the oil was low, extension of soaking period intensified wettability alteration and emulsification mechanisms. Other pore-scale phenomena were also observed during visualization tests such as coalescence of microdroplets during the extended waterflooding stage, snap-off mechanism creating daughter droplets during the extended waterflooding stage, occasional flow of bulk oil films toward the production end, and wettability reversal during various flooding stages. Attempts were also made to conduct statistical analysis of emulsion droplet sizes under different test conditions. Several parameters, including chemical concentration as well as ion concentration in brines, were found to significantly affect the emulsion droplet size distribution.

Montes, L.F., Oliveira, E.C.S., Neto, Á.C., Menezes, S.M.C., Castro, E.R.V., Barbosa, L.L., 2019. fLow-field NMR: A new alternative to determine the aromatic content of petroleum distillates. Fuel 239, 413-420.


Petroleum and distillates contain different concentrations of aromatic hydrocarbons. These compounds are important downstream as process indicators for product formulation. They can reduce the calorific value of some distillates, poison catalysts, be resistant to certain processes, and can provoke environmental impacts. The quantification of these compounds expressed by aromaticity factor (fa) is usually determined using 13C high-resolution NMR spectroscopy following the procedure of the ASTM D5292 standard test. However, this technique presents some disadvantages, such as long time of analysis, high cost and the use of solvents for sample preparation. In this study we proposed the use of low-field NMR (LF-NMR) at 2.2 MHz for detecting the 1H nucleus as an interesting, quicker and cheaper alternative to estimate the fa value of 42 distillates produced from atmospheric distillation (ASTM D2892 method) of four oils with °API between 17.9 (heavy) and 34.9 (light). The results showed the great potential of LF-NMR to quantify the aromaticity in light, medium and heavy distillates with aromatic carbon (Car) contents between 0.4 and 13.9 wt%. Furthermore, it was possible predict fa values, either hydrogen or carbon, based only on the transverse relaxation time (T2) obtained from the NMR experiments in time domain.

Monteverde, D.R., Sylvan, J.B., Suffridge, C., Baronas, J.J., Fichot, E., Fuhrman, J., Berelson, W., Sañudo-Wilhelmy, S.A., 2018. Distribution of extracellular flavins in a coastal marine basin and their relationship to redox gradients and microbial community members. Environmental Science & Technology 52, 12265-12274.


The flavins (including flavin mononucleotide (FMN) and riboflavin (RF)) are a class of organic compounds synthesized by organisms to assist in critical redox reactions. While known to be secreted extracellularly by some species in laboratory-based cultures, flavin concentrations are largely unreported in the natural environment. Here, we present pore water and water column profiles of extracellular flavins (FMN and RF) and two degradation products (lumiflavin and lumichrome) from a coastal marine basin in the Southern California Bight alongside ancillary geochemical and 16S rRNA microbial community data. Flavins were detectable at picomolar concentrations in the water

column (93–300 pM FMN, 14–40 pM RF) and low nanomolar concentrations in pore waters (250–2070 pM FMN, 11–210 pM RF). Elevated pore water flavin concentrations displayed an increasing trend with sediment depth and were significantly correlated with the total dissolved Fe (negative) and Mn (positive) concentrations. Network analysis revealed a positive relationship between flavins and the relative abundance of Dehalococcoidia and the MSBL9 clade of Planctomycetes, indicating possible secretion by members of these lineages. These results suggest that flavins are a common component of the so-called shared extracellular metabolite pool, especially in anoxic marine sediments where they exist at physiologically relevant concentrations for metal oxide reduction.

Moore, T.R., Large, D., Talbot, J., Wang, M., Riley, J.L., 2018. The stoichiometry of carbon, hydrogen, and oxygen in peat. Journal of Geophysical Research: Biogeosciences 123, 3101-3110.

https://doi.org/10.1029/2018JG004574

Abstract: Carbon (C), hydrogen (H), and oxygen (O) form ~90% by mass of peat, a product of the input of plant tissues and litter and the output of decomposition under aerobic and anaerobic conditions. We examined patterns of these elements, as the O:C and H:C atomic ratios, in over 1,300 peat samples collected from over 400 profiles in Ontario, Canada, representing bogs, fens, and swamps. The overall O:C ratio decreased from the surface (0.6 to 0.7) to ~0.5 at a depth of 50 cm and showed little further change to a depth of 5 m. In contrast, the H:C ratio decreased only slightly (1.30 to 1.25) over the top 1 m and showed no further significant decline with depth. The C oxidative state (Cox) and oxidation ratio showed strong decreases and increases, respectively, with depth with most changes occurring in the top 0.5 m. The O:C ratio, and Cox and oxidation ratio values were significantly correlated with the von Post humification index, with most changes occurring in index values 1 through 4, the latter representing a slight degree of decomposition. Collation of the Ontario peats with other data sets revealed the very large range in O:C and H:C values, with a general decrease from temperate to tropical and subtropical peatlands. Estimation of the O:C and H:C ratios of input (litter) and output (mineralization to CO2, methanogenesis to CH4 and CO2, and loss as dissolved organic C) allowed an estimation of the degree of decomposition or C loss.

Plain Language Summary: Carbon, hydrogen, and oxygen form about 90% of the mass of peat, derived from the decomposition of dead plant and animal material. Using a large database from bog, fen, and swamp peatlands in Ontario and in Europe, North America, and Indonesia, we show that the ratios, or stoichiometry, between these three elements is a function of their input in litter and decomposition pathways and intensity. We suggest that the ratios, particularly the atomic oxygen:carbon ratio, can be used to predict the proportion of carbon that has been lost through decomposition and peat formation.

Morimoto, M., Fukatsu, N., Tanaka, R., Takanohashi, T., Kumagai, H., Morita, T., Tykwinski, R.R., Scott, D.E., Stryker, J.M., Gray, M.R., Sato, T., Yamamoto, H., 2018. Determination of Hansen solubility parameters of asphaltene model compounds. Energy & Fuels 32, 11296-11303.


The Hansen solubility parameters (HSPs) of asphaltene model compounds were determined experimentally via solubility testing. For the test, we synthesized various archipelago- and continental-type molecule model compounds: 5 were steroid-derived naphthoquinoline compounds; 14 were phenanthrene/pyrene-derived compounds; 2 were nickel porphyrins; and 1 was an alkyl hexabenzocoronene molecule. Some of them contain nitrogen as the quinoline or porphyrin structure, oxygen as the furan structure, and sulfur as the thiophene structure. Using the Hansen sphere method,

the HSPs δd, δp, and δh were successfully determined with only small errors, with values of 18.7–21.0, 2.7–8.1, and 2.2–6.5 MPa1/2, respectively. For real asphaltenes, these values were about 19, 4, and 4 MPa1/2, respectively. The solubility characteristics of the model compounds were found to be complex, because there is not clear relationships between solubility and chemical structures. Even slight structural differences, such as the type and location of heteroatoms, greatly changed the Hansen sphere radius, R0. The HSP analyses will enable the development of a mixing strategy for model compounds, to mimic asphaltene.

Morken, J.P., 2018. Practically simple reactions convert hydrocarbons to precious chemicals. Nature 563, 336-337.

https://www.nature.com/articles/d41586-018-07333-w

Operationally simple chemistry enables aliphatic carbon–carbon bonds — the ‘girders’ in the framework of many organic molecules — to be prepared from widely available hydrocarbons known as alkenes.

Many valued reagents and catalysts used in the preparation of organic compounds are highly reactive and are therefore incompatible with exposure to the open atmosphere — in some cases, dangerously so. The instrumentation required to carry out reactions with these compounds, such as high-vacuum apparatus and gloveboxes (isolation chambers), is costly and demands special training. Chemical processes that do not have such requirements are therefore more likely to make a big impact on how chemists synthesize molecules, be it for the development of new materials, pharmaceuticals or agrochemicals. The reactions reported by Fu and co-workers1 in Nature are a case in point. Not only are they simple to carry out, but they also deliver a variety of useful products that are otherwise much more difficult to make.Parallels are often drawn between the fields of organic synthesis and architecture2: aliphatic carbon–carbon (C–C) bonds are the architect’s ‘girders’ on which many structurally complex molecules are built. Installing these girders is challenging, and necessitates the use of highly reactive reagents. To add to the challenge, the orientation in which new C–C bonds are installed — the stereochemistry of the reaction — affects the overall shape of the final molecule3, which in turn can affect the molecule’s function in applications.

Fu and colleagues’ advance addresses these challenges. The authors describe a new C–C bond-forming reaction, known as a cross-coupling reaction, that produces one isomer of the reaction product to the near exclusion of the product’s mirror-image isomer (in chemists’ terms, the reaction is said to be enantioselective). Moreover, the process does not require the use of highly reactive and fragile reagents.

The authors’ approach requires three reagents: an alkene, a silane and an alkyl halide (Fig. 1a). Alkenes are not sensitive to air, which distinguishes Fu and colleagues’ reactions from the majority of cross-coupling reactions4, in which the alkene is replaced by an air-sensitive organometallic compound, either as a reagent or as the precursor to a reagent. The new reactions seem to involve an orchestrated set of events wherein the alkene first attaches to a catalytic nickel complex, which is generated in situ by a process that involves the silane reagent. The attachment of the alkene produces a transient reactive species, which then reacts with the alkyl halide to form the new C–C bond.

Fu and co-workers’ nickel-catalysed process is related to one reported5 by another team in 2016, but enhances the usefulness of that approach by addressing two key challenges. First, a catalyst had to be identified that not only promotes stereoselective C–C bond formation for an array of different substrates, but also activates the alkene without promoting side reactions between the silane and either the alkyl halide or the alkene. Second, reaction conditions had to be identified that allowed a

base to drive catalytic cycles — which is difficult in this context, because bases often interconvert mirror-image isomers.

Not only is the use of alkenes as replacements for reactive organometallic reagents appealing in terms of its practical simplicity, but it also broadens the range of substrates that can be used in Fu and colleagues’ reactions. Alkenes are widely available, many are produced industrially on a large scale, and they can be generated by a variety of chemical processes. Alkenes are also especially attractive as reagents for chemical synthesis: they are chemically inert to a range of reagents, but can be induced to react in the presence of the right catalyst and under the right set of conditions. Impressively, the catalytic conditions used by the authors allow alkenes to react without interference when a variety of other common organic groups are also attached to the alkene (see Fig. 2a of the paper1).

Intriguingly, when Fu and colleagues used internal alkenes — in which the characteristic carbon–carbon double bond of the alkene is in the middle of a chain of carbon atoms — in their reactions, they observed a phenomenon called chain-walking6, which causes the double bond to migrate to the end of the carbon chain before reacting. This observation means that products obtained from an increasingly used type of reaction known as olefin cross-metathesis7 (which produces internal alkenes) might be suitable substrates. It will also be exciting to find out whether the step in which the alkene attaches to the nickel complex can be made to be enantioselective, because this would allow products containing multiple stereogenic centres (carbon atoms to which three different groups are attached by carbon atoms) to be generated enantioselectively.

A particularly notable feature of Fu and co-workers’ strategy is that a considerable array of alkyl halides can be used, some of which are not effective substrates for cross-coupling reactions with organometallic reagents. For example, the authors use alkyl halides known as secondary α-halo amides in their reactions, and show that this provides a simple and enantioselective route to prepare compounds that contain a carbonyl (C=O) group next to a stereogenic centre (Fig. 1b). Such compounds are potentially versatile intermediates for chemical synthesis, and have most commonly been prepared using a much less efficient approach based on the use of compounds called chiral auxiliaries8. The researchers also demonstrate that they can use their enantioselective reactions to make certain fluorine-containing compounds (see Fig. 1c, for example), which might be useful in medicinal chemistry. Moreover, the chemistry can be used to make compounds that contain quaternary stereocentres (Fig. 1d) — carbon atoms to which four different groups are attached by carbon atoms, which are some of the most difficult structures to prepare enantioselectively.

Overall, this advance is a much-needed method for the enantioselective synthesis of an impressive assortment of versatile small organic molecules, many of which will be of value to research at the frontiers of chemistry.

References1. Wang, Z., Yin, H. & Fu, G. C. Nature 563, 379–383 (2018).2. Trauner, D. Angew. Chem. Int. Edn 57, 4177–4191 (2018).3. Nguyen, L. A., He, H. & Pham-Huy, C. Int. J. Biomed. Sci. 2, 85–100 (2006).4. Magano, J. & Dunetz, J. R. Chem. Rev. 111, 2177–2250 (2011).5. Lu, X. et al. Nature Commun. 7, 11129–11136 (2016).6. Vasseur, A., Bruffaerts, J. & Marek, I. Nature Chem. 8, 209–216 (2016).7. Hoveyda, A. H. & Zhugralin, A. R. Nature 450, 243–251 (2007).8. Kohler, M. C., Wengryniuk, S. E. & Coltart, D. M. in Stereoselective Synthesis of Drugs and

Natural Products (eds Andrushko, V. & Andrushko, N.) 183–213 (Wiley, 2013).

Moroeng, O.M., Wagner, N.J., Hall, G., Roberts, R.J., 2018. Using δ15N and δ13C and nitrogen functionalities to support a fire origin for certain inertinite macerals in a No. 4 Seam Upper Witbank coal, South Africa. Organic Geochemistry 126, 23-32.


Fires are likely to have been central to the formation of certain inertinite macerals in South African coals. To investigate this hypothesis, a Permian, medium rank C bituminous Witbank coal (No. 4 Seam Upper) was density fractionated to yield an inertinite-rich and a vitrinite-rich sample, and assessed using stable nitrogen and carbon (δ15N and δ13C) isotopes in conjunction with nitrogen functionalities. The parent coal comprises of 41.6 vol% vitrinite and 48.5 vol% inertinite. The vitrinite-rich sample is dominated by collotelinite and collodetrinite (81 vol% vitrinite), and the inertinite-rich sample by fusinite, semifusinite, and inertodetrinite (63 vol% inertinite). The δ15N and δ13C values and nitrogen functionalities were used to constrain early coal formation pathways for the dominant macerals in the density fractionated samples. The vitrinite-rich sample has a lower δ13C relative to the inertinite-rich counterpart. However, the inertinite-rich sample has the lower δ15N value, along with a lower concentration of N-quaternary and higher N-pyrrolic compounds. Because these samples are of the same coal maturity, and the major macerals were derived from similar precursors, differences in δ15N and δ13C and nitrogen functionalities reflect differences in coal formation pathways. Degradation of 13C-rich cellulose in wood through either charring or bacterial activity leads to lower δ13C values. The lower 14N content for the vitrinite-rich sample along with higher N-quaternary and N-pyridinic suggests cellulose degradation driven by bacterial activity. In contrast, the higher 14N coupled with higher N-pyrrolic and N-oxide complexes for the inertinite-rich sample, suggests fusinite and semifusinite were formed through charring. Inertodetrinite is attributed to the disintegration of the charred matter.

Morrison, A.E., Dhoonmoon, C., White, H.K., 2018. Chemical characterization of natural and anthropogenic-derived oil residues on Gulf of Mexico beaches. Marine Pollution Bulletin 137, 501-508.


Oil residues originating from the Deepwater Horizon (DWH) incident persist on Gulf of Mexico beaches alongside oil from offshore industrial activity, natural seepage, and asphalt from parking lots and roads. To determine the primary differences in the chemical composition of these oil residues, a variety of samples were collected from beaches from Florida to Alabama over a two-year period from 2015 to 2017. Bulk chemical characteristics of the oil residues were examined via gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC–MS), as well as thin layer chromatography with flame ionization detection (TLC-FID), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR). These bulk chemical analyses revealed features unique to the different sample types, expanding our understanding of the chemical composition and variability of persistent oil residues, and providing a means to detect and monitor their long-term fate in the coastal environment.

Nader, F.H., Inati, L., Ghalayini, R., Hawie, N., Bou Daher, S., 2018. Key geological characteristics of the Saida-Tyr Platform along the eastern margin of the Levant Basin, offshore Lebanon: implications for hydrocarbon exploration. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 50.


More than 60 trillion cubic feet (Tcf) of natural gas have been recently discovered in the Levant Basin (eastern Mediterranean region) offshore Cyprus, Egypt and Israel, Palestine. Un-explored areas, such as the Lebanese offshore, may yield additional discoveries. This contribution focuses the Saida-Tyr Platform (STP), an offshore geological feature adjacent to the southern Lebanese coastline – part of the eastern margin of the Levant Basin. First, an extensive synthesis of recent published research work, tackling crustal modeling, structural geology and stratigraphy will be presented. Then, a new local crustal model and the interpretation of seismic reflection specifically on the STP are discussed and emplaced in the context of the upcoming petroleum exploration activities in this region. Characteristic structural features form the limits of the STP which is believed to be an extension of the Arabian continent into the Levant Basin. Its westernmost limit consists of the extension of the crustal interface, previously termed “hinge zone”, where major plate-scale deformations are preferentially localized. The northward extension of this “hinge zone” beyond the STP can be mapped by means of major similar deformation structures (i.e. S-N-trending anticlines) and can be associated to the Levant Fracture System (LFS) – the northwestern border of the Arabian plate. The northern limit of the STP (i.e. the Saida Fault) is a typical E-W, presently active, structure that is inherited from an older, deeply rooted regional fault system, extending eastward throughout the Palmyra Basin. The STP is characterized by a variety of potential plays for hydrocarbon exploration. Jurassic and Cretaceous clastics and carbonates are believed to include reservoir plays, which could have been charged by deeper Mesozoic source rocks, and sealed by Upper Cretaceous marly layers. The edge of the Cretaceous carbonate platforms and potential carbonate buildups are well recognizable on seismic reflection profiles. The western and northern anticlinal structures bordering the STP are excellent targets for Oligo-Miocene biogenic gas charging systems. Based on integrating geodynamics, tectono-stratigraphic interpretations and petroleum systems analyses, such plays are well constrained and the exploration risk is therefore lowered.



Elemental and/or isotopic signatures of calcareous tests of foraminifera are commonly used to reconstruct paleoenvironmental conditions. A major problem, often referred to as the vital effect, is that such geochemical signatures stored in inorganic calcium carbonates differ greatly under the same environmental conditions, as well as between taxa, species, individuals, etc. This effect was previously explained by relative contributions between passive vs. active ion transport patterns, but their details are still under investigation. In this study, the functional role of pseudopodial structures during chamber formation is elucidated by detailed observation of Ammonia beccarii (Linnaeus, 1758) using a time-lapse optical imaging system and high-resolution electron microscopy. We document triple organic layers sandwiching carbonate precipitation sites for the first time. The three major organic layers (outer organic layer, primary organic sheet, and inner organic layer) are formed by an initial framework of pseudopodia overlaid with further layer-like pseudopodia. The primary organic sheet seems to facilitate early calcium carbonate nucleation, then entrapped by double precipitation sites. We further show that calcification starts when outer or inner organic layers still exhibit tiny gaps (holes within the framework) that may serve as pathways for passive ion exchange (e.g. Mg2+) between seawater and the confined precipitation space. Nevertheless, the majority of wall thickening occurs when the precipitation site is completely isolated from seawater, which implies active ion exchange. This may explain the differences in Mg∕Ca ratios in early and later stages of calcification observed in previous studies. Our study provides insight into resolving a key missing piece in understanding foraminiferal calcification through culture experiments and in-depth

observations of living animals. Our findings contribute to interpreting and understanding biogeochemical proxies by showing that the vital effect, specifically elemental and isotopic ratios along chamber walls, is directly linked to spatio-temporal organization of the biomineralization sandwich controlled by the three major organic layers.

Naimark, E., Kalinina, M., Shokurov, A., Markov, A., Zaytseva, L., Boeva, N., 2018. Mineral composition of host sediments influences the fossilization of soft tissues. Canadian Journal of Earth Sciences 55, 1271-1283.


Cambrian Lagerstätten host rocks are frequently composed of kaolinite and chlorite in varying amounts; accordingly, our goal was to study the preservation potential of crustaceans in these two clays. We conducted long-term experiments (12–18 months, the longest duration of actualistic taphonomy experiments from published literature) on the decay of Artemia salina in these clay sediments. The degree of preservation, transformed mineralogical composition of the sediments, and the elemental composition of the nauplial remains were examined. We demonstrate that the kaolinite and chlorite sediment enhanced the preservation (in the kaolinite the effect was considerably higher than in the chlorite) compared with the sediment-free control. pH inside the sediments dropped to 6.5–7.1 and was even lower (<4) around the buried carcasses, facilitating the dissolution of clays. This phenomenon was confirmed by mineralogical analyses of the experimental sediments, which showed mineralogical signatures of such dissolution and new mineral phases. According to the variations in the dissolved minerals in the sediments, different cations entered the buried remains as was shown by the multiple energy dispersive X-ray analyses. An increased level of Mg was detected in the carcasses buried in chlorite, whereas Al and Si concentrations were higher in the kaolinite; in both cases, Ca rapidly entered the decaying tissues from marine water. Bacteria underwent similar mineralization as the macroremains and apparently had no direct effect on the mineralization. The results confirmed an important role of dissolved Al ions in preservation of soft-bodied organisms in clay-dominated sediments and explained wide variation in chemical composition of their fossils.

Nandwani, S.K., Chakraborty, M., Gupta, S., 2019. Chemical flooding with ionic liquid and nonionic surfactant mixture in artificially prepared carbonate cores: A diffusion controlled CFD simulation. Journal of Petroleum Science and Engineering 173, 835-843.


Improved computational techniques have served as reliable tool in providing accurate reservoir characterisation and also predicting production of oil for a given EOR process. In the present study, COMPUTATIONAL FLUID DYNAMICS (CFD) has been used to simulate surfactant flooding experiments in a 3D geometrical model that replicates an actual artificially prepared calcite powder packed bed (a proxy of carbonate reservoir)) in which core flooding experiments have been carried out. The surfactant slug used in the study is a high salinity aqueous mixture containing surface active ionic liquid (C16mimBr) and a nonionic surfactant (TERGITOL 15-S-9). ANSYS WORKBENCH 15.0 software is used to create the 3D geometry and ANSYS FLUENT 15.0 has been used for solving the governing equations for the system. A mixture model is considered as the multiphase model to study the flow of multiple phases in the porous bed. To take into account the mass transfer of the surfactant into the oil phase as well as the water phase, a species transport model is incorporated in the present simulation.

Simulation results were confirmed by the experimental data such that the species transport model coupled with mixture model were found to fit in well to the multiphase flow dynamics. It was found that the mixed surfactants system showed higher efficiency in recovering oil due to minimal fingering effects, ultralow IFT between the surfactant solution and oil and low diffusion rates of surfactant species into residual oil and brine. A delayed water breakthrough time was observed during simulation which attributed to higher oil recovery. Also there was a good match in water breakthrough time for both simulation and experimental surfactant flooding process.

Natali, C., Bianchini, G., Vittori Antisari, L., Natale, M., Tessari, U., 2018. Carbon and nitrogen pools in Padanian soils (Italy): Origin and dynamics of soil organic matter. Chemie der Erde 78, 490-499.


Carbon and nitrogen elemental (C-N, wt%) and isotopic (δ13C-δ15N, ‰) investigation has been carried out on alluvial and deltaic soils from the Padanian plain (northern Italy), an area interested by intensive agricultural activities, to refine previous inferences on depositional facies, pedogenetic processes and anthropogenic influences. Soil analysis, carried out by EA-IRMS, have been focused on inorganic and organic fractions properly speciated by a thermally-based method, whereas further insights on the organic matter constituents have been obtained by sequential fractionation. The bulk EA-IRMS analyses reveal a remarkable compositional heterogeneity of the investigated soils (TC 0.89 to 11.93 wt%, TN 0.01 to 0.78 wt%, δ13CTC -1.2 to -28.2‰, δ15N -1.2 to 10.0‰) that has to be explained as an integration between inorganic and organic pools. The latter have been subdivided in Non-Extractable Organic Matter (NEOM, δ13C -16.3 to -28.6‰) and in extractable fractions as Fulvic (FA, δ13C -24.7 to -27.5‰, δ15N 0.6 to 5.7‰) and Humic (HA, δ13C -24.6 to -27.0‰, δ15N 1.0 to 9.7‰) Acids, which have been used to infer soil dynamics and Soil Organic Matter (SOM) stability processes. Results indicate that SOM at depth of 100 cm was generally affected by microbial reworking, with the exception of clayey and peaty deposits in which biological activity seems inhibited. Peaty and clayey soils display an organic fraction loss of ca. 20% toward the surface, suggesting deterioration possibly induced by intensive agricultural activities. These latter may be the cause of the ubiquitous losses of organic fraction throughout the investigated area over the last seventy years, evaluated by the comparison with historical data on corresponding topsoils. The obtained insights are very important because these soils are carbon (and nitrogen) sinks that are vulnerable and can be degraded, loosing agricultural productivity and potentially contributing to greenhouse gases fluxes.

Neubauer, C., Sweredoski, M.J., Moradian, A., Newman, D.K., Robins, R.J., Eiler, J.M., 2018. Scanning the isotopic structure of molecules by tandem mass spectrometry. International Journal of Mass Spectrometry 434, 276-286.


Biomolecules generally exist as mixtures of diverse isotopologues that differ in the number and sites of rare-isotope substitutions. The exact proportion of isotopologues of a biomolecule may depend on the molecular, cellular, organismal and environmental factors involved in its biosynthesis, localization and consumption. Molecular isotopic structure can thus be a valuable tool to elucidate biochemical mechanisms and for the reconstruction of physiological, ecological and climatic processes. However, little information about this record is accessible by conventional methods of stable isotope chemistry. Here, we report an easy to implement mass spectrometric method that quantifies intramolecular isotope distributions and is specifically designed for use on samples containing low, natural abundances of the rare isotopes. Its essential feature is the use of a narrow

initial mass selection window to isolate ions that are heavier due to the presence of one or more isotopic substitutions. This pre-selection greatly increases the relative proportions of the various rare-isotope substituted isotopologues. The selected ions are then fragmented, and within seconds to minutes the isotopic pattern of the fragment peaks reveals information about the intramolecular distribution of isotopes. This approach requires ∼0.1–10 nanomole of analyte, which is about five orders of magnitude less than NMR. We demonstrate the ability to measure the site-specific isotope ratios of metabolites by resolving the 13C content in the amino acid methionine among multiple non-equivalent carbon sites. This technique enables rapid origin assignments for a wide range of organic molecules and can be used for new applications of molecular isotopic structure in medicine and environmental sciences.

Neveu, M., Hays, L.E., Voytek, M.A., New, M.H., Schulte, M.D., 2018. The ladder of life detection. Astrobiology 18, 1375-1402.

https://doi.org/10.1089/ast.2017.1773

We describe the history and features of the Ladder of Life Detection, a tool intended to guide the design of investigations to detect microbial life within the practical constraints of robotic space missions. To build the Ladder, we have drawn from lessons learned from previous attempts at detecting life and derived criteria for a measurement (or suite of measurements) to constitute convincing evidence for indigenous life. We summarize features of life as we know it, how specific they are to life, and how they can be measured, and sort these features in a general sense based on their likelihood of indicating life. Because indigenous life is the hypothesis of last resort in interpreting life-detection measurements, we propose a small but expandable set of decision rules determining whether the abiotic hypothesis is disproved. In light of these rules, we evaluate past and upcoming attempts at life detection. The Ladder of Life Detection is not intended to endorse specific biosignatures or instruments for life-detection measurements, and is by no means a definitive, final product. It is intended as a starting point to stimulate discussion, debate, and further research on the characteristics of life, what constitutes a biosignature, and the means to measure them.



Abstract: Here, a new medium, named intensive soil extract medium (ISEM), based on new soil extract (NSE) using 80% methanol, was used to efficiently isolate previously uncultured bacteria and new taxonomic candidates, which accounted for 49% and 55% of the total isolates examined (n = 258), respectively. The new isolates were affiliated with seven phyla (Proteobacteria, Acidobacteria, Firmicutes, Actinobacteria, Verrucomicrobia, Planctomycetes, and Bacteroidetes). The result of chemical analysis showed that NSE included more diverse components of low-molecular-weight organic substances than two conventional soil extracts made using distilled water. Cultivation of previously uncultured bacteria is expected to extend knowledge through the discovery of new phenotypic, physiological, and functional properties and even roles of unknown genes.

Importance:Both metagenomics and single-cell sequencing can detect unknown genes from uncultured microbial strains in environments, and either method may find the significant potential metabolites and roles of these strains. However, such gene/genome-based techniques do not allow detailed investigations that are possible with cultures. To solve this problem, various approaches for

cultivation of uncultured bacteria have been developed, but there are still difficulties in maintaining pure cultures by subculture.

Ni, X.M., Jia, Q.F., Wang, Y.B., 2018. Characterization of permeability changes in coal of high rank during the CH4-CO2 replacement process. Geofluids 2018, 8.

https://doi.org/10.1155/2018/8321974

The influences of coal matrix expansion/contraction and effective stress on the permeability of coal with different thermal maturities are different during the CH4-CO2 replacement process due to different mechanical properties and gas adsorption capacities. To accurately predict the variation law of coal permeability during the CH4-CO2 replacement process, it is critical to understand how the matrix expansion/contraction and effective stress affect the permeability of coal at different thermal maturities during the CH4-CO2 replacement. In this study, the permeability of two coal specimens with anthracite and high-rank bituminous coal during the CH4-CO2 replacement process under different confining and injection pressures was tested using a CBM replacement testing machine. The results demonstrate that with decreasing gas injection pressure, the permeability of the two coal specimens exhibited a U-shaped correlation under different confining pressures. Under the same gas injection pressure, with increasing effective stress, the permeability presented a negative exponential decrease and the permeability of the anthracite decreased more significantly. Moreover, under the same confining pressure, with increasing gas injection pressure, the decreasing permeability agreed with Langmuir curve and the permeability of high-rank bituminous coal was more significantly reduced.

Nicholson, D.P., Michel, A.P.M., Wankel, S.D., Manganini, K., Sugrue, R.A., Sandwith, Z.O., Monk, S.A., 2018. Rapid mapping of dissolved methane and carbon dioxide in coastal ecosystems using the ChemYak autonomous surface vehicle. Environmental Science & Technology 52, 13314-13324.


Coastal ecosystems host high levels of primary productivity leading to exceptionally dynamic elemental cycling in both water and sediments. In such environments, carbon is rapidly cycled leading to high rates of burial as organic matter and/or high rates of loss to the atmosphere and laterally to the coastal ocean in simpler forms, such as carbon dioxide (CO2) and methane (CH4). To better understand carbon cycling across these heterogeneous environments, new technologies beyond discrete sample collection and analysis are needed to characterize spatial and temporal variability. Here, we describe the ChemYak, an autonomous surface vehicle outfitted with a suite of in situ sensors, developed to achieve large spatial scale chemical mapping of these environments. Dissolved methane and carbon dioxide are measured by a laser spectrometer coupled to a gas extraction unit for continuous quantification during operation. The gas-powered vehicle is capable of rapidly surveying the coastal system with an endurance of up to 10 h at operating speeds in excess of 10 km h–1. Here, we demonstrate its ability to spatially characterize distributions of CO2, CH4, oxygen, and nitrate throughout a New England saltmarsh estuary.

Nicot, J.-P., Gherabati, A., Darvari, R., Mickler, P.J., 2018. Salinity reversal and water freshening in the Eagle Ford Shale, Texas, USA. ACS Earth and Space Chemistry 2, 1087-1094.

https://doi.org/10.1021/acsearthspacechem.8b00095

Effective, considerate shale play water management supports operations and protects the environment. A parameter often overlooked is total dissolved solids (TDS) of produced water from the formation. Knowledge of TDS is important to meet these dual goals. Subsurface TDS typically increases with depth. However, produced-water samples from the Eagle Ford Shale show a strong TDS decrease by a factor of ~10 with increasing well depth (~200,000 ppm at ~2.5 km to 18,000 ppm at ~3.6 km). Water stable isotopes strongly suggest that the low TDS is not due to dilution by meteoric water. Rather, we attribute the change to smectite-to-illite conversion, in which the smectite interlayer water is released into the pore space. Depth, temperature, and other related indicators (source for K, excess silica) support such a mechanism. In addition, water-isotope patterns and 87Sr/86Sr ratios suggest a conversion operating with limited contributions external to the shale. Order-of-magnitude calculations show that the 8% of mixed-layer clay present on average in the Lower Eagle Ford Shale is sufficient to bring formation water TDS to observed levels when some of the resident water is expelled. Understanding that the low salinity is an intrinsic property of the formation water rather than due to short-term mixing allows stakeholders to have a more optimistic outlook on water recycling and on using produced water for other uses (irrigation, municipal).

Niemeyer, H.M., de Souza, P., Camilo, C., Echeverría, J., 2018. Chemical evidence of prehistoric passive tobacco consumption by a human perinate (early Formative Period, South-Central Andes). Journal of Archaeological Science 100, 130-138.


Consumption of psychoactive substances is a long-standing tradition among indigenous peoples of the Americas. Archaeologically, consumption of tobacco has been shown through analysis of archaeological smoking pipe residues, mummy hair and dental calculus. Analysis of the hair of a perinate recovered from a rock shelter in Northern Chile and dated ca. 2400 yrs BP showed the presence of nicotine and its main metabolic product, cotinine. Quantitative segmental hair analysis showed that nicotine was taken up from the mother via the placenta and not through breast milk and that the death of the perinate occurred soon before or at the time of delivery. The analysis also indicated that the mother consumed high quantities of tobacco, suggesting she was a “tobacco shamaness” who might have experienced a miscarriage, since tobacco consumption by pregnant women is strongly associated to spontaneous abortions and perinatal death. Thus, at the dawn of pastoralism and agriculture in the highlands of the Atacama Desert, female individuals were already intensively consuming this psychoactive plant, transmitting its signals, and perhaps its lethal effects, to a child during gestation. This is the first evidence of simultaneous presence of nicotine and cotinine in pre-Hispanic bioanthropological remains from the Americas, thus constituting unequivocal direct evidence of tobacco consumption, and it refers to the currently earliest and youngest passive tobacco consumer in the Americas.

Norrman, K., Sølling, T.I., Ceccato, M., Stamate, E., Bovet, N., Stipp, S.L.S., 2018. Chemical composition and structure of adsorbed material on pore surfaces in Middle East reservoir rocks. Energy & Fuels 32, 11234-11242.


Several recent studies have shown that some skeletal limestone reservoirs are far more oil-wet than the typical, water wet, biogenic, limestone reservoirs, such as chalk. It is challenging, even with state-of-the-art approaches, to completely remove the residual hydrocarbons from skeletal limestone core samples and restore the pore surfaces to the water wet conditions that are assumed to prevail before oil entered from the source rock. We used a combination of gas chromatography mass spectrometry,

X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry to investigate pore surface composition and we propose an explanation for the phenomena. The hydrophobic nature of pore surfaces is likely caused by adsorbed organic molecules that are strongly attached to the calcite surfaces through carboxylic functional groups and their fatty ends serve as anchors for the lipophilic oil components. The strong binding of the carboxylate to the pore surfaces explains why it is only possible to remove some of the organic material using the conventional core cleaning methods, such as Soxhlet solvent extraction. Unless a solvent is able to replace the carboxylate terminated species, the rock remains oil-wet or at least mixed wet, regardless of the type or extent of the cleaning procedure.

Nowak, A., Hodson, A., Turchyn, A.V., 2018. Spatial and temporal dynamics of dissolved organic carbon, chlorophyll, nutrients, and trace metals in maritime Antarctic snow and snowmelt. Frontiers in Earth Science 6, 201. doi: 10.3389/feart.2018.00201.


Despite scientific interest in the investigation of biogeochemical changes in meltwaters of the Antarctic Peninsula, we still lack an understanding of the seasonal dynamics and release of dissolved and particulate carbon, nutrients, as well as trace metals from Antarctic snowpacks. Harsh conditions, lack of appreciation of the heterogeneity of the environment, as well as logistical constraints during fieldwork mean there is great demand for more detailed and comprehensive research. Therefore, a unique, comprehensive study of snowpack biogeochemistry was performed in the Ryder Bay area of the Antarctic Peninsula during the entire 2016/2017 melt season. Two-hundred snowpack and snowmelt samples were collected throughout the campaign, to quantify for the first time, seasonal dynamics and export of dissolved carbon, in-vivo chlorophyll, nutrient and trace metals from Antarctic snowpack in various locations. Our study uncovered the importance of environmental heterogeneity with respect to the export of solutes and carbon. A distinctive split in the temporal dynamics of solute export was found, suggesting that some solutes are rapidly delivered to coastal environments early in the summer whilst others are delivered more gradually throughout it. Coastal, low elevation snowpacks were identified as “power plants” of microbial activity, playing an important role in the regulation of land-ocean fluxes of labile carbon and bio-limiting macro- and micro-nutrients. We also found that multiannual snow residing deep below the surface can further contribute to biogeochemical enrichment of coastal ecosystems. Additionally, inland snowpack have been identified as a store for nutrients, dissolved organic carbon and chlorophyll. Lastly, we show that a number of factors (environmental characteristics, geochemical heterogeneity and internal biogeochemical processes in snow) make simple snowpack surveys insufficient for the prediction of biogeochemical fluxes carried by snowmelt runoff into the marine environment. A return to significant fieldwork-based research in Antarctica is therefore necessary to advance our knowledge of the complex biogeochemical processes occurring there. This study therefore provides crucial data and process insights for more accurate predictions of how changing climate will influence the Antarctic carbon cycle and the globally important Southern Ocean ecosystem.

Nutz, A., Schuster, M., 2018. Comments on: “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya” by Lupien et al. [Quat. Sci. Rev. 186 (2018), 225–235]. Quaternary Science Reviews 201, 505-507.


Refers to: R.L. Lupien, J.M. Russell, C. Feibel, C. Beck, I. Castañeda, A. Deino, A.S. Cohen. A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya. Quaternary Science Reviews 186, 225-235

Referred to by: R.L. Lupien, J.M. Russell, C. Feibel, C. Beck, I. Castãneda, A. Deino, A.S. Cohen, Reply to comments by Nutz and Schuster (2018) on “A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya” Quaternary Science Reviews 201, 508-510

In a recent paper, Lupien et al. (2018) present an innovative study of an HSPDP drill core recovered from West Turkana (Kenya) (Cohen et al., 2016). The authors use shifts in the hydrogen-isotope composition of terrestrial leaf waxes as a proxy of changes in regional hydrology between 1.86 and 1.37 Ma, a critical period for human evolution. This remarkable study provides valuable and novel Quaternary paleoclimate proxy data for the Turkana Depression and, as such, represents an important contribution to geological and paleoenvironmental investigations in this area. Nonetheless, some interpretations of this recent paper are in contradiction with field interpretations published by Nutz et al. (2017), a paper not cited nor discussed by Lupien et al. (2018). Hence, we believe that some of the interpretations of Lupien et al. (2018) should be discussed and nuanced.

Nutz et al. (2017) applied facies and sequence stratigraphy analyses to exposed sediments of the Nachukui Fm (Omo Group) along the western shore of Lake Turkana. Dated between 1.95 and 1.72 Ma, the period discussed in Nutz et al. (2017) covers ca. 29% of the period discussed by Lupien et al. (2018). Based on a sedimentary succession that ranged from offshore to coastal lake depositional environments, Nutz et al. (2017) traced the progradation-retrogradation patterns of the paleoshoreline. They reflect regression-transgression of paleolake Turkana, and serve as a proxy of regional hydroclimate evolution. Nutz et al. (2017) demonstrated that from 1.95 to 1.72 Ma (i) the expansion and contraction of paleolake Turkana occurred at an orbital scale with a first-order trend of 400 ka (eccentricity) having superimposed higher frequency cycles at 20 ka (precession), (ii) the 400-ka periodicity drove important changes in bathymetry (>40 m), and (iii) the 20-ka periodicity triggered more limited changes in bathymetry (<25 m) associated with a relatively restricted lateral shift of the shoreline (3–4 km); these changes are of a lower magnitude than those of the last African Humid Period (Holocene). Finally, Nutz et al. (2017) conclude that from 1.95 to 1.72 Ma the lake level of paleolake Turkana was relatively stable. Thus, this period does not reflect a period of marked climate variability.

Hereafter, we focus on five points of Lupien et al. (2018) for which interpretations are, in our view, not accurate or that are contradicted by direct field observations....

To conclude, core analysis such as the one provided by Lupien et al. (2018) is essential for identifying the climate processes that have impacted a particular region. However, the study of outcrops, such as presented in Nutz et al. (2017), remains the only approach permitting the deciphering of the real impacts of the different climate processes on paleoenvironments and paleolandscapes. Since both of these aspects are crucial, especially when discussing the context of human evolution, we believe that future methodological breakthroughs will involve a combined approach to prevent over-interpretations of both 1-D high-resolution proxy analysis and 2.5-D outcrop-based studies.

Ogala, J.E., Kalaitzidis, S., Christanis, K., Omo-Irabor, O.O., Akinmosin, A., Yusuf, C.U., Pasadakis, N., Constantinopoulos, M., Papaefthymiou, H., 2019. Geochemical and organic petrological study of bituminous sediments from Dahomey Basin, SW Nigeria. Marine and Petroleum Geology 99, 577-595.


The Dahomey Basin, SW Nigeria, hosts a 3000-m-thick sedimentary succession of Cretaceous and Cenozoic age, of which the Turonian-Maastrichtian Afowo Formation includes sandstones, arkoses, shales, shelly limestones, unconsolidated sand, clay and most importantly, bituminous (tar) sand strata. Eighteen samples were picked up from outcrops exposed by streams and channels, and were examined applying sedimentological, mineralogical, petrographical, geochemical (inorganic and organic) and radiological techniques with the aim of assessing the origin and the thermal maturity of the organic facies. The samples represent mostly coarse-grained sands and subordinately shales, referred usually as ‘tar sands’; they consist of mainly quartz and kaolinite, with variable amounts of mixed clay layers of illite-montmorillonite, mica and pyrite, probably derived from weathering of the Migmatite Gneiss Complex exposed to the north of the basin; this can also explain the relative enrichment in the natural radionuclides 40K, 238U, 226Ra and 232Th for some samples, although the radioactivity falls within the range for world values for soils. The clastic material of Afowo Formation was deposited in a rather oxic shallow marine environment. The particulate organic matter of the bituminous sediments comprises solid hydrocarbons, coalified (huminite) and partially oxidized (inertinite) remnants of terrestrial plants, and minor amounts of both terrestrial and marine liptinite macerals. The random reflectance values of the indigenous huminite population ranges between 0.40 and 0.45% pointing to an immature stage for oil generation. The respective reflectance of the migrabitumens ranges from 0.49 to 0.59% corresponding to vitrinite equivalent reflectance values of 0.70–0.76% falling well within the oil window. This study concludes that the hydrocarbons contained in the Afowo Formation are upwards migrating from parts of the basin where Afowo Formation has subsided at depths corresponding well within the oil window; the source rock corresponds to the middle shale horizon, whereas the sandy horizons act as migration paths and/or reservoirs.

Olarte, M.V., Albrecht, K.O., Bays, J.T., Polikarpov, E., Maddi, B., Linehan, J.C., O'Hagan, M.J., Gaspar, D.J., 2019. Autoignition and select properties of low sample volume thermochemical mixtures from renewable sources. Fuel 238, 493-506.


Catalytic thermochemical processes can convert biomass-derived liquids into hydrocarbon mixtures that are potential liquid transportation blendstocks. However, few measurements of the autoignition behavior of these mixtures are reported in the open literature. Pacific Northwest National Laboratory reports on the autoignition behavior of 36 mixtures of catalytically upgraded liquids—including distillation fractions—from biomass liquefaction technologies. The technologies whose output was subsequently upgraded include direct routes (fast pyrolysis and hydrothermal liquefaction) and indirect routes (syngas to ethanol). The propensity of the biomass-derived hydrocarbons to autoignite was measured using an ignition quality tester (IQT) according to ASTM D6890, which measures the time it takes a fuel-air mixture to autoignite under conditions relevant to cetane number measurements to yield a derived cetane number (DCN). This measurement was converted to a derived research octane number (dRON) using three empirical correlations reported in the literature (Kalghatgi et al., 2005; Naser et al., 2017; McCormick et al., 2017). The simulated distillation curve of each sample was measured using ASTM D2887, and the autoignition behavior in different boiling range fractions was evaluated. Gas chromatography/mass spectrometry and 1H/13C nuclear magnetic resonance spectroscopy were used to determine the chemical composition of the liquids, and the impact on the research octane number of various functional groups present in the mixture was assessed. In general, aromatics and olefins enhanced octane number, in agreement with existing literature. The presence of esters was also found to increase dRON. The dRON method required

smaller samples and gave an acceptable approximation of the research octane number measured using a certified fuel rating engine.

Old, G.H., Naden, P.S., Harman, M., Bowes, M.J., Roberts, C., Scarlett, P.M., Nicholls, D.J.E., Armstrong, L.K., Wickham, H.D., Read, D.S., 2019. Using dissolved organic matter fluorescence to identify the provenance of nutrients in a lowland catchment; the River Thames, England. Science of The Total Environment 653, 1240-1252.


Catchment based solutions are being sought to mitigate water quality pressures and achieve multiple benefits but their success depends on a sound understanding of catchment functioning. Novel approaches to monitoring and data analysis are urgently needed. In this paper we explore the potential of river water fluorescence at the catchment scale in understanding nutrient concentrations, sources and pathways. Data were collected from across the River Thames basin from January 2012 to March 2015.

Analysing emission excitation matrices (EEMs) using both PARAFAC and optimal area averaging produced consistent results for humic-like component 1 and tryptophan-like component 4 in the absence of a subset of samples that exhibited an unusual peak; illustrating the importance of inspecting the entire EEM before using peak averaging methods. Strong relationships between fluorescence components and dissolved organic carbon (DOC), soluble reactive phosphorus (SRP), and ammonium clearly demonstrated its potential, in this study basin, as a field based surrogate for nutrients. Analysing relationships between fluorescence, catchment characteristics and boron from across the basin enabled new insights into the provenance of nutrients. These include evidence for diffuse sources of DOC from near surface hydrological pathways (i.e. soil horizons); point source inputs of nutrients from sewage effluent discharges; and diffuse contributions of nutrients from agriculture and/or sewage (e.g. septic tanks).

The information gained by broad scale catchment wide monitoring of fluorescence could support catchment managers in (a) prioritising subcatchments for nutrient mitigation; (b) providing information on relative nutrient source contributions; and (c) providing evidence of the effectiveness of investment in pollution mitigation measures. The collection of high resolution fluorescence data at the catchment scale and, in particular, over shorter event timescales would complement broad scale assessments by enhancing our hydro-biogeochemical process understanding.

Olsson-Francis, K., Billi, D., Teske, A., de Vera, J.-P.P., 2018. Editorial: Habitability beyond Earth. Frontiers in Microbiology 9, 2645. doi: 10.3389/fmicb.2018.02645.


The question of whether Earth is a unique location for life remains one of the most enduring questions of our time. Geochemical data suggests that habitable environments may exist, or may have existed, elsewhere in the Solar System with promising targets including Mars and icy bodies where liquid water is believed to exist (Kargel, 2000; Grotzinger et al., 2014; Glein et al., 2015). Furthermore, potential habitable Exoplanets have been discovered where potentially there is sufficient atmospheric pressure to maintain liquid water (Jenkins et al., 2015; Gillon et al., 2017; Orosei et al., 2018). Yet, for life to exist it is not solely dependent on liquid water as it also needs bio-essential elements, an energy source, and the environmental conditions, that are conducive to life (Nixon et al., 2013). To investigate the feasibility of life elsewhere in the Solar System a combination of field and

laboratory based studies, in-situ space experiments, and theoretical modeling is required. Here, we present 14 original research papers, one mini review, and two hypothesis and theory papers highlighting the novel and diverse methods that are employed to investigate potential life beyond the Earth. The overall focus of this collection of work is to understand if terrestrial life could exist elsewhere in the Solar System, and if so, what evidence (bio-signatures) could be used to support or negate the hypothesis of life.

Our understanding of life in extreme environments on Earth forms the basic concepts of where life could exist elsewhere in the Solar System. Extremophilic microorganisms have adapted to live in environments where parameters, such as, pH, temperature and pressure, and water availability are deemed extreme. Determining the limits of life in regard to these parameters is important for defining the limits of life. As Schulze-Makuch et al. demonstrates the limits of terrestrial life can be used to outline a range of possible habitable environments, some that are present in our Solar System and others that are hypothetical.

Extreme environments on Earth can also be used as terrestrial analog sites. These are sites that exhibit similar environmental conditions, such as pH, pressure, atmosphere composition, and water availability, as environments on other planets or moons (Martins et al., 2017). Historically analog studies have predominantly been focused on Mars. Evidence proposes that conditions on early Mars were clement and less oxidizing than they are today (e.g., Carr and Head, 2010; Mangold et al., 2012). Data from Mars Science Laboratory (MSL) shows that habitable environments may have existed at Gale Crater (Grotzinger et al., 2014). Chemolithotrophy has been recommended ed as a plausible metabolism for life on Mars and using data from MSL, Price et al. suggests the feasibility of iron oxidation-nitrate reduction as a plausible metabolism for life on ancient Mars.

As the conditions on Mars evolved from wet to dry during the Hesperian period ephemeral lakes are thought to have formed. For example, the presence of hydrated magnesium sulfates within the rim of Columbia Crater is ascribed to the existence of a paleolake, which at times must have been hypersaline in nature (Wray et al., 2011). Pontefract et al. shows, using a sulfate rich analog site for the ancient hypersaline palolakes, Spotted Lake (British Columbia, Canada) that sulfate salt deposits may have offered periodically habitable environments, and could have concentrated and preserved organic materials or their biomarkers over geologic time.

On modern day Mars, the evaporitic past is evident by the widespread deposition of sulfate, perchlorates and chloride salts observed today on the martian surface (Wanke et al., 2001; Clark et al., 2005). It has been hypothesized that perchlorates may bind water from the atmosphere forming brines, which remain liquid at low temperatures (e.g., Toner and Catling, 2016). Beblo-Vranesevic et al. demonstrates that Hydrogenothermus marinus, a desiccation tolerant bacterium, was able to tolerate high concentrations of perchlorates, which highlights the possibility of using this microorganism as a model microorganism in future experiments. Evaporitic deposits on the surface of Mars also suggests that water in the near sub-surface would by saline. Recent work has emphasized that the hypersaline springs on Axel Heiberg are a unique analog to represent putative subsurface aquifers on Mars (e.g., Sapers et al.). Based on the microbial diversity within these hypersaline springs, Sapers et al. shows that even a small chemical variation in propinquities sites in the martian sub-surface would have significant implications for community structure, and resulting bio-signatures.

Increasingly, data suggests that habitable environments may exist in the sub-surface oceans of the icy moons. For example, the Galileo, Cassini-Huygens, and Hubble Space Telescope missions support the theory of a potential briny ocean beneath the outer ice shells of Europa, Ganymede and Enceladus. Using environmental characteristics of icy worlds and terrestrial glaciers and ice sheets,

Garcia-Lopez et al. concludes that the icy worlds such as Europa and Enceladus are the most likely locations to harbor life of the Solar System.

Analogue environments can also be used to test and develop new instrumentation for future life detection missions. Ideally these methods are low cost with small mass and energy requirement. Using the Canadian high Artic as an analog, Goordial proposes three techniques: the cryo-iPlate for culturing microorganisms (2) a Microbial Activity Microassay (MAM) plate (BIOLOG Ecoplate) for detecting viable extant microorganisms, and (3) the Oxford Nanopore MinION for nucleic acid detection and sequencing. Additionally, based on work carried out in the hyper-arid Namib Desert, Hinchliffe et al. recommends advanced photogrammetry as a method for future autonomous rovers to detect viable surface colonization on the surface of Mars. However, as Fox and Strasdeit discusses there are problems with misinterpreting bio-signatures on other planets and moons that need to be considered.

In addition to environmental analog studies, laboratory simulation experiments are used to further our understanding of potential processes on Mars. Based on data from past mission, Mars regolith analog material can be prepared and used to study potential biogeochemical cycling on Mars. Using Mars simulants as a source of metals, Kölbl et al. demonstrates that surface bioprocesses on the regolith surface could be used as a bio-signature for future missions. However, laboratory based experiments are short-term and Olsson-Francis et al. shows that combining laboratory based experiments with thermochemical modeling is a feasible method for identifying geochemical bio-signatures that are produced over geological timescales. Laboratory based simulation experiments are also used to determine the effect of the extraterrestrial conditions on microbial survivability and activity. For example, de la Torre Noetzel et al. establishes that lichens can survive 30 days in simulated Mars conditions, but the photobiont was unable to perform photosynthesis under these conditions. Microorganisms have been extensively studied under simulated conditions at the surface of Mars (for review see Olsson-Francis and Cockell, 2010). However, Bak et al. proves for the first time that stress effect induced by silicates abraded in a Mars-like atmosphere would be detrimental to life at the martian surface.

Laboratory simulation experiments have revealed that ionizing radiations represents the major hazard for microbial survival, persistence of detectable biosignatures, and operation of spacecraft equipment (Dartnell, 2011). The international STARLIFE-irradiation campaign studied the response of increased doses of ionizing radiation and heavy ions, mimicking Galactic cosmic rays, on astrobiological relevant microorganisms (Moeller et al., 2017). As part of this study, Pacelli et al. illustrates that exposure of the black fungus Cryomyces antarcticus CCFEE 515 showed that the fungus maintained high survival and metabolic activity with no detectable DNA and ultrastructural damage, even after the highest dose irradiation.

However, to fully understand the effect of extraterrestrial conditions on microorganisms and bio-signatures a combination of laboratory based and in-situ space experiments are required. Exposure experiments in Low Earth Orbit (LEO) exposes samples to several radiation types, such as ionizing, UV, and cosmic radiation (galactic cosmic rays and solar particle events) combined with other conditions, such as vacuum and dust bombardment, which cannot be simulated on Earth. Long-term exposure experiments are carried out on the outside on the International Space Station (ISS). Exposure facilities include the ESA funded EXPOSE-R and an in-depth description of the facility is described in detail by Rabbowet et al.. The samples are exposed long-term to the conditions of LEO to investigate the effect of exposure on microorganisms and their associated bio-signatures, before returning to Earth for analysis (for review see Cottin et al., 2017). Bio-signatures include biomarkers, such as carotenoid deinixanthin, which can be used as evidence on past life on Mars. Leuko et al. demonstrates that this biomarker is strongly resistant to LEO conditions and simulated Mars

conditions (when protected from solar radiation), suggesting that it could be used as a target for future missions.

In future, as technology develops microorganisms could play a key part in space exploration, such as in-situ resource utilization, and life support systems. On Earth, previous work has shown that the microorganism C. metallidurans CH34 is able to leach bio-essential elements from basaltic material (Olsson-Francis et al., 2010). Building on this work, Byloos et al. investigates the effect of space flight and long-term storage on C. metallidurans CH34 and interactions with basaltic material (a lunar-type rock), which was the first step to determining the feasibility of bio-mining in space. Although more work is needed the results may “open the door future studies and potential application in space.”

With future missions planned to Mars and the icy moons, understanding the limits of microbial life and their associated bio-signatures is vital. This Research Topic presents advances in our understanding of habitability and bio-signatures using a suit of state-of-the-art methods. To date research has predominantly focused on Mars, but as our understanding of the icy moons increases, our attention most expands to the outer Solar System.

ReferencesCarr, M. H., and Head, J. W. (2010). Geologic history of Mars. Earth Planet. Sci. Lett. 294, 185–203.

doi: 10.1016/j.epsl.2009.06.042Clark, B. C., Morris, R. V., Mclennan, S. M., Gellert, R., Jolliff, B., Knoll, A. H., et al. (2005).

Chemistry and mineralogy of outcrops at Meridiani Planum. Earth Planet. Sci. Lett. 240, 73–94. doi:

Cottin, H., Kotler, J. M., Billi, D., Cockell, C., Demets, R., Ehrenfreund, P., et al. (2017). Space as a tool for astrobiology: review and recommendations for experimentations in earth orbit and beyond. Space Sci. Rev. 209, 83–181. doi: 10.1007/s11214-017-0365-5

Dartnell, L. R. (2011). Ionizing radiation and life. Astrobiology 11, 551–582. doi: 10.1089/ast.2010.0528

Gillon, M., Triaud, A. H. M. J., Demory, B.-O., Jehin, E., Agol, E., Deck, K. M., et al. (2017). Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1. Nature 542, 456–460. doi: 10.1038/nature21360

Glein, C. R., Baross, J. A., and Waite, J. H. (2015). The pH of Enceladus' ocean. Geochim. Cosmochim. Acta 162, 202–219. doi: 10.1016/j.gca.2015.04.017

Grotzinger, J. P., Sumner, D. Y., Kah, L. C., Stack, K., Gupta, S., Edgar, L., et al. (2014), A.T.M.T. (2014). A habitable fluvio-lacustrine environment at Yellowknife Bay, Gale Crater, Mars. Science 343:14. doi: 10.1126/science.1242777

Jenkins, J. M., Twicken, J. D., Batalha, N. M., Caldwell, D. A., Cochran, W. D., Endl, M., et al. (2015). Discovery and validation of Kepler-452b: A 1.6 R⊕ Super Earth Exoplanet in the habitable zone of a G2 Star. Astronom. J. 150:56. doi: 10.1088/0004-6256/150/2/56

Kargel, J. S. E. A. (2000). Europa's crust and ocean: origin, composition, and the prospects for life. Icarus 148, 226–265. doi: 10.1006/icar.2000.6471

Mangold, N., Kite, E. S., Kleinhans, M. G., Newsom, H., Ansan, V., Hauber, E., et al. (2012). The origin and timing of fluvial activity at Eberswalde crater, Mars. Icarus 220, 530–551. doi: 10.1016/j.icarus.2012.05.026

Martins, Z., Cottin, H., Kotler, J. M., Carrasco, N., Cockell, C. S., Noetzel, R. D., et al. (2017). Earth as a tool for astrobiology-a european perspective. Space Sci. Rev. 209, 43–81. doi: 10.1007/s11214-017-0369-1

Moeller, R., Raguse, M., Leuko, S., Berger, T., Hellweg, C. E., Fujimori, A., et al. (2017). STARLIFE-an international campaign to study the role of galactic cosmic radiation in astrobiological model systems. Astrobiology 17, 101–109. doi: 10.1089/ast.2016.1571

Nixon, S. L., Cockell, C. S., and Cousins, C. R. (2013). Plausible microbial metabolisms on Mars. Astronomy Geophys. 54, 13–16. doi: 10.1093/astrogeo/ats034

Olsson-Francis, K., and Cockell, C. S. (2010). Experimental methods for studying microbial survival in extraterrestrial environments. J. Microbiol. Methods 80, 1–13. doi: 10.1016/j.mimet.2009.10.004

Olsson-Francis, K., Van Houdt, R., Mergeay, M., Leys, N., and Cockell, C. S. (2010). Microarray analysis of a microbe-mineral interaction. Geobiology 8, 446–456. doi: 10.1111/j.1472-4669.2010.00253.x

Orosei, R., Lauro, S. E., Pettinelli, E., Cicchetti, A., Coradini, M., Cosciotti, B., et al. (2018). Radar evidence of subglacial liquid water on Mars. Science 361, 490–493. doi: 10.1126/science.aar7268

Toner, J. D., and Catling, D. C. (2016). Water activities of NaClO4, Ca(ClO4)2, and Mg(ClO4)2 brines from experimental heat capacities: Water activity > 0.6 below 200 K. Geochim. Cosmochim. Acta 181, 164–174. doi: 10.1016/j.gca.2016.03.005

Wanke, H., Bruckner, J., Dreibus, G., Rieder, R., and Ryabchikov, I. (2001). Chemical composition of rocks and soils at the Pathfinder site. Space Sci. Rev. 96, 317–330. doi: 10.1023/A:1011961725645

Wray, J. J., Milliken, R. E., Dundas, C. M., Swayze, G. A., Andrews-Hanna, J. C., Baldridge, A. M., et al. (2011). Columbus crater and other possible groundwater-fed paleolakes of Terra Sirenum, Mars. J. Geophys. Res. Planets 116:3694. doi: 10.1029/2010JE003694

Omara, M., Zimmerman, N., Sullivan, M.R., Li, X., Ellis, A., Cesa, R., Subramanian, R., Presto, A.A., Robinson, A.L., 2018. Methane emissions from natural gas production sites in the United States: Data synthesis and national estimate. Environmental Science & Technology 52, 12915-12925.


We used site-level methane (CH4) emissions data from over 1000 natural gas (NG) production sites in eight basins, including 92 new site-level CH4 measurements in the Uinta, northeastern Marcellus, and Denver-Julesburg basins, to investigate CH4 emissions characteristics and develop a new national CH4 emission estimate for the NG production sector. The distribution of site-level emissions is highly skewed, with the top 5% of sites accounting for 50% of cumulative emissions. High emitting sites are predominantly also high producing (>10 Mcfd). However, low NG production sites emit a larger fraction of their CH4 production. When combined with activity data, we predict that this creates substantial variability in the basin-level CH4 emissions which, as a fraction of basin-level CH4 production, range from 0.90% for the Appalachian and Greater Green River to >4.5% in the San Juan and San Joaquin. This suggests that much of the basin-level differences in production-normalized CH4 emissions reported by aircraft studies can be explained by differences in site size and distribution of site-level production rates. We estimate that NG production sites emit total CH4 emissions of 830 Mg/h (95% CI: 530–1200), 63% of which come from the sites producing <100 Mcfd that account for only 10% of total NG production. Our total CH4 emissions estimate is 2.3 times higher than the U.S. Environmental Protection Agency’s estimate and likely attributable to the disproportionate influence of high emitting sites.

Omari, I., Zhu, H., McGarvey, G.B., McIndoe, J.S., 2019. Acid-selective mass spectrometric analysis of petroleum fractions. International Journal of Mass Spectrometry 435, 315-320.


Naphthenic acids are cycloaliphatic carboxylic acids that are naturally-occurring constituents of petroleum. Analytical mass spectrometric methods aimed at carboxylic acids tend to involve

deprotonation to generate carboxylate anions, but also produce detectable ions of every acidic component of the mixture. A charged tag carbodiimide is able to facilitate detection of model naphthenic acids as well as low levels of naphthenic acids in petroleum fractions via tandem electrospray ionization mass spectrometry. This approach exhibits greater selectivity than deprotonation, and a picture of the acidic components of a petroleum fraction emerges after a quick derivatization step and without the use of chromatographic separation. The method may prove useful in the context of characterizing the naphthenic acid components of complicated matrices.



Extremophiles are organisms capable of adjust, survive or thrive in hostile habitats that were previously thought to be adverse or lethal for life. Chile gathers a wide range of extreme environments: salars, geothermal springs, and geysers located at Altiplano and Atacama Desert, salars and cold mountains in Central Chile, and ice fields, cold lakes and fjords, and geothermal sites in Patagonia and Antarctica. The aims of this review are to describe extremophiles that inhabit main extreme biotopes in Chile, and their molecular and physiological capabilities that may be advantageous for bioremediation processes. After briefly describing the main ecological niches of extremophiles along Chilean territory, this review is focused on the microbial diversity and composition of these biotopes microbiomes. Extremophiles have been isolated in diverse zones in Chile that possess extreme conditions such as Altiplano, Atacama Desert, Central Chile, Patagonia, and Antarctica. Interesting extremophiles from Chile with potential biotechnological applications include thermophiles (e.g., Methanofollis tationis from Tatio Geyser), acidophiles (e.g., Acidithiobacillus ferrooxidans, Leptospirillum ferriphilum from Atacama Desert and Central Chile copper ores), halophiles (e.g., Shewanella sp. Asc-3 from Altiplano, Streptomyces sp. HKF-8 from Patagonia), alkaliphiles (Exiguobacterium sp. SH31 from Altiplano), xerotolerant bacteria (S. atacamensis from Atacama Desert), UV- and Gamma-resistant bacteria (Deinococcus peraridilitoris from Atacama Desert) and psychrophiles (e.g., Pseudomonas putida ATH-43 from Antarctica). The molecular and physiological properties of diverse extremophiles from Chile and their application in bioremediation or waste treatments are further discussed. Interestingly, the remarkable adaptative capabilities of extremophiles convert them into an attractive source of catalysts for bioremediation and industrial processes.

Orlando, L., 2018. Late Bronze Age cultural origins of dairy pastoralism in Mongolia. Proceedings of the National Academy of Sciences 115, 12083-12085.


Dairy products provide a substantial part of the food energy intake for many populations around the world. Fresh milk is an important source of many proteins (whey β-lactoglobulin and caseins), fats, vitamin D, calcium, and electrolytes—but it has only a single carbohydrate, lactose (1). We can all digest lactose as newborns but, after weaning, only some of us continue to express the lactase enzyme in our small intestine that digests lactose into glucose and galactose. Individuals with lactase persistence (LP) are thus lactose tolerant. Conversely, in lactase-nonpersistent individuals, the undigested lactose reaches the large intestine, where it undergoes bacterial fermentation, leading to a range of harmful symptoms, including diarrhea, flatulence, and constipation (2). The preparation of cheese and several milk beverages involves lactose fermentation, which is why lactose-intolerant

persons can still benefit from the nutritional virtues of milk without suffering strong symptoms after consumption. With time, such food products have become part of the culinary identity of several countries, such as French cheese, Greek yogurt, and fermented mare’s milk known as kumis in Kazakhstan and airag in Mongolia.

Archaeological evidence shows that dairy consumption came soon after the domestication of ruminants. Cattle-specific β-lactoglobulin and casein peptides have been detected in ∼8,000-y-old vessel sherds from Çatalhöyük in Turkey, only two millennia after taurine cattle were first domesticated (3). In Europe, lipid signatures indicative of cheese making were found in ∼7,400- to 6,800-y-old strainer vessels (4) [the earliest cheese ever found was preserved in an Egyptian jar for ∼3,300 y (5)]. In the central Asian steppe, the isotopic content of fatty acids in pottery has suggested that dairy consumption accompanied the early stages of horse domestication, some ∼5,500 y ago (6, 7).

In contrast, the early origins of dairy consumption in the eastern Eurasian steppe, east of the Altai (or …

Owen, R.B., Muiruri, V.M., Lowenstein, T.K., Renaut, R.W., Rabideaux, N., Luo, S., Deino, A.L., Sier, M.J., Dupont-Nivet, G., McNulty, E.P., Leet, K., Cohen, A., Campisano, C., Deocampo, D., Shen, C.-C., Billingsley, A., Mbuthia, A., 2018. Progressive aridification in East Africa over the last half million years and implications for human evolution. Proceedings of the National Academy of Sciences 115, 11174-11179.


Significance: Previous research hypotheses have related hominin evolution to climate change. However, most theories lack basin-scale evidence for a link between environment and hominin evolution. This study documents continental, core-based evidence for a progressive increase in aridity since about 575 ka in the Magadi Basin, with a significant change from the Mid-Brunhes Event (∼430 ka). Intense aridification in the Magadi Basin corresponds with faunal extinctions and changes in toolkits in the nearby Olorgesailie Basin. Our data are consistent with climate variability as an important driver in hominin evolution, but also suggest that intensifying aridity may have had a significant influence on the origins of modern Homo sapiens and the onset of the Middle Stone Age.

Abstract: Evidence for Quaternary climate change in East Africa has been derived from outcrops on land and lake cores and from marine dust, leaf wax, and pollen records. These data have previously been used to evaluate the impact of climate change on hominin evolution, but correlations have proved to be difficult, given poor data continuity and the great distances between marine cores and terrestrial basins where fossil evidence is located. Here, we present continental coring evidence for progressive aridification since about 575 thousand years before present (ka), based on Lake Magadi (Kenya) sediments. This long-term drying trend was interrupted by many wet–dry cycles, with the greatest variability developing during times of high eccentricity-modulated precession. Intense aridification apparent in the Magadi record took place between 525 and 400 ka, with relatively persistent arid conditions after 350 ka and through to the present. Arid conditions in the Magadi Basin coincide with the Mid-Brunhes Event and overlap with mammalian extinctions in the South Kenya Rift between 500 and 400 ka. The 525 to 400 ka arid phase developed in the South Kenya Rift between the period when the last Acheulean tools are reported (at about 500 ka) and before the appearance of Middle Stone Age artifacts (by about 320 ka). Our data suggest that increasing Middle- to Late-Pleistocene aridification and environmental variability may have been drivers in the physical and cultural evolution of Homo sapiens in East Africa.

Pal, N., Kumar, N., Verma, A., Ojha, K., Mandal, A., 2018. Performance evaluation of novel sunflower oil-based gemini surfactant(s) with different spacer lengths: Application in enhanced oil recovery. Energy & Fuels 32, 11344-11361.


A series of novel, nonionic gemini surfactants (GSs) with varying spacer lengths were synthesized from sunflower (Helianthus) oil for application in enhanced oil recovery (EOR). The surfactants were characterized by 1H-NMR and thermogravimetric analyses (TGA). Critical micelle concentration values increased with temperature due to a delay in micellization of GS molecules in bulk phase. Hydrolytic stability studies revealed that GS solutions possess the ability to displace acidic crude oil through reservoir pores. Crude oil miscibility studies showed the formation of stable emulsion systems. Ultralow interfacial tension was achieved at the oil–aqueous interface in the presence of salt. Surfactant solutions exhibited good tolerance to varying salinity and hardness conditions. GS solutions showed favorably low lime soap dispersion requirement, indicating improved dispersing ability. GS-based foam systems showed enhanced kinetic stabilities with increasing concentration and pseudoplastic flow character that are considered desirable for EOR operations. Half-life times decreased with temperature due to thinning and subsequent rupture of the foam film boundary. Single-phase continuous emulsion(s) were observed during 15 days for n-heptane/GS/aqueous-based emulsions. Dynamic light scattering and microscopic investigations showed that emulsion stability decreased with time due to gradual coalescence of oil droplets. Therefore, studies pertaining to characterization and performance evaluation of synthesized GSs confirm their potentiality as effective oil-displacing agents under reservoir conditions.



Methane adsorption/desorption not only causes coal matrix shrinkage and swelling, but also has an important influence on the microcrystalline structure of coal. In this study, high-pressure isothermal adsorption/desorption experiments were carried out for 8 coal samples with different degrees of metamorphosis. The microcrystalline structure of the samples before and after methane adsorption/desorption were quantitatively examined using X-ray diffraction, high-resolution transmission electron microscopy, and laser Raman spectroscopy. The results showed that after methane adsorption/desorption, the interplanar spacing (d002) of the coal samples increased, and the unit stacking height (Lc) and unit lateral size (La) of coal crystallites decreased as compared with the raw samples. The changes in Lc were greater than those in La for the same sample. In other words, deformation from high-pressure adsorption/desorption has an especially significant impact on Lc. Furthermore, the fringe spacing of the samples increased, and the proportion sized 0.36–0.40 nm increased in the frequency histogram. While the fringe length showed a decreasing trend, the proportion in the range of 0.30–1.00 nm was significantly increased in the frequency histogram. In addition, the D peak positions of the samples increased while those of the G peak decreased, and their difference decreased. Moreover, the full widths at half maximum of G and D peaks, and the area ratio between D and G all increased. These results are of great significance for further understanding the source of excess coalbed methane (CBM) and its state.

Pan, Z., Wang, Z., Zhang, Z., Ma, G., Zhang, L., Huang, Y., 2018. Natural gas hydrate formation dynamics in a diesel water-in-oil emulsion system. Petroleum Science and Technology 36, 1649-1656.

https://doi.org/10.1080/10916466.2018.1501386

Although gas hydrate is an excellent clean fuel and energy storage form, its natural generation rate is very slow. The key to accelerate the industrialization is to find an appropriate promotion method. In this paper, Span80 and Tween80 were used to study the rapid formation technology of hydrate in diesel water-in-oil emulsion at 275.15 K and 7 MPa. Firstly, hydrate formation in different water cut systems was studied. Results show that hydrate with higher water cut has a faster formation rate and a higher gas storage density, and the system has the shortest induction time with a 40% water cut. The addition of PEG400 and SDS to the original emulsion system resulted in higher gas densities and denser hydrates. Moreover, the addition of emulsifier can reduce the interfacial energy and form a stable interface membrane. Gas storage density also reflects the same phenomenon. Finally, the double electron layer structure formed by different charged ions can also make the emulsion system more stable and promote hydrate formation. Hydrate can be rapidly formed in the diesel water-in-oil emulsion system, which has a great reference value for the future hydrate storage and transportation.

Paris, C.B., Berenshtein, I., Trillo, M.L., Faillettaz, R., Olascoaga, M.J., Aman, Z.M., Schlüter, M., Joye, S.B., 2018. BP Gulf Science Data reveals ineffectual subsea dispersant injection for the Macondo blowout. Frontiers in Marine Science 5, 389. doi: 10.3389/fmars.2018.00389.


After the Deepwater Horizon oil platform explosion, an estimated 172.2 million gallons of gas-saturated oil was discharged uncontrollably into the Gulf of Mexico, causing the largest deep-sea blowout in history. In an attempt to keep the oil submerged, massive quantities of the chemical dispersant Corexit® 9500 were deployed 1522 m deep at the gushing riser pipe of the Macondo prospect’s wellhead. Understanding the effectiveness of this unprecedented subsea dispersant injection (SSDI) is critical because deep-water drilling is increasing worldwide. Here we use the comprehensive BP Gulf Science Data (GSD) to quantify petroleum dynamics throughout the 87-day long blowout. The spatio-temporal distribution of petroleum hydrocarbons revealed consistent higher concentrations at the sea surface and in a deep intrusion below 1000 m. The relative importance of these two layers depended on the hydrocarbon mass fractions as expected from their partitioning along temperature and pressure changes. Further, analyses of water column polycyclic aromatic hydrocarbons (PAH) of GSD extensively sampled within a 10-km radius of the blowout source demonstrated that substantial amounts of oil continued to surface near the response site, with no significant effect of SSDI volume on PAH vertical distribution and concentration. The turbulent energy associated with the spewing of gas-saturated oil at the deep-sea blowout may have minimized the effectiveness of the SSDI response approach. Given the potential for toxic chemical dispersants to cause environmental damage by increasing oil bioavailability and toxicity while suppressing its biodegradation, unrestricted SSDI application in response to deep-sea blowout is highly questionable. More efforts are required to inform response plans in future oil spills.

Park, J., Schilling, M.R., Khanjian, H., Lee, J., 2018. Stratigraphic examination of a Korean lacquered wooden coffin sample by pyrolysis/GC/MS. Chromatographia 81, 1685-1694.

https://doi.org/10.1007/s10337-018-3628-8

A lacquered wooden coffin decorated with gilded Sanskrit letters excavated in the Nongso ancient tomb site was constructed around the fourteenth century in Korea. Pyrolysis/gas chromatography/mass spectrometry was employed to identify the materials of the lacquered surface by analyzing the individual layers. The components of lacquer were detected in all four layers of

wood substrate, black, brown, and gilded layers, indicating the coating material was Asian lacquer. The wood seems to be a kind of pine tree from the observation that pine resin-related components were detected in much of the wood substrate and decreasing in the upward direction. Markers of drying oil like azelaic acid and palmitic acid existed in large quantities in the black, brown, and gilded layers, indicating that drying oil was intentionally added to give a luster. In addition, compared with dried Asian lacquer from Korea, the lacquer used in the coffin was determined to be of the same type.

Park, J.J., Kim, H.J., 2018. Use of a forensic geochemical technique and a hydrogeological assessment to determine the source of petroleum hydrocarbon contamination at a foreshore site in Korea. Environmental Earth Sciences 77, 742.

https://doi.org/10.1007/s12665-018-7928-y

Investigations undertaken in 2013 at a foreshore site that was historically used for ship repairs in Korea indicated that soil and groundwater were contaminated with petroleum hydrocarbons over an area of 10,000 m2. Groundwater investigations and modelling were undertaken to determine the characteristics of aquifers beneath the site, including the direction and rate of groundwater flow and the extent of dispersion of total petroleum hydrocarbon contamination. To identify petroleum products residing in contaminated soils, the hump of an unresolved complex mixture on the baseline found in the data of gas chromatography was used as a new method. Based on objective facts obtained from basic investigation, the current state of contamination, and discrimination of oil species, the polluter as specified in the Korean Soil Environment Conservation Act was identified.

Patel, K., Shah, M., Sircar, A., 2018. Plasma pulse technology: An uprising EOR technique. Petroleum Research 3, 180-188.


Conventionally oil recovery factor is too low, which leaves great prospects for the application of enhanced oil recovery (EOR) methods to increase recovery factor. EOR methods are capital intensive and few are environmentally hazardous. So the paper discusses on the alternate enhanced oil recovery technique which has tremendous potential to curb the challenges of conventional EOR methods. Plasma pulse technology (PPT) aided EOR treatment is administered with an electric wireline conveyed plasma pulse generator tool that is run in the well and positioned alongside the perforations. Using energy stored in the generator's capacitors, a plasma arc is created that emits a tremendous amount of heat and pressure for a fraction of a second. This in turn creates a broad band of hydraulic impulse acoustic waves that are powerful enough to clean perforations and near wellbore damage. These waves continue to resonate deep into the reservoir, exciting the fluid molecules and increasing the reservoirs natural resonance to the degree that it can break larger hydrocarbon molecules to smaller one and simultaneously reducing adhesion tension which results in increased mobility of hydrocarbons. The plasma pulse technology has been successfully used on production as well as injection wells. It has been used often as a remedial procedure to increase well's productivity that has been on production for a period of time. This paper throws light on fundamentals of this advancing plasma pulse technology, contrasting it with recent EOR techniques. Effectiveness of treatment in increasing oil recovery, it's applicability to different reservoir types and results achieved so far are also covered in the paper.

Patil, R.A., Talebi, M., Sidisky, L.M., Berthod, A., Armstrong, D.W., 2018. Gas chromatography selectivity of new phosphonium-based dicationic ionic liquid stationary phases. Journal of Separation Science 41, 4142-4148.

https://doi.org/10.1002/jssc.201800695

Three phosphonium-based dicationic ionic liquids were synthesized as bis(trifluoromethylsulfonyl) imide salts. The three dications had a nonyl spacer between two identical phosphonium-substituted groups. The three phosphonium moieties were dipropyl(phenyl), diphenyl(propyl), and diphenyl(toluyl). The physicochemical properties of the dicationic ionic liquids were appropriate to prepare 30 m capillary columns that were tested in gas chromatography. A unique selectivity compared to different polysiloxane or polar cyanosiloxane commercial columns was observed for selected mixes of phthalates, polyaromatic hydrocarbons, polychlorobiphenyls, and dioxins. Only minor selectivity variations were observed with the three dicationic ionic liquids. The different number of aromatic rings on the positively charged phosphonium group did not influence the dicationic ionic liquid selectivity significantly.

Patrushev, Y.V., Sidelnikov, V.N., 2018. Selection of the porous layer open tubular columns for separation of light components in comprehensive two-dimensional gas chromatography. Journal of Chromatography A 1579, 83-88.


Up to the present, comprehensive two-dimensional gas chromatography was commonly performed using combinations of columns with stationary liquid phases. There are singular examples with a porous layer open tubular (PLOT) column used only in the second dimension. However, GC × GC systems with two PLOT columns are not reported in the literature. Our work describes the application of two PLOT columns in the GC × GC mode. In the first and second dimensions we used columns with the sorbents based on organic porous polymers with different selectivity: Rt-Q-BOND (nonpolar column consist of 100% divinylbenzene-styrene), Rt-S-BOND (intermediate polar column, which contain 4-vinylpyridine), Rt-U-BOND (polar column based on divinylbenzene - ethylene glycol dimethylacrylate copolymer), DVB-VIm (divinylbenzene-vinylimidazole copolymer), a column PTMSP with poly-(1-trimethylsilyl-1-propyne) sorbent, and a GASPRO column with porous silica as a stationary phase.

The degree of orthogonality was calculated for five different combinations of columns, where a column with the porous polymer was used in the first dimension, and GASPRO column – in the second dimension. Orthogonality was estimated from the correlation coefficient of retention times in the first and second dimensions.

Examples of the separation of C1-C5 hydrocarbons on a combination of PTMSP - GASPRO and Rt-Q-BOND - GASPRO columns are reported. It is shown that not only light hydrocarbons but also compounds belonging to different chemical classes can be separated with the use of PLOT columns.

Patterson, N.H., Tuck, M., Lewis, A., Kaushansky, A., Norris, J.L., Van de Plas, R., Caprioli, R.M., 2018. Next generation histology-directed imaging mass spectrometry driven by autofluorescence microscopy. Analytical Chemistry 90, 12404-12413.


Histology-directed imaging mass spectrometry (IMS) is a spatially targeted IMS acquisition method informed by expert annotation that provides rapid molecular characterization of select tissue structures. The expert annotations are usually determined on digital whole slide images of histological stains where the staining preparation is incompatible with optimal IMS preparation, necessitating serial sections: one for annotation, one for IMS. Registration is then used to align staining annotations onto the IMS tissue section. Herein, we report a next-generation histology-directed platform implementing IMS-compatible autofluorescence (AF) microscopy taken prior to any staining or IMS. The platform enables two histology-directed workflows, one that improves the registration process between two separate tissue sections using automated, computational monomodal AF-to-AF microscopy image registration, and a registration-free approach that utilizes AF directly to identify ROIs and acquire IMS on the same section. The registration approach is fully automated and delivers state of the art accuracy in histology-directed workflows for transfer of annotations (∼3–10 μm based on 4 organs from 2 species) while the direct AF approach is registration-free, allowing targeting of the finest structures visible by AF microscopy. We demonstrate the platform in biologically relevant case studies of liver stage malaria and human kidney disease with spatially targeted acquisition of sparsely distributed (composing less than one tenth of 1% of the tissue section area) malaria infected mouse hepatocytes and glomeruli in the human kidney case study.

Patterson, N.H., Tuck, M., Van de Plas, R., Caprioli, R.M., 2018. Advanced registration and analysis of MALDI imaging mass spectrometry measurements through autofluorescence microscopy. Analytical Chemistry 90, 12395-12403.


The correlation of imaging mass spectrometry (IMS) with histopathology can help relate novel molecular findings obtained through IMS to the well-characterized and validated histopathology knowledge base. The quality of correlation between these two modalities is limited by the quality of the spatial mapping that is obtained by registration of the two image types. In this work, we develop novel workflows for MALDI IMS-to-microscopy data registration and analysis using nondestructive IMS-compatible wide field autofluorescence (AF) microscopy combined with computational image registration. First, a substantially automated procedure for high-accuracy registration between IMS and microscopy data of the same section is described that explicitly links the MALDI laser ablation pattern imaged by microscopy to its corresponding IMS pixel. Subsequent examination of the registered data allows for high-confidence colocalization of image features between the two modalities, down to single-cell scales within tissue. Building on this IMS-microscopy spatial mapping, we furthermore demonstrate the automated spatial correlation between IMS measurements from serial sections. This AF-registration-driven inter-section analysis, using a combination of nonlinear AF-to-AF and IMS-to-AF image registrations, can be applied to tissue sections that are prepared and imaged with different sample preparations (e.g., lipids vs proteins) and/or that are measured using different spatial resolutions. Importantly, all registrations, whether within a single section or across serial sections, are entirely independent of the IMS intensity signal content and thus unbiased by it.

Payne, S., McCarthy, S., Johnson, T., North, E., Blum, P., 2018. Nonmutational mechanism of inheritance in the Archaeon Sulfolobus solfataricus. Proceedings of the National Academy of Sciences 115, 12271-12276.


Significance: Archaea have considerable importance in ecology and evolution and have emerging roles in health. However, many of their cellular processes are under active study. Archaea are thought to acquire and inherit adaptive traits solely through mutation. Here, adaptive laboratory evolution of an extremophile trait revealed that an alternative nonmutational process was operative. When genes whose expression had been altered in a heritable manner were replaced by recombination using identical DNA, the evolved traits were changed. This implicated a regulatory role for chromatin proteins and was consistent with an epigenetic-like regulatory mechanism. This finding has evolutionary relevance for the origin of epigenetics, transcriptional regulation, and functional genome architecture.

Abstract: Epigenetic phenomena have not yet been reported in archaea, which are presumed to use a classical genetic process of heritability. Here, analysis of independent lineages of Sulfolobus solfataricus evolved for enhanced fitness implicated a non-Mendelian basis for trait inheritance. The evolved strains, called super acid-resistant Crenarchaeota (SARC), acquired traits of extreme acid resistance and genome stability relative to their wild-type parental lines. Acid resistance was heritable because it was retained regardless of extensive passage without selection. Despite the hereditary pattern, in one strain, it was impossible for these SARC traits to result from mutation because its resequenced genome had no mutation. All strains also had conserved, heritable transcriptomes implicated in acid resistance. In addition, they had improved genome stability with absent or greatly decreased mutation and transposition relative to a passaged control. A mechanism that would confer these traits without DNA sequence alteration could involve posttranslationally modified archaeal chromatin proteins. To test this idea, homologous recombination with isogenic DNA was used to perturb native chromatin structure. Recombination at up-regulated loci from the heritable SARC transcriptome reduced acid resistance and gene expression in the majority of recombinants. In contrast, recombination at a control locus that was not part of the heritable transcriptome changed neither acid resistance nor gene expression. Variation in the amount of phenotypic and expression changes across individuals was consistent with Rad54-dependent chromatin remodeling that dictated crossover location and branch migration. These data support an epigenetic model implicating chromatin structure as a contributor to heritable traits.

Pederzani, S., Britton, K., 2019. Oxygen isotopes in bioarchaeology: Principles and applications, challenges and opportunities. Earth-Science Reviews 188, 77-107.


Oxygen isotope analyses of skeletal remains (18O/16O, δ18O) are a powerful tool for exploring major themes in bioarchaeology (the study of biological archaeological remains) and can aid in the reconstruction of past human-environment interactions, socio-cultural decisions and individual life histories. Making use of the preserved animal and human tooth and bone commonly found at archaeological sites, applications include the reconstruction of palaeoclimate and palaeoseasonality; animal husbandry and management practices; human and animal lifetime mobility and provenance; and cultural practices such as breastfeeding, weaning and even past culinary preparation techniques. With a range of other uses across the natural, physical, chemical and biological sciences, oxygen isotope analyses are also highly cross-disciplinary, with developments in the field of isotope bioarchaeology potentially feeding into other fields and vice-versa. The purpose of this paper is to provide a summary of the biogeochemical background of oxygen isotope systematics from the water cycle to human and animal skeletal tissues for archaeologists and other scientists, and to explore how these have been utilised in terrestrial bioarchaeological research. In this way, we aim to provide an overview resource for stable isotope analysts in archaeology and the wider earth science community, as well as for archaeological practitioners and consumers interested in specific applications. By providing a summary of fundamental isotope mechanics alongside a review of recent developments in

the field, we hope to highlight the potential of oxygen isotope bioarchaeology to not only reveal environmental and ecological aspects of the past relevant to human groups using archaeological materials, but also to illuminate past human decisions and behaviours. Current limitations and caveats of the approaches used are also explored.

Perchuk, A.L., Safonov, O.G., Smit, C.A., van Reenen, D.D., Zakharov, V.S., Gerya, T.V., 2018. Precambrian ultra-hot orogenic factory: Making and reworking of continental crust. Tectonophysics 746, 572-586.


Mechanisms of Precambrian orogeny and their contribution to the origin of ultrahigh temperature granulites, granite-greenstone terranes and net crustal growth remain debatable. Here, we use 2D numerical models with 150°C higher mantle temperatures compared to present day conditions to investigate physical and petrological controls of Precambrian orogeny during forced continental plates convergence. Numerical experiments show that convergence between two relatively thin blocks of continental lithosphere with fertile mantle creates a short-lived cold collisional belt that later becomes absorbed by a long-lived thick and flat ultra-hot accretionary orogen with Moho temperatures of 700–1100°C. The orogen underlain by hot partially molten depleted asthenospheric mantle spreads with plate tectonic rates towards the incoming lithospheric block. The accretionary orogeny is driven by delamination of incoming lithospheric mantle with attached mafic lower crust and invasion of the hot partially molten asthenospheric wedge under the accreted crust. A very fast convective cell forms atop the subducting slab, in which hot asthenospheric mantle rises against the motion of the slab and transports heat towards the moving orogenic front. Juvenile crustal growth during the orogeny is accompanied by net crustal loss due to the lower crust subduction. Stability of an ultra-hot orogeny is critically dependent on the presence of relatively thin and warm continental lithosphere with thin crust and dense fertile mantle roots subjected to plate convergence. Increased thickness of the continental crust and subcontinental lithospheric mantle, pronounced buoyancy of the lithospheric roots, and decreased mantle and continental Moho temperature favor colder and more collision-like orogenic styles with thick crust, reduced magmatic activity, lowered metamorphic temperatures, and decreased degree of crustal modification. Our numerical modeling results thus indicate that different types of orogens (cold, mixed-hot and ultra-hot) could be created at the same time in the Early Earth, depending on compositional and thermal structures of interacting continental blocks.

Percival, L.M.E., Jenkyns, H.C., Mather, T.A., Dickson, A.J., Batenburg, S.J., Ruhl, M., Hesselbo, S.P., Barclay, R., Jarvis, I., Robinson, S.A., Woelders, L., 2018. Does large igneous province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-Cretaceous to other Mesozoic events. American Journal of Science 318, 799-860.

http://www.ajsonline.org/content/318/8/799.abstract

Mercury (Hg) is increasingly being used as a sedimentary tracer of Large Igneous Province (LIP) volcanism, and supports hypotheses of a coincidence between the formation of several LIPs and episodes of mass extinction and major environmental perturbation. However, numerous important questions remain to be answered before Hg can be claimed as an unequivocal fingerprint of LIP volcanism, as well as an understanding of why some sedimentary records document clear Hg enrichment signals whilst others do not. Of particular importance is evaluating the impact of different volcanic styles on the global mercury cycle, as well as the role played by depositional processes in recording global Hg-cycle perturbations. Here, new mercury records of Cretaceous Oceanic Anoxic

Event 2 (OAE 2: ∼94 Ma) and the latest Cretaceous (∼67–66.0 Ma) are presented. OAE 2 is associated with the emplacement of multiple, predominantly submarine, LIPs; the latest Cretaceous with subaerial volcanism of the Deccan Traps. Both of these connections are strongly supported by previously published trends towards unradiogenic osmium- (Os) isotope values in globally distributed sedimentary records. Hg data from both events show considerable variation between different locations, attributed to the effectiveness of different sediment types in registering the Hg signal, with lithologically homogeneous records documenting more clear Hg enrichments than sections with major changes in lithology such as limestones to claystones or organic-rich shales. Crucially, there is no geographically consistent signal of sedimentary Hg enrichment in stratigraphic records of either OAE 2 or the latest Cretaceous that matches Os-isotope evidence for LIP emplacement, indicating that volcanism did not cause a global Hg perturbation throughout the entire eruptive history of the LIPs formed at those times. It is suggested that the discrepancy between Os-isotope and Hg trends in records of OAE 2 is caused by the limited dispersal range of Hg emitted from submarine volcanoes compared to the global-scale distribution of Os. A similar lack of correlation between these two proxies in uppermost Cretaceous strata indicates that, although subaerial volcanism can perturb the global Hg cycle, not all subaerial eruptions will do so. These results highlight the variable impact of different volcanogenic processes on the efficiency of Hg dispersal across the globe. Factors that could influence the impact of LIP eruptions on the global mercury cycle include submarine versus subaerial volcanism, volcanic intensity or explosivity, and the potential contribution of thermogenic mercury from reactions between ascending magma and surrounding organic-rich sediments.



The objective of this study was to shed light on structural features which underlay intensity of long wave absorbance of natural organic matter (NOM) using 1H NMR spectroscopy. For this purpose, a set of the NOM samples was assembled from arctic and nonarctic sampling sites (the Kolyma river basin and Moscow region, respectively). It was to ensure a substantial difference in the humification degree of the isolated organic matter—the biogeochemical proxy of the long-wave absorbance of NOM. The assembled NOM set was analyzed using solution-state 1H NMR spectroscopy. The distribution of both backbone and exchangeable protons was determined using acquisition of spectra in three different solvents. The substantially higher contribution of nonfunctionalized aliphatic moieties CHn (e.g., materials derived from linear terpenoids, MDLT) in the arctic NOM samples was revealed as compared to the nonarctic ones. The latter were characterized with the higher content of CHα protons adjacent to electron-withdrawing groups which belong to carboxyl rich alicyclic moieties (CRAMs) or to aromatic constituents of NOM. We have calculated a ratio of CHn to CHα protons as a structural descriptor which showed significant inverse correlation to intensity of long wave absorbance assessed with a use of E4/E6 ratio and the slope of absorption spectrum. The steric hindrance of aromatic chromophoric groups of the NOM ensemble by bulky nonfunctionalized aliphatic moieties (e.g., MDLT) was set as a hypothesis for explanation of this phenomenon. The bulky aliphatics might increase a distance between the interacting groups resulting in inhibition of electronic (e.g., charge-transfer) interactions in the NOM ensemble. The obtained relationships were further explored using Fourier transform mass spectrometry as complementary technique to 1H NMR spectroscopy. The data obtained on correlation of molecular composition of NOM with 1H NMR data and optical properties were very supportive of our hypothesis that capabilities of NOM ensemble of

charge transfer interactions can be dependent on structural arrangement and relative abundance of nonabsorbing aliphatic moieties.

Perruchini, E., Glatz, C., Hald, M.M., Casana, J., Toney, J.L., 2018. Revealing invisible brews: A new approach to the chemical identification of ancient beer. Journal of Archaeological Science 100, 176-190.


While ancient Near Eastern cuneiform texts and iconography unambiguously demonstrate the social, economic, and ritual significance of beer, direct archaeological evidence for beer production or consumption remains surprisingly rare. This scarcity of material evidence renders it difficult to extrapolate information about the ingredients and production processes of beer, on the one hand, and the paraphernalia and social contexts of its consumption, on the other. In recent decades, organic residue analysis has become an essential tool in the identification of ancient alcoholic beverages, but research on Near Eastern beer has focused largely on production and storage vessels, whose form, archaeological context, and associated macroscopic residues already indicated their use in beer production. In this paper, we present a novel field sampling protocol that prevents contamination along with a refined organic residue analysis methodology that relies on a series of co-occurring compounds to identify confidently beer in ceramic vessels. The same compounds were identified in several modern beer samples and, thus, support our identification of a similar fermented barley-based beverage in archaeological samples from the late second millennium BCE site of Khani Masi in northeastern Iraq. The results presented in this paper allow us, for the first time, to unambiguously link a diverse range of vessel types to the consumption and production of beer, identify a fundamental change in Mesopotamian consumption practices, and shed light on the cultural dimensions of Babylonia's encounter with the Zagros-Mesopotamian borderlands.



The authors regret that some of the peaks in Fig. 10 of Pestilho et al. (2018) were incorrectly labeled. This only applies to the m/z 217 mass fragmentogram for the fluid inclusion from the Açu Formation.



Mosses contribute an average of 20% of boreal upland forest net primary productivity and are frequently observed to degrade slowly compared to vascular plants. If this is caused primarily by the chemical complexity of their tissues, moss decomposition could exhibit high temperature sensitivity (measured as Q10) due to high activation energy, which would imply that soil organic carbon (SOC) stocks derived from moss remains are especially vulnerable to decomposition with warming. Alternatively, the physical structure of the moss cell-wall biochemical matrix could inhibit decomposition, resulting in low decay rates and low temperature sensitivity. We tested these

hypotheses by incubating mosses collected from two boreal forests in Newfoundland, Canada, for 959 days at 5°C and 18°C, while monitoring changes in the moss tissue composition using total hydrolyzable amino acid (THAA) analysis and 13C nuclear magnetic resonance (NMR) spectroscopy. Less than 40% of C was respired in all incubations, revealing a large pool of apparently recalcitrant C. The decay rate of the labile fraction increased in the warmer treatment, but the total amount of C loss increased only slightly, resulting in low Q10 values (1.23–1.33) compared to L horizon soils collected from the same forests. NMR spectra were dominated by O-alkyl C throughout the experiment, indicating the persistence of potentially labile C. The accumulation of hydroxyproline (derived primarily from plant cell-wall proteins) and aromatic C indicates the selective preservation of biochemicals associated with the moss cell wall. This was supported by scanning electron microscope (SEM) images of the moss tissues, which revealed few changes in the physical structure of the cell wall after incubation. This suggests that the moss cell-wall matrix protected labile C from microbial decomposition, accounting for the low temperature sensitivity of moss decomposition despite low decay rates. Climate drivers of moss biomass and productivity, therefore, represent a potentially important regulator of boreal forest SOC responses to climate change that needs to be assessed to improve our understanding of carbon–climate feedbacks.



The fluorescence evolution of oils has been measured by simulation of petroleum generation and expulsion in a half-closed system using hydrous pyrolysis based on four oil-prone source rocks (Type I and II kerogens) from the Dongying Depression, Bohai Bay Basin, China. The results suggest that the fluorescence characteristics of expelled oil are independent of oil-prone kerogen types, but are strongly related to oil generation and expulsion processes which are controlled by thermal maturity of source rocks. The fluorescence spectral parameters (λmax, Q650/500 and QF-535) of expelled oils show no obvious variation, or even show gradual redshifts when the highest λmax occurs at peak bitumen generation, depending on the expulsion process. A blueshift of fluorescence color occurs only during the main oil generation and expulsion stage, which immediately follows the peak bitumen generation stage. However, the expelled oil mainly exhibits green to yellow fluorescence colors (500 nm < λmax < 590 nm), which suggests that it is impossible for blue fluorescent oil inclusions to be trapped from the oil directly generated in an open or half-closed source rock system for oil-prone source rocks based on the experimental results. This study demonstrates that the relationship between the fluorescence color of oil inclusions and thermal maturity for oil-prone source rocks is valid only when the source rocks reach the main oil generation and expulsion stage, where the source rocks should have consistent expulsion characteristics. Under this situation, the green fluorescent oil inclusions (500 nm < λmax < 550 nm) generally have a higher thermal maturity than the oil inclusions with yellow fluorescence (580 nm < λmax < 590 nm). Otherwise, the petroleum expulsion processes may complicate the relationship between the fluorescence color of oil inclusions and thermal maturity, and oil inclusions with yellow fluorescence do not necessarily have a low thermal maturity. Our experiments have established the first boundary conditions for the fluorescence behaviour of oil as a function of thermal maturity, acknowledging that compositional change of the oil is also occurring during migration, and hence before entrapment in reservoirs.

Piotrowski, P.K., Tasker, T.L., Burgos, W.D., Dorman, F.L., 2018. Applications of thermal desorption coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for

hydrocarbon fingerprinting of hydraulically fractured shale rocks. Journal of Chromatography A 1579, 99-105.


Development of shale gas resources through the use of hydraulic fracturing has raised a multitude of environmental concerns and motivated research towards the understanding of shale gas systems. Previous research has demonstrated the potential of utilizing hydrocarbon distributions towards the fingerprinting of a potential environmental contamination event arising from shale gas operations. However, to apply hydrocarbon distributions from shale gas wells towards point-source identification and apportionment, a better understanding of hydrocarbon origins must be achieved. Here we present an efficient and repeatable thermal desorption method, as a sample introduction methodology for GC × GC analysis of shale rock samples that results in comparable chromatograms to those produced by solvent extraction. This novel and robust characterization technique of shale cores from Marcellus and Utica formations by thermal desorption followed by GC × GC enables the understanding of hydrocarbon speciation within the native rock with minimal sample preparation time and solvent use. The detailed shale chemistry gives insight into utilizing hydrocarbon differences towards point-source identification methodologies of environmental contamination events associated with unconventional gas development. Additionally, this analytical technique may provide a more detailed analysis of hydrocarbons than what is currently implemented in the industry to pinpoint the most advantageous areas to exploit by hydraulic fracturing, yet avoiding undesirable areas such as those with a high abundance of sulfur containing compounds.

Plado, J., Hietala, S., Kreitsmann, T., Lerssi, J., Nenonen, J., Pesonen, L.J., 2018. Summanen, a new meteorite impact structure in Central Finland. Meteoritics & Planetary Science 53, 2413-2426.


The Summanen structure (62°39.0?N, 25°22.5?E) is located within the Paleoproterozoic Central Finland Granite Belt, Fennoscandian Shield. The structure is hidden under Lake Summanen and not directly observable. It owes its discovery to low-altitude airborne geophysical data, which revealed a circular, ~2.6 km wide electromagnetic in-phase, and resistivity, anomalies. Two field campaigns were conducted in 2017 to search for impact signatures. The fieldwork concentrated on the southeastern side of the lake following the ice flow direction of the latest (Weichselian) glaciation. In addition, the islands and the SE peninsulas of the mainland were investigated for outcrops and glacial erratics. A few tens of erratic boulders with shatter cones and striated features, and a few brecciated rocks were discovered. Lamposaari Island in the eastern part of the lake revealed one fractured outcrop containing in situ porphyritic granite with converging striated features. Microscopic shock metamorphic features in two shatter-cone-bearing samples of porphyritic granite were found. These are planar deformation features (PDFs; up to two sets) in quartz and kink bands in biotite. Based on these geological, geophysical, and petrographic results, we suggest that Lake Summanen hides a relatively small, probably simple, meteorite impact structure, the twelfth confirmed one in Finland, of so far unknown age.

Ponnusamy, V.K., Nguyen, D.D., Dharmaraja, J., Shobana, S., Banu, J.R., Saratale, R.G., Chang, S.W., Kumar, G., 2019. A review on lignin structure, pretreatments, fermentation reactions and biorefinery potential. Bioresource Technology 271, 462-472.


In recent years, lignin valorization is commercially an important and advanced sustainable process for lignocellulosic biomass-based industries, primarily through the depolymerization path. The conversion of the lignin moieties into biofuels and other high value-added products are still challenging to the researchers due to the heterogeneity and complex structure of lignin-containing biomass. Besides, the involvement of different microorganisms that carries varying metabolic and enzymatic complex systems towards degradation and conversion of the lignin moieties also discussed. These microorganisms are frequently short of the traits which are obligatory for the industrial application to achieve maximum yields and productivity. This review mainly focuses on the current progress and developments in the pretreatment routes for enhancing lignin degradation and also assesses the liquid and gaseous biofuel production by fermentation, gasification and hybrid technologies along with the biorefinery schemes which involves the synthesis of high value-added chemicals, biochar and other valuable products.



Instability of shale formations is one of the major challenges during a drilling operation. Shale swelling is a time-dependent process in which water gradually infiltrates the shale structure. Due to very low permeability of shales (10−9-10−3 md) and relatively large size of solid materials of drilling mud compared to shale pore throats (3–100 nm), filter cake is not capable of hindering this process. As a result, mud filtrate continuously seeps into shale, concurrently increasing pore pressure and reducing mechanical strength of the formation, where it may result in wellbore caving. One remedy to this hazard is usage of Nano-particles to block the entrance of mud filtrate into shale formations. The important factor to use of nano material in order to solve wellbore instability is the selection of practical and affordable concentration of nano particle in drilling fluid. The present research investigates the application of Nano ZnO in controlling water invasion. This Nano particle benefits size adequacy as well as suitable interfacial properties in hindering mud filtration. The impact of adding nano ZnO to reduce water seepage into shale is investigated using PPT apparatus. This test shows the increase in pore pressure in the formation due to mud filtrate invasion, hence enabling us to study the effect of different concentration of applied Nano particle on stability of shales. The results show that Nano ZnO particles, due to their size and other properties such as Hydrophilic behavior and positive charge enhance the stability of shale. Using 0.25, 0.5 and 0.75 wt/volume percentage of Nano-ZnO mixture showed respectively 60%, 87%, and 96% reduction in pore pressure transmission compared to sea water sample.

Prabhu, A.A., Gadela, R., Bharali, B., Deshavath, N.N., Dasu, V.V., 2019. Development of high biomass and lipid yielding medium for newly isolated Rhodotorula mucilaginosa. Fuel 239, 874-885.


Conversion of plant-based biomass into biofuels has been singled out as a way to achieve economically viable production chains. Over past few decades development in yeast oil production have been witnessed, which includes isolation of high lipid accumulating strains, understanding the metabolic pathways for oil production, genetic engineering strategies for overproduction of lipids and optimization of cultivation processes for converting lignocellulose biomass to oil. In the present investigation, screening, isolation and characterization of novel oleaginous yeast from oil refinery was carried out. The strain was identified as Rhodotorula mucilaginosa by 26s rRNA sequencing (Accession Number: KX533469). Glucose and peptone were identified as best carbon and nitrogen

source for high biomass induction. Further, two-stage optimization using taguchi orthogonal array method and multi objective optimization using genetic algorithm was applied for the development of an optimized medium. Malt extract was found to be a key influencing factor in both biomass and lipid induction with high S/N ratio, followed by peptone and glucose. Batch bioreactor studies revealed that the lipid productivity follows mixed growth associated pattern with the higher lipid accumulation of 0.25 g/g biomass.

Pulschen, A.A., de Araujo, G.G., de Carvalho, A.C.S.R., Cerini, M.F., Fonseca, L.d.M., Galante, D., Rodrigues, F., 2018. Survival of extremophilic yeasts in the stratospheric environment during balloon flights and in laboratory simulations. Applied and Environmental Microbiology 84, Article e01942-18.


Abstract: The high-altitude atmosphere is a harsh environment with extremely low temperatures, low pressure, and high UV irradiation. For this reason, it has been proposed as an analogue for Mars, presenting deleterious factors similar to those on the surface of that planet. We evaluated the survival of extremophilic UV-resistant yeasts isolated from a high-elevation area in the Atacama Desert under stratospheric conditions. As biological controls, intrinsically resistant Bacillus subtilis spores were used. Experiments were performed in two independent stratospheric balloon flights and with an environmental simulation chamber. The three following different conditions were evaluated: (i) desiccation, (ii) desiccation plus exposure to stratospheric low pressure and temperature, and (3) desiccation plus exposure to the full stratospheric environment (UV, low pressure, and temperature). Two strains, Naganishia (Cryptococcus) friedmannii 16LV2 and Exophiala sp. strain 15LV1, survived full exposures to the stratosphere in larger numbers than did B. subtilis spores. Holtermanniella watticus (also known as Holtermanniella wattica) 16LV1, however, suffered a substantial loss in viability upon desiccation and did not survive the stratospheric UV exposure. The remarkable resilience of N. friedmannii and Exophiala sp. 15LV1 under the extreme Mars-like conditions of the stratosphere confirms its potential as a eukaryotic model for astrobiology. Additionally, our results with N. friedmannii strengthen the recent hypothesis that yeasts belonging to the Naganishia genus are fit for aerial dispersion, which might account for the observed abundance of this species in high-elevation soils.

Importance: Studies of eukaryotic microorganisms under conditions of astrobiological relevance, as well as the aerial dispersion potential of extremophilic yeasts, are still lacking in the literature compared to works with bacteria. Using stratospheric balloon flights and a simulation chamber, we demonstrate that yeasts isolated from an extreme environment are capable of surviving all stressors found in the stratosphere, including intense UV irradiation, scoring an even higher survival than B. subtilis spores. Notably, the yeast N. friedmannii, which displayed one of the highest tolerances to the stratospheric environment in the experiments, was recently proposed to be adapted to airborne transportation, although such a hypothesis had not yet been tested. Our results strengthen such an assumption and can help explain the observed distribution and ecology of this particular yeast species.



Fractures are crucial for unconventional hydrocarbon exploitation, but it is difficult to accurately observe the 3D spatial distribution characteristics of fractures. Microtomography (micro-CT) technology makes it possible to observe the 3D structures of fractures at micro-scale. In this study, micron-CT scanning is conducted on multiple mud-shale samples of source rocks in the Permian Lucaogou Formation, Junggar Basin. The Avizo® software is applied to process and segment the micron-CT images, so as to obtain the 3D fracture structure model inside rock core. Therefore, the independently-developed CTSTA program is adopted to quantitatively describe the micro-fractures inside rock core, including fracture dimension, extension direction and extension scale. Meanwhile, this study summarizes the classification characteristics of fractures and their anisotropy. On this basis, the fractal dimensions of fractures can also be extracted. Previous studies show that the geometric features of fractures have self-similarity at large and small scales, which can be described by exponential laws; and the fractal dimension is a typical exponent. Through the quantitative description or characterization of 3D fractures at micro-scale, the distribution characteristics of fractures in large scales could be known.

Qi , C., Wang, X., Wang, W., Liu, J., Tuo, J., Liu, K., 2018. Three-dimensional fine characterization method of micro-fractures in shale reservoirs. Acta Petrolei Sinica 39, 1175-1185 http://www.syxb-cps.com.cn/EN/abstract/abstract5555.shtml

Fractures are crucial for unconventional hydrocarbon exploitation, but it is difficult to accurately observe the 3D spatial distribution characteristics of fractures. Microtomography (micro-CT)technology makes it possible to observe the 3D structures of fractures at micro-scale. In this study, micro-CT scanning is conducted on multiple mud-shale samples of source rocks in the Permian Lucaogou Formation, Junggar Basin. The Avizo software is applied to process and segment the micro-CT images, so as to obtain the 3D fracture structure model inside rock core. Therefore, the independently-developed CTSTA program is adopted to quantitatively describe the micro-fractures inside rock core, including fracture dimension, extension direction and extension scale. Meanwhile, this study summarizes the classification characteristics of fractures and their anisotropy. On this basis, the fractal dimensions of fractures can also be extracted. Previous studies have shown that the geometric features of fractures have self-similarity at a large or small scales, which can be described by exponential laws; and the fractal dimension is a typical exponent. Through the quantitative description or characterization of 3D fractures at micro-scale, the distribution characteristics of fractures on a large scale could be known.

Qian, K.-R., He, Z.-L., Liu, X.-W., Chen, Y.-Q., 2018. Intelligent prediction and integral analysis of shale oil and gas sweet spots. Petroleum Science 15, 744-755.

https://doi.org/10.1007/s12182-018-0261-y

Shale reservoirs are characterized by low porosity and strong anisotropy. Conventional geophysical methods are far from perfect when it comes to the prediction of shale sweet spot locations, and even less reliable when attempting to delineate unconventional features of shale oil and gas. Based on some mathematical algorithms such as fuzzy mathematics, machine learning and multiple regression analysis, an effective workflow is proposed to allow intelligent prediction of sweet spots and comprehensive quantitative characterization of shale oil and gas reservoirs. This workflow can effectively combine multi-scale and multi-disciplinary data such as geology, well drilling, logging and seismic data. Following the maximum subordination and attribute optimization principle, we establish a machine learning model by adopting the support vector machine method to arrive at multi-attribute prediction of reservoir sweet spot location. Additionally, multiple regression analysis technology is applied to quantitatively predict a number of sweet spot attributes. The practical

application of these methods to areas of interest shows high accuracy of sweet spot prediction, indicating that it is a good approach for describing the distribution of high-quality regions within shale reservoirs. Based on these sweet spot attributes, quantitative characterization of unconventional reservoirs can provide a reliable evaluation of shale reservoir potential.

Qian, K., Fredriksen, T.R., Mennito, A.S., Zhang, Y., Harper, M.R., Merchant, S., Kushnerick, J.D., Rytting, B.M., Kilpatrick, P.K., 2019. Evidence of naturally-occurring vanadyl porphyrins containing multiple S and O atoms. Fuel 239, 1258-1264.


A host of vanadyl petroporphyrins containing multiple sulfur and oxygen atoms and their combinations (CcH2c+ZN4VOoSs, s = 0–3, o = 1–4, Z = −28 to −70) in a vacuum residue were observed by a combination of extensive enrichment of petroporphyrins and detailed analysis using ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). Many of the petroporphyrin species are being observed for the very first time. The patterns of the porphyrin type distribution revealed dramatic differences in the sulfur and oxygen atom incorporations and their impact on Z number. For each sulfur atom addition, the average Z-number was reduced by ∼4–7, implying that sulfur may be incorporated by the additions of thiophene or cyclic thiophene moieties. In contrast, oxygen addition had little to no impact on the average Z number, implying that oxygen may be incorporated as carbonyl or hydroxyl groups. The porphyrin-based structures were found to contain as many as 8 aromatic rings in addition to the porphyrin macrocycle. Petroporphyrins in longer wavelength absorption fractions were found to contain more heteroatoms and more condensed aromatic rings.

Qiao, W., Luo, F., Lomheim, L., Mack, E.E., Ye, S., Wu, J., Edwards, E.A., 2018. A Dehalogenimonas population respires 1,2,4-trichlorobenzene and dichlorobenzenes. Environmental Science & Technology 52, 13391-13398.


Chlorobenzenes are ubiquitous contaminants in groundwater and soil at many industrial sites. Previously, we demonstrated the natural attenuation of chlorobenzenes and benzene at a contaminated site inferred from a 5 year site investigation and parallel laboratory microcosm studies. To identify the microbes responsible for the observed dechlorination of chlorobenzenes, the microbial community was surveyed using 16S rRNA gene amplicon sequencing. Members of the Dehalobacter and Dehalococcoides are reported to respire chlorobenzenes; however, neither were abundant in our sediment microcosms. Instead, we observed a significant increase in the relative abundance of Dehalogenimonas from <1% to 16–30% during dechlorination of 1,2,4-trichlorobenzene (TCB), 1,2-dichlorobenzene (DCB), and 1,3-DCB over 19 months. Quantitative PCR (qPCR) confirmed that Dehalogenimonas gene copies increased by 2 orders of magnitude with an average yield of 3.6 ± 2.3 g cells per mol Cl– released (N = 12). In transfer cultures derived from sediment microcosms, dechlorination of 1,4-DCB and monochlorobenzene (MCB) was carried out by Dehalobacter spp. with a growth yield of 3.0 ± 2.1 g cells per mol Cl– released (N = 5). Here we show that a Dehalogenimonas population respire 1,2,4-TCB and 1,2-/1,3-DCB isomers. This finding emphasizes the need to monitor a broader spectrum of organohalide-respiring bacteria, including Dehalogenimonas, at sites contaminated with halogenated organic compounds.

Qiao, W., Tao, J., Luo, Y., Tang, T., Miao, J., Yang, Q., 2018. Microbial oil production from solid-state fermentation by a newly isolated oleaginous fungus, Mucor circinelloides Q531 from mulberry branches. Royal Society Open Science 5, Article 180551.

http://rsos.royalsocietypublishing.org/content/5/11/180551.abstract

In this study, a newly isolated oleaginous fungus, Mucor circinelloides (M. circinelloides) Q531, was able to convert mulberry branches into lipids. The highest yield and the maximum lipid content produced by the fungal cells were 42.43 ± 4.01 mg per gram dry substrate (gds) and 28.8 ± 2.85%, respectively. The main components of lignocellulosic biomass were gradually reduced during solid-state fermentation (SSF). Cellulose, hemicellulose and lignin were decreased from 45.11, 31.39 and 17.36% to 41.48, 28.71, and 15.1%, respectively. Gas chromatography analysis showed that the major compositions of the fermented products were palmitic acid (C16:0, 18.42%), palmitoleic acid (C16:1, 5.56%), stearic acid (C18:0, 5.87%), oleic acid (C18:1, 33.89%), linoleic acid (C18:2, 14.45%) and γ-linolenic acid (C18:3 n6, 22.53%) after 2 days of SSF. The fatty acid methyl esters contained unsaturated fatty acids with a ratio of 75.95%. The composition and content obtained in this study are more advantageous than those of many other biomass lipids. Meanwhile, the oleaginous fungus had a high cellulase activity of 1.39 ± 0.09 FPU gds−1. The results indicate that the enzyme activity of the isolated fungus was capable of converting the cellulose and hemicelluloses to available sugar monomers which are beneficial for the production of lipids.

Qin, M., Huang, S., He, Z., Xu, Q., Song, J., Liu, Z., Guo, Q., 2018. Evolution of tectonic uplift, hydrocarbon migration, and uranium mineralization in the NW Junggar Basin: An apatite fission-track thermochronology study. Acta Geologica Sinica - English Edition 92, 1901-1916.

https://doi.org/10.1111/1755-6724.13684

The Mesozoic–Cenozoic tectonic movement largely controls the northwest region of the Junggar Basin (NWJB), which is a significant area for the exploration of petroleum and sandstone‐type uranium deposits in China. This work collected six samples from this sedimentary basin and surrounding mountains to conduct apatite fission track (AFT) dating, and utilized the dating results for thermochronological modeling to reconstruct the uplift history of the NWJB and its response to hydrocarbon migration and uranium mineralization. The results indicate that a single continuous uplift event has occurred since the Early Cretaceous, showing spatiotemporal variation in the uplift and exhumation patterns throughout the NWJB. Uplift and exhumation initiated in the northwest and then proceeded to the southeast, suggesting that the fault system induced a post spread‐thrust nappe into the basin during the Late Yanshanian. Modeling results indicate that the NWJB mountains have undergone three distinct stages of rapid cooling: Early Cretaceous (ca. 140–115 Ma), Late Cretaceous (ca. 80–60 Ma), and Miocene–present (since ca. 20 Ma). These three stages regionally correspond to the Lhasa‐Eurasian collision during the Late Jurassic–Early Cretaceous (ca. 140–125 Ma), the Lhasa‐Gandise collision during the Late Cretaceous (ca. 80–70 Ma), and a remote response to the India‐Asian collision since ca. 55 Ma, respectively. These tectonic events also resulted in several regional unconformities between the J3/K1, K2/E, and E/N, and three large‐scale hydrocarbon injection events in the Piedmont Thrust Belt (PTB). Particularly, the hydrocarbon charge event during the Early Cretaceous resulted in the initial inundation and protection of paleo‐uranium ore bodies that were formed during the Middle–Late Jurassic. The uplift and denudation of the PTB was extremely slow from 40 Ma onward due to a slight influence from the Himalayan orogeny. However, the uplift of the PTB was faster after the Miocene, which led to re‐uplift and exposure at the surface during the Quaternary, resulting in its oxidation and the formation of small uranium ore bodies.

Qin, S., Zhou, G., Zhou, Z., Yang, Y., 2018. Geochemical characteristics of natural gases from different petroleum systems in the Longgang gas field, Sichuan Basin, China. Energy Exploration & Exploitation 36, 1376-1394.

https://doi.org/10.1177/0144598718763902

Located in the Sichuan Basin, China, the Longgang gas field consists of three vertically developed petroleum systems with the Triassic Leikoupo Formation as a dividing interface. There is one marine petroleum system below the interface and one continental petroleum system above it. The marine petroleum system is composed of coal measures, the main source rock in the Longtan Formation, and marine reef reservoirs in the Changxing and Feixianguan formations. The continental petroleum system can also be subdivided into two sets. One is the Xujiahe petroleum system sourced from the Xujiahe coal measures in the Upper Triassic formation. The other is a Jurassic petroleum system that is sourced from Jurassic lacustrine black shales. The gas pools in the marine system contain H2S gas. The gases are very dry and the δ13C1 and δ13C2 values display less negative values with an average of −29.2 and −25.0‰, respectively. The gases are humic origin generated at highly to over mature stages from coal measures of the Longtan Formation. The natural gas in the continental petroleum system does not contain H2S. The natural gases from the Xujiahe petroleum system are mainly wet gases with a few dry gases, and belong to typical humic type sourced from coal measures of the Xujiahe Formation. All the gases from this Jurassic petroleum system are wet gases and the alkane gases show more negative carbon isotopic values typical of sapropels. These are derived from the lower Jurassic lacustrine black mudstone. The three sets of petroleum systems in the Longgang gas field are vertically well separated. Each system has its own source rock, and there are no gases from other sources despite multiple tectonic events in the past. The reservoirs had been in a relatively stable tectonic condition with excellent seals by cap rocks during the gas accumulation period.

Qing, O., Zhou, C., Xiao, S., Chen, Z., Shao, Y., 2019. Acanthomorphic acritarchs from the Ediacaran Doushantuo Formation at Zhangcunping in South China, with implications for the evolution of early Ediacaran eukaryotes. Precambrian Research 320, 171-192.


Microfossil assemblages preserved in the Ediacaran Doushantuo Formation phosphorites (i.e., the Weng’an biota) and chert nodules in South China provide key evidence for the diversification of marine eukaryotes in the aftermath of Cryogenian global glaciation. Two biozones (i.e., the lower Tianzhushania spinosa biozone and the upper Hocosphaeridium anozos biozone) have been proposed on the basis of acanthomorphic acritarchs preserved in the Doushantuo Formation chert nodules in the Yangtze Gorges area. Strata containing the Weng’an biota at Weng’an have been correlated either with the upper acritarch biozone based mainly on chemostratigraphic data, or with the lower acritarch biozone according to the occurrence of Tianzhushania spinosa in both assemblages. These alternative correlations need to be resolved in order to improve our understanding of the evolutionary pattern of microscopic eukaryotes after the Marinoan glaciation. To address this problem, we carried out an integrated litho-, bio-, and chemostratigraphic study of the Doushantuo Formation in the Zhangcunping area, where the microfossil assemblage resembles the Weng’an biota at Weng’an in both taxonomic composition and biostratigraphic ranges. Our study supports the litho- and chemostratigraphic correlation of the Doushantuo Formation between the Zhangcunping and Yangtze Gorges areas. Thus, the Doushantuo Formation at Zhangcunping provides a link between the Weng’an and Yangtze Gorges areas. Together with published paleontological and stratigraphic data, the present study favors a correlation between the fossiliferous strata at Zhangcunping and the upper part of the T. spinosa biozone recognized in the Yangtze Gorges area. The strata yielding the Weng’an biota at Weng’an can be at least partially correlated with the T. spinosa biozone, supporting

the idea that the Weng’an microfossil assemblage is biostratigraphically transitional between the lower and upper acanthomorphic assemblages. This correlation is consistent with the fact that several taxa that used to be regarded characteristic of the H. anozos biozone may actually range downsection into the T. spinosa biozone, thus supporting an earlier diversification of Doushantuo acanthomorphs. These results call for more detailed investigation on the taxonomic composition and biostratigraphic ranges of acanthomorphs in the T. spinosa biozone, and re-consideration of acanthomorphic biozonation of the Doushantuo Formation in the Yangtze Gorges area.

Race, A.M., Römpp, A., 2018. Error-free data visualization and processing through imzML and mzML validation. Analytical Chemistry 90, 13378-13384.


Open data formats are key to facilitating data processing, sharing, and integration. The imzML format (<http://imzml.org/>) has drastically improved these aspects of mass spectrometry imaging data. Efficient processing of data depends on data sets which are consistent and adhere to the specifications; however, this is not always the case. Here we present a validation tool for data stored in both imzML and the HUPO-PSI mass spectrometery counterpart, mzML, to identify any deviations from the published (i)mzML standard which could cause issues for the user when visualizing or processing data. The tool is released in two forms, a graphical user interface (GUI) for ease of use, and a command line version to fit into existing workflows and pipelines. When certain known issues are encountered, such as the presence of negative values for the location of the binary data, the validator resolves the issue automatically upon saving. The GUI version of the validator also allows editing of the metadata included within the (i)mzML files in order to resolve inconsistencies. We also present a means of performing conditional validation on the metadata within (i)mzML files, where user-defined rules are validated against depending on whether specific metadata are present (or not). For example, if the MALDI term is present, then additional rules related to MALDI (such as the requirement of inclusion of laser parameters) can be validated against this. This enables a flexible and more thorough automated validation of (i)mzML data. Such a system is necessary for validating data against more comprehensive sets of metadata such as minimum reporting guidelines or metadata requirements prior to submission and acceptance of data to data repositories. We demonstrate how this tool can be used to validate against the proposed minimum reporting guidelines in MSI as well as institute specific metadata criteria. The validator tool is endorsed for validation of imzML (<http://imzml.org/>) and mzML (<http://www.psidev.info/mzml>) and is made available through the respective Web sites. The validator is also released as open source under Mozilla Public License 2.0 at <https://gitlab.com/imzML/imzMLValidator>


https://doi.org/10.1139/cjm-2018-0254

We report an investigation of microbially induced carbonate precipitation by seven indigenous bacteria isolated from a landfill in China. Bacterial strains were cultured in a medium supplemented with 25 mmol/L calcium chloride and 333 mmol/L urea. The experiments were carried out at 30 °C for 7 days with agitation by a shaking table at 130 r/min. Scanning electron microscopic and X-ray diffraction analyses showed variations in calcium carbonate polymorphs and mineral composition induced by all bacterial strains. The amount of carbonate precipitation was quantified by titration. The amount of carbonate precipitated in the medium varied among isolates, with the lowest being Bacillus

aerius rawirorabr15 (LC092833) precipitating around 1.5 times more carbonate per unit volume than the abiotic (blank) solution. Pseudomonas nitroreducens szh_asesj15 (LC090854) was found to be the most efficient, precipitating 3.2 times more carbonate than the abiotic solution. Our results indicate that bacterial carbonate precipitation occurred through ureolysis and suggest that variations in carbonate crystal polymorphs and rates of precipitation were driven by strain-specific differences in urease expression and response to the alkaline environment. These results and the method applied provide benchmarking and screening data for assessing the bioremediation potential of indigenous bacteria for containment of contaminants in landfills.

Ratié, G., Quantin, C., Maia De Freitas, A., Echevarria, G., Ponzevera, E., Garnier, J., 2019. The behavior of nickel isotopes at the biogeochemical interface between ultramafic soils and Ni accumulator species. Journal of Geochemical Exploration 196, 182-191.


Ultramafic derived soils are characterized by low nutrient soils, a low Ca:Mg ratio, and high metal contents such as Ni, Co and Cr. The vegetation growing on these soils is highly adapted and includes both Ni hyperaccumulator and accumulator species. Today, approximately 530 Ni hyperaccumulator species are listed worldwide and the Ni concentration can be extremely high, e.g. up to 25% in latex from Pycnandra acuminata (Sapotaceae), a tree found in New Caledonia. The aim of this study is to identify the potential role of Ni hyperaccumulator plants in the Ni biogeochemical cycle at the soil surface by using Ni isotopes. A set of Ni hyperaccumulator and Ni accumulator plants as well as topsoils were sampled on the Barro Alto and Niquelândia ultramafic complexes (Goiás State, Brazil). Three Ni hyperaccumulator plants were collected: Justicia lanstyakii, Heliotropium aff. salicoides, Cnidoscolus aff. urens, as well as one Ni accumulator plant, Manihot sp. The isotopic compositions of the whole plants were determined and compared to those of the bulk topsoils and DTPA-extractable Ni. The topsoils exhibited δ60Ni values ranging from −0.30 ± 0.06‰ to 0.16 ± 0.05‰. The DTPA-extractable Ni in the topsoils ranged from 94 to 623 mg kg−1, i.e. 0.9–4.9% of the total soil Ni and was found to be isotopically heavier than the corresponding topsoil (from −0.30 ± 0.05‰ to 0.34 ± 0.08‰). The δ60Ni values for the Ni accumulator plants showed an enrichment in heavy Ni isotopes in the aerial parts of the plant compared to the roots, whereas similar δ60Ni values for the roots, stems and aerial parts suggested that no significant fractionation results from Ni uptake and translocation in Ni hyperaccumulator plants. Moreover, the aerial parts (i.e. leaves and flowers) from all of the plants analyzed showed the highest Ni concentrations and the heaviest δ60Ni values up to 1.21 ± 0.05‰. The enrichment in heavy Ni isotopes in the leaves (0.09 ± 0.06‰ < Δ60Nileaves-

soil < 1.06 ± 0.03‰) may result in a heavy Ni input in the litter during organic matter restitution. There is a non-negligible amount of Ni uptake by Ni accumulator and Ni hyperaccumulator plants and this may modify both the Ni isotope composition at the soil-plant interface and the overall cycle of Ni in surface soils.

Regier, P., He, D., Saunders, C.J., Jara, B., Hansen, C., Newman, S., Tate-Boldt, E., Coronado-Molina, C., Jaffé, R., 2018. Sheet flow effects on sediment transport in a degraded ridge-and-slough wetland: Insights using molecular markers. Journal of Geophysical Research: Biogeosciences 123, 3124-3139.

https://doi.org/10.1029/2018JG004648

Abstract: Wetland ecosystems are often characterized by self‐organized landscape patterning, driven by abiotic and biotic factors. In the Florida Everglades, natural sheet flow is hypothesized to have distributed sediments to form the pattern of linear emergent ridges and submerged sloughs. Drainage and barriers to flow have degraded these microtopographic features. As part of the Comprehensive

Everglades Restoration Plan, the Decompartmentalization Physical Model is a landscape‐scale experiment to evaluate ecosystem responses to restored sheet flow by increasing freshwater inputs and removing barriers to flow. To test the proposed mechanism that flow rebuilds ridge‐slough microtopography by remobilizing slough sediments into ridges, four molecular markers capable of distinguishing ridge, slough, and microbial sources were evaluated in flocculent benthic sediments (floc) and advected sediments (collected in traps) during preflow, high‐flow, and postflow conditions over 4 years. The combined use of the four biomarkers, namely, the aquatic proxy (Paq), C20 highly branched isoprenoids, kaurenes, and botryococcenes, showed compositional patterns that clearly distinguished ridge and slough organic matter. Of these molecular parameters, the Paq was the most reliable in distinguishing among organic matter sources. Long‐term patterns in floc Paq at ridge and slough sites indicate a general increase, indicative of preferential mobilization of slough material. The Paq values for advected sediments are also strongly associated with slough environments, supporting temporal trends in floc samples. Our results tentatively confirm the hypothesis that increased flow in degraded ridge‐and‐slough wetlands, and associated sediment transport, is a potentially viable mechanism to restore historic patterns of microtopography.

Plain Language Summary: We examined how experimental flows within the Decompartmentalization Physical Model (DPM) altered the movement of benthic sediment (floc) in ridge and slough habitats, an important mechanism for restoring pattern and topography of the historic Everglades ridge‐and‐slough landscape. The approach is novel in utilizing molecular organic biomarkers that identify sources of organic matter from ridges and sloughs to infer the movement of floc. Results so far are promising in suggesting that sediment redistribution does occur and may over longer time periods help rebuild topography, an important objective of large‐scale flow restoration projects such as those proposed in the Comprehensive Everglades Restoration Plan (CERP).

Regmi, B.P., Agah, M., 2018. Micro gas chromatography: An overview of critical components and their integration. Analytical Chemistry 90, 13133-13150.


Among a number of gas analyzers, portable gas chromatography (GC) systems created by the integration of microfabricated components are promising candidates for rapid and on-site analysis of a number of complex chemical mixtures. This Feature provides a snapshot of the progress made in developing micro gas chromatography (μGC) systems in the last 4 decades. In particular, we discuss the development of microfabricated preconcentrators, separation columns, and detectors. Furthermore, we review different stationary phase materials used to coat the separation columns and the major efforts toward the development of an integrated μGC.

Driven by the rising demands for on-site and rapid chemical analysis of a wide range of complex mixtures, interest in the development of portable or hand-held analytical instruments has significantly increased in the past few decades. On-site chemical analysis provides a number of clear benefits as compared to the laboratory-based measurements. On-site measurements (1) offer rapid analysis and turnaround time for making time-sensitive decisions, (2) assist in the development of effective sampling plans, and (3) minimize the changes in sample composition owing to a number of processes such as evaporation, adsorption, degradation, and oxidation.(1−3)

Among a number of portable devices, a miniaturized version of gas chromatography (GC) system is a very promising technique for rapid and sensitive analysis of complex chemical mixtures. While a conventional GC is a powerful and versatile tool, it is relatively bulky and requires high power with a typical peak power requirement of 2000–3000 V-ampere.(4) Hence, these instruments are normally not field portable. With an aim to develop compact, low power, and field portable GC instruments,

considerable research has been conducted over the past 40 years. There has been increased marketability of portable GC instruments, and these products are being developed in both research(5−19) and commercial laboratories (Table S1 in the Supporting Information).(20−24) The nomenclature of these miniaturized GC-based devices is not clear-cut. For example, INFICON 3000 Micro GC (portable model) weighs 36.5 lb, Agilent 490 Micro GC (with 4 channels) weighs 23.4 lb, and Vernier Mini GC Plus (developed by Seacoast Science, Inc.) weighs 2.87 lb, indicating that the use of word “mini” or “micro” is not based on weights. Moreover, the use of the term “micro” is also not based on the type of column used, as miniature GC systems comprising conventional capillary columns are sometimes named as micro GCs.(19,25,26) Throughout this article, we use the term “micro gas chromatograph” (μGC) to refer any field portable versions of a GC comprising one or more microfabricated components. A μGC comprises a number of components, including a source of carrier gas, preconcentrator-injector, separation column, detector, pump, valves, and software for instrument control, data acquisition, and analysis.

This feature discusses the theory of (micro) GC, different types of microcolumns and stationary phase materials, preconcentrator, detectors, and a brief history of the development of μGCs. Interested readers are referred to recently published reviews to cover μGC(27−30) or some specific aspects of μGC.(31−34) An extensive and up-to-date review on various microcolumns, stationary phases, and separation performance has been recently published by Ghosh et al.(34)

Rehman, K., Imran, A., Amin, I., Afzal, M., 2019. Enhancement of oil field-produced wastewater remediation by bacterially-augmented floating treatment wetlands. Chemosphere 217, 576-583.


Plants and bacteria individually as well as in synergism with each other hold a great potential to degrade a wide range of environmental pollutants. Floating treatment wetlands (FTWs) is an efficient and low-cost technology that uses the synergistic interaction between plant roots and microbes for in situ remediation of wastewater. The present study aims to assess the feasibility of FTW-based remediation of oil field-produced wastewater using an interaction between two plant species, Typha domingensis and Leptochloa fusca, in partnership with a consortium of crude oil-degrading bacterial species, Bacillus subtilis LORI66, Klebsiella sp. LCRI87, Acinetobacter Junii TYRH47, and Acinetobacter sp. BRSI56. All the treatments reduced contaminant levels, but T. domingensis, in combination with bacterial inoculation, exhibited the highest reduction in hydrocarbon (95%), COD (90%), and BOD content (93%) as compared to L. fusca. This combination maximally promoted increases in fresh biomass (31%), dry biomass (52%), and length (25%) of plants as well. This effect was further signified by the persistence of bacteria (40%) and considerable abundance (27%) and expression (28.5%) of the alkB gene in the rhizoplane of T. domingensis in comparison to that of L. fusca. The study, therefore, suggests that T. domingensis, in combination with bacterial consortium, has significant potential for treatment of oil field-produced water and can be exploited on large scale in FTWs.

Rellegadla, S., Bairwa, H.K., Kumari, M.R., Prajapat, G., Nimesh, S., Pareek, N., Jain, S., Agrawal, A., 2018. An effective approach for enhanced oil recovery using nickel nanoparticles assisted polymer flooding. Energy & Fuels 32, 11212-11221.


The addition of polymer to injection fluid increases the crude oil recovery by improved sweep efficiency. Although it is the most widely used method for chemical enhanced oil recovery (CEOR),

limitations such as lower stability of the polymer under reservoir conditions hinder the efficiency of the process. In the current study, a novel nanoparticle assisted polymer flooding approach was carried out to overcome these limitations. To determine whether nanoparticles influence the displacement efficiency of the injected fluid, we used a blend of xanthan gum and nickel nanoparticles. We have evaluated the changes in the dilute solution viscosity of xanthan when the nickel nanoparticles are added and have found out that a xanthan-nickel nanoparticles mixture has a higher intrinsic viscosity of 55.25 dL/g compared to 49.13 dL/g for the gum solution. Efficiency of nanoparticle assisted polymer flooding was evaluated in sand packed bioreactors with ∼0.6 PV of residual oil in place (ROIP). Flooding results demonstrated the highest recovery of 5.98% of additional ROIP with xanthan-nickel nanoparticle mixture compared to 4.48 and 4.58% of ROIP during the separate flooding of xanthan and nanoparticles, respectively. Results suggested the novel nanoparticle assisted polymer flooding approach is able to increase oil recovery beyond available methods.

Ren, J., Zheng, Q., Guo, P., Peng, S., Wang, Z., Du, J., 2019. Pore-scale lattice Boltzmann simulation of two-component shale gas flow. Journal of Natural Gas Science and Engineering 61, 46-70.


Shale gas is usually a multi-component gas mixture dominated by CH4. Moreover, CO2 sequestration in shale reservoirs and CO2-enhanced shale-gas recovery also result in multi-component gas flow in shale reservoirs. Therefore, compared with single-component gas flow, multi-component gas flow is more often encountered in practice. Furthermore, shale rock contains a lot of nano-pores in which the micro-scale effect makes the multi-component gas flow become more complex. In this paper, the lattice Boltzmann method is employed to simulate the two-component shale gas flow in a two-dimensional micropore under different conditions. The pore-scale transport mechanism of the two-component shale gas is investigated and the gas separation phenomenon for the shale gas flow is discussed in detail. It is found that the molar fraction of each species in shale gas does not distribute uniformly along the micropore and the gas separation phenomenon exists in the two-component pressure-driven shale gas flow. The molar fraction distribution of each species along the micropore is affected by the Knudsen number, pressure ratio, shale gas composition and molar fraction of each species for the pressure-driven gas flows. In particular, we find that the molar fraction distribution and pressure distribution for two-component shale gas along the micropore are related to the pressure ratio and are unrelated to the pressure gradient. With increasing the molar fraction of CH4 in shale gas, both the gas-mixture velocity at the outlet and the slip velocity along the micropore become larger. Both the Knudsen number and pressure ratio affect the molar fraction distribution of CO2 for the CH4-CO2 mixture in the micropore during CO2 injection, while the influence of them works oppositely. Furthermore, the concentration diffusion without the external force is affected by the micropore width and the concentration difference between the gas mixtures.



According to the aeromagnetic, seismic, and geological data, the surface structure, sedimentation, and distribution characteristics as well as the deep dynamic mechanism of the north-south differentiated Neoproterozoic rift basins were well investigated to reveal the tectonic evolution and its control on the distribution of the Early Cambrian sedimentary basin and source rocks in the Tarim Basin. The rift basin in the southern Tarim was a product of superplume activities during the early breakup period of the Rodinia supercontinent. It initiated in the Early Cryogenian (about 780 Ma) and

appeared as NE-direction aulacogens extending into the Tarim Basin. The rift basin in the northern Tarim was a back-arc rift basin derived from the subduction of Pan-Rodinian oceanic plate, which initiated in the Late Cryogenian (about 740 Ma) and occurred as a nearly EW-direction narrow band across the Tarim Basin. The northern Tarim back-arc rift basin had similar formation and evolution process to the Late Mesozoic-Cenozoic back-arc rift basins in East Asia, both showing an oceanward migration; however, the Tarim rift basin finally evolved from the fault-depression basins into passive continental margin. The Neoproterozoic rift basins controlled not only the distribution of source rocks in the syn-rift period but also the development of Early Cambrian sedimentary basin. Nearly EW-distributed syn-rift (Cryogenian to Ediacaran) and post-rift (Lower Cambrian Yurtusi period) source rocks were likely to develop between the present Tabei uplift and central uplift belt.

Renault, H., Werck-Reichhart, D., Weng, J.-K., 2019. Harnessing lignin evolution for biotechnological applications. Current Opinion in Biotechnology 56, 105-111.


Lignin evolved concomitantly with the rise of vascular plants on planet earth ∼450 million years ago. Several iterations of exploiting ancestral phenylpropanoid metabolism for biopolymers occurred prior to lignin that facilitated early plants’ adaptation to terrestrial environments. The first true lignin was constructed via oxidative coupling of a number of simple phenylpropanoid alcohols to form a sturdy polymer that supports long-distance water transport. This invention has directly contributed to the dominance of vascular plants in the Earth’s flora, and has had a profound impact on the establishment of the rich terrestrial ecosystems as we know them today. Within vascular plants, new lignin traits continued to emerge with expanded biological functions pertinent to host fitness under complex environmental niches. Understanding the chemical and biochemical basis for lignin’s evolution in diverse plants therefore offers new opportunities and tools for engineering desirable lignin traits in crops with economic significance.

Reyes, J., Jiang, C., Lavoie, D., Armstrong, D.K., Milovic, M., Robinson, R., 2018. Organic petrographic analysis of artificially matured chitinozoan- and graptolite-rich Upper Ordovician shale from Hudson Bay Basin, Canada. International Journal of Coal Geology 199, 138-151.


Chitinozoan, graptolite and organic-rich immature Upper Ordovician mudstone was artificially matured using closed hydrous pyrolysis. The pyrolysis was performed at isothermal temperatures of 310-350 °C at 10 °C increments for 72 h. This temperature range simulates the subsurface thermogenic hydrocarbon generation window based on previous laboratory simulations. The objectives of this study are to (a) qualitatively and quantitatively assess the degree of physicochemical transformation of dispersed organic matter (DOM) and zooclasts in BRF petroleum source rock after artificial maturation; and (b) determine the relationship between graptolite, chitinozoan, vitrinite-like particle and bitumen reflectance (Ro) with increasing pyrolysis temperature and the thermal maturity. Petrographic analysis shows that bituminite and amorphous kerogen were the first organic macerals to thermally decompose after the first pyrolysis temperature. This is followed by liptodetrinite, thin-walled alginite, acritarch, and telalginite as pyrolysis temperature increases. Concurrently, the fluorescence properties of the telalginite shifted from greenish yellow to reddish-orange after the last stage (350 °C) pyrolysis. In addition, significant amount of bright fluorescing labile hydrocarbons produced during pyrolysis were observed oozing from pore spaces and on the surface of the rock matrix. Pore-filling, orange to reddish-orange fluorescing solid bitumen were also found in pores spaces created by the thermal decomposition of DOM. The lack of

morphological evidence for the thermal decomposition of chitinozoans and graptolites suggests that these zooclasts macerals may have limited or have no contribution to the overall hydrocarbon generation. Nonetheless, their respective reflectance (Ro) increased (0.64% to 1.34% and 0.55% to 1.38%) as the pyrolysis temperature was increased. These Ro values are significantly higher than the vitrinite-like particles (0.49% to 1.07%) and solid bitumen (0.30% to 1.09%). The measured RocK-Eval Tmax and solid bitumen vitrinite reflectance equivalent (VRo-eqv) are comparable to the average vitrinite-like particles. The relationship between rate of increase in chitinozoan and graptolite, and vitrinite-like particles Ro, expressed by the equations: Ro-vit-like = 0.77 Rchi and Ro-vit-like = 0.79 Rgrap, are comparable to those observed in geologically matured source rocks.

Rezaei Dehshibi, R., Mohebbi, A., Riazi, M., Danafar, F., 2019. Visualization study of the effects of oil type and model geometry on oil recovery under ultrasonic irradiation in a glass micro-model. Fuel 239, 709-716.


If the current trends of oil recovery from the oil reservoirs continue, the level of oil production will significantly reduce soon. This intense reduction will challenge the current methods for enhanced oil recovery since they will lose their capability and efficiency to meet the required targets. Accordingly, applying new and efficient methods to improve oil recovery are essential. In this study, ultrasound waves were applied to investigate its effect on oil recovery during distilled waterflooding under temperature control. The effect of ultrasound on the oil recovery was studied in a glass micro-model for different model geometries. Experiments were conducted using two types of oil (different in their viscosities) and micro models (different in their geometries). One of the micro models had three types of different geometries and fluid after passing through each geometry enters into the next geometry. Results showed that ultrasonic waves improved oil recovery, oil mobility and eventually oil percolation paths. However, the ultimate recovery of the oil not only depends upon the viscosity of the oil but also the geometry of the micro-model used. The effect of ultrasonic waves was more significant for the oil with lower viscosity. The ability of ultrasonic waves on fluid flow in a porous medium depends on the stratigraphy and geometry of these media. Consequently, if ultrasonic waves are used for EOR/IOR, the type of oil and geometry of porous media should be considered.

Riedman, L.A., Porter, S.M., Calver, C.R., 2018. Vase-shaped microfossil biostratigraphy with new data from Tasmania, Svalbard, Greenland, Sweden and the Yukon. Precambrian Research 319, 19-36.


The recent revision of the Cryogenian lower boundary from 850 Ma to 720 Ma has nearly doubled the duration of the Tonian Period to 280 Myrs, an interval longer than the Mesozoic and Cenozoic eras combined. Although subdivision of the Tonian will likely emphasize chemostratigraphy, the relatively rich fossil record of this time period may also be useful. In particular, vase-shaped microfossils (VSMs) occur globally and often abundantly in a variety of lithofacies, exhibit a variety of preservational modes, and are stratigraphically constrained by the two major carbon isotopic events of the Tonian Period, the Bitter Springs and Islay anomalies. VSMs have been used as informal, grade-level indicators of late Tonian age (e.g. ca. 800–700 Ma) for several decades but here, based on new data from an assemblage in northwestern Tasmania and restudy of samples from Svalbard, Greenland, Sweden and the Yukon, we report a species-level faunal assemblage indicative of the interval ca. 789 to 729 Ma. Species-level VSM biostratigraphy presents an opportunity for potential biostratigraphic subdivision of the lengthy Tonian Period and is particularly useful in successions where chemostratigraphy and radiometric age constraints are absent.

Eight taxa are described from shales and early diagenetic cherts of the Black River Dolomite, Togari Group, Tasmania, including seven previously named species (Bombycion micron, Bonniea dacruchares, Bonniea pytinaia, Cycliocyrillium simplex, Cycliocyrillium torquata, Melanocyrillium hexodiadema and Palaeoarcella athanata), and one newly described genus and species Pakupaku kabin n. gen et n. sp. Study of additional units resulted in new recognition of B. pytinaia, C. simplex and C. torquata in the Draken Formation, Spitsbergen, Svalbard, B. dacruchares and P. athanata in the Ryssö Formation, Nordaustlandet, Svalbard, B. dacruchares, B. pytinaia, C. torquata and P. athanata in Bed 18 of the Eleonore Bay Group, Greenland, and B. dacruchares, B. pytinaia and Bombycion micron in the Visingsö Group, Sweden.

Riedman, L.A., Sadler, P.M., 2018. Global species richness record and biostratigraphic potential of early to middle Neoproterozoic eukaryote fossils. Precambrian Research 319, 6-18.


Over the past several decades, a number of studies have addressed the record of eukaryotic species richness in the Proterozoic, each making quite clear that during the Neoproterozoic Era, in particular, tremendous changes occurred in Earth’s biota. The relative scarcity of radiometric age constraints for rocks of this interval, however, have necessitated the use of coarse time bins (∼100 Ma) and the omission of fossiliferous but poorly dated units, resulting in low resolution of eukaryotic richness trends. Here we present a new estimate of early to middle Neoproterozoic (Tonian and Cryogenian) eukaryotic richness developed by use of the CONOP seriation algorithm; this approach permits inclusion of poorly dated and un-dated units and allows for greater resolution.

The CONOP (constrained optimization) algorithm operates by evolutionary ordination—considering evidence of stratigraphic order from all locations simultaneously and starting from a random ordinal sequence that improves by mutations retained or removed according to best-fit rules. This program has been applied successfully to biochronologic and biostratigraphic problems throughout the Phanerozoic geologic record. Here we apply this objective approach to a new compilation of taxonomically well-constrained organic-walled microfossil occurrences as well as geochemical, sedimentological and geochronological data from more than 160 formations from 60 groups in paleogeographically distant successions. From this dataset was developed a high-resolution eukaryotic species richness record for the early to middle Neoproterozoic Era (∼1000 to 635 Ma).

This new estimate of eukaryotic species richness indicates an increase in richness began ∼800 Ma and continued towards a peak ∼770 Ma when it declined with the losses of many long-lived acritarch taxa. The overall decline is punctuated by a sharp richness increase with a ∼738 Ma peak due to the iconic and short-lived Tonian vase-shaped microfossil taxa such as Cycliocyrillium simplex. These VSM taxa were lost ∼733 Ma and richness continued to decline until flat-lining well in advance of the ∼720 Ma onset of the Cryogenian Snowball Earth glaciations. Eukaryotic species richness did not rebound until after the termination of the second Cryogenian glaciation when a new suite of acritarch taxa appeared in the Ediacaran Period.

Use of CONOP with this dataset also permitted assessment of fossil taxa that had previously been suggested as Neoproterozoic biostratigraphic index taxa. Our results provide particular support for biostratigraphic use of the acritarch Cerebrosphaera globosa (=C. buickii) and for species of vase-shaped microfossils.

Roberts, P., Stewart, M., Alagaili, A.N., Breeze, P., Candy, I., Drake, N., Groucutt, H.S., Scerri, E.M.L., Lee-Thorp, J., Louys, J., Zalmout, I.S., Al-Mufarreh, Y.S.A., Zech, J., Alsharekh, A.M., al Omari, A.,

Boivin, N., Petraglia, M., 2018. Fossil herbivore stable isotopes reveal middle Pleistocene hominin palaeoenvironment in ‘Green Arabia’. Nature Ecology & Evolution 2, 1871-1878.

https://doi.org/10.1038/s41559-018-0698-9

Despite its largely hyper-arid and inhospitable climate today, the Arabian Peninsula is emerging as an important area for investigating Pleistocene hominin dispersals. Recently, a member of our own species was found in northern Arabia dating to ca. 90 ka, while stone tools and fossil finds have hinted at an earlier, middle Pleistocene, hominin presence. However, there remain few direct insights into Pleistocene environments, and associated hominin adaptations, that accompanied the movement of populations into this region. Here, we apply stable carbon and oxygen isotope analysis to fossil mammal tooth enamel (n = 21) from the middle Pleistocene locality of Ti’s al Ghadah in Saudi Arabia associated with newly discovered stone tools and probable cutmarks. The results demonstrate productive grasslands in the interior of the Arabian Peninsula ca. 300–500 ka, as well as aridity levels similar to those found in open savannah settings in eastern Africa today. The association between this palaeoenvironmental information and the earliest traces for hominin activity in this part of the world lead us to argue that middle Pleistocene hominin dispersals into the interior of the Arabian Peninsula required no major novel adaptation.



Fluid petroleum coke generated at oil sands operations in the Athabasca Oil Sands Region of northern Alberta, Canada, contains elevated concentrations of molybdenum (Mo) and other metals including nickel (Ni) and vanadium (V). Solid-phase Mo concentrations in fluid petroleum coke are typically 10 to 100 times lower than V and Ni, yet dissolved Mo concentrations in associated pore waters are often comparable with these metals. We collected pore water and solids from fluid petroleum coke deposits in the AOSR to examine geochemical controls on Mo mobility. Dissolved Mo concentrations increased with depth below the water table, reaching maxima of 1.4–2.2 mg L−1, within a mixing zone between slightly acidic and oxic meteoric water and mildly alkaline and anoxic oil sands process-affected water (OSPW). Dissolved Mo concentrations decreased slightly with depth below the mixing zone. X-ray absorption spectroscopy revealed that Mo(VI) and Mo(IV) species were present in coke solids. The Mo(VI) occurred as tetrahedrally coordinated MoO4

2− adsorbed via inner- and outer-sphere complexation, and was coordinated in an environment similar to Fe-(hydr)oxide surface complexes. The OSPW likely promoted desorption of outer-sphere Mo(VI) complexes, resulting in higher dissolved Mo concentrations in the mixing zone. The principal Mo(IV) species was MoS2, which originated as a catalyst added upstream of the fluid coking process. Although MoS2 is likely stable under anoxic conditions below the mixing zone, oxidative weathering in the presence of meteoric water may promote long-term Mo release.

Rodrigues, M.L., 2018. The multifunctional fungal ergosterol. mBio 9, Article e01755-18.

http://mbio.asm.org/content/9/5/e01755-18.abstract

The roles of ergosterol in the regulation of membrane fluidity and structure, as well its role as a target for the activity of antifungals, have been known for decades. Two recent studies, however, demonstrated that ergosterol is an immunologically active lipid that induces pyroptosis and that

virtually all steps of its biosynthetic process are potential drug targets. In combination, those two reports strongly indicate that the biological relevance of ergosterol is broader than the current literature suggests.The views expressed in this Commentary do not necessarily reflect the views of this journal or of ASM.

Romanczyk, M., Ramirez Velasco, J.H., Xu, L., Vozka, P., Dissanayake, P., Wehde, K.E., Roe, N., Keating, E., Kilaz, G., Trice, R.W., Luning Prak, D.J., Kenttӓmaa, H., 2019. The capability of organic compounds to swell acrylonitrile butadiene O-rings and their effects on O-ring mechanical properties. Fuel 238, 483-492.


As interest in replacing petroleum-derived aviation fuels with resilient, alternative fuels increases, the ability to derive correlations between the chemical compositions of aviation fuels and their properties and performance becomes more important. In this work, correlations between the exact chemical structures of organic compounds and their ability to increase the volume and decrease the tensile strength of Buna-N o-ring seals were explored. Buna-N o-ring seals are a representative group of essential seals in the hydraulic and pneumatic components of aircraft fuel delivery systems. They are utilized to prevent fuel leakage within the pumps, metering devices, and connectors. To measure the volume swell percent of o-ring seals caused by various organic compounds, a test rig was assembled that suspended o-ring seals in neat Sasol IPK (isoparaffinic kerosene) or in Sasol IPK doped individually with an organic compound at 8% by volume. Of the aromatic compounds tested, ethylbenzene and indane swelled o-ring seals most effectively, with volume swell percent values of 3.1 ± 0.2% and 2.8 ± 0.1%, respectively. In comparison, the approved aviation fuel Jet A/HEFA has volume swell percent value of 2.2 ± 0.2%. Alkylbenzenes with a smaller number of alkyl groups, less branching in the alkyl groups, and shorter alkyl chains caused greater swelling and greater decrease in the tensile strength for o-ring seals. Naphthene-containing aromatic compounds (i.e., indane and tetralin) swelled o-ring seals more effectively than alkylbenzenes with the same number of carbons (i.e., n-propylbenzene and n-butylbenzene). Therefore, steric hindrance seems to have an important impact on the ability of these compounds to swell o-rings. Nonaromatic unsaturated hydrocarbons, such as cyclohexene, were also found to swell o-ring seals to some extent. On the other hand, saturated hydrocarbons, such as cyclohexane, contributed to minimum or no swelling. Tensile strengths of intact o-rings were measured using an MTS Insight Electromechanical Testing Instrument. Aromatic compounds that facilitated greater swelling of o-ring seals also caused greater decrease in the tensile strength. For example, ethylbenzene and sec-butylbenzene, with volume swell percent values of 3.1 ± 0.2% and 0.9 ± 0.1%, respectively, reduced the o-ring tensile strength from 15.4 MPa to 13.6 MPa and 14.9 MPa, respectively. Additional experiments demonstrated that volume swell and tensile strength of o-ring seals are reversible properties. Hence, a decrease in tensile strength for o-ring seals does not imply irreversible damage. Overall, the extent of volume swelling and the lowering of tensile strength for o-ring seals was found to depend on the exact chemical structure of the organic compound.

Romsdahl, J., Blachowicz, A., Chiang, A.J., Singh, N., Stajich, J.E., Kalkum, M., Venkateswaran, K., Wang, C.C.C., 2018. Characterization of Aspergillus niger isolated from the International Space Station. mSystems 3, Article e00112-18.


Abstract: The initial characterization of the Aspergillus niger isolate JSC-093350089, collected from U.S. segment surfaces of the International Space Station (ISS), is reported, along with a comparison

to the extensively studied strain ATCC 1015. Whole-genome sequencing of the ISS isolate enabled its phylogenetic placement within the A. niger/welwitschiae/lacticoffeatus clade and revealed that the genome of JSC-093350089 is within the observed genetic variance of other sequenced A. niger strains. The ISS isolate exhibited an increased rate of growth and pigment distribution compared to a terrestrial strain. Analysis of the isolate’s proteome revealed significant differences in the molecular phenotype of JSC-093350089, including increased abundance of proteins involved in the A. niger starvation response, oxidative stress resistance, cell wall modulation, and nutrient acquisition. Together, these data reveal the existence of a distinct strain of A. niger on board the ISS and provide insight into the characteristics of melanized fungal species inhabiting spacecraft environments.

Importance: A thorough understanding of how fungi respond and adapt to the various stimuli encountered during spaceflight presents many economic benefits and is imperative for the health of crew. As A. niger is a predominant ISS isolate frequently detected in built environments, studies of A. niger strains inhabiting closed systems may reveal information fundamental to the success of long-duration space missions. This investigation provides valuable insights into the adaptive mechanisms of fungi in extreme environments as well as countermeasures to eradicate unfavorable microbes. Further, it enhances understanding of host-microbe interactions in closed systems, which can help NASA’s Human Research Program maintain a habitat healthy for crew during long-term manned space missions.:



The main challenge faced by enhanced oil recovery processes (EOR) is to further increase production of the residual oil trapped within the reservoir porous media beyond conventional recovery methods. Chemical EOR processes, such as surfactant flooding, could be employed to dislocate the residual oil to a production well through the reduction of the water/oil (w/o) interfacial tension. Surfactant Flooding is an efficient method, but a large part of the injected surfactant is lost by adsorption on the rock surface before reaching the oil site, turning it often economically unfeasible. This work aimed to evaluate the potential of lipid nanostructures as surfactant nanocarriers for the EOR process. In this new concept, nanocarriers formed by hydrophobic nanoparticles (NPs), should be able to store and carry the surfactant molecules through the reservoir porous media, releasing the surfactant only at the w/o interface, triggered by the nanocarriers solubilization. The released surfactant did lead to a w/o interfacial tension reduction, improving the recovery factor. Nanoparticles were produced through nano-emulsification techniques with beeswax (BW) as the lipid structure and nonylphenol ethoxylate (NPE10) as surfactant. The nanocarriers were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and surfactant entrapment in the nanocarriers. Interfacial tension (IFT) measurements and Fourier transform infrared spectroscopy (FTIR) analysis were used to evaluate the surfactant release and unconsolidated sandpack column tests were conducted to evaluate the transport behavior of the NPs system. The results did demonstrate that the nanocarriers should be able to permeate through the porous media and release the surfactant at the w/o interface, reducing the IFT to values compatible with the ones obtained when employing solely the surfactant solution. The effect of the nanoparticles production process, temperature and salt concentration on the efficiency of the nanoparticles in the delivery of the surfactant at the oil/water interface was evaluated and the results showed the great potential of this type of system as surfactant nanocarrier for the EOR process.

Royer, D.L., Moynihan, K.M., McKee, M.L., Londoño, L., Franks, P.J., 2018. Sensitivity of a leaf gas-exchange model for estimating paleoatmospheric CO2 concentration. Climate of the Past Discussions 2018, 1-23.

https://www.clim-past-discuss.net/cp-2018-156/

Leaf gas-exchange models show considerable promise as paleo-CO2 proxies. They are largely mechanistic in nature, provide well-constrained estimates even when CO2 is high, and can be applied to most subaerial, stomata-bearing leaves from C3 taxa, regardless of age or taxonomy. Here we place additional observational and theoretical constraints on one of these models, the Franks model. In order to gauge the model's general accuracy in a way that is appropriate for fossil studies, we estimated CO2 from 40 species of extant angiosperms, conifers, and ferns based only on measurements that can be made directly from fossils (leaf δ13C and stomatal density and size) and a limited sample size (1–3 leaves per species). The mean error rate is 28%, which is similar to or better than the accuracy of other leading paleo-CO2 proxies. We find that leaf temperature and photorespiration do not strongly affect estimated CO2, although more work is warranted on the possible influence of O2 concentration on photorespiration. Leaves from the lowermost 1–2m of closed-canopy forests should not be used because the local air δ13C value is lower than the global well-mixed value. Such leaves are not common in the fossil record, but can be identified by morphological and isotopic means.

Royle, S.H., Tan, J., Kounaves, S.P., Sephton, M.A., 2018. Survivability of 1-chloronapthalene during simulated early diagenesis: Implications for chlorinated hydrocarbon detection on Mars. Journal of Geophysical Research: Planets 123, 2790-2802.

https://doi.org/10.1029/2018JE005711

Abstract. All missions to Mars which have attempted to detect organic molecules have detected simple chlorohydrocarbons, the source of which has yet to be firmly established. This study assessed the likelihood of these chlorinated molecules being indigenous to the sedimentary units in which they were detected or if they were chlorinated during analysis. The survivability of 1‐chloronapthalene was examined via hydrous pyrolysis experiments and its dechlorination kinetics were determined. The results of these experiments were used to model the survivability of this simple chlorohydrocarbon under Mars‐relevant diagenetic conditions using the Sheepbed mudstone unit as a case study. It was found that 1‐chloronapthalene was rapidly dechlorinated under Noachian conditions, and thus, the detected Martian chlorohydrocarbons are unlikely to be ancient and probably formed within the rover's sample handling chain during analysis.

Plain Language Summary. The search for past or present life on Mars is centered on the detection of organic molecules. Most attempts to detect organic molecules on Mars have only found simple chlorinated compounds. The source of these chlorinated compounds has not been firmly established. It has been hypothesized that chlorinated organic compounds could form on the Martian surface via reactions between chlorine‐bearing salts and organic compounds delivered by meteorites. This study examined the ability of simple chlorinated organic molecules to survive the high pressures and temperatures associated with burial over geological time scales. Our aim was to calculate whether chlorinated molecules detected on Mars could be ancient and preserved in the rock units, or if they formed during the analysis process, as other studies have assumed. It was found that, on a warmer ancient Mars when the sediments the chlorinated molecules were detected in were deposited, the increased surface temperatures would have promoted the loss of chlorine relatively rapidly, and the intact chlorinated organic molecules would not have survived the burial and exhumation processes to

the present day. The chlorinated organics detected on Mars are therefore likely to have been formed recently, most probably through reactions with chlorine‐bearing salts when heated during analysis.

Rubin, A.E., 2018. Carbonaceous and noncarbonaceous iron meteorites: Differences in chemical, physical, and collective properties. Meteoritics & Planetary Science 53, 2357-2371.


Iron-meteorite groups that appear from published isotopic data to have been derived from melted carbonaceous-chondrite-like precursors (CC irons) (IIC, IID, IIF, IIIF, IVB) tend to have higher median refractory siderophile element (RSE) contents, higher median Ni contents, and higher median Ir/Ni and Ir/Au ratios than magmatic noncarbonaceous (NC) iron-meteorite groups (IC, IIAB, IIIAB, IIIE, IVA). (Group IIG is also NC.) One potential source of RSEs in magmatic CC irons is the set of refractory metal nuggets from inherited CAIs. Magmatic CC-iron groups tend to have longer cosmic-ray exposure (CRE) ages than magmatic NC-iron groups, indicating long residence times as small bodies in interplanetary space. The lower membership of CC-iron groups is probably mainly due to the high oxidation state of their precursors. Such oxidation would have produced lesser amounts of free metal; parent body differentiation of such bodies would have produced smaller cores, resulting in fewer samples available to make CC-iron meteorites in the first place. (Ungrouped magmatic irons, most of which can be considered groups with only one member, also tend to be carbonaceous.) It is possible that a subset of the chondrule-poor dark inclusions in many carbonaceous chondrites represent unmelted materials related to the precursors of the CC irons. The Eagle Station pallasites (also CC-related) are analogous to CC irons in being more oxidized, richer in Ni and RSEs, and fewer in number than main-group pallasites (PMG). However, Eagle Station has a shorter CRE age than most PMG.

Ruebsam, W., Mayer, B., Schwark, L., 2019. Cryosphere carbon dynamics control early Toarcian global warming and sea level evolution. Global and Planetary Change 172, 440-453.


The Earth's cryosphere represents a huge climate-sensitive carbon reservoir capable of releasing carbon dioxide (CO2) and methane (CH4) from permafrost soils or gas reservoirs capped by permafrost and ice caps upon rising global temperatures. Carbon release from these reservoirs has the potential to further accelerate global warming. Present day cryosphere demise is a focus of scientific research. The potential role of cryosphere carbon reservoirs in Mesozoic climate perturbations is even lesser known and currently underinvestigated. In contrast to previous views of a constantly warm Early Jurassic period, virtually lacking a cryosphere, recent studies have identified icehouse conditions for this time interval. Following these icehouse conditions, global warming occurred during the early Toarcian (~183 Ma) and was accompanied by a major carbon cycle anomaly as manifested in recurring negative carbon isotope excursions (CIEs). We propose that an initially volcanic-driven gentle rise of atmospheric temperature in the Early Toarcian triggered a melt-down of Earth's cryosphere which during the preceding Pliensbachian had expanded to the mid-latitudes and thus was highly vulnerable to warming. The rapid release of greenhouse gases, mainly as 13C-depleted CH4, or its oxidation product CO2, is recorded in the carbon isotope ratios of sedimentary organic matter and carbonates. Toarcian sediments display a series of orbitally-forced negative CIEs characterized by a frequency shift from eccentricity to obliquity cycles comparable to Pleistocene climate rhythms. This pattern is explained by a self-sustaining destabilization of labile cryosphere carbon reservoirs which started at mid-latitudes where eccentricity is most effective and then

rhythmically progressed poleward to latitudes where obliquity dominates. The hitherto underestimated presence of a temperature-sensitive Pliensbachian cryosphere constituted an essential precondition for the early Toarcian climate change and its associated sea-level rise. The Pliensbachian cooling had transferred water into the terrestrial cryosphere causing a severe sea-level fall. Transgressive pulses at the Pliensbachian-Toarcian boundary and in the early Toarcian occurred concomitant to rising global temperatures and resulted from the meltdown of continental ice caps. This ice-volume effect and the massive discharge of freshwater into the oceans is well preserved in the exceptionally low δ18O values of carbonates formed during the cryosphere demise and sea-level increase. Carbon and oxygen isotope ratios, climate and sea-level shifts thus underpin the presence of an Early Jurassic cryosphere and thereby highlight the role of glacio-eustatic mechanisms as main drivers of late Pliensbachian to early Toarcian geodynamics.

Russell, J.M., Hopmans, E.C., Loomis, S.E., Liang, J., Sinninghe Damsté, J.S., 2018. Corrigendum to “Distributions of 5- and 6-methyl branched glycerol dialkyl glycerol tetraethers (brGDGTs) in East African lake sediment: Effects of temperature, pH, and new lacustrine paleotemperature calibrations” [Org. Geochem. 117 (2018) 56–69]. Organic Geochemistry 125, 299.


The authors regret that in this paper there were three mistakes in formulae in the statistical methods section. Corrections to Eq1, Eq2 and E13. The authors would like to apologize for any inconvenience caused.

Russell, P., 2018. Recent advances in routine core analysis on the Montney Formation. Bulletin of Canadian Petroleum Geology 66, 363-393.

https://pubs.geoscienceworld.org/cspg/bcpg/article/66/2/363/565805/recent-advances-in-routine-core-analysis-on-the

The Montney Formation in Alberta and British Columbia presents many challenges for core analysis. Its high saline and sub-irreducible formation water, organic matter content and type, nanometer sized pores, and friability from laminations prevent core analysis from being dependable. Despite this, Routine Core Analysis (RCA) is still commonly performed without modifying the techniques to address these challenges.

Over the past five years, RCA has been conducted and examined by the author on over thirty Montney cores. Each step of RCA has been assessed to identify and quantify sources of error and uncertainty. The Montney Formation has been found to be very sensitive to errors that are associated with the limitations of RCA methods. Excluding standard errors, the combination of inappropriate analysis types, ineffective RCA processes, and RCA method limitations, can lead to additional absolute porosity errors that range from -0.8% to +0.6%. The presence of unobservable fractures has been found to incorrectly increase permeability up to three orders of magnitude. The low porosity and permeability of the Montney Formation magnify the relative errors which significantly affect the accuracy stated by American Petroleum Institute Recommended Practice 40 (API RP 40) (1998).

Modifications to the RCA process have been made to minimize errors and uncertainties. The techniques discussed were developed to improve accuracy on the Montney Formation, but most are applicable to any rock types that are suitable for RCA.

Ryan, D.J., Spraggins, J.M., Caprioli, R.M., 2019. Protein identification strategies in MALDI imaging mass spectrometry: a brief review. Current Opinion in Chemical Biology 48, 64-72.


Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) is a powerful technology used to investigate the spatial distributions of thousands of molecules throughout a tissue section from a single experiment. As proteins represent an important group of functional molecules in tissue and cells, the imaging of proteins has been an important point of focus in the development of IMS technologies and methods. Protein identification is crucial for the biological contextualization of molecular imaging data. However, gas-phase fragmentation efficiency of MALDI generated proteins presents significant challenges, making protein identification directly from tissue difficult. This review highlights methods and technologies specifically related to protein identification that have been developed to overcome these challenges in MALDI IMS experiments.

Sad, C.M.S., da Silva, M., dos Santos, F.D., Pereira, L.B., Corona, R.R.B., Silva, S.R.C., Portela, N.A., Castro, E.V.R., Filgueiras, P.R., Lacerda, V., 2019. Multivariate data analysis applied in the evaluation of crude oil blends. Fuel 239, 421-428.


In this paper, monitoring of the physicochemical properties of crude oil blends during production stages is described. The data of the properties of crude oil blends were obtained by laboratory characterization, and then analyzed by principal component analysis (PCA), hierarchical cluster analysis (HCA), and Mahanalobis distance. Thus, the quality of the blends was monitored quickly with simple multivariate tools. The results indicate that a change in the contribution of different wells in the blends caused a change in the profile. The PCA demonstrated that in each period, the physicochemical properties in the blends contributed to verifying the spread of the data. The blends could be organized by HCA, and it was possible to identify outlier samples with different quality standards for the oil. This information is important because it allows checking the changes in the oil profile, which helps in making adjustments to improve the quality of the final product in the primary process.


https://doi.org/10.3390/microorganisms6040105

Knowledge of microbial community dynamics in relation to process perturbations is fundamental to understand and deal with the instability of anaerobic digestion (AD) processes. This study aims to investigate the microbial community structure and function of a thermophilic AD process, fed with a chemically defined substrate, and its association with process performance stability. Next generation amplicon sequencing of 16S ribosomal RNA (rRNA) genes revealed that variations in relative abundances of the predominant bacterial species, Defluviitoga tunisiensis and Anaerobaculum hydrogeniformans, were not linked to the process performance stability, while dynamics of bacterial genera of low abundance, Coprothermobacter and Defluviitoga (other than D. tunisiensis), were associated with microbial community function and process stability. A decrease in the diversity of the archaeal community was observed in conjunction with process recovery and stable performance, implying that the high abundance of specific archaeal group(s) contributed to the stable AD.

Dominance of hydrogenotrophic Methanoculleus particularly corresponded to an enhanced microbial acetate and propionate turnover capacity, whereas the prevalence of hydrogenotrophic Methanothermobacter and acetoclastic Methanosaeta was associated with instable AD. Acetate oxidation via syntrophic interactions between Coprothermobacter and Methanoculleus was potentially the main methane-formation pathway during the stable process. We observed that supplementation of Se and W to the medium improved the propionate turnover by the thermophilic consortium. The outcomes of our study provided insights into the community dynamics and trace element requirements in relation to the process performance stability of thermophilic AD.

Sakarika, M., Kornaros, M., 2019. Chlorella vulgaris as a green biofuel factory: Comparison between biodiesel, biogas and combustible biomass production. Bioresource Technology 273, 237-243.


Biofuels are viewed as the answer to safeguard the currently challenged energy security. To this end, the present study provides a comparison between approaches regarding microalgal biomass conversion to bioenergy, with a view on sustainable implementation. The energetic valorization of Chlorella vulgaris biomass cultivated under heterotrophic, sulfur-limited conditions was investigated through the biofuels biodiesel, biogas (biomethane) and combustible dry biomass. The lipid productivity can reach the value of 442.9 ± 6.5 mg L−1 d−1 containing suitable fatty acids for biodiesel production. Next, biochemical methane potential (BMP) assays yielded 360.9 ± 20.2 mL CH4 g VS−1added under mesophilic conditions, while the calorific value of dry C. vulgaris biomass was measured as 24,538 ± 182 kJ kgDW

−1 (5,865 ± 43 kcal kgDW−1). Considering the

downstream processing required in each approach, the most promising energy valorization method is anaerobic digestion able to reach values up to 20,862 kJ Lreactor

−1 day−1 in continuous systems

Sallam, M.A., El-Banbi, A.H., 2018. Analysis of multi-layered commingled and compartmentalized gas reservoirs. Journal of Petroleum Exploration and Production Technology 8, 1573-1586.

https://doi.org/10.1007/s13202-018-0454-3

The evaluation and performance prediction of multi-layered compartmentalized gas systems can be difficult. This is mostly due to the uncertainties related to production allocation either within each commingled well or between interrelated reservoir compartments. This paper presents a model that can provide reliable estimates of the total gas in place for multi-layered commingled and compartmentalized reservoirs. The model is also capable of generating prediction profiles for every well in the production system in addition to forecasting individual layers production for each compartment. The proposed model is based on coupling the layered stabilized flow model for material balance calculation in commingled systems with communicating reservoir model that is used as material balance tool for compartmentalized gas reservoirs. The model has the flexibility to be applied for history matching and prediction purposes. In history matching, the model solves the equations simultaneously using optimization routine to find the best parameters of original gas in place (OGIP), deliverability coefficients and compartment transmissibility coefficients. The model requires the knowledge of initial reservoir pressure in every compartment, some rate production history and bottom-hole flowing pressures. The model can also utilize additional information such as shut-in pressures per layer, repeat formation tester and production logging tool measurements (if available) to improve the history match. For prediction, the model uses the estimated parameters (compartment OGIP, transmissibility coefficients between compartments and flow parameters for each layer) to calculate the production rates and reservoir pressures for every well/tank based on a provided bottom-hole flowing pressure. The model was verified against a commercial reservoir

simulator for several synthetic cases. The model was also applied on different field cases to estimate OGIP and flow coefficients for every layer as well as compartment transmissibility coefficients. Moreover, calculation of cumulative gas transferred across the communicating reservoirs allows detection of poorly drained compartments, which could be included in future redevelopment plans.

Samanipour, S., Hooshyari, M., Baz-Lomba, J.A., Reid, M.J., Casale, M., Thomas, K.V., 2019. The effect of extraction methodology on the recovery and distribution of naphthenic acids of oilfield produced water. Science of The Total Environment 652, 1416-1423.


Comprehensive chemical characterization of naphthenic acids (NAs) in oilfield produced water is a challenging task due to sample complexity. The recovery of NAs from produced water, and the corresponding distribution of detectable NAs are strongly influenced by sample extraction methodologies. In this study, we evaluated the effect of the extraction method on chemical space (i.e. the total number of chemicals present in a sample), relative recovery, and the distribution of NAs in a produced water sample. Three generic and pre-established extraction methods (i.e. liquid-liquid extraction (Lq), and solid phase extraction using HLB cartridges (HLB), and the combination of ENV+ and C8 (ENV) cartridges) were employed for our evaluation. The ENV method produced the largest number of detected NAs (134 out of 181) whereas the HLB and Lq methods produced 108 and 91 positive detections, respectively, in the tested produced water sample. For the relative recoveries, the ENV performed better than the other two methods. The uni-variate and multi-variate statistical analysis of our results indicated that the ENV and Lq methods explained most of the variance observed in our data. When looking at the distribution of NAs in our sample the ENV method appeared to provide a more complete picture of the chemical diversity of NAs in that sample. Finally, the results are further discussed.

Samaraweera, M.A., Hall, L.M., Hill, D.W., Grant, D.F., 2018. Evaluation of an artificial neural network retention index model for chemical structure identification in nontargeted metabolomics. Analytical Chemistry 90, 12752-12760.


Liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is a major analytical technique used for nontargeted identification of metabolites in biological fluids. Typically, in LC-ESI-MS/MS based database assisted structure elucidation pipelines, the exact mass of an unknown compound is used to mine a chemical structure database to acquire an initial set of possible candidates. Subsequent matching of the collision induced dissociation (CID) spectrum of the unknown to the CID spectra of candidate structures facilitates identification. However, this approach often fails because of the large numbers of potential candidates (i.e., false positives) for which CID spectra are not available. To overcome this problem, CID fragmentation predication programs have been developed, but these also have limited success if large numbers of isomers with similar CID spectra are present in the candidate set. In this study, we investigated the use of a retention index (RI) predictive model as an orthogonal method to help improve identification rates. The model was used to eliminate candidate structures whose predicted RI values differed significantly from the experimentally determined RI value of the unknown compound. We tested this approach using a set of ninety-one endogenous metabolites and four in silico CID fragmentation algorithms: CFM-ID, CSI:FingerID, Mass Frontier, and MetFrag. Candidate sets obtained from PubChem and the Human Metabolite Database (HMDB) were ranked with and without RI filtering followed by in silico spectral matching. Upon RI filtering, 12 of the ninety-one

metabolites were eliminated from their respective candidate sets, i.e., were scored incorrectly as negatives. For the remaining seventy-nine compounds, we show that RI filtering eliminated an average of 58% from PubChem candidate sets. This resulted in an approximately 2-fold improvement in average rankings when using CFM-ID, Mass Frontier, and MetFrag. In addition, RI filtering slightly increased the occurrence of number one rankings for all 4 fragmentation algorithms. However, RI filtering did not significantly improve average rankings when HMDB was used as the candidate database, nor did it significantly improve average rankings when using CSI:FingerID. Overall, we show that the current RI model incorrectly eliminated more true positives (12) than were expected (4–5) on the basis of the filtering method. However, it slightly improved the number of correct first place rankings and improved overall average rankings when using CFM-ID, Mass Frontier, and MetFrag.

Samokhin, A., 2018. Spectral skewing in gas chromatography–mass spectrometry: Misconceptions and realities. Journal of Chromatography A 1576, 113-119.


In the field of gas chromatography–mass spectrometry, linear quadrupole instruments remain the most popular. Quadrupole mass spectrometers are scanning instruments. It means that ions with different m/z values pass through the quadrupole sequentially. When analyte concentration changes during scan period, recorded mass spectrum is distorted. This phenomenon is called spectral skewing. There are two misconceptions associated with the spectral skewing: (1) the spectral skewing can affect the results of library search; (2) bilinear chemometric methods are often applied to skewed (distorted) GC/MS data to perform automatic data processing. We attempt to clarify these misconceptions. We can conclude that even strong distortion of mass spectrum (caused by the spectral skewing) practically does not change efficiency of automatic search against mass spectral database. On the other hand, even minor distortion of data (caused by the spectral skewing) can significantly distort results of automatic data processing (especially in the case of minor components). Interactive Excel files (presented in Supplementary material) illustrate our findings.



Coal-Supercritical CO2 (S-CO2) interaction causes severe mechanical alterations in coal that can possibly affect the mechanical competency and the coal seam integrity. Conventional static mechanical testings often fail to conduct repetitive and temporal measurements on coal specimens in the process of coal-S-CO2 interaction, thus unable to attain at decisive and reliable conclusions. Moreover, the said techniques fail to capture the mechanical anisotropies of heterogeneous coal mass that arise due to complex spatial distribution of mineral/maceral phases and fracture network. We combine three non-destructive techniques, viz. gamma-ray attenuation, ultrasonic technique and micro computed tomography to evaluate the S-CO2 interaction induced localized and anisotropic micro-structural alterations and the consequent mechanical response of a heterogeneous coal core specimen. Dynamic moduli were computed at radial and axial directions at natural condition, after 14 days and 45 days of S-CO2 interaction, and the resultant mechanical alterations were elucidated with the 3D-reconstructed micro-CT data collected at the same stages. Visualization and quantification of coal micro-structure emphasize that S-CO2-interacted coal mass is subjected to severe micro-cracking

due to differential and free swelling, drying induced shrinkage and surface energy reduction, which can possibly lead to mechanical degradation. Spatial distribution of minerals and fractures at specific orientations significantly affects the gamma and ultrasonic wave propagation, thus can be successfully utilized to reflect the mechanical anisotropies. For same interaction condition and period, coal mass exhibits mechanical anisotropies and strength alterations at different levels, in which more heterogeneous mineral/maceral distribution causes significant localized mechanical alterations in mineral-rich areas, compared to that of comparatively homogeneous coal-rich regions. Temporal evaluation of strength parameters suggests that regardless of the considered orientations, significant strength alterations occur at initial stage of the coal-S-CO2 interaction process and the longer interaction causes only a slight strength reduction. Overall results conclude that S-CO2 induced mechanical property alterations in heterogeneous coal are highly localized and anisotropic, thus should be carefully evaluated in CO2 sequestration and ECBM extraction processes.

Sang, G., Liu, S., Zhang, R., Elsworth, D., He, L., 2018. Nanopore characterization of mine roof shales by SANS, nitrogen adsorption, and mercury intrusion: Impact on water adsorption/retention behavior. International Journal of Coal Geology 200, 173-185.


Moisture-induced reduction in the strength of shales is one of the primary mechanisms of roof degradation affecting the stability and safety of underground coal mines. The underlying mechanisms of nanoscale matrix-water interactions remains unclear. Thus, an improved understanding of the nanopore structure, and dependent water adsorption and retention behavior of shale is key in defining strength degradation due to seasonal variations in humidity and temperature in underground coal mines. We use small-angle neutron scattering (SANS), low-pressure N2 adsorption (LPNA), and high-pressure mercury intrusion porosimetry (MIP) to characterize the nanopore structure of a fireclay (7F) and four coal mine roof shales (6R, 5A, 6F, H6) from the Illinois basin. The results show that overall distributions of pore volume obtained from SANS, LPNA and MIP techniques agree well between methods and over a wide range of pore size from ~1 nm to ~100 nm. Mercury porosities for the five ordered (7F, 6R, 5A, 6F, H6) samples (7.3%, 7.8%, 8.3%, 12.3%, 4.6%) are higher than the respective N2 porosities (5.0%, 6.3%, 3.8%, 8.2%, 2.5%), as attributed to the dilation of mesopores and compression of the grain skeleton induced by high pressure intrusion of mercury. The SANS porosities for samples 7F, 6R, 5A, 6F (4.0%, 6.2%, 4.1%, 8.8%) are in good agreement with their N2 porosities. Among all tested samples, H6 shale exhibits a relatively high SANS porosity (8.0%) but the lowest N2 (2.5%) and mercury porosities (4.6%). This is attributed to the interlayer micro-pore spaces within montmorillonite, which is detected by SANS but not by the two fluid penetration methods due to the inaccessibility of N2 molecules and mercury. Based on LPNA, larger micropores (1.5–2 nm) and mesopores (2–50 nm) predominantly contribute to the total porosity (~77.8%–87.6%) for the five tested samples.

The water adsorption isotherms are measured by dynamic vapor sorption (DVS) and water retention curves are calculated based on the characterized pore size distribution (PSD) by LPNA and MIP techniques. Pore structures of the five studied samples evidently exert a strong influence on their water adsorption and retention behaviors. Water adsorption capacity correlates positively with total porosity/specific surface area (SSA), with a large proportion of micro/meso-pores resulting in the strong water retention capacity with matric suction reaching ~100–150 MPa for liquid saturation < 3%. Among the studied fireclay/shales, samples with higher retention capacity tend to adsorb more water. Thus, nanopore structure and its impact on water adsorption and retention behavior exert the key controls on shale-water interaction and its implication on strength reduction of roof shales in underground coal mines.

Sang, Q., Zhang, S., Li, Y., Dong, M., Bryant, S., 2018. Determination of organic and inorganic hydrocarbon saturations and effective porosities in shale using vacuum-imbibition method. International Journal of Coal Geology 200, 123-134.


Shale oil is a significant unconventional energy resource worldwide. Shale formations are complex systems, with both inorganic and organic content and porosities. Oil saturation in a shale oil formation consists of two components: inorganic saturation (free oil-dominated) and organic saturation (ad- and absorbed oil-dominated). Shale porosity includes inorganic and organic porosities. There is no reported research that identifies the two porosities and saturations. We therefore recently performed, for the first time, two types of vacuum-imbibition tests - water imbibition and oil imbibition - on 20 shale oil rock samples to distinguish these two porosities and two saturations. In case of 100% oil saturated, the final imbibed oil volume in oil imbibition test represents the total oil content that a sample can hold, the final imbibed water volume in water imbibition test represents the inorganic content, and the difference between the two represents the organic content. Helium saturation tests were conducted to determine the total pore volume in shale rock samples. The content of ad- and absorbed oil is obtained from the difference between the total imbibed oil volume and the pore volume. The difference between the organic content and the ad−/absorbed oil content represents the organic pore volume, thereby obtaining the organic and inorganic porosities. Our results indicate that, for the shale rock samples tested, the maximum possible oil content in organic matter ranges from 6% to 55% of the total oil content, and 50% to 90% of the organic oil content is ad- and absorbed in kerogen. The organic porosity ranges from 2% to 50% of the total porosity. Both the organic oil saturation and the organic porosity exhibit a growing trend with total organic carbon of shale rock samples.

Santini, T.C., Raudsepp, M., Hamilton, J., Nunn, J., 2018. Extreme geochemical conditions and dispersal limitation retard primary succession of microbial communities in gold tailings. Frontiers in Microbiology 9, 2785. doi: 10.3389/fmicb.2018.02785.


Microbial community succession in tailings materials is poorly understood at present, and likely to be substantially different from similar processes in natural primary successional environments due to the unusual geochemical properties of tailings and the isolated design of tailings storage facilities. This is the first study to evaluate processes of primary succession in microbial communities colonizing unamended tailings, and compare the relative importance of stochastic (predominantly dust-borne dispersal) and deterministic (strong selection pressures from extreme geochemical properties) processes in governing community assembly rates and trajectories to those observed in natural environments. Dispersal-based recruitment required > 6 months to shift microbial community composition in unamended, field-weathered gold tailings; and in the absence of targeted inoculants, recruitment was dominated by salt- and alkali-tolerant species. In addition, cell numbers were less than 106 cells/g tailings until > 6 months after deposition. Laboratory experiments simulating microbial cell addition via dust revealed that high (>6 months’ equivalent) dust addition rates were required to effect stabilization of microbial cell counts in tailings. In field-weathered tailings, topsoil addition during rehabilitation works exerted a double effect, acting as a microbial inoculant and correcting geochemical properties of tailings. However, microbial communities in rehabilitated tailings remained compositionally distinct from those of reference soils in surrounding environments. pH, water extractable Mg, and water extractable Fe emerged as major controls on microbial community composition in the field-weathered gold tailings. Overall, this study highlights the need for application of targeted microbial inoculants to accelerate rates of microbial community succession

in tailings, which are limited primarily by slow dispersal due to physical and spatial isolation of tailings facilities from inoculant sources; and for geochemical properties of tailings to be amended to moderate values to encourage microbial community diversification and succession.

Santos Silva, H., Alfarra, A., Vallverdu, G., Bégué, D., Bouyssiere, B., Baraille, I., 2018. Impact of H-bonds and porphyrins on asphaltene aggregation as revealed by molecular dynamics simulations. Energy & Fuels 32, 11153-11164.


The presence of metalloporphyrins alongside asphaltenes in heavy fractions of crude oil is a key issue in petroleum exploration and upgrading. These compounds are also expected to display interfacial activity in water/toluene mixtures, but the origin of this phenomenon remains uncertain. In this work, we use molecular dynamics simulations to investigate complex asphaltene mixtures constituted of 10 different molecules, under also multifaceted solvation conditions (toluene/n-heptane/water). We add nickel and vanadium (under the form of vanadyl) porphyrins with occasionally grafted polar lateral chains, in these mixtures. The aggregation behavior and interaction with water molecules (as a model to have insights from the interfacial activity of such molecules) are intimately linked to the type of porphyrin and to the molecular properties of the asphaltenes (mainly the presence of polar lateral chains). Vanadium porphyrins, even without polar lateral chains, can form H-bonds that might contribute to their presence within asphaltene nanoaggregates. Moreover, when polar lateral chains are present in asphaltene molecules, the systems display a supramolecular organization with several distinct interactions at the same time. The shapes of these systems do not totally agree with the traditional Yen–Mullins model. In the first part of this work, we finally propose that complex asphaltene systems in complex solvent mixtures seem to have a supramolecular behavior with non-negligent colloidal behavior as well. This should be indicative that Yen–Mullins and Gray’s models of asphaltene self-assembly are neither conflictual nor antagonistic. They are two facets of a scale- and molecular structure-dependent complex mechanism.



Anionic surfactants are widely used as an effective chemical for enhanced oil recovery because of their unique characteristics of reducing interfacial tension (IFT) between the trapped crude oil and water, and alteration of wettability of reservoir rock from oil-wet to water-wet. However, the loss of surfactant by adsorption onto the solid rock surface is a major concern that reduces the efficiency of the surfactant flooding process and must be considered while designing the process. Present study highlights the equilibrium adsorption and kinetics of an anionic surfactant synthesized from soap-nut fruit on sandstone, carbonate and bentonite clay as representative of reservoir rocks. The mineralogy and morphology of the rocks were investigated by FE-SEM, XRD and BET surface area analysis. UV–Visible spectroscopy was used to measure the amount of surfactant adsorbed on solid rock/clay surface in batch experiments. The experimental equilibrium adsorption data were analyzed by using Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models and adsorption parameters were calculated. Adsorption kinetics of the surfactant system were studied and pseudo second order kinetic model was best fitted for the surfactant/rock/clay systems. Presence of salt was found to increase surfactant adsorption on rock/clay marginally. However, presence of alkali and nanoparticles was found to reduce the loss of surfactant by adsorption and shows synergistic effects on IFT

reduction, which is beneficial for application of the surfactant in oil recovery. The findings of the study are quite helpful in proper designing of the surfactant flooding for enhanced oil recovery.

Sayed, A.M., Olesen, K.B., Alkahala, A.S., Sølling, T.I., Alyafei, N., 2019. The effect of organic acids and salinity on the interfacial tension of n-decane/ water systems. Journal of Petroleum Science and Engineering 173, 1047-1052.


We have investigated how a homologous series of straight-chain carboxylic acids with a cyclohexyl substituent in the opposite end of the functional groups impacts the interfacial tension (IFT) between decane (oil) and water. The employed method was the pendant droplet technique. We do not observe any striking effect of expanding the chain length: all acids reduced the IFT compared to water by approximately 20 mN/m. Additionally, the effect of changing the chemical character and the concentration of the cation in a series of brines where studied too, and again we do not observe a significant IFT impact. The only modification that significantly reduces the IFT is the modification of the anion from chloride to carbonate, a change that results in an increased pH and thus a transformation of the constituent acids from their neutral to their anionic form. This is expected to result in a reduced IFT because of the polar end of the surfactant is even more polar which alleviates the stress on the surface.



For our ancestors, oil seeps were both a fascination and a resource but as the planet's reserves of high quality low density oil becomes increasingly depleted, so there is now a renewed interest in heavier, biodegraded oils such as those encountered in terrestrial seeps. One such seep is Pitch Lake in the Caribbean island of Trinidad, which is the largest natural deposit of asphalt in the world. At the northern end of the Caribbean, oil emerges along a tectonic contact on the island on Cuba. The sources of the oils from these seeps are relatively recent and both are subject to intense weathering due to the tropical conditions. When analysed by gas chromatography (GC) both oils appear as unresolved complex mixtures (UCM) and show a very high degree of biodegradation thus presenting an analytical challenge. In this case study, these two Caribbean seep oils were analysed by comprehensive two dimensional GC with time of flight mass spectrometry (GC×GC-TOFMS) to expose many thousands of the individual compounds that comprise the UCM. The high chromatographic resolution of the GC×GC-TOFMS produced good quality mass spectra allowing many compounds including molecular fossil ‘biomarkers’ to be identified. Compound classes included diamondoid hydrocarbons, demethylated hopanes and seco-hopanes, mono- and tri-aromatic steroids. D-ring aromatised structures of the 8,14-seco-hopanes, including demethylated forms were present in both oils but further demethylation, probably at position C-25 during biodegradation, was only observed in the Pitch Lake oil. Many polycyclic aromatic hydrocarbons (PAHs) were absent although the fungal-derived pentacyclic PAH perylene was present in both oils. The presence of the angiosperm biomarker lupane in the Pitch Lake oil constrained the age to the Late Cretaceous. The higher degree of biodegradation observed in the Cuban oil was likely due to relatively slow anaerobic processes whereas oil within Pitch Lake was probably subject to additional more rapid aerobic metabolism within the lake.

Scheller, E.L., Dickson, A.J., Canfield, D.E., Korte, C., Kristiansen, K.K., Dahl, T.W., 2018. Ocean redox conditions between the snowballs – Geochemical constraints from Arena Formation, East Greenland. Precambrian Research 319, 173-186.


The emergence of animal ecosystems is largely believed to have occurred in increasingly oxygenated oceans after the termination of the Sturtian and Marinoan glaciations. This transition has led to several hypotheses for the mechanism driving ocean oxygenation and animal evolution. One hypothesis is that enhanced weathering increased oceanic nutrient levels, primary productivity and organic carbon burial, and ultimately oxygenated the atmosphere and oceans. Another hypothesis suggests that an animal-driven reorganization of the marine biogeochemical cycles might have oxygenated the oceans. Through molybdenum (Mo), carbon (C), sulfur (S) isotopes and iron (Fe) speciation results from the Arena Fm, East Greenland, this study constrains ocean redox conditions during the Cryogenian, after the Sturtian deglaciation and before the major radiation of animals. Carbon and sulfur isotope stratigraphy is used to correlate the Arena Fm with other formations worldwide between the Sturtian and Marinoan glaciations (∼720–635 Ma). The lower part of the Arena Fm (∼25 m) consists of black shales deposited under locally euxinic conditions as evidenced by high proportions of highly reactive iron (FeHR/FeT > 0.38) and pyrite (FePY/FeHR > 0.7). These black shales display small Mo enrichments (<3 ppm) and low Mo/TOC compared to overlying shales and Phanerozoic euxinic sediments. The maximum δ98Mo value is observed in the basal Arena Fm (1.5‰). Many samples display lower δ98Mo than typical oceanic input fluxes, which can be explained by Mo isotope fractionation from a marine Mo pool with δ98Mo ∼ 1.3‰, similar to that inferred from other Cryogenic euxinic basins. The combination of low [Mo] and δ98Mo suggests that widespread anoxia prevailed in the oceans at this time. Our data are consistent with most other studies from this time suggesting that ocean oxygenation was not linked to Snowball Earth deglaciation, but was delayed until animals effectively entered the scene.


tps://doi.org/10.5194/bg-15-6481-2018

Intact polar lipids (IPLs) are the main building blocks of cellular membranes and contain chemotaxonomic, ecophysiological and metabolic information, making them valuable biomarkers in microbial ecology and biogeochemistry. This study investigates IPLs in suspended particulate matter (SPM) in the water column of the eastern tropical North Pacific Ocean (ETNP), one of the most extensive open-ocean oxygen minimum zones (OMZs) in the world, with strong gradients of nutrients, temperature and redox conditions. A wide structural variety in polar lipid head-group composition and core structures exists along physical and geochemical gradients within the water column, from the oxygenated photic zone to the aphotic OMZ. We use this structural diversity in IPLs to evaluate the ecology and ecophysiological adaptations that affect organisms inhabiting the water column, especially the mid-depth OMZ in the context of biogeochemical cycles. Diacylglycerol phospholipids are present at all depths, but exhibit the highest relative abundance and compositional variety (including mixed acyl/ether core structures) in the upper and core OMZ where prokaryotic biomass was enriched. Surface ocean SPM is dominated by diacylglycerol glycolipids that are found in photosynthetic membranes. These and other glycolipids with varying core structures composed of ceramides and hydroxylated fatty acids are also detected with varying relative abundances in the OMZ and deep oxycline, signifying additional non-phototrophic bacterial sources for these lipids. Betaine lipids (with zero or multiple hydroxylations in the core structures) that are typically assigned

to microalgae are found throughout the water column down to the deep oxycline but do not show a depth-related trend in relative abundance. Archaeal IPLs comprised of glycosidic and mixed glycosidic-phosphatidic glycerol dibiphytanyl glycerol tetraethers (GDGTs) are most abundant in the upper OMZ, where nitrate maxima point to ammonium oxidation but increase in relative abundance in the core OMZ and deep oxycline. The presence of non-phosphorus substitute lipids within the OMZ suggest that the indigenous microbes might be phosphorus limited (P starved) at ambient phosphate concentrations of 1 to 3.5µM, although specific microbial sources for many of these lipids still remain unknown.

Schulte, M., Jochmann, M.A., Gehrke, T., Denecke, M., Schmidt, T.C., 2018. Carbon isotopic fractionation via diffusion in a coarse material. Geochemistry, Geophysics, Geosystems 19, 3246-3253.

https://doi.org/10.1029/2017GC007378

Abstract Methane oxidation is a major environmental process in different types of soil. Due to its global warming potential, exact fluxes of methane from soil to the atmosphere are relevant for atmospheric and carbon flux modeling. In this context the investigation of the methane oxidation turnover rates is often carried out by measuring the isotopic fractionation during the involved biodegradation processes. Unfortunately, isotopic fractionation can be a result of both biodegradation and diffusion. Therefore, a thorough estimation of the diffusion-related isotopic fractionation is mandatory for a correction of biotransformation relevant kinetic isotope effects. Here for the first time, we investigated the isotopic fractionation of methane by diffusion in a coarsely mixed crushed stone and soil material. Determined isotopic fractionations by diffusion in terms of enrichment factors were ?0.0212 ± 0.005 at 22.5 °C and ?0.0218 ± 0.003 at 30 °C. When estimating biotransformation of methane from stable isotope measurements, the fractionation by diffusion has to be subtracted for estimating correct biotransformation rates. The obtained data are relevant not only for the investigation of oxidation processes in landfills but can also be adapted to other coarse materials such as arctic and tundra as well as wetland and volcanic soils. As a consequence, including the isotopic fractionation by diffusion within calculations of biotransformation will allow determining more exact values under well-known conditions for methane flux calculations.

Schulz, F., Alteio, L., Goudeau, D., Ryan, E.M., Yu, F.B., Malmstrom, R.R., Blanchard, J., Woyke, T., 2018. Hidden diversity of soil giant viruses. Nature Communications 9, Article 4881.

https://doi.org/10.1038/s41467-018-07335-2

Known giant virus diversity is currently skewed towards viruses isolated from aquatic environments and cultivated in the laboratory. Here, we employ cultivation-independent metagenomics and mini-metagenomics on soils from the Harvard Forest, leading to the discovery of 16 novel giant viruses, chiefly recovered by mini-metagenomics. The candidate viruses greatly expand phylogenetic diversity of known giant viruses and either represented novel lineages or are affiliated with klosneuviruses, Cafeteria roenbergensis virus or tupanviruses. One assembled genome with a size of 2.4 Mb represents the largest currently known viral genome in the Mimiviridae, and others encode up to 80% orphan genes. In addition, we find more than 240 major capsid proteins encoded on unbinned metagenome fragments, further indicating that giant viruses are underexplored in soil ecosystems. The fact that most of these novel viruses evaded detection in bulk metagenomes suggests that mini-metagenomics could be a valuable approach to unearth viral giants.



Abiotic methane (CH4) is today widely reported in gas seeps and hyperalkaline springs in ophiolites and peridotite massifs characterized by low temperature continental serpentinization. Origin and distribution of this gas have far reaching implications in microbiology, astrobiology and carbon cycle. We report an in-depth study of a recently described abiotic CH4 seep occurring in shallow seafloor along the western coast of Elba Island, Tyrrhenian Sea (Italy). The gas is characterized by stable C and H isotopic compositions of CH4 (δ13C ∼ −18‰; δ2H ∼ −141‰) and a very low CO2 content that are typical of abiotic gas in continental ultramafic rock systems. Based on local geothermal gradients, the temperature of methane production is estimated to be below 100 °C. The isotope signature of methane is similar to that occurring in the Liguria region, about 200 km north of Elba Island, where the same ophiolite unit exposed. A mantle CO2 component, suggested by relatively high 3He/4He ratios, has likely acted as CH4 precursor. The reconstruction of the geological-structural setting of Elba ophiolite sequence highlighted that the seep occurs in correspondence with a faulted reverse limb of the antiform of the ophiolite unit. The gas bearing fault forms a contact between mafic and ultramafic serpentinized rocks, as typically observed in other continental seeps and springs related to ophiolites. Magmatic intrusions in the island may have contributed to the C feedstock of methane.

Scott, W.G., Nagai, K., 2018. Recruiting more proteins to the RNA world. Science 362, 644-645.


Ribonuclease P (RNase P) recognizes precursor transfer RNA (pre-tRNA) and processes it to generate mature tRNAs that are used for assembling proteins. Unlike almost all other enzymes, RNase P is a ribozyme, an enzyme with an active site that is composed of RNA, and it is present in every living organism. RNase P is among the most ancient of enzymes, a living molecular fossil from an “RNA world” in which life is thought to have originated. On page 657 of this issue, Lan et al. (1) present structures of the yeast RNase P enzyme by itself and bound to its pre-tRNA substrate. Additionally, the structure of the human form, by itself and bound to its tRNA product, is reported by Wu et al. (2). These reveal the detailed mechanism by which RNase P hydrolyzes pre-tRNA to produce the required 5′-phosphorylated tRNA of exactly the correct length. These structures unambiguously reveal how an assortment of proteins conspire to form a measuring device that ensures that the pre-tRNA substrate is correctly processed by the catalytic RNA subunit of this universal and essential enzyme.

RNase P was discovered by Robertson, Altman, and Smith in 1972 (3), who described an enzyme in the bacterium Escherichia coli that precisely removes the 5′ end of pre-tRNAs to produce mature tRNA products, the adaptor molecules that are required for translating the genetic code into proteins. A decade later, Altman, Pace, and colleagues published a remarkable discovery: The RNA subunit of bacterial RNase P is the active catalytic component (4). Before this discovery, and the nearly simultaneous discovery by Zaug and Cech of self-splicing RNA (5, 6), it was assumed that only proteins could be enzymes. Altman and Cech soon shared the Nobel Prize, and added renewed traction to the “RNA world hypothesis” (7), which proposes that life began with RNA or an RNA-like molecule that can carry both genetic information and catalytic activity.

Although the RNA subunit in bacterial RNase P is catalytic, the enzyme also has a single protein subunit that appears to play an ancillary role in substrate recognition. More complex versions of

RNase P are found in Archaea and Eukarya. Although they all possess similar RNA subunits, the archaeal and eukaryotic versions also contain multiple proteins. Are these more complicated RNase P enzymes also ribozymes? Or has evolution replaced the catalytic component with more conventional protein active sites? The new structures of yeast and human RNase P finally answer this question and in so doing provide a fascinating glimpse of the evolutionary transition between the RNA and protein worlds.

In addition to the RNA subunit, yeast RNase P has 10 protein subunits. The yeast RNase P RNA has a more elaborate structure compared with its more compact bacterial counterpart, but it shares a similar central region (8, 9). In the yeast enzyme, the proteins form a “hook” that wraps around the RNA subunit, stabilizing the entire structure. The resulting protein-RNA complex forms a precise measuring device that targets pre-tRNAs for hydrolysis by the enzyme's active site, which is composed entirely of RNA (see the figure). The new structures show that yeast RNase P, despite being adorned with proteins, is indeed still a ribozyme.

Similar to bacterial RNase P, the active site of the yeast enzyme reveals two Mg2+ cations coordinated by adjacent nonbridging phosphates within the backbone of the RNA subunit, as well as the phosphate at the cleavage site of the pre-tRNA. One of the Mg2+ ions is also coordinated by a conserved nucleotide base in the RNA, as previously observed in the bacterial enzyme (8, 9)—apparently the only nucleotide base that participates directly in catalysis. Many of the other known ribozymes also have active sites with two Mg2+ cations, which is consistent with an early but insightful prediction (10); they are observed in every ribozyme involved in RNA splicing, including the spliceosome (5, 6, 11–14). In the case of RNase P, one of the Mg2+ ions activates a water molecule to hydrolyze (break) the phosphodiester backbone of the pre-tRNA substrate. This geometrical arrangement of the reactants explains not only how the phosphate comes to reside on the 5′ end of the product tRNA as required but also how a more typical RNA degradation reaction, which could result from phosphodiester isomerization, is prevented. Lan et al. also provide a thorough and compelling set of computational reaction simulation results, demonstrating the plausibility of their proposed tRNA cleavage mechanism.

Like the yeast enzyme, human RNase P has one RNA (H1) and 10 homologous proteins. Therefore, the architecture of the holoenzyme is similar to that of yeast RNase P, and the mechanism of tRNA recognition is conserved. However, in the human structure, the 5′ end of the bound tRNA product is disordered, and the structure does not reveal bound catalytic metal cations (2).

Much of our prior knowledge of the recognition mechanism of RNase P was based on the crystal structure of bacterial RNase P, in complex with the mature tRNA reaction product (9). The single protein subunit in the bacterial RNase P guides binding of the 5′ leader sequence of pre-tRNA. The multiple protein components in yeast and human RNase P stabilize the catalytic RNA subunit and similarly guide pre-tRNA binding.

Many intriguing questions about the origin, evolution, and function of RNase P sharpen in focus with these new structures. Why has eukaryotic RNase P recruited many more noncatalytic protein subunits, given that bacterial RNase P, with a single protein subunit, is optimized for tRNA processing? Do these proteins extend the functionality of RNase P in processing other structural RNAs in eukaryotic cells? A multitude of other, entirely protein-based RNase enzymes exist, even including some forms of RNase P (15). Despite this, with one intriguing exception to the rule (16), the ribozyme version of RNase P is found in every cell of every organism, implying not only that this ribozyme is indeed a living fossil that dates back to the original life forms, but that the catalytic RNA subunit has been rigorously conserved during several billion years of evolution instead of being replaced with recruited proteins. What is it about this RNA that is so indispensable? The same type of

hydrolysis reaction can be catalyzed by a variety of proteins that possess an RNase III catalytic domain. The new structures provide us with many intriguing hints.

References1. P. Lan et al., Science 362, eaat6678 (2018).2. J. Wu et al., Cell 10.1016/j.cell.2018.10.003 (2018).3. H. D. Robertson et al., J. Biol. Chem. 247, 5243 (1972).4. C. Guerrier-Takada et al., Cell 35, 849 (1983).5. A. J. Zaug, T. R. Cech, Cell 19, 331 (1980).6. A. J. Zaug, T. R. Cech, Science 231, 470 (1986).7. W. Gilbert, Nature 319, 618 (1986).8. A. V. Kazantsev et al., Proc. Natl. Acad. Sci. U.S.A. 102, 13392 (2005).9. N. J. Reiter et al., Nature 468, 784 (2010).10. T. A. Steitz, J. A. Steitz, Proc. Natl. Acad. Sci. U.S.A. 90, 6498 (1993).11. N. Toor et al., Science 320, 77 (2008).12 .S. M. Fica et al., Nature 503, 229 (2013).13. R. Wan et al., Science 353, 895 (2016).14. W. P. Galej et al., Nature 537, 197 (2016).15. J. Holzmann et al., Cell 135, 462 (2008).16. A. I. Nickel et al., Proc. Natl. Acad. Sci. U.S.A. 114, 11121 (2017).

Seifan, M., Berenjian, A., 2018. Application of microbially induced calcium carbonate precipitation in designing bio self-healing concrete. World Journal of Microbiology and Biotechnology 34, 168.

https://doi.org/10.1007/s11274-018-2552-2

Concrete is one of the most broadly used construction materials in the world due to its number of performance characteristics. Despite the long life of concrete structure under ideal conditions, it tends to crack and this phenomenon results in a considerable reduction in service life and performance. Evidence of microbial involvement in the precipitation of minerals has led to a massive investigation on adapting this technology for addressing the concrete cracking issue. Calcium carbonate is one of most compatible materials with the concrete constituents and it can be induced via biological process. In this review paper, the effects of different factors, such as nucleation site, pH, nutrient and temperature, on the biosynthesis of calcium carbonate are elucidated. Moreover, the influences of effective factors on calcium carbonate polymorphism are extensively elaborated. Finally, the limitations for the future application of this innovative technology in construction industry are highlighted.


https://doi.org/10.1038/s41561-018-0218-1

The fate of the vast stocks of organic carbon stored in permafrost of the Western Siberian Lowland, the world’s largest peatland, is uncertain. Specifically, the amount of greenhouse gas emissions from rivers in the region is unknown. Here we present estimates of annual CO2 emissions from 58 rivers across all permafrost zones of the Western Siberian Lowland, between 56 and 67° N. We find that emissions peak at the permafrost boundary, and decrease where permafrost is more prevalent and in

colder climatic conditions. River CO2 emissions were high, and on average two times greater than downstream carbon export. We suggest that high emissions and emission/export ratios are a result of warm temperatures and the long transit times of river water. We show that rivers in the Western Siberian Lowland play an important role in the carbon cycle by degassing terrestrial carbon before its transport to the Arctic Ocean, and suggest that changes in both temperature and precipitation are important for understanding and predicting high-latitude river CO2 emissions in a changing climate.



Amber (fossil resin) is not common throughout the fossil record, and previously the only globally significant deposits were thought to occur during the Cretaceous, Eocene, Oligocene and Miocene periods. Recent finds of Late Triassic (Carnian) ambers highlight a significantly older set of deposits. Here we review these ambers that appear coincident with the Carnian Pluvial Episode, a time interval of major climate change and biotic turnover. Much of the amber is found in a palaeolatitudinal belt between 5° and 30° N, and covers Italian, Austrian, Swiss, Hungarian, Spanish and Arizona (USA) deposits, with one exception from Lesotho, Southern Africa (c. 40° S). Most deposits are small and allochthonous, with the major exception of the autochthonous–parautochthonous amber deposit found as droplets in a palaeosol from the Dolomites (Italy). In some of these deposits there is even direct evidence of the source plants that produced the preserved resin. The oldest confirmed organisms found preserved in amber are from Carnian droplets from the Dolomites in Italy and include arthropods and microorganisms. The occurrence of amber in different localities and within the same time interval suggests a widespread stressed flora, and major biological turnover in the terrestrial ecosystems during the Carnian Pluvial Episode.

Shafer, W.D., Davis, B.H., 2018. Exchange interference for a range of partially deuterated hydrocarbons using a GC-EI-MSD. Journal of Mass Spectrometry 53, 1169-1177.

https://doi.org/10.1002/jms.4287

Industrial catalyst processes, such as the Fischer‐Tropsch (FT) process, produce a vast array of products from syngas (H2/CO), such as jet fuel, gasoline, diesel, synthetic rubbers, monomers for plastics industries, and other oil/wax materials for specific purposes such as cosmetics. Multitudes of publications since the discovery of the FT process in 1925 have been composed, attempting to elucidate the mechanism. Many of these publications attempt to investigate the mechanism of FT by the utilization of specific deuterium experimentation through the switching of the syngas from H2/CO to D2/CO. Results from this switching indicated that hydrogen was involved in the rate‐limited step; the overall process conversion produced an inverse kinetic isotope effect. To confirm that results were not hindered by the physical switch of the hydrogen isotopes, further experimentation was performed using equal molar of each isotope competitively (equal molar H2/D2)/CO. Complications arose from this competitive work as it generated fully exchanged products, i.e. all partially deuterated hydrocarbons that could not be separated by chromatography. These compounds could no longer be separated by the chromatography and required a further separation by mass. The overall scope for this work was to determine if a range of partially deuterated paraffin compounds, generated by FT, can be analyzed using an EI‐MSD without interinstrumental H/D exchange. Results indicate that no real exchange occurs in the EI MSD for a carbon range from about C6 to C16. Even though the materials cannot be separated chromatographically, they can be further separated and analyzed to determine the overall H/D content for these specific chain lengths.



Argillites that strongly luminesce under UV radiation were detected in the Bazhenov Shale Formation (BSF) of the West Siberian Basin during routine core examination and found to be persistent over a wide lateral area. The mineralogy and fabric of these luminescent layers were characterized by optical and fluorescence microscopy, SEM, TEM, XRD and IR methods. Optical and fluorescence microscopy showed that the luminescent layers were to a large extent derived from volcanic ash falls and could be described as meta-tuffites, although normal detrital sedimentation continued at the same time. The layers have a thickness of several mm to a maximum of 3–4 cm and can be defined as a clay-rich regional horizons extending for over 500 km. XRD showed that two principal clay minerals were predominant, namely a kaolinite group minerals, (kaolinite-rich) and a mixed-layer illite-smectite (I/S) similar to that found in K-bentonite. Total organic matter in the luminescent layers is much lower than that in the enclosing BSF clayey-silty siliceous sediments above and below as shown by pyrolytic analyses. Evidence is presented that the luminescent characteristic of the argillites is related to their clay mineralogy, specifically to their content of kaolin minerals, although a contribution from nitrogenous organic matter cannot be entirely discounted. In some ways the luminescent argillites can be compared with bentonites associated with ash transformations or with tonsteins in coal beds, which are also derived from volcanic ash falls and contain highly crystalline kaolinite. However, tonsteins originate at or near land surface whereas the argillites were apparently formed in the deep ocean. But just as tonsteins can be used for detailed stratigraphic studies and are valuable in the context of coal exploration, so may the luminescent argillites prove to be significant both stratigraphically and in the search for economic hydrocarbon deposits, bearing in mind that their clay mineralogy may be sensitive to temperature and depth of burial and related to their placement in the oil and gas window.

Shao, R., Shen, Z., Li, D., Sun, Z., Pei, L., Liu, X., Li, W., Dan, Y., 2018. Investigation on composition and structure of asphaltenes during low-temperature coal tar hydrotreatment under various reaction pressures. Journal of Analytical and Applied Pyrolysis 136, 44-52.


Hydrotreatment (HDT) of low-temperature coal tar (LCT) were carried out in a fixed-bed hydrogenation equipment under various reaction pressures. Asphaltenes were characterized by elemental analysis (EA), gel permeation chromatography (GPC), and proton nuclear magnetic resonance (1H-NMR). As the reaction pressure increased from 6 to 12 MPa, the content of toluene insoluble compounds and asphaltenes as well as the polydispersity of asphaltenes decreased gradually, indicating that the increase of pressure inhibited the condensation reaction of macromolecular radicals to produce toluene insoluble substance. What’s more, the removal rate of sulfur and nitrogen increased about 20% and 3%, respectively. This phenomenon revealed that sulfides were gradually removed as reaction pressure increased, owing to different removal degree of alkylates, thioethers, sulfoxides and sulfones in sulfides of LCT asphaltenes. By contrast, the increase of reaction pressure had negligible effect on removal rate of nitrogen because aromaticity (fA) of LCT asphaltenes is high and nitrogen mainly exist in the form of heterocyclic nitrides (more than 85%),

which are difficult to be removed. By analyzing the structure, fA of LCT asphaltenes tended to decrease and the condensation degree parameter of the aromatic ring system (HAU/CA) increased gradually, indicating that the aromatic of the asphaltenes’ unit layers lessened and the condensation degree of aromatic rings decreased. In addition, the naphthenic ring number (Rn) remains almost unchanged, while the aromatic ring number (RA) reduced with the increase of pressure, demonstrating that the ring-opening rate of naphthenic ring is slightly larger than the hydrogenation saturation rate of aromatic ring during the HDT process of LCT.

Sharifzadeh, M., Sadeqzadeh, M., Guo, M., Borhani, T.N., Murthy Konda, N.V.S.N., Garcia, M.C., Wang, L., Hallett, J., Shah, N., 2019. The multi-scale challenges of biomass fast pyrolysis and bio-oil upgrading: Review of the state of art and future research directions. Progress in Energy and Combustion Science 71, 1-80.


Biomass fast pyrolysis is potentially one of the cheapest routes toward renewable liquid fuels. Its commercialization, however, poses a multi-scale challenge, which starts with the characterization of feedstock, products and reaction intermediates at molecular scales, and continues with understanding the complex reaction network taking place in different reactor configurations, and in the case of catalytic pyrolysis and upgrading on different catalysts. In addition, crude pyrolysis oil is not immediately usable in the current energy infrastructure, due to undesirable properties such as low energy content and corrosiveness as a result of its high oxygenate content. It, therefore, needs to be upgraded and fractionated to desired specifications. While various types of pyrolysis reactors and upgrading technologies are under development, knowledge transfer and closing the gap between theory and application requires model development. In-depth understanding of the reaction mechanisms and kinetics should be combined with the knowledge of multi-scale transport phenomena to enable design, optimization, and control of complex pyrolysis reactors. Finally, underpinning economic and environmental impacts of biofuel production requires expanding the system boundaries to include the overall process and supply chain. The present contribution aims at providing a comprehensive multi-scale review that discusses the state of the art of each of these aspects, as well as their multi-scale interactions. The study is mainly focused on fast pyrolysis, although reference to other types of pyrolysis technologies is made for the sake of comparison and knowledge transfer.

Shi, L., Liu, P., Shen, D., Liu, P., Xi, C., Zhang, Y., 2019. Improving heavy oil recovery using a top-driving, CO2-assisted hot-water flooding method in deep and pressure-depleted reservoirs. Journal of Petroleum Science and Engineering 173, 922-931.


The primary recovery of conventional heavy oil (with viscosity <150 mPa s) in deep reservoirs often has a low recovery factor (RF) and high-pressure drawdown. It is important to propose effective and economic recovery methods to enhance oil recovery of these reservoirs. A top-driving, carbon dioxide (CO2)-assisted hot-water flooding method is developed and presented in this paper. Laboratory experiments, including CO2 solubility and one-dimensional (1D) core flooding tests, were conducted based on oil samples from a deep and pressure-depleted conventional heavy oil reservoir. Numerical simulations were conducted to study and discuss the mechanisms. The results from laboratory experiments show that the dissolved CO2 in the oil reduced the oil viscosity by 30% at 57 °C and 2.0 MPa, and the displacement efficiency of carbonated 120 °C hot-water flooding was comparable to that of 200 °C steam flooding. The CO2-assisted hot-water flooding method requires substantially less energy input than the steam flooding method. Numerical simulation indicates that

the CO2 and hot-water co-injecting process results in viscosity reduction, increased pressure, increased sweeping volume, and, consequently, improved oil recovery. The top-driving and CO2-assisted hot-water flooding method provides a technical and cost-effective method for enhancing oil recovery in the post-primary recovered heavy oil reservoirs.

Shields, G.A., Halverson, G.P., Porter, S.M., 2018. Descent into the Cryogenian. Precambrian Research 319, 1-5.


The Cryogenian Period brackets an interval of profound glaciation, commonly referred to by the evocative epithet ‘Snowball Earth’. According to its recent redefinition, the Cryogenian began before the onset of low-latitude glaciation ca. 717 Ma and ended during its final and catastrophic melting phase ca. 635.5 Ma. Pending future ratification of a Global Stratotype Section and Point or GSSP, the onset of the Cryogenian Period is estimated at about 720 Ma. However, no consensus has yet been reached concerning the best section or criteria for its definition. The articles in this special issue represent the state-of-the-art in Tonian-Cryogenian transition stratigraphy around the world and will contribute to the selection of the future GSSP.

Shigaev, V.Y., 2018. Foundations of petroleum prediction based on the activation of geochemical processes by direct current. Russian Geology and Geophysics 59, 1508-1513.


Petroleum prediction in local objects and the applicability of geologic environment parameters in this regard are considered. The proposed guidelines for petroleum potential prediction are based on the analysis of the distribution of typomorphic epigenetic multivalent elements loosely fixed in rocks before and after electric current treatment. The advantage of geoelectrochemical methods providing data on the chemical composition of above-productive deposits is demonstrated.


https://www.biogeosciences-discuss.net/bg-2018-456/

The response of CH4 emission from natural wetlands to meteorological conditions is important because of its strong greenhouse effect. To understand relationship between CH4 flux and wetting, we observed interannual variations in chamber CH4 flux, and concentration, δ13C, and δD of dissolved CH4 in summers from 2009 to 2013 at the taiga-tundra boundary in the vicinity of Chokurdakh (70°37'N, 147°55'E) on the lowland of the Indigirka River in northeastern Siberia. We also conducted incubation experiments to interpret δ13C and δD of CH4 to investigate variations in CH4 production and oxidation processes. Methane flux showed large interannual variation in wet areas of sphagnum mosses and sedges (36–140mgCH4m−2day−1 as emission). Increased CH4 flux was recorded in summer 2011 when a wetting event with extreme precipitation occurred. Although water level decreased from 2011 to 2013, CH4 flux remained relatively large in 2012, and increased further in 2013. Concurrently, dissolved CH4 concentration rose by one order of magnitude from 2011 to 2012, and increased further from 2012 to 2013. Large variations in δ13C and δD of dissolved CH4 were observed in 2011, and less variations were seen in 2012 and 2013, suggesting both enhancement of CH4 production and depression of CH4 oxidation. These multi-year effects of wetting on CH4 dynamics

may have been caused by continued soil reduction across multiple years after wetting, which suggests that duration of water saturation in the active layer can be important for predicting CH4 emission following a wetting event in permafrost ecosystem.

Shkolyar, S., Farmer, J.D., 2018. Biosignature preservation potential in playa evaporites: Impacts of diagenesis and implications for Mars exploration. Astrobiology 18, 1460-1478.

https://doi.org/10.1089/ast.2018.1849

Assessing biosignature preservation potential (BPP) in ancient habitable environments on Mars is a top NASA priority. We address this goal through the study of Miocene-Pliocene evaporites of the Verde Formation (central Arizona). We assessed the effects of diagenesis on BPP, integrating outcrop-scale observations with six lab analyses: thin-section petrography, X-ray diffraction, Raman spectroscopy, total organic carbon (TOC), electron probe microanalysis (EPMA), and visible to near-infrared (VNIR) reflectance spectroscopy. We recognized five facies and their diagenetic pathways. Two facies included mudstones which contain clusters of displacive growth gypsum (DGG). Early DGG was altered during diagenesis by dissolution forming crystal cavities and later underwent recrystallization, cation substitution, and sulfate dehydration. Another facies was identified by lenticular beds dominated by halite and late diagenetic thenardite (Na2SO4). These pods are overlain by a sequence of interbedded gray and red mudstones which record cyclic oxidation and Fe-oxide cementation. During the Pleistocene, a lacustrine environment developed, accompanied by magnesite cementation of playa mudstones. TOC analyses were used as a proxy for inferring the BPP in each facies. The highest BPP was associated with both red and gray mudstone facies. This study provides a taphonomic framework for playa environments on Earth that record the impacts of diagenesis on BPP, with potential applications to Mars sample return (MSR) missions.

Shulga, N.A., 2018. Characteristics of alkanes in ferromanganese nodules of the Clarion–Clipperton Fracture Zone. Oceanology 58, 672-678.

https://doi.org/10.1134/S0001437018050156

This work presents the first results of a comparative study on the composition and distribution of organic matter (OM) (TOC, n-alkanes, pristane, phytane) in ferromanganese nodules and underlying sediments (0–1 cm) from three sites within the Clarion–Clipperton Fracture Zone, Pacific Ocean. Samples were collected during Cruise 120 of the RSS James Cook in 2015. The studied nodules differ in size, shape, and morphology. The TOC content in the nodules is 0.15% on average with insignificant variations which is less than in the sediments. The molecular composition of n-alkanes in the nodules is mainly determined by modern bacterial activity with high preservation of terrigenous n-alkanes in the environment of the ore deposit formation. Original Russian Text © N.A. Shulga, 2018, published in Okeanologiya, 2018, Vol. 58, No. 5, pp. 731–738.

Sibilska, I., Feng, Y., Li, L., Yin, J., 2018. Trimetaphosphate activates prebiotic peptide synthesis across a wide range of temperature and pH. Origins of Life and Evolution of Biospheres 48, 277-287.

https://doi.org/10.1007/s11084-018-9564-7

The biochemical activation of amino acids by adenosine triphosphate (ATP) drives the synthesis of proteins that are essential for all life. On the early Earth, before the emergence of cellular life, the chemical condensation of amino acids to form prebiotic peptides or proteins may have been activated by inorganic polyphosphates, such as tri metaphosphate (TP). Plausible volcanic and other potential

sources of TP are known, and TP readily activates amino acids for peptide synthesis. But de novo peptide synthesis also depends on pH, temperature, and processes of solvent drying, which together define a varied range of potential activating conditions. Although we cannot replay the tape of life on Earth, we can examine how activator, temperature, acidity and other conditions may have collectively shaped its prebiotic evolution. Here, reactions of two simple amino acids, glycine and alanine, were tested, with or without TP, over a wide range of temperature (0–100 °C) and acidity (pH 1–12), while open to the atmosphere. After 24 h, products were analyzed by HPLC and mass spectrometry. In the absence of TP, glycine and alanine readily formed peptides under harsh near-boiling temperatures, extremes of pH, and within dry solid residues. In the presence of TP, however, peptides arose over a much wider range of conditions, including ambient temperature, neutral pH, and in water. These results show how polyphosphates such as TP may have enabled the transition of peptide synthesis from harsh to mild early Earth environments, setting the stage for the emergence of more complex prebiotic chemistries.

Sierra, C.A., Hoyt, A.M., He, Y., Trumbore, S.E., 2018. Soil organic matter persistence as a stochastic process: Age and transit time distributions of carbon in soils. Global Biogeochemical Cycles 32, 1574-1588.

https://doi.org/10.1029/2018GB005950

The question of why some types of organic matter are more persistent while others decompose quickly in soils has motivated a large amount of research in recent years. Persistence is commonly characterized as turnover or mean residence time of soil organic matter (SOM). However, turnover and residence times are ambiguous measures of persistence, because they could represent the concept of either age or transit time. To disambiguate these concepts and propose a metric to assess SOM persistence, we calculated age and transit time distributions for a wide range of soil organic carbon models. Furthermore, we show how age and transit time distributions can be obtained from a stochastic approach that takes a deterministic model of mass transfers among different pools and creates an equivalent stochastic model at the level of atoms. Using this approach we show the following: (1) Age distributions have relatively old mean values and long tails in relation to transit time distributions, suggesting that carbon stored in soils is on average much older than carbon in the release flux. (2) The difference between mean ages and mean transit times is large, with estimates of soil organic carbon persistence on the order of centuries or millennia when assessed using ages and on the order of decades when using transit or turnover times. (3) The age distribution is an appropriate metric to characterize persistence of SOM. An important implication of our analysis is that random chance is a factor that helps to explain why some organic matter persists for millennia in soil.

Sinha, U., Dindoruk, B., Soliman, M.Y., 2019. Development of a new correlation to determine relative viscosity of heavy oils with varying asphaltene content and temperature. Journal of Petroleum Science and Engineering 173, 1020-1030.


One of the important challenges in the oil industry is to transport high viscosity heavy oils through pipelines while minimizing potential transport issues due to implications of asphaltenes. After evaluation of what is available in the literature (Pal and Rhodes, 1989; Krieger and Dougherty, 1959), we have developed a new correlation for relative viscosity of heavy oils which is not only simpler with easy to obtain input data but also more accurate than the leading correlations published in the literature. For example, the proposed correlation requires the incorporation of only one fluid-specific

parameter where the structure and size of unsolvated asphaltene nanoaggregate was taken based on the “Yen-Mullins” (Mullins et al., 2012) model. To check the accuracy and validity of the correlation along with the assumptions utilized, calculated values of the relative viscosity were cross-plotted against the available experimental data from the literature. The results were also compared with the results obtained from some of the leading published correlations, such as “Pal - Rhodes” (Pal and Rhodes, 1989) and “Krieger - Dougherty” (Krieger and Dougherty, 1959) correlations. The R2 (R-squared) along with the other statistical parameters obtained for our model were shown to be superior to the other correlations considered, indicating that our correlation is able to explain the relative viscosity variations with respect to the selected parameters better than the subject set of correlations. In addition, we have also developed a methodology to predict the value of maximum packing volume fraction of asphaltene particles dispersed in deasphalted oils that can also be used in calculating the relative viscosity using “Krieger - Dougherty” (Krieger and Dougherty, 1959) and “Brouwers” (Brouwers, 2010) models.

Siveter, D.J., Briggs, D.E.G., Siveter, D.J., Sutton, M.D., 2018. A well-preserved respiratory system in a Silurian ostracod. Biology Letters 14, Article 20180464.

http://rsbl.royalsocietypublishing.org/content/14/11/20180464.abstract

Ostracod crustaceans are diverse and ubiquitous in aqueous environments today but relatively few known species have gills. Ostracods are the most abundant fossil arthropods but examples of soft-part preservation, especially of gills, are exceptionally rare. A new ostracod, Spiricopia aurita (Myodocopa), from the marine Silurian Herefordshire Lagerstätte (430 Mya), UK, preserves appendages, lateral eyes and gills. The respiratory system includes five pairs of gill lamellae with hypobranchial and epibranchial canals that conveyed haemolymph. A heart and associated vessels had likely evolved in ostracods by the Mid-Silurian.

Sizova, E., Gerya, T., Brown, M., Stüwe, K., 2018. What drives metamorphism in early Archean greenstone belts? Insights from numerical modeling. Tectonophysics 746, 587-601.


Geodynamic regimes responsible for the formation of Eoarchean-to-Mesoarchean continental crust may be investigated using numerical modeling in which deeper mantle processes are coupled with shallower processes responsible for the formation and modification of the crust. In an earlier study using a 2D coupled petrological–thermomechanical tectono-magmatic numerical model constrained by information from the geological record, experiments with initial conditions appropriate to the Eoarchean–Mesoarchean revealed multiple tectonic processes by which mostly felsic continental crust could have been formed from an initial primary mafic crust in a non-uniformitarian geodynamic regime. We use the model pressure–temperature–time (P–T–t) paths for material particles from our previous study to test the hypothesis that the range of metamorphic P–T conditions recorded in Archean granite–greenstone domains could have been generated without subduction and plate tectonics. We compare the experimental results with P–T and age data recovered from two early Archean domains, the East Pilbara Terrane (EPT), part of the Pilbara craton in Western Australia, and the Barberton greenstone belt (BGB), part of the Kapvaal craton in South Africa. The dome-and-keel structures that develop in the crust in the numerical experiment and the associated P–T–t paths at various locations within these structures are similar to the structures and P–T and age data recovered from the early Archean crust in the EPT and BGB. This study shows that metamorphism in granite–greenstone-like crust could have been the result of both vertical and horizontal tectonic processes (coupled with crustal convective overturns) that occurred over linked sites of crustal delamination and

mantle upwelling. The range of thermal gradients derived from peak P–T values for markers in the experiment matches the range of apparent thermal gradients retrieved from the EPT and BGB, demonstrating that even the lowest apparent thermal gradients associated with dome-and-keel structures in greenstone belts can be achieved in the absence of subduction.

Skelton, A., Löwhagen, L., Fairchild, I.J., Boyce, A., Mörth, C.-M., Siegmund, H., Webster, D., Spencer, A.M., 2019. Stable isotopes of oxygen and hydrogen in meteoric water during the Cryogenian Period. Precambrian Research 320, 253-260.


We measured δ18O and δ2H values of muscovite and carbonate mineral separates from metamorphosed carbonate-bearing mudstone layers in late Tonian to early Cryogenian strata, including Sturtian glacial deposits, which were deposited in a coastal setting at an approximate paleolatitude of 30–35°S and now crop out on Islay and the Garvellach Islands, Scotland. From these values, we calculated δ18O and δ2H values of meteoric water that equilibrated with clay at diagenetic conditions which we infer were reached shortly after deposition (i.e. before the end of the Cryogenian Period) because sediment accumulation was rapid due to fast subsidence at that time. This calculation required removal of the effects of exchange with reservoir rocks, metamorphic volatilization and mixing with metamorphic fluids on δ18O and δ2H values. The values we calculated for meteoric water fall within the 2σ ranges δ18O = −1 to −4‰ and δ2H = 0 to −23‰, respectively. These ranges are similar to present day values at equivalent latitudes. This finding is consistent with sediment accumulation in the Cryogenian Period having occurred in a climate similar to present day (Ice Age) conditions. This conclusion is not at odds with the Snowball Earth hypothesis because one of its predictions is that sediment accumulation occurred as the climate warmed at the end of panglaciation, a prediction supported by sedimentological evidence of multiple glacial advances and retreats in our study area and elsewhere.

Smith, K.L., Ruhl, H.A., Huffard, C.L., Messié, M., Kahru, M., 2018. Episodic organic carbon fluxes from surface ocean to abyssal depths during long-term monitoring in NE Pacific. Proceedings of the National Academy of Sciences 115, 12235-12240.


Significance: Ignoring temporal fluctuations in the oceanic carbon budget leads to a significant misrepresentation of the cycling of organic matter from production in surface waters to consumption and sequestration in the abyssal ocean. A 29-year time series (1989 to 2017) of particulate organic carbon (POC) fluxes and sea-floor measurements of sediment community oxygen consumption (SCOC) revealed episodic, high-magnitude events over the past 7 years. Time lags between changes in satellite-estimated export flux, POC flux and SCOC varied from 0 to 70 days. A commonly used model to estimate carbon flux through the water column significantly underestimated the measured carbon fluxes by almost 50%. Episodic pulses of organic carbon into the deep sea must be accounted for to balance the oceanic carbon budget.

Abstract: Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events (≥mean + 2 σ), and 43% from 2011 to 2017. From 2011 to 2017, when high-resolution SCOC data were available, time

lags between changes in satellite-estimated export flux (EF), POC flux, and SCOC on the sea floor varied between six flux events from 0 to 70 days, suggesting variable remineralization rates and/or particle sinking speeds. Half of POC flux pulse events correlated with prior increases in EF and/or subsequent SCOC increases. Peaks in EF overlying Station M frequently translated to changes in POC flux at abyssal depths. A power-law model (Martin curve) was used to estimate abyssal fluxes from EF and midwater temperature variation. While the background POC flux at 3,400-m depth was described well by the model, the episodic events were significantly underestimated by ∼80% and total flux by almost 50%. Quantifying episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of POC sequestration and understanding the global carbon cycle.

Smith, S.M., Sprain, C.J., Clemens, W.A., Lofgren, D.L., Renne, P.R., Wilson, G.P., 2018. Early mammalian recovery after the end-Cretaceous mass extinction: A high-resolution view from McGuire Creek area, Montana, USA. GSA Bulletin 130, 2000-2014.

http://dx.doi.org/10.1130/B31926.1

Changes in mammalian faunal composition and structure following the Cretaceous–Paleogene mass extinction are central to understanding not only how terrestrial communities recovered from this ecological perturbation but also the evolution of archaic groups leading to extant mammalian clades. Here, we analyzed changes in mammalian local faunas during the earliest Paleogene biotic recovery on a small spatiotemporal scale. We compiled samples of mammals from four localities in the Hell Creek Formation and Tullock Member of the Fort Union Formation, in the McGuire Creek area, McCone County, Montana, USA, and placed these localities into a high-precision chronostratigraphic framework using 40Ar/39Ar tephra ages and magnetostratigraphy. Within this framework, we quantitatively compared faunal composition, heterogeneity, and richness among McGuire Creek local faunas and made broader comparisons to other earliest Paleogene faunas from throughout the Western Interior of North America. In the first ∼320 k.y. of the recovery, mammalian local faunas at McGuire Creek, all of which can be placed in the Puercan 1 North American Land Mammal Age (NALMA) interval zone, underwent modest increases in taxonomic richness and heterogeneity, indicating the beginning of biotic recovery; however, no McGuire Creek fauna reached fully recovered levels of taxonomic richness. Further, appearance of immigrant taxa such as Purgatorius in younger McGuire Creek faunas demonstrates important compositional changes within the Pu1 of McGuire Creek. These results highlight the difficulties with describing the nuanced mammalian recovery process using the NALMA system and emphasize the increasing importance of high-precision dating, especially when comparing faunas across large geographic distances.

Snyder, D.T., Szalwinski, L.J., Wells, J.M., Cooks, R.G., 2018. Logical MS/MS scans: a new set of operations for tandem mass spectrometry. Analyst 143, 5438-5452.

http://dx.doi.org/10.1039/C8AN01661E

A new set of operations for tandem mass spectrometry in a linear ion trap is described. Logical MS/MS operations categorize compounds in mixtures based on characteristic structural features as revealed by MS/MS behavior recorded in multiple fragmentation pathways. This approach is a conceptual extension of tandem mass spectrometry in which interrogation of the full data domain is performed by simultaneous implementation of precursor and neutral loss scans. This process can be thought of as moving through the 2D MS/MS data domain along multiple scan lines simultaneously, which allows experiments that explore the 2D data domain of MS/MS to be couched in terms of logical operations, AND, NAND (not and), OR (inclusive or), XOR (exclusive or), NOT, etc.

Examples of particular logical conditions include all precursor ions that fragment to both of two selected product ions (logical AND), or all precursor ions that do not produce a specified fragment ion (logical NOT). These and other operational modes (TRUE/FALSE, XOR, OR, etc.) complement and extend the existing set of conventional MS/MS scans, namely product scans, precursor scans, and neutral loss scans. We describe the implementation of logical MS/MS scans on a commercial linear ion trap mass spectrometer using simple mixtures of amphetamines and fentanyl analogues and argue their utility for complex mixture analysis.

Soares, G.G., Van Kranendonk, M.J., Belousova, E., Thomson, S., 2019. Phosphogenesis in the immediate aftermath of the Great Oxidation Event: Evidence from the Turee Creek Group, Western Australia. Precambrian Research 320, 193-212.


Phosphatic peloids and pebble-sized microbially-bound sediment clasts have been identified within dolomitic sediment that separates centimetric columnar stromatolites in a 20–150 cm thick horizon from the 2.4–2.2 Ga Turee Creek Group in Western Australia.

Petrographic examination of the phosphatic clasts reveals complex internal textures that are defined by different mixtures of fine-grained apatite, medium-grained dolomite, irregular domains of partly euhedral micro-quartz, and carbonaceous matter.

Phosphatic sand-sized peloids observed within microbially-bound sediment clasts are similar in size, texture, and composition to the individual peloids in the intercolumn sediment. Both occurrences have finely dispersed kerogen throughout and zoned cores that are packed with both microscopic apatite granules and larger, euhedral quartz crystals. The percentage of apatite vs quartz vs kerogen varies between studied peloids.

Similar-sized, white peloids in the intercolumn sediment and in the microbially-bound sediment clasts contain illite and are lined internally by euhedral apatite crystals, 20–100 µm in size. Some peloids are kerogenous in one domain and illite-bearing in another.

The phosphatic microbially-bound sediment clasts and peloids are interpreted to represent fragments of a peritidal phosphorite, redeposited in an offshore setting during high energy events. Peloids formed within the microbially-bound sediment and were subsequently eroded out and redeposited in the intercolumn sediment. White peloids are interpreted to represent peloids affected by surficial weathering during temporary exposure, when the fine-grained kerogenous interior was replaced by clays. These weathered peloids were then re-sedimented and captured both within microbially-bound sediment and in the intercolumn sediment.

Euhedral apatite crystals that line the insides of illite-bearing white peloids were dated to 2104 ± 70 Ma and 2041 ± 33 Ma, using U-Pb and Th-Pb dating methods, respectively. This age is interpreted to represent the time of metamorphic fluid circulation during a period of known regional metamorphism, and provides a minimum age of the reef complex.



New fossils and sites are helping make sense of the mysterious flowering of animal life half a billion years ago.

The drumming of the jackhammer deepens. Then, a block of shale butterflies open, exposing to crisp mountain air a surface that hasn't seen sunlight in half a billion years. “Woo!” says paleontologist Cédric Aria of the Nanjing Institute of Geology and Palaeontology in China, bracing the top slab of rock upright.

Its underside bears charcoal-colored smudges that look vaguely like horseshoe crabs or the Millennium Falcon from Star Wars. “It's a spaceship landing area here,” says expedition leader Jean-Bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum (ROM) in Toronto, Canada.

Those “spaceships” are carapaces, molted onto a long-vanished ocean floor by a species new to science. This field season they've been spilling out of the rocks here, where Caron's team has spent the past few years unearthing groundbreaking animal fossils from the Cambrian period, the coming-out party for animal life on Earth. During the Cambrian, which began about 540 million years ago, nearly all modern animal groups—as diverse as mollusks and chordates—leapt into the fossil record. Those early marine animals exhibited a dazzling array of body plans, as though evolution needed to indulge a creative streak before buckling down. For more than a century, scientists have struggled to make heads or tails—sometimes literally—of those specimens, figure out how they relate to life today, and understand what fueled the evolutionary explosion.

Gingerly, Aria and Caron place the top piece of their slab aside. Space is hard to come by in the quarry, perched on a ledge the size of a small bedroom at an altitude of 2500 meters, far above Tokumm Creek. For years, an equally forbidding site about 40 kilometers northwest of this valley offered the clearest window on the Cambrian. There, in 1909, U.S. paleontologist Charles Doolittle Walcott discovered the Burgess Shale, a fossil formation that preserves not only hard shells, but also soft features such as the legs, eyes, and guts of Cambrian creepy-crawlies.

But in recent years, Caron has shown that the richest fossil-bearing rock extends many kilometers beyond Walcott's site. This summer's excavation marks his latest visit to this long Cambrian tapestry. Each new stop has offered striking views of unfamiliar animals, many already described in high-profile papers: the little fish relative Metaspriggina, a vertebrate ancestor that Caron now speculates clustered in schools; the pincered Tokummia; and the ice cream cone–shaped fossils called hyoliths, which Caron's Ph.D. student Joseph Moysiuk last year linked to shelled animals called brachiopods, some of which persist today.

Other sites around the world are also opening new vistas of the Cambrian. Scientists can now explore the animal explosion with a highlight reel of specimens, along with results from new imaging technologies and genetic and developmental studies of living organisms. “There have been a host of new discoveries,” says paleontologist Doug Erwin of the Smithsonian Institution's National Museum of Natural History in Washington, D.C. Researchers may be closer than ever to fitting these strange creatures into their proper places in the tree of life—and understanding the “explosion” that birthed them.

Each new find brings the simple joy of unearthing and imagining a seemingly alien creature. On a break, Caron cautiously shows off this year's crown jewel, found about a week earlier. It's an intact, hand-size carapace with a center spine, like a Prussian spiked helmet frozen in ancient rock. Another undescribed species, it seems to be related to the spaceships. Caron's team calls it the mothership.

He's nervous just holding it. Burgess Shale fossils are so valuable that Parks Canada keeps the exact locations of Caron's sites secret, monitors them with cameras, and prosecutes fossil poachers. ROM once insured a Burgess Shale specimen for half a million Canadian dollars when it went on loan, he says—and that was an animal known through multiple fossils. This is one of a kind.

“It's going to be iconic,” Caron says. “It's the most extraordinary fossil I've ever found.”

For years, Caron suspected Walcott's site might be rivaled elsewhere in the Rocky Mountains. The breakthrough came in 2012, near an area called Marble Canyon, where a 2003 wildfire had burned off the trees. While crossing an avalanche chute filled with broken tiles of rock, his reconnaissance party found itself surrounded by impressions of soft-bodied creatures, many with unfamiliar shapes. “It was clear that nobody had ever been walking over this pile of rocks before with this purpose in mind,” says Bob Gaines, a geochemist from Pomona College in Claremont, California, who has joined Caron's expeditions since the beginning.

They returned to excavate in 2014. At least one in five of the animals they found at Marble Canyon belongs to species new to science, the team concluded. Now, they've moved on to other sites along the valley.

How Cambrian species are related to today's animals has been debated since the fossils first came to light. Walcott classified his oddities within known groups, noting that some Burgess Shale fossils, such as the brachiopods, persisted after the Cambrian or even into the present. So, for example, he concluded almost all the creatures resembling today's arthropods were crustaceans.

But later paleontologists had other ideas. Harvard University's Stephen Jay Gould perhaps best captured the charisma of Cambrian life in his 1989 book Wonderful Life: The Burgess Shale and the Nature of History, in which he lavished attention on the “weird wonders” excavated from Walcott's city block–size quarry. Gould argued that oddballs such as the aptly named Hallucigenia, a worm with legs and hard spines, seem unrelated to later animals. He slotted the unusual forms into their own phyla and argued that they were evolution's forgotten experiments, later cast aside by contingencies of fate.

Contemporary paleontologists have settled on yet another way to understand them. Consider the arthropods, arguably Earth's most successful animals. In a family tree, the spray of recent branches that end in living arthropods—spiders, insects, crustaceans—constitutes a “crown” group. But some animals in the Burgess Shale probably come from earlier “stems” that branched off before the crown arthropods. These branches of the tree don't have surviving descendants, like a childless great-uncle grinning out from a family photo. In that view, many of Gould's weird wonders are stem group organisms, related to the ancestors of current creatures although not ancestors themselves. Newer fossils from the Canadian Rockies help support that view. Caron argued in 2015, for example, that his specimens of Hallucigenia have features suggesting the animal belongs on a stem group of the velvet worms, creatures that still crawl around in tropical forests spitting slime.

Similar analysis awaits the spaceships. At first glance, Caron's team thinks they are a new species or group of radiodontans, stem arthropods that also include Anomalocaris, the Cambrian's charismatic apex predator—a clawed, fearsome-jawed swimmer half a meter long. Filling out the branches of that stem group gives a “step-by-step view of how an arthropod built its body” through evolutionary time, says paleontologist Allison Daley at the University of Lausanne in Switzerland.

Throughout much of Cambrian paleontology, that's the game—a high-stakes, sometimes contentious race to find diagnostic body parts on known or new fossils, make arguments about what taxonomic groups they belong to, and maybe revise evolutionary history in the process.

In the past few years, paleontologists have approached the problem with an array of new techniques. Those include scanning electron microscopes, which can discern a specimen's chemical makeup as well as image it, and computerized tomography (CT) scans, which can penetrate fossils without scraping away material. Those tools have also illuminated a startling series of internal features:

fossilized Cambrian brains. Beginning in 2011, paleontologist Xiaoya Ma, now at the University of Exeter in the United Kingdom, published a string of papers tracing nervous tissue in exceptionally preserved Chinese fossils. Those nervous system architectures offer a parallel way to sort animals into evolutionary groups, beyond the usual anatomical structures, and other teams have presented their own compelling specimens.

In fossils of the shrimplike Chengjiangocaris kunmingensis from southwest China, for example, “we have this structure that looks almost like a pearl necklace,” running almost head to tail, says Javier Ortega-Hernández, an incoming professor at Harvard. His team, led by Jie Yang at Yunnan University in Kunming, China, argued in 2016 that the necklace is a nerve cord studded with smaller clusters of neurons, themselves sprouting tiny nerve fibers. Living arthropods no longer have those fibers. But today's velvet worms and priapulid worms do, implying kinship between long-vanished stem arthropods and those groups.

Critics argue that paleontologists such as Ma and Ortega-Hernández overinterpret some fossils, spotting nervous tissues that aren't there. Many of those structures, the critics say, might just be “halos,” biofilms formed when microbes broke down internal parts like muscles or guts after death. But other researchers are convinced. “If you look at the best-preserved nervous systems, there's no doubt” that the features are real, says Graham Budd, a paleontologist at Uppsala University in Sweden and an architect of the current stem-and-crown concept.

Bold claims that use anatomy to revise family trees engender similar controversy throughout the field. One argument that Hallucigenia fits with the velvet worms, for example, depends on the exact shape of its claws. But other teams counter that the claws aren't diagnostic of ancestry.

The uncertainties leave paleontologists ever hungry for newer, better specimens. “When there is a debate, you bring a new fossil and say, ‘Look, this is the feature we see,’” Caron says, warming up in a tent perched high above Tokumm Creek. “Without fossils, it's speculation.”

The fossils make up for the discomfort: 6 weeks in tents above the tree line warding off grizzlies with an electrified fence, contending with hot days and snow days and wildfire smoke, obeying the smelly requirement to carry everything—everything—out of the national park at the expedition's end.

It's a chilly August morning, 1 day before a helicopter comes to take all human traces away. Today is the last chance to stumble on a fossil that could crack a mystery—say, to find the body that belongs in the mothership carapace.

The nine-member team hikes from camp to their quarry, up steep, rock-littered slopes. Ridged trilobite fossils poke out from exposed layers, but on this expedition, they don't even warrant a second glance. At the quarry, most people split rock while Caron's grad students help ROM curator Maryam Akrami pack away the most recent finds in swimming-pool noodles. “It's the last day,” Caron says. “No injuries!”

Each successive excavation in this valley has targeted the same band of rock, which records a single slice of geologic time. But each dig has yielded a different array of new species. That's because conditions varied across the ancient sea floor, favoring different animals. Such variation is “not a shock to anybody that has ever strapped on a snorkel and swum around,” Gaines says. But this vast, wide-open valley captures that kind of diversity at a single moment, allowing glimpses of how the earliest animal ecosystems were structured.

As Caron's quarries bring this moment into ever-sharper focus, other sites have opened portals on other stages of the Cambrian. Nearly everywhere, the fossils preserve levels of squishy detail that are absent in specimens from later in Earth's fossil record. In 2012, Gaines and colleagues proposed a

reason: Perhaps unique chemical conditions suffused Cambrian seas. After dead animals settled into mud on the sea floor, low levels of sulfates could have slowed decay by sulfur-loving bacteria while alkaline chemistry encased the dead animals in coats of carbonate, sealing soft tissues inside.

In summer 1984, for example, paleontologist Hou Xian-guang of Yunnan University uncovered an arthropod glistening in Cambrian mudstone, its legs seemingly alive. He had discovered the Chengjiang biota, a trove of immaculate fossils that sprawls over a region in southwest China.

Slightly older than the Burgess Shale—about 518 million years old compared with the Burgess's roughly 507 million years—those deposits showcase related animals in a different style of preservation. Unlike Caron's sites, where geologic processes have squashed the fossils almost flat, the Chengjiang animals still retain some depth. Since 2015, Chinese researchers, including Hou, have capitalized on that by using CT scans to make 3D images of the specimens without destroying them. Today, three rival Chinese teams, each with international collaborators, compete to pull out new discoveries from the site. “There is an absolute landslide of material,” Ortega-Hernández says.

Add to that sites such as Emu Bay in Australia, where paleontologists announced in 2011 that they had unearthed radiodontan fossils revealing their complex, multifaceted eyes; and Morocco's Fezouata Formation, which paleontologist Peter Van Roy at Ghent University in Belgium reported in 2010. Each site offers distinct insights. “Every fossil assemblage is horrifically biased,” says paleontologist Nick Butterfield of the University of Cambridge in the United Kingdom, “but they're horrifically biased in different ways.”

The Moroccan samples, for example, date to a little after the Cambrian, and they show a blend between the Cambrian's signature oddities and the more familiar fauna that dominated later periods. “We are still at the point of unpacking fossils,” says Daley, a collaborator on that research. “This is a chance to study why some taxa go extinct and why others are able to replace them.”

Although show-stopping animals keep falling out of the strata, the full significance of the Cambrian explosion remains a mystery. Arthropods, the most diverse and common creatures known from the time, littered Cambrian ecosystems. Judging by the fossils, Daley argued in a paper in May, the Cambrian witnessed both the birth and step-by-step diversification of many modern groups. Another approach yields a different answer, however. Geneticists use a tool called molecular clocks to trace back down the tree of life. By starting with genetic differences between living animals, which have accrued as a result of random mutations over the eons, molecular clocks can rewind time to the point where branches diverged.

According to recent studies using that method, modern animals began to march off into their separate phyla some 100 million years before the Cambrian. The finding implies that those groups then hung out, inconspicuous or unnoticed in the fossil record, before suddenly stepping on stage.

Paleontologists have a cryptic set of clues about life before the explosion. Long before the odd beasts of the Cambrian evolved, an even more alien set of ocean organisms left impressions on sedimentary rocks now seen in Namibia and Australia. The Ediacarans, as those fossils are called, taunt paleontologists with the same kind of interpretive challenge as the Cambrian's weird wonders. But they're even weirder. Their imprints suggest some grew in fractal patterns; others had three-part symmetry. Unhelpfully, they don't have obvious mouths, guts, or appendages. “That's where the freak flags are going now,” says Jo Wolfe, a paleontologist at the Massachusetts Institute of Technology in Cambridge.

Most Ediacarans vanished before Cambrian deposits, perhaps perishing in the world's first mass extinction. But many researchers suspect some belong on the tree of animal life, perhaps as early

stems. One Ediacaran, Kimberella, looks like an animal: a snail or slug that grazed along the sea floor. In August, Stromatoveris, a frondlike Cambrian creature already thought to be an animal, was pegged as an Ediacaran survivor on the basis of its fractal branches. That would make its Ediacaran relatives animals, too. And in September, researchers announced that an iconic Ediacaran fossil called Dickinsonia, which looks like a halved Christmas ham, contained lipid molecules that resemble those of living animals.

“We're seeing the beginning of the advent of animals in the Ediacaran,” says paleobiologist Mary Droser of the University of California, Riverside. “It's more fun and exciting than just the Cambrian explosion.”

And yet even as the Ediacarans shove Cambrian creatures off their perch as the first animals, Cambrian science itself continues to explode. Caron and others keep hunting for fossil features that could reveal the relationships among Ediacaran, Cambrian, and present-day groups. Other researchers struggle to explain what caused the explosion of animal forms. Atmospheric oxygen may have spiked, enabling animals to grow bigger, stronger, and more active. Or erosion could have dumped toxic calcium into the oceans, prompting organisms to shunt it into building hard skeletons.

Or biology itself could have led the way. Inventions such as predation, free swimming, and burrowing into the sea floor—all first seen in or shortly before the Cambrian—could have transformed a placid global ecology into a high-stakes contest, spurring waves of call-and-response innovation between groups. The explosion might also mark the moment when, after millions of years of quiet progress, animals had finally accrued the developmental recipes to build body parts and improvise on basic themes. That genetic toolkit, Butterfield argues, is “absolutely, astronomically, inconceivably complex. It just took a while to figure that out.” Or, of course, multiple causes could have piled up together.

After a lunch break, the paleontologists chisel into a few more slabs. Gaines takes rock samples from each layer of their quarries, hoping to reconstruct each environment's chemistry. Then Caron delivers the announcement: “It's over, guys. No more digging.”

The next day, its last, the ROM team breaks camp. Over several hours, a helicopter ferries nets sagging with fossils toward a staging area by the highway, making the roughly 10-minute trip again and again. Some specimens, like the spaceships, will be rushed to publication in coming months, now that visiting journalists have seen them. Other finds will sit in drawers, awaiting new techniques or the graduate student who asks the right question.

As the team huddles, waiting for its helicopter ride, tiny, rabbitlike mammals called pikas cry out from the hills. Each helicopter trip erases the signs of human presence one by one, until only carved-out quarries remain. More fossils still rest inside, pressed between folio sheets of rock, waiting for the next season.



Mylonitized-soft-coal is common throughout central China and results from the crushing of intact coal into fine particles under extreme tectonic stress. The fine particles result in very low permeability and hydraulic fracturing to recover natural gas is difficult due to the very low mechanical strength. Enhancing structural integrity and mechanical strength of these coals are the keys to efficiently extracting coalbed methane (CBM). The following explores using microbially-induced calcium

carbonate cementation to strengthen and stiffen the coal – and therefore enable successful hydraulic fracturing. We explore the impact of this cementation on the mechanical properties and on microscopic mechanisms of failure for granular assemblages of four sizes. Results indicate significant strength gain after only short periods of biochemical reaction (hours to days) with four cycles of microbial injection (~2 days) yielding a maximum compressive strength (UCS) of ~12 MPa and a brittleness index of 0.17 exceeding that of hard coal. Notably, a higher calcium carbonate content does not automatically guarantee a higher strength- indicating that the distribution of the mineralization and the quality of the particle-particle bonding exerts key control. Also, for identical injection volumes, the resulting calcium carbonate content differs significantly with particle size – larger particle size samples can accommodate larger masses of calcium carbonate. Imaging by SEM indicates that precipitation first occurs on the particle surface, partially enveloping it, before creating particle-particle bonds – thus maintaining grain-pore and pore-pore fluid transport connectivity. As the void is occupied, the cementation process slows, halts, as bacteria and nutrient are expended, and further supply is limited. Therefore, for a fixed duration of supply, the interparticle space of the smaller particle-size will be the first to be bonded and the carbonate content of the smaller particle-size samples will be lower than that for larger particles.

Song, J., Qu, B., Li, X., Yuan, H., Li, N., Duan, L., 2018. Carbon sinks/sources in the Yellow and East China Seas—Air-sea interface exchange, dissolution in seawater, and burial in sediments. Science China Earth Sciences 61, 1583-1593.

https://doi.org/10.1007/s11430-017-9213-6

The sinks/sources of carbon in the Yellow Sea (YS) and East China Sea (ECS), which are important continental shelf seas in China, could exert a great influence on coastal ecosystem dynamics and the regional climate change process. The CO2 exchange process across the seawater-air interface, dissolved and particulate carbon in seawater, and carbon burial in sediments were studied to understand the sinks/sources of carbon in the continental shelf seas of China. The YS and the ECS generally have different patterns of seasonal air-sea CO2 exchange. In the YS, regions west of 124°E can absorb CO2 from the atmosphere during spring and winter, and release CO2 to the atmosphere during summer and autumn. The entire YS is considered as a CO2 source throughout the year with respect to the atmosphere, but there are still uncertainties regarding the exact air-sea CO2 exchange flux. Surface temperature and phytoplankton production were the key controlling factors of the air-sea CO2 exchange flux in the offshore region and nearshore region of the YS, respectively. The ECS can absorb CO2 during spring, summer, and winter and release CO2 to the atmosphere during autumn. The annual average exchange rate in the ECS was −4.2±3.2 mmol m−2 d−1 and it served as an obvious sink for atmospheric CO2 with an air-sea exchange flux of 13.7×106 t. The controlling factors of the air-sea CO2 exchange in the ECS varied significantly seasonally. Storage of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) in the YS and the ECS were 425×106 t and 1364×106 t, and 28.2×106 t and 54.1×106 t, respectively. Long-term observation showed that the DOC content in the YS had a decreasing trend, indicating that the “practical carbon sink” in the YS was decreasing. The total amount of particulate organic carbon (POC) stored in the YS and ECS was 10.6×106 t, which was comparable to the air-sea CO2 flux in these two continental shelf seas. The amounts of carbon sequestered by phytoplankton in the YS and the ECS were 60.42×106 t and 153.41×106 t, respectively. Artificial breeding of macroalgae could effectively enhance blue carbon sequestration, which could fix 0.36×106–0.45×106 t of carbon annually. Organic carbon (OC) buried in the sediments of the YS was estimated to be 4.75×106 t, and OC of marine origin was 3.03×106 t, accounting for 5.0% of the TOC fixed by phytoplankton primary production. In the ECS, the corresponding depositional flux of OC in the sediment was estimated to be 7.4×106 t yr−1, and the marine-origin OC was 5.5×106 t, accounting for 5.4% of the phytoplankton primary production. Due

to the relatively high average depositional flux of OC in the sediment, the YS and ECS have considerable potential to store a vast amount of “blue carbon.”

Souayeh, M., Al-Maamari, R.S., Aoudia, M., Karimi, M., Hadji, M., 2018. Experimental investigation of wettability alteration of oil-wet carbonates by a non-ionic surfactant. Energy & Fuels 32, 11222-11233.


Wettability alteration toward a more water-wet state was found to be a promising approach for oil recovery improvement in oil-wet and naturally fractured carbonate reservoirs. This approach has been extensively studied in the literature using low-salinity/smart water and surfactant injection separately. However, application of surfactants in enhanced oil recovery is limited by their compatibility with the conditions of the reservoirs. In this study, polyethoxylated non-ionic surfactants with different ethylene oxide units were combined with low-salinity brine for a more efficient and cost-effective process. The compatibility of the surfactant solutions highly improved by reducing the salinity in the range of 200–2 g/L. Interfacial tension (IFT) measurements revealed that IFT decreased with increasing salinity. Contact angle measurements of calcite surfaces showed that wettability can be altered from a strong oil-wet state to a water-wet state after treatment with solutions of non-ionic surfactants over a wide range of salinities (∼2–110 g/L). ζ potential, Fourier transform infrared spectroscopy, and thermogravimetric analysis revealed that the non-ionic surfactant could partially displace carboxylate compounds from the surface and adsorb by forming a hydrogen bond with the hydroxyl group on the calcite surface. The formation of hydrogen bonds between ethoxy groups of the surfactant and hydroxyl or carboxylic groups on the solid surface can result in the replacement of organic compounds on the calcite surface. The organic compounds could form a new layer on the layer of adsorbed surfactant molecules via hydrophobic interactions. In addition, adsorption of the hydrophobic part of the non-ionic surfactant on the hydrophobic calcite surface and the formation of a surfactant double layer could partially contribute to the wettability alteration process.

Souraki, Y., Hosseini, E., Yaghodous, A., 2019. Wettability alteration of carbonate reservoir rock using amphoteric and cationic surfactants: Experimental investigation. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects 41, 349-359.

https://doi.org/10.1080/15567036.2018.1518353

The objective of this study is to prove that altering the wettability of reservoir rocks by two surfactants (hexadecyl amino benzene sulfonic acid [HABSA] and cationic hexa decyl trimethyl ammonum bromide [CTAB]). Changing the wettability to preferentially water-wet condition will reduce the residual oil saturation (Sor). Because of reducing Sor, the percentage of recovered oil is increased. All surfactants were tested for their ability to alter the wettability of reservoir rocks. This alteration was measured based on the contact angle methods. Results of this study show that both amphoteric HABSA and CTAB surfactants alter the wettability of carbonate rocks from oil-wet to water-wet, while CTAB alters the wettability from oil-wet to water-wet more than HABSA. Also, recovery factor in CTAB injection was more than HABSA injection. Ultimately, the results show that the CTAB surfactant is more effective than HABSA surfactant to alter the wettability and improve oil recovery from carbonate reservoirs.



Sulfuritalea hydrogenivorans sk43H is well recognized as a chemolithoautotrophic microorganism that oxidizes thiosulfate, sulfur or hydrogen. In this study, pathways for aromatic compound degradation were identified in the respective genome and proved for functionality by cultivation. S. hydrogenivorans sk43H harbors gene clusters encoding pathways for the anaerobic degradation of benzoate and phenylacetate via benzoyl-CoA as well as a partial pathway for anaerobic cinnamate degradation. Aerobic hybrid pathways were identified for the degradation of benzoate and 2-aminobenzoate. An aerobic pathway involving mono- and dioxygenases was found for 4-hydroxybenzoate. The organization of the gene clusters for anaerobic aromatic compound degradation in S. hydrogenivorans sk43H was found to be similar to that of the corresponding gene clusters in ‘Aromatoleum aromaticum’ strain EbN1. Cultivation experiments revealed that S. hydrogenivorans sk43H degrades benzoate, 4-hydroxybenzoate, phenylacetate and 4-hydroxyphenylacetate under nitrate-reducing conditions. The results imply a so far overlooked role of this microorganism in anaerobic aromatic compound degradation. Due to the frequent detection of Sulfuritalea-related microorganisms at hydrocarbon-contaminated sites, an involvement of this genus in the degradation of aromatic pollutants should be considered.

Sperfeld, M., Diekert, G., Studenik, S., 2019. Community dynamics in a nitrate-reducing microbial consortium cultivated with p-alkylated vs. non-p-alkylated aromatic compounds. FEMS Microbiology Ecology 95, fiy200-fiy200.


In this study, we established the nitrate-reducing, aromatic compound-degrading enrichment culture pMB18. Its community structure was controlled by the aromatic substrate applied. In the presence of a p-alkylated substrate, microorganisms related to Sulfuritalea, Ignavibacterium and Comamonadaceae were abundant. Non-p-alkylated structural analogues promoted the enrichment of Azoarcus, which was probably favored by the excretion of nitrite. The analysis of the bamA gene, which is a functional marker for anaerobic aromatic compound degradation, as well as a differential abundance analysis suggested the involvement of Sulfuritalea and Comamonadaceae in the degradation of p-alkylated substrates. Members of the genus Azoarcus were assumed to be the key players for the degradation of the non-p-alkylated substrates. A gene cluster encoding a putative 4-methylbenzoyl-CoA reductase, which is supposed to be specific for the dearomatization of p-alkylated benzoyl-CoA intermediates, was detected in culture pMB18 dominated by Sulfuritalea, Ignavibacterium and Comamonadaceae, but not in an Azoarcus-dominated culture. This study allowed insight into a microbial community, whose composition was guided by the aromatic substrate applied.

Spini, G., Spina, F., Poli, A., Blieux, A.-L., Regnier, T., Gramellini, C., Varese, G.C., Puglisi, E., 2018. Molecular and microbiological insights on the enrichment procedures for the isolation of petroleum degrading bacteria and fungi. Frontiers in Microbiology 9, 2543. doi: 10.3389/fmicb.2018.02543.


Autochthonous bioaugmentation, by exploiting the indigenous microorganisms of the contaminated environment to be treated, can represent a successful bioremediation strategy. In this perspective, we have assessed by molecular methods the evolution of bacterial and fungal communities during the selective enrichment on different pollutants of a soil strongly polluted by mixtures of aliphatic and polycyclic hydrocarbons. Three consecutive enrichments were carried out on soil samples from

different soil depths (0–1, 1–2, 2–3 m), and analyzed at each step by means of high-throughput sequencing of bacterial and fungal amplicons biomarkers. At the end of the enrichments, bacterial and fungal contaminants degrading strains were isolated and identified in order to (i) compare the composition of enriched communities by culture-dependent and culture-independent molecular methods and to (ii) obtain a collection of hydrocarbon degrading microorganisms potentially exploitable for soil bioremediation. Molecular results highlighted that for both bacteria and fungi the pollutant had a partial shaping effect on the enriched communities, with paraffin creating distinct enriched bacterial community from oil, and polycyclic aromatic hydrocarbons generally overlapping; interestingly neither the soil depth or the enrichment step had significant effects on the composition of the final enriched communities. Molecular analyses well-agreed with culture-dependent analyses in terms of most abundant microbial genera. A total of 95 bacterial and 94 fungal strains were isolated after selective enrichment procedure on different pollutants. On the whole, isolated bacteria where manly ascribed to Pseudomonas genus followed by Sphingobacterium, Bacillus, Stenothrophomonas, Achromobacter, and Serratia. As for fungi, Fusarium was the most abundant genus followed by Trichoderma and Aspergillus. The species comprising more isolates, such as Pseudomonas putida, Achromobacter xylosoxidans and Ochromobactrum anthropi for bacteria, Fusarium oxysporum and Fusarium solani for fungi, were also the dominant OTUs assessed in Illumina.

Sreenivasan, S.P., Bera, M.K., Samanta, A., Vadlamani, R., 2018. Palaeocene–Eocene carbon isotopic excursion from the shallow-marine-carbonate sequence of northeast India: Implications on the CIE magnitude and geometry. Journal of Earth System Science 127, 105.

https://doi.org/10.1007/s12040-018-1018-0

The exact magnitude of the carbon isotopic excursion (CIE) for the Palaeocene–Eocene Thermal Maximum (PETM) is essential for our understanding of the carbon cycle perturbation. Global compilation of the PETM CIE magnitudes indicates that the shallow-marine inorganic carbonate could be a potential candidate to decipher the actual CIE magnitude. The present study, therefore, made an attempt to explore the thick Palaeogene shallow-marine carbonate sequence of the Sylhet Limestone exposed in the Jaintia Hills of northeast (NE) India, in terms of the preservation and magnitude of the PETM CIE. Exploratory sampling carried out across the Sylhet Limestone suggests that this sequence was deposited during the Late Palaeocene and Early Eocene, as evident from the age-diagnostic foraminifera. The observed ∼3.4 CIE at the top of the Lakadong Limestone, ‱resting above the Miscellanea miscella and Ranikothalia nuttalli foraminifera-bearing horizon, can, therefore, be correlated with the PETM CIE. Although the magnitude of the CIE from our limited data set agrees well with the global compilation, the absence of a stepped profile questions the preservation of the CIE reported elsewhere from the Tethyan sequence. Further work is needed for a better understanding of the PETM interval in NE India.

Steele, A., Benning, L.G., Wirth, R., Siljeström, S., Fries, M.D., Hauri, E., Conrad, P.G., Rogers, K., Eigenbrode, J., Schreiber, A., Needham, A., Wang, J.H., McCubbin, F.M., Kilcoyne, D., Rodriguez Blanco, J.D., 2018. Organic synthesis on Mars by electrochemical reduction of CO2. Science Advances 4, Article eaat5118.

http://advances.sciencemag.org/content/4/10/eaat5118.abstract

The sources and nature of organic carbon on Mars have been a subject of intense research. Steele et al. (2012) showed that 10 martian meteorites contain macromolecular carbon phases contained within pyroxene- and olivine-hosted melt inclusions. Here, we show that martian meteorites Tissint, Nakhla, and NWA 1950 have an inventory of organic carbon species associated with fluid-mineral reactions

that are remarkably consistent with those detected by the Mars Science Laboratory (MSL) mission. We advance the hypothesis that interactions among spinel-group minerals, sulfides, and a brine enable the electrochemical reduction of aqueous CO2 to organic molecules. Although documented here in martian samples, a similar process likely occurs wherever igneous rocks containing spinel-group minerals and/or sulfides encounter brines.

Stoporev, A.S., Sizikov, A.A., Cheshkova, T.V., Loskutova, A.O., Grinko, A.A., Yarkova, E.A., Semenov, A.P., Manakov, A.Y., Vinokurov, V.A., 2018. Influence of fractions isolated from crude oils and refined petroleum product on decomposition process of methane hydrate. Energy & Fuels 32, 11279-11288.


Decomposition of methane hydrate in systems containing asphaltenes, resins, or oils isolated from two types of crude petroleum and transformer oil has been studied. To prepare a sample of methane hydrate suspension in a fraction isolated, a pure hydrate powder with water to hydrate conversion of 0.92 ± 0.08 was used. The hydrate powder with particle size less than 250 μm was mixed with the powdered fractions at the liquid nitrogen temperature. Then the mixture was heated to melt the fractions and allow their components to be adsorbed on the hydrate particles surface. All stages of suspension preparation were carried out in the hydrate stability zone. Similar studies with hydrate particles suspended in saturated/aromatic components and solutions of polar compounds isolated from petroleum/transformer oils as well as in n-decane/toluene were also carried out. As a result, it has been found that fraction of oils as well as its subfraction of saturated hydrocarbons contribute to the manifestation of methane hydrate self-preservation effect. Fourier transform infrared and gas chromatography–mass spectrometry analyses of the fractions showed that the self-preservation took place in systems containing hydrate particles among a mixture of isoalkanes. The data obtained contribute to a comprehensive understanding of the self-preservation phenomenon.

Storey, S., Ashaari, M.M., Clipson, N., Doyle, E., de Menezes, A.B., 2018. Opportunistic bacteria dominate the soil microbiome response to phenanthrene in a microcosm-based study. Frontiers in Microbiology 9, 2815. doi: 10.3389/fmicb.2018.02815.


Bioremediation offers a sustainable approach for removal of polycyclic aromatic hydrocarbons (PAHs) from the environment; however, information regarding the microbial communities involved remains limited. In this study, microbial community dynamics and the abundance of the key gene (PAH-RHDα) encoding a ring hydroxylating dioxygenase involved in PAH degradation were examined during degradation of phenanthrene in a podzolic soil from the site of a former timber treatment facility. The 10,000-fold greater abundance of this gene associated with Gram-positive bacteria found in phenanthrene-amended soil compared to unamended soil indicated the likely role of Gram-positive bacteria in PAH degradation. In contrast, the abundance of the Gram-negative PAHs-RHDα gene was very low throughout the experiment. While phenanthrene induced increases in the abundance of a small number of OTUs from the Actinomycetales and Sphingomonadale, most of the remainder of the community remained stable. A single unclassified OTU from the Micrococcaceae family increased ~20-fold in relative abundance, reaching 32% of the total sequences in amended microcosms on day 7 of the experiment. The relative abundance of this same OTU increased 4.5-fold in unamended soils, and a similar pattern was observed for the second most abundant PAH-responsive OTU, classified into the Sphingomonas genus. Furthermore, the relative abundance of both of these OTUs decreased substantially between days 7 and 17 in the phenanthrene-amended and

control microcosms. This suggests that their opportunistic phenotype, in addition to likely PAH-degrading ability, was determinant in the vigorous growth of dominant PAH-responsive OTUs following phenanthrene amendment. This study provides new information on the temporal response of soil microbial communities to the presence and degradation of a significant environmental pollutant, and as such has the potential to inform the design of PAH bioremediation protocols.

Su, H., Jia, N., Yang, Y., Wang, Z., Jiang, Z., Feng, L., Yang, J., Lv, W., 2018. Micro-pore structure and oil displacement mechanism analysis for deep zone and low permeability reservoir in Mobei oilfield. Petroleum Research 3, 159-164.


The Mobei reservoir is a low-permeability-sandstone reservoir, due to differences in pore geometry, it can be divided into two independent reservoirs: A1 reservoir and A2 reservoir. For better understanding the water flooding development effects of Mobei reservoir, the mercury intrusion porosimetry, water flooding CT scanning and micro-CT scanning experiments are used in this study. The result shows that the reservoir has the strong heterogeneity which is weaken gradually from A1 reservoir to A2 reservoir. Reservoir pore radius is mainly distributed in the 100–200 microns, the throat radius is mainly distributed in the 1–3 micron. The water flooding core experiment in each reservoir shows a short water-free oil production period and rapid water cut after breakthrough. The A2 reservoir core flooding process is similar to piston displacement, the A1 reservoir core flooding process refers to the phenomenon (The fingering phenomenon in the process of core flooding in the A1 reservoir is obvious). The calculated water drive efficiency of the A2 reservoir is 61.2%, which is higher than 49.1% of the A1 reservoir. According to the CT scanning process, the Mobei oilfield has low micro displacement efficiency and the A1 reservoir has a smaller spread (sweep area) and higher residual oil saturation.



Two-dimensional gas hydrate petroleum system modeling was conducted to understand gas hydrate accumulation mechanisms and spatial distribution related to geologic and geochemical processes in the first experimental gas hydrate exploitation region in the Shenhu area of the South China Sea. Based on the gas production in core samples, a new biogenic methane generation model was created and incorporated into a kinetic model. With the results of a rock pyrolysis experiment, a thermogenic gas kinetic model for deep formations in the study area was also developed. The entire dynamic evolution process from gas generation to migration and gas hydrate formation and accumulation in the perspective area was simulated with the petroleum system modeling method. The results showed that the gas hydrate stability zone (GHSZ) began to form after 3.88 Ma, and its thickness was greatest when the paleowater depth peaked at 3.66 Ma. The mass of thermogenic gas generation in deep formations is large, and that of biogenic gas in shallow formations is relatively small. Formations that overlap the gas hydrate bearing layers act as cap rocks that prevent the gas from migrating vertically to shallow layers. There was a geological time gap between thermogenic gas generation, migration and GHSZ formation. However, the timing of biogenic gas generation, which is typically of recent generation in the shallow layer, matched well with the formation of the GHSZ. Finally, coupling of the age and space of gas migration and GHSZ formation has allowed gas hydrate accumulation at structural highs in the Shenhu area. The evaluation technique of petroleum system modeling is of

great significance for the improvement of gas hydrate exploration in frontier areas in the future, particularly where survey data are limited.

Sugai, Y., Owaki, Y., Sasaki, K., Kaneko, F., Sakai, T., 2018. Numerical modelling of the growth of sulfate-reducing bacteria indigenous to an oilfield in Japan. Petroleum Science and Technology 36, 1597-1604.

https://doi.org/10.1080/10916466.2018.1496102

We performed kinetic studies of the growth of sulfate-reducing bacteria (SRB) indigenous to the water in an oilfield in Japan. The SRB growth was most active in injection water supplemented with ethanol; therefore, the SRB inhabiting the injection water of the reservoir were assumed to grow predominantly by assimilating sulfate and ethanol and generating H2S. Based on this mechanism and the results of incubation experiments in the injection water, we derived numerical models that calculate the growth rate and H2S generation of the SRB under three variables (temperature, sulfate concentration, and ethanol concentration).

Sui, Y., Huang, C., Zhang, R., Wang, Z., Ogg, J., Kemp, D.B., 2018. Astronomical time scale for the lower Doushantuo Formation of early Ediacaran, South China. Science Bulletin 63, 1485-1494.


Nearly 90% of the Ediacaran Period (635–541 Ma) of the Neoproterozoic is represented by the Doushantuo Formation (DST Fm) in South China. Its lowest Member I is a 3.7 m-thick cap carbonate deposited at the termination of the Cryogenian Marinoan glaciation. The DST Fm consists of alternating organic-rich black shale and thinly bedded dolostone, and it contains some of the oldest records of multi-cellular life and three pronounced negative carbon isotope excursions. The Jiulongwan (JLW) section is a well-studied reference section for these Ediacaran events. Spectral analysis of geochemical data through the lower DST Fm (22.3 m) shows 27 predominant ∼90 cm sedimentary cycles that correspond to 405-ka long eccentricity cycles. The power spectra of the 405-ka tuned Ca and Fe/Ti series show significant peaks at ∼1.2-Ma, 405-ka, 133-ka, 128-ka, 100-ka, 82-ka, ∼31-ka and 29-ka periods, respectively. A 11.16 Ma-long astronomical time scale has been constructed for the lower DST Fm and provide a duration of 1.6 Ma for the cap carbonate (Member I) based on the 405-ka long eccentricity cycle tuning. Using the U-Pb age of 635.2 ± 0.6 Ma for the volcanic ash bed at the Member I/II boundary, we proposed a 636.8 Ma age for the base of the DST Fm. These ages and astronomical timescale provide important new constraints on the subdivision of Ediacaran strata, and have implications for understanding the character of the first negative δ13C excursion (EN1). Orbital forcing may have been played an important role for the climate changes and the evolution of Ediacaran multi-cellular life and the carbon cycle variations.

Šuklje, K., Carlin, S., Stanstrup, J., Antalick, G., Blackman, J.W., Meeks, C., Deloire, A., Schmidtke, L.M., Vrhovsek, U., 2019. Unravelling wine volatile evolution during Shiraz grape ripening by untargeted HS-SPME-GC×GC-TOFMS. Food Chemistry 277, 753-765.


The influence of grape maturity on wine volatome was investigated using HS-SPME-GC×GC-TOFMS. Shiraz wines were made from grapes harvested from four different vineyards from two berry maturity levels. A total of 1,276 putative compounds were detected in at least one of the wine

samples and 175 showed significant trends related to grape maturity. The first two dimensions of the Principal component analysis accounted for 57% of the variation and separated the samples according to the harvest date. Wines from the first harvest date were characterised by an abundance of lipoxygenase derived compounds, norisoprenoids and sulfur-containing compounds whereas a significant increase in some acetate esters was observed in wines produced from the more mature grapes.

This study demonstrated a common evolution of grape volatiles for Shiraz inside the same mesoclimate. During the late ripening stage of the grape, a direct nexus between sugar concentration and wine volatile evolution was not observed.

Sulpis, O., Boudreau, B.P., Mucci, A., Jenkins, C., Trossman, D.S., Arbic, B.K., Key, R.M., 2018. Current CaCO3 dissolution at the seafloor caused by anthropogenic CO2. Proceedings of the National Academy of Sciences 115, 11700-11705.


Significance: The geological record contains numerous examples of “greenhouse periods” and ocean acidification episodes, where the spreading of corrosive (CO2-enriched) bottom waters enhances the dissolution of CaCO3 minerals delivered to the seafloor or contained within deep-sea sediments. The dissolution of sedimentary CaCO3 neutralizes excess CO2, thus preventing runaway acidification, and acts as a negative-feedback mechanism in regulating atmospheric CO2 levels over timescales of centuries to millennia. We report an observation-based indication and quantification of significant CaCO3 dissolution at the seafloor caused by man-made CO2. This dissolution is already occurring at various locations in the deep ocean, particularly in the northern Atlantic and near the Southern Ocean, where the bottom waters are young and rich in anthropogenic CO2.

Abstract: Oceanic uptake of anthropogenic CO2 leads to decreased pH, carbonate ion concentration, and saturation state with respect to CaCO3 minerals, causing increased dissolution of these minerals at the deep seafloor. This additional dissolution will figure prominently in the neutralization of man-made CO2. However, there has been no concerted assessment of the current extent of anthropogenic CaCO3 dissolution at the deep seafloor. Here, recent databases of bottom-water chemistry, benthic currents, and CaCO3 content of deep-sea sediments are combined with a rate model to derive the global distribution of benthic calcite dissolution rates and obtain primary confirmation of an anthropogenic component. By comparing preindustrial with present-day rates, we determine that significant anthropogenic dissolution now occurs in the western North Atlantic, amounting to 40–100% of the total seafloor dissolution at its most intense locations. At these locations, the calcite compensation depth has risen ∼300 m. Increased benthic dissolution was also revealed at various hot spots in the southern extent of the Atlantic, Indian, and Pacific Oceans. Our findings place constraints on future predictions of ocean acidification, are consequential to the fate of benthic calcifiers, and indicate that a by-product of human activities is currently altering the geological record of the deep sea.

Suma, M.S., Basheer, R., Sreelekshmy, B.R., Vipinlal, V., Sha, M.A., Jineesh, P., Krishnan, A., Archana, S.R., Saji, V.S., Shibli, S.M.A., 2019. Pseudomonas putida RSS biopassivation of mild steel for long term corrosion inhibition. International Biodeterioration & Biodegradation 137, 59-67.


It is critical to develop highly tolerant, durable and efficient microbial corrosion inhibition methods for mild steel when use of chemical inhibitors is not feasible. Here, we developed a novel, long-lasting and commercially viable bacterial mediated corrosion inhibitive/biopassivating system for mild steel by employing Pseudomonas putida (P. putida) RSS biofilm. Enhancement in surface biopassivation was achieved by enhancing the biofilm formation in P. putida RSS culture when supplemented with 2.5% each of sucrose and potassium nitrate for a period of 96 h. The corrosion rate of mild steel could be decreased by 28 – fold when immersed in the optimized system in comparison to the control. This is due to the formation of a strong and stable iron-extracellular polymeric substance (Fe-EPS) coating over the concrete bacterial phosphate layer. The developed biofilm remained adhered on the surface of the mild steel surface even after the death of bacterial cells, and it conferred further protection. The corrosion resistance of mild steel surface after mechanically removing biofilm was also investigated. Results of electrochemical studies showed no traces of corrosion even after 12 months of immersion with negligible corrosion rate of 3.01 × 10−2 mmpy. The developed surface biopassivation system can be employed for long term corrosion inhibition of steel structures in aquatic systems.



Organic matter export from the euphotic zone is a key component of oceanic carbon (C) and nitrogen (N) cycles. Although interactions between these two cycles are important, studies on geochemical processes to directly connect them are limited. Here we show that sunlight can induce chemical aggregation of dissolved organic matter (DOM) into high N containing photo-aggregates. The size of microgels in natural coastal seawaters increased by18~25% compared to corresponding dark controls. Within a relatively short time (1 h), the C and N sequestered into the photo-aggregates accounted for 10% and 13% of the bulk particulate C and N, respectively. The N/C ratio of the photo-aggregates was two times higher after sunlight irradiation. Furthermore, we show that the aggregation process was dependent on reactive oxygen species (ROS). To accommodate for the different organic material in the marine environment, we monitored the particle size in various extracellular polymeric substances (EPS) and model biopolymers using flow cytometry, dynamic laser scattering, and scanning electron microscopy. We found that proteins play important roles in light-induced aggregation, which is in contrast to previous views that sunlight can break down DOM and interrupt aggregation. The photo-flocculation process involving organic N provides new insights into DOM assembly, bioavailability, and sedimentation, and thus potentially link the C and N cycles.

Sun, Q., Lian, B., 2019. The different roles of Aspergillus nidulans carbonic anhydrases in wollastonite weathering accompanied by carbonation. Geochimica et Cosmochimica Acta 244, 437-450.


The microbial weathering of silicate minerals is an important part of the elemental biogeochemical cycle on Earth. It can even affect the migration and transformation of carbon, a process in which microbial carbonic anhydrase (CA) plays an important role. However, whether multiple microbial CAs are involved in silicate weathering and carbonation is still poorly understood. In this work, gene deletion, overexpression, and bioinformatics were used to reveal the functional differences that two Aspergillus nidulans CA genes, canA and canB, have in wollastonite weathering. The results show that canA is involved in silicate weathering and can be accompanied by carbonation. However, canB

is indispensable for the survival of A. nidulans in present ambient conditions (c. 0.04% CO2, v/v), where it is mainly obligated to cellular respiration and biosynthesis. This study highlights the contribution of microbial CAs to regulating the atmospheric CO2 cycle through silicate mineral bio-weathering. It also presents a potential application of sequestration of CO2 via biochemical weathering.

Sun, W., Xiao, E., Häggblom, M., Krumins, V., Dong, Y., Sun, X., Li, F., Wang, Q., Li, B., Yan, B., 2018. Bacterial survival strategies in an alkaline tailing site and the physiological mechanisms of dominant phylotypes as revealed by metagenomic analyses. Environmental Science & Technology 52, 13370-13380.


Microorganisms inhabiting mine tailings require specific metabolic strategies to survive, which may hold potential for pollution clean up. Effective in situ bioremediation will rely on an in-depth understanding of the function of the bacterial communities, especially the abundant and metabolically active phylotypes. In this study, the bacterial communities collected from an alkaline tailing site were profiled by 16S rRNA gene amplicon sequencing as well as shotgun metagenomic analysis. Our results indicated that potentials for carbon and nitrogen fixation as well as metal resistance and transformation were widespread among the bacterial community members, especially in highly enriched phylotypes, such as members of Thiobacillus and Meiothermus. Important functional microbial guilds including carbon and nitrogen fixers may contribute to phytoremediation by providing nutrients for hyperaccumulator plants. In addition, metal-metabolizing bacteria may influence metal speciation and solubility. This discovery provides an understanding for microbial survival strategies in the tailings and lays the foundation for future potential manipulation of the tailing microbiome for in situ bioremediation.



The pore structure and fractal characteristics of the Lower Cambrian Niutitang formation shale in northern Guizhou were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD) observations and nuclear magnetic resonance (NMR). The relationships between mineral compositions, total organic carbon (TOC), porosity, permeability and NMR fractal dimensions of shale samples were discussed, and the properties of organic pores and organic matter were quantitatively analyzed by pore extraction based on SEM images. The shale pore distribution is irregular and complex, with multifractal and anisotropic characteristics. Fractal characteristics of shale samples were studied by NMR and apply to analyze the lithology and physical properties. Db and Dm represent fractal characteristics of bound fluid and movable fluid pore respectively. The quartz content is the negative correlation with Db and positive correlation with Dm. The clay content is the negative correlation with Db and positive correlation with Dm, and the feldspar content is the positive correlation with Db and negative correlation with Dm, whereas TOC content has no correlation with Db but is the negative correlation with Dm. The relationship between feldspar content and fractal dimension depends on the chemical reaction process in the diagenetic stage. Db has no obvious relationship with porosity and permeability, and Dm has negative correlation with porosity and positive correlation with permeability. The fractal dimension Db represents the roughness and complexity of adsorption pores surface. The fractal dimensions Dm represents the roughness and

complexity of seepage pores surface. The fractal analysis provides a novel idea for the study of shale reservoir properties and lithology.



In this work, we investigated heavy oil/brine systems on oil-wet sandstone surfaces to quantify the performance of hybrid nanofluids (HNFs) for wettability alteration. In the first step, nanofluid stability analysis was conducted to screen effective single nanoparticles for formulating HNFs and ensure that the properties of the formulated HNFs did not change during the experiments. Then, the ability of HNFs to change the wettability of oil-wet sandstone surfaces to a water-wet state was systematically examined and compared with five types of single nanofluids by contact angle measurements. Then, the effects of HNF composition, hybrid nanoparticle concentration, salinity, and exposure time on the wettability change of sandstones were investigated. Finally, the mechanisms for the wettability shift by HNFs were proposed and verified by scanning electron microscopy visualizations. The results showed that the SiO2 + Al2O3, SiO2 + TiO2, and Al2O3 + TiO2 nanofluids could maintain their stability in the harsh reservoir conditions and that they efficiently induced the wettability change of oil-wet sandstone surfaces to a strongly water-wet state under all operational conditions. The SiO2 + Al2O3 nanofluid achieved the highest wettability alteration efficiency (from 156° to 21° at 0.1 wt % HNF). The efficiency was improved by adding a nonionic surfactant and increasing the hybrid nanoparticle concentration, salinity, and exposure time. However, beyond a certain value, the efficiency slightly decreased due to the instability of the HNFs. Two adsorption kinetics models were applied to predict the measured contact angles at different concentrations and exposure times with good agreement. The stronger adsorption of hybrid nanoparticles on sandstone surfaces was considered to be the underlying mechanism for the higher efficiency of HNFs for the wettability shift than that of single nanofluids.

Sun, X., Zhang, Y., Gai, Z., Zhao, H., Chen, G., Song, Z., 2019. Comprehensive experimental study of the interfacial stability of foamy oil and identification of the characteristic responsible for foamy oil formation. Fuel 238, 514-525.


Solution gas drive from some heavy oil reservoirs exhibits foamy oil behavior. However, the characteristics of oil that determine whether foamy oil behavior occurs have not been clarified. Therefore, we performed a comprehensive experimental study of gas-oil interfacial properties to provide more in-depth information about foamy oil formation. A new experimental setup for single film stability was designed to investigate the gas-oil interfacial stability and its influencing factors under reservoir conditions. Then, a series of micromodel experiments was conducted in high-pressure etched glass micromodels with foamy and nonfoamy oils to visually study the oil-gas interfacial stability in porous media. Finally, chemical characterization (acid and base number measurements, elemental analyses, nuclear magnetic resonance (NMR), and Fourier transformed infrared spectroscopy (FTIR)) was conducted to reveal the characteristic of foamy oil related to foamy oil formation. The results showed that the gas-oil interfacial stability increased at high oil component concentrations, small interfacial areas, and low temperatures. CO2-oil films exhibited higher gas-oil interfacial stability than N2 and mixed gas (90 mol% CH4 and 10 mol% CO2) for both foamy and nonfoamy oils. A pressure at which the interfacial stability was minimized was observed. In addition,

the gas-oil interface of foamy oil was much more stable than that of nonfoamy oil because the asphaltenes from foamy oil contain a greater number of polar functional groups (hydroxyl groups, carboxylic groups, amine, and heterocyclic rings), which adsorb at the oil-gas interface and increase stability. Therefore, a high asphaltene concentration with abundant polar functional groups could be the characteristic of oils responsible for foamy oil formation.

Sun, Y.-Y., Zhang, S.-Y., Yang, Z.-P., Sang, G.-Q., Li, T., Li, Y.-C., 2018. Laboratory simulation and CO2 flooding efficiency of oil-water transition zones in a low permeability reservoir in the Jilin Oilfield. Petroleum Research 3, 283-287.


Geological reserves of oil-water transition zone (OWTZ) in low-permeability reservoirs have been considered as uneconomical resources because of high water cut and low abundance. Though the OWTZ may account for 30 %–50% of a reservoir, it has not been paid more attentions yet. The average oil saturation of the OWTZ is about 35%, which is equal to that of a reservoir after water flooding. Currently, CO2 flooding is an effective technique for residual oil recovery after water flooding, which could reduce the residual oil saturation greatly. Therefore, it is of significance for the EOR of the low-permeability reservoir if the CO2 flooding could be successfully applied in the OWTZ. In this study, a method based on a long core to simulate distribution of oil saturation in OWTZs is set up in the laboratory using bidirectional saturation. In order to investigate CO2 flooding characteristics in OWTZs, experiments are carried out on 3 sets of initial oil saturation, and the recoverable reserves of the OWTZ and its contribution to the EOR are calculated based on the WJ reservoir in the Jilin Oilfield, China.



High-field asymmetric waveform ion mobility spectrometry (FAIMS) was coupled to a high-resolution Orbitrap mass spectrometer (MS) with a heated electrospray ionization (HESI) source for the analysis of crude oil and respective saturate, aromatic, and resin fractions. Four classes of compounds N1, N1S1, O1S1, and O2S1 were investigated using FAIMS one-dimensional compensation field scans from −3 to 5 Td for the crude oil and FAIMS static scans from 0.5 to 2.5 Td with 0.5 Td increments for fractions. In all cases, the incorporation of FAIMS into the analysis resulted in an increased number of detected peaks for both the crude oil and fractions. The most significant change was noticed in the aromatic fraction, with an increase of 218% for N1 and up to 514% for the O2S1 class of compounds observed. In addition, pre-analytical fractionation combined with FAIMS–MS enabled a higher number of molecular features to be observed in comparison to whole oil for three classes of compounds N1, O1S1, and O2S1 by 19, 45, and 83%, respectively.

Tabzar, A., Fathinasab, M., Salehi, A., Bahrami, B., Mohammadi, A.H., 2018. Multiphase flow modeling of asphaltene precipitation and deposition. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles 73, Article 51.


Asphaltene precipitation in reservoirs during production and Enhanced Oil Recovery (EOR) can cause serious problems that lead to reduction of reservoir fluid production. In order to study asphaltene tendency to precipitate and change in flow rate as a function of distance from wellbore, an equation of state (Peng-Robinson) based model namely Nghiem et al.’s model has been employed in this study. The heaviest components of crude oil are separated into two parts: The first portion is considered as non-precipitating component (C31A+) and the second one is considered as precipitating component (C31B+) and the precipitated asphaltene is considered as pure solid. For determination of the acentric factor and critical properties, Lee-Kesler and Twu correlations are employed, respectively. In this study, a multiphase flow (oil, gas and asphaltene) model for an asphaltenic crude oil for which asphaltene is considered as solid particles (precipitated, flocculated and deposited particles), has been developed. Furthermore, effect of asphaltene precipitation on porosity and permeability reduction has been studied. Results of this study indicate that asphaltene tendency to precipitate increases and permeability of porous medium decreases by increasing oil flow rate in under-saturated oil reservoirs and dropping reservoir pressure under bubble point pressure. On the other hand, asphaltene tendency to precipitate decreases with pressure reduction to a level lower than bubble point pressure where asphaltene starts to dissolve back into oil phase. Moreover, it is observed that precipitation zone around the wellbore develops with time as pressure declines to bubble point pressure (production rate increases up). Also, there is an equilibrium area near wellbore region at which reservoir fluid properties such as UAOP (Upper Asphaltene Onset Pressure) and LAOP (Lower Asphaltene Onset Pressure) are constant and independent of the distance from wellbore.

Tanaka, K., Yokoe, S., Igarashi, K., Takashino, M., Ishikawa, M., Hori, K., Nakanishi, S., Kato, S., 2018. Extracellular electron transfer via outer membrane cytochromes in a methanotrophic bacterium Methylococcus capsulatus (Bath). Frontiers in Microbiology 9, 2905. doi: 10.3389/fmicb.2018.02905.


ectron exchange reactions between microbial cells and solid materials, referred to as extracellular electron transfer (EET), have attracted attention in the fields of microbial physiology, microbial ecology, and biotechnology. Studies of model species of iron-reducing, or equivalently, current-generating bacteria such as Geobacter spp. and Shewanella spp. have revealed that redox-active proteins, especially outer membrane c-type cytochromes (OMCs), play a pivotal role in the EET process. Recent (meta)genomic analyses have revealed that diverse microorganisms that have not been demonstrated to have EET ability also harbor OMC-like proteins, indicating that EET via OMCs could be more widely preserved in microorganisms than originally thought. A methanotrophic bacterium Methylococcus capsulatus (Bath) was reported to harbor multiple OMC genes whose expression is elevated by Cu starvation. However, the physiological role of these genes is unknown. Therefore, in this study, we explored whether M. capsulatus (Bath) displays EET abilities via OMCs. In electrochemical analysis, M. capsulatus (Bath) generated anodic current only when electron donors such as formate were available, and could reduce insoluble iron oxides in the presence of electron donor compounds. Furthermore, the current-generating and iron-reducing activities of M. capsulatus (Bath) cells that were cultured in a Cu-deficient medium, which promotes high levels of OMC expression, were higher than those cultured in a Cu-supplemented medium. Anodic current production by the Cu-deficient cells was significantly suppressed by disruption of MCA0421, a highly expressed OMC gene, and by treatment with carbon monoxide (CO) gas (an inhibitor of c-type cytochromes). Our results provide evidence of EET in M. capsulatus (Bath) and demonstrate the pivotal role of OMCs in this process. This study raises the possibility that EET to solid compounds is a novel survival strategy of methanotrophic bacteria.

Tang, H.L., Tang, L., Xie, Y.F., 2018. Aerated electrolysis for reducing impacts of shale gas production wastewater on water sources regarding disinfection byproduct formation. Environmental Science & Technology Letters 5, 681-686.

https://doi.org/10.1021/acs.estlett.8b00482

Advances in treatment technologies of shale gas production wastewater are needed to minimize its toxic potency in polluted water sources. An aerated electrolysis (AE) process was employed for treatment of both synthetic and field production wastewaters. Results showed AE led to a 64% reduction in the formation of total disinfection byproducts (DBPs) analyzed in this study and 79% reduction in the formation of more toxic brominated DBPs (Br-DBPs) in polluted natural water in an 8-h treatment, suggesting a potential of scaling up as an in situ pretreatment strategy to reduce negative impacts caused by accidental spills or surface discharges during transportation. The mechanisms for reduced formation of DBPs were associated with bromide oxidation followed by bromine stripping from production wastewater, as evidenced by first-order kinetics on bromide removal. Along with bromide removal that led to the reduction of Br-DBP formation and decreased bromine substitution factors (BSFs), the results also revealed alteration of organic DBP precursors during the AE process by exploring the profile of formed DBP species. Formation of bromate in production wastewater was minimal, as bromate was consistently found below a reporting limit of 500 μg/L during the 8-h AE treatment. The lowest energy consumption at 5.9 kWh/m3 warrants further investigations on process optimization. Application of this technology on site of shale gas exploration is beneficial for water utilities that are facing challenges due to contamination of water sources by production wastewater and inability of conventional water treatment processes in attenuation of DBP precursors.

Tang, X., 2019. Surface thermodynamics of hydrocarbon vapors and carbon dioxide adsorption on shales. Fuel 238, 402-411.


Understanding hydrocarbon vapors and carbon dioxide adsorption mechanism on shales lays the foundation for in situ hydrocarbon resource estimation and enhanced hydrocarbon recovery via carbon dioxide injection. However, surface thermodynamic potentials of hydrocarbon vapor and carbon dioxide adsorption on shales have rarely been reported. This work develops a rigorous framework for direct description of hydrocarbon vapors and carbon dioxide adsorption isotherms on shales and for straightforward calculation of the intrinsic thermodynamic potentials by considering non-ideal gas behavior. On the basis of the Langmuir adsorption model, the maximum adsorption capacity of methane, ethane, propane, n-butane, iso-butane and carbon dioxide adsorption on shales positively correlates to each gas’ molecular mass. Carbon dioxide adsorption capacity is higher than methane and ethane but is lower than propane, n-butane and iso-butane. According to the generalized multilayer adsorption model, the monolayer adsorption capacity of n-hexane is slightly higher than that of n-heptane due to the small molecular diameter of n-hexane. The temperature-dependent behavior of isosteric enthalpy and entropy for these vapors is attributed to their non-ideal gas behavior and the temperature-dependent adsorption uptakes. Isosteric enthalpy and entropy in general positively correlate to the molecular mass of vapors. Isosteric enthalpy and entropy of carbon dioxide and propane are almost identical in behavior given that their molecular masses are very close. Isosteric enthalpy and entropy of iso-butane are lower than that of n-butane due to their molecule polarity difference. The shale selectivity of propane, n-butane and iso-butane is higher than carbon dioxide while the shale selectivity of methane and ethane is lower than carbon dioxide. These surface thermodynamic characteristics therefore provide new perspectives on understanding the interaction of

hydrocarbon vapors/carbon dioxide and shales for enhanced hydrocarbon recovery via carbon dioxide injection.

Tang, X., Jiang, S., Jiang, Z., Li, Z., He, Z., Long, S., Zhu, D., 2019. Heterogeneity of Paleozoic Wufeng-Longmaxi formation shale and its effects on the shale gas accumulation in the Upper Yangtze Region, China. Fuel 239, 387-402.


Shale gas as an unconventional gas has made a significant impact on worldwide energy supply. The heterogeneity of the shale reservoir has a dramatic effect on the shale gas accumulation. The heterogeneity characterization of the Paleozoic Wufeng-Longmaxi Formation Shale in the Upper Yangtze Region is studied within a sequence stratigraphic framework by testing in situ gas content, organic matter, minerals, porosity, permeability, and the observation and description of core and thin sections, and data statistics. Results show that the shelf depocenter has higher porosity than the shelf margin and the permeability is obviously lower at the transitional zone compared to neighboring areas. The most obvious characteristic of organic matter and mineral composition is that the TOC and quartz content at the lower section of the formation deposited during transgressive systems tract is higher than that at the upper section of the formation deposited during highstand systems tract throughout the whole deposition zone. The laminae are primarily developed at the upper section of the formation. The natural fracture is mainly developed at the Qiyueshan fault zone and the Xuefeng Mountain fault zone. The primary controlling factors of shale gas accumulation are organic matter and porosity. The transgressive systems tracts with high organic matter content and porosity at the lower section of the formation are more favorable for gas accumulation. The shale gas resources and exploration potential are mainly concentrated in the shelf depocenter.

Terrett, O.M., Dupree, P., 2019. Covalent interactions between lignin and hemicelluloses in plant secondary cell walls. Current Opinion in Biotechnology 56, 97-104.


The plant secondary cell wall is a complex structure composed of polysaccharides and lignin, and is a key evolutionary innovation of vascular land plants. Although cell wall composition is well understood, the cross-linking of the different polymers is only now yielding to investigation. Cross-linking between hemicelluloses and lignin occurs via two different mechanisms: incorporation into lignin by radical coupling of ferulate substitutions on xylan in commelinid monocots, and incorporation of hemicellulosic glycosyl residues by re-aromatisation of lignification intermediates. Recent genetic evidence indicates that hemicellulose:lignin cross-linking has a substantial impact on plant cell wall recalcitrance. Engineering plant biomass with modified frequencies of cross-links will have significant impacts on biomass utilisation.

Testamanti, M.N., Rezaee, R., 2019. Considerations for the acquisition and inversion of NMR T2 data in shales. Journal of Petroleum Science and Engineering 174, 177-188.


Low-field Nuclear Magnetic Resonance (NMR) is a non-invasive method widely used in the petroleum industry for the evaluation of reservoirs. Pore structure and fluid properties can be evaluated from transverse relaxation (T2) distributions, obtained by inverting the raw NMR signal measured at subsurface conditions or in the laboratory. This paper aims to cast some light into the

best practices for the T2 data acquisition and inversion in shales, with a focus on the suitability of different inversion methods. For this purpose, the sensitivity to various signal acquisition parameters was evaluated from T2 experiments using a real shale core plug. Then, four of the most common inversion methods were tested on synthetic T2 decays, simulating components often associated with shales, and their performance was evaluated. These inversion algorithms were finally applied to real T2 data from laboratory NMR measurements in brine-saturated shale samples. Methods using a unique regularization parameter were found to produce solutions with a good balance between the level of misfit and bias, but could not resolve adjacent fast T2 components. In contrast, methods applying variable regularization – based on the noise level of the data – returned T2 distributions with better accuracy at short times, in exchange of larger bias in the overall solution. When it comes to reproducing individual T2 components characteristic of shales, the Butler-Reeds-Dawson (BRD) algorithm was found to have the best performance. In addition, our findings suggest that threshold T2 cut-offs may be derived analytically, upon visual inspection of the T2 distributions obtained by two different NMR inversion methods.

ThomasArrigo, L.K., Byrne, J.M., Kappler, A., Kretzschmar, R., 2018. Impact of organic matter on iron(II)-catalyzed mineral transformations in ferrihydrite–organic matter coprecipitates. Environmental Science & Technology 52, 12316-12326.


Poorly crystalline Fe(III) (oxyhydr)oxides like ferrihydrite are abundant in soils and sediments and are often associated with organic matter (OM) in the form of mineral-organic aggregates. Under anoxic conditions, interactions between aqueous Fe(II) and ferrihydrite lead to the formation of crystalline secondary minerals, like lepidocrocite, goethite, or magnetite. However, the extent to which Fe(II)-catalyzed mineral transformations are influenced by ferrihydrite-associated OM is not well understood. We therefore reacted ferrihydrite-PGA coprecipitates (PGA = polygalacturonic acid, C:Fe molar ratios = 0–2.5) and natural Fe-rich organic flocs (C:Fe molar ratio = 2.2) with 0.5–5.0 mM isotopically labeled 57Fe(II) at pH 7 for 5 weeks. Relying on the combination of stable Fe isotope tracers, a novel application of the PONKCS method to Rietveld fitting of X-ray diffraction (XRD) patterns, and 57Fe Mössbauer spectroscopy, we sought to follow the temporal evolution in Fe mineralogy and elucidate the fate of adsorbed 57Fe(II). At low C:Fe molar ratios (0–0.05), rapid oxidation of surface-adsorbed 57Fe(II) resulted in 57Fe-enriched crystalline minerals and nearly complete mineral transformation within days. With increasing OM content, the atom exchange between the added aqueous 57Fe(II) and Fe in the organic-rich solids still occurred; however, XRD analysis showed that crystalline mineral precipitation was strongly inhibited. For high OM-content materials (C:Fe ≥ 1.2), Mössbauer spectroscopy revealed up to 39% lepidocrocite in the final Fe(II)-reacted samples. Because lepidocrocite was not detectable by XRD, we suggest that the Mössbauer-detected lepidocrocite consisted of nanosized clusters with lepidocrocite-like local structure, similar to the lepidocrocite found in natural flocs. Collectively, our results demonstrate that the C content of ferrihydrite–OM coprecipitates strongly impacts the degree and pathways of Fe mineral transformations and iron atom exchange during reactions with aqueous Fe(II).

Thorhaug, A.L., Poulos, H.M., López-Portillo, J., Barr, J., Lara-Domínguez, A.L., Ku, T.C., Berlyn, G.P., 2019. Gulf of Mexico estuarine blue carbon stock, extent and flux: Mangroves, marshes, and seagrasses: A North American hotspot. Science of The Total Environment 653, 1253-1261.


The Gulf of Mexico blue carbon habitats (mangroves, seagrass, and salt marshes) form an important North American blue carbon hot spot. These habitats cover 2,161,446 ha and grow profusely in estuaries that occupy 38,000 km2 to store substantial sedimentary organic carbon of 480.48 Tg C. New investigations around GoM for Mexican mangroves, Louisiana salt marshes and seagrasses motivated our integration of buried organic carbon to elucidate a new estimate of GoM blue carbon stocks. Factors creating this include: large GoM watersheds enriching carbon slowly flowing through shallow estuarine habitats with long residence times; fewer SE Mexican hurricanes allowing enhanced carbon storage; mangrove carbon productivity enhanced by warm southern basin winter temperatures; large Preservation reserves amongst high anthropogenic development. The dominant total GoM mangrove blue carbon stock 196.88 Tg from total mangrove extent 650,482 ha is highlighted from new Mexican data. Mexican mangrove organic carbon stock is 112.74 Tg (1st sediment meter) plus USA 84.14 Tg. Mexican mangroves vary greatly in storage, total carbon depositional depths and in sediment age (to 3500 y). We report Mexican mangrove's conservative storage fraction for the normally-compared top meter, whereas the full storage depth estimates ranging above 366.78 Tg (high productivity in very deep sediment along the central Veracruz/Tabasco coast) are not reflected in our reported estimates. Seagrasses stock of 184.1 Tg C organic is derived from 972,327 ha areal extent (in 1st meter). The Louisiana marshes form the heart of GoM salt marsh carbon storage 99.5 Tg (in 1st meter), followed by lesser stocks in Florida, Texas, finally Mexico derived from salt marsh extent totaling 650,482 ha. Constraints on the partial estuarine fluxes given for this new data are discussed as well as widespread anthropogenic destruction of the GoM blue carbon. A new North American comparison of our GoM blue carbon stocks versus Atlantic coastal blue carbon stock estimates is presented.

Thume, K., Gebser, B., Chen, L., Meyer, N., Kieber, D.J., Pohnert, G., 2018. The metabolite dimethylsulfoxonium propionate extends the marine organosulfur cycle. Nature 563, 412-415.

https://doi.org/10.1038/s41586-018-0675-0

Algae produce massive amounts of dimethylsulfoniopropionate (DMSP), which fuel the organosulfur cycle. On a global scale, several petagrams of this sulfur species are produced annually, thereby driving fundamental processes and the marine food web. An important DMSP transformation product is dimethylsulfide, which can be either emitted to the atmosphere or oxidized to dimethylsulfoxide (DMSO) and other products. Here we report the discovery of a structurally unusual metabolite, dimethylsulfoxonium propionate (DMSOP), that is synthesized by several DMSP-producing microalgae and marine bacteria. As with DMSP, DMSOP is a low-molecular-weight zwitterionic metabolite that carries both a positively and a negatively charged functional group. Isotope labelling studies demonstrate that DMSOP is produced from DMSP, and is readily metabolized to DMSO by marine bacteria. DMSOP was found in near nanomolar amounts in field samples and in algal culture media, and thus represents—to our knowledge—a previously undescribed biogenic source for DMSO in the marine environment. The estimated annual oceanic production of oxidized sulfur from this pathway is in the teragram range, similar to the calculated dimethylsulfide flux to the atmosphere. This sulfoxonium metabolite is therefore a key metabolite of a previously undescribed pathway in the marine sulfur cycle. These findings highlight the importance of DMSOP in the marine organosulfur cycle.

Todd, S.E., Pufahl, P.K., Murphy, J.B., Taylor, K.G., 2019. Sedimentology and oceanography of Early Ordovician ironstone, Bell Island, Newfoundland: Ferruginous seawater and upwelling in the Rheic Ocean. Sedimentary Geology 379, 1-15.


The Bell Island and Wabana groups together comprise a ca. 150-m-thick succession of interbedded clastic and chemical sedimentary rocks composed of eight distinct lithofacies that accumulated along the northern margin of the Rheic Ocean. Lithofacies stacking patterns indicate that deposition occurred during a marine transgression with superimposed small-scale sea level fluctuations producing at least six parasequences. Parasequences containing ironstone are 10 to 20-m-thick and composed of hummocky cross-stratified sandstone interbedded with organic-rich mudstone and phosphatic Fe-silicate-bearing siltstone, which is overlain by hematitic granular ironstone capped by an erosive flooding surface.

This lithofacies association is interpreted to record the deposition of upwelling-related ironstone on a storm-dominated shelf. The close relationship between Fe-silicates and phosphorite typical of upwelling systems suggests that Fe was delivered from deep, anoxic, nutrient-rich seawater that also stimulated high surface productivities. The result was the precipitation of authigenic sedimentary apatite in anoxic organic-rich sediments that accumulated near the upwelling front. The gradual advection of Fe-rich waters away from the upwelling front, initiated precipitation of Fe-silicate coated grains and cements in suboxic pore-waters. Iron pumped into shallower environments through advection and Fe-redox cycling is interpreted to have precipitated Fe-(oxyhydr)oxide grains in sediment of the oxygenated middle shelf. These coated grains were subsequently concentrated by fairweather and storm currents on the shoreface to create granular economic Fe deposits.

We challenge conventional models of Paleozoic ironstone deposition that rely on a continental source of Fe by proposing a hydrothermal source that supplied Fe2+ to the shelf through upwelling. It also highlights the potential connection between the delivery of anoxic, ferruginous seawater to the margins of the Rheic Ocean and the Early Ordovician extinctions that punctuated the beginning of the Great Ordovician Biodiversification Event.

Tostevin, R., Clarkson, M.O., Gangl, S., Shields, G.A., Wood, R.A., Bowyer, F., Penny, A.M., Stirling, C.H., 2019. Uranium isotope evidence for an expansion of anoxia in terminal Ediacaran oceans. Earth and Planetary Science Letters 506, 104-112.


Anoxic and iron-rich oceanic conditions prevailed throughout most of the Archean and Proterozoic (4000 to c.540 million years ago, Ma), but the oceans are hypothesised to have become progressively oxygen-rich during the Ediacaran–Cambrian transition interval, coincident with the rise of animal life. We utilise the uranium isotope ratio of seawater (238U/235U; reformulated as δ238U), an effective tracer of oceanic redox conditions, as a proxy for changes in the global proportion of anoxic seafloor. We present a new δ238U dataset for carbonate rocks from the Lower Nama Group, Namibia, deposited in a shelf ramp succession during the terminal Neoproterozoic (∼550 to ∼547 Ma). These data capture a transition from δ238U similar to the modern ocean towards persistently low δ238U (average = −0.81 ± 0.06‰). Such low δ238U are consistent with enhanced U drawdown from the water column under anoxic conditions, and the preferential export of ‘heavy’ 238U to sediments following U(VI)–U(IV) reduction. Placing our results into a steady state ocean box model suggests at least a third of the global seafloor was covered by anoxic bottom waters compared with only 0.3% in today's oxygenated oceans. Comparison with δ238U from older sediments deposited in other basins further supports an expansion of anoxic bottom waters towards the end of the Ediacaran. Our data are consistent with an emerging picture of a dominantly anoxic Ediacaran ocean punctuated by brief ocean oxygenation events. In the Nama Group, the transition towards globally widespread anoxic conditions post-dates the first appearance of both skeletal metazoans and soft-bodied fauna of the Nama Assemblage. This suggests that the global expansion of anoxia did not coincide with the decline of the Ediacaran biota, or drive the biotic turnover between the White Sea and Nama

Assemblages. The impact of this global redox change on metazoan ecosystems is unclear, since the expansion of anoxia, if contained mainly within deeper waters, may not have impinged significantly upon continental shelves that host the majority of biodiversity.

Trindade, G.F., Abel, M.-L., Watts, J.F., 2018. simsMVA: A tool for multivariate analysis of ToF-SIMS datasets. Chemometrics and Intelligent Laboratory Systems 182, 180-187.


Imaging mass spectrometry datasets are every year larger and more complex, with unsupervised multivariate analysis (MVA) becoming a routine procedure for most researchers. Moreover, the increasing interdisciplinarity of the field demands the development of software for rapid and accessible MVA for researchers of various backgrounds. This paper presents a MATLAB-based software for performing principal component analysis (PCA), non-negative matrix factorisation (NMF) and k-means clustering of large analytical chemistry datasets with a particular focus on of time-of-flight secondary ions mass spectrometry (ToF-SIMS). All five modes of operation (spectra, profiles, images, 3D and multi) are described with a few examples of typical applications at The Surface Analysis Laboratory of the University of Surrey: point spectra analysis of wood growth regions, depth profiling of a metallic multi-layered sample, imaging of an organic coating on a metal substrate and 3D characterisation of an automotive grade polypropylene.

Trinkaus, E., 2018. An abundance of developmental anomalies and abnormalities in Pleistocene people. Proceedings of the National Academy of Sciences 115, 11941-11946.


Significance: The patterns and incidences of developmental abnormalities and anomalies through Pleistocene human evolution may provide insights into issues of survival, stress, consanguinity, and mortuary behavior among these foraging populations. A synthesis of these developmental variants through the Homo fossil record provides 75 cases from 66 individuals, an exceptional total given the small paleontological samples. These are primarily from the past 200,000 years, given better preservation through burial, but are known from up to 1.5 million years ago. One-third of them have moderately low probabilities (P < 0.05), yet 14% are very rare (P < 0.0001), and 19% have no known etiology. No single factor accounts for the extremely low cumulative probability of finding these abnormalities, but this raises questions concerning the natures of Pleistocene human populations.

Abstract: Diverse developmental abnormalities and anomalous features are evident in the Pleistocene Homo fossil record, varying from minor but rare dental, vertebral, and carpal variants to exceptional systemic disorders. There are currently 75 documented anomalies or abnormalities from 66 individuals, spanning the Pleistocene but primarily from the Late Pleistocene Middle and Upper Paleolithic with their more complete skeletal remains. The expected probabilities of finding these variants or developmental disorders vary from <5% to <0.0001%, based on either recent human incidences or relevant Pleistocene sample distributions. Given the modest sample sizes available for the skeletal or dental elements in question, especially if the samples are appropriately limited in time and geography, the cumulative multiplicative probability of finding these developmental changes is vanishingly small. These data raise questions regarding social survival abilities, differing mortuary treatments of the biologically unusual, the role of ubiquitous stress among these Pleistocene foragers, and their levels of consanguinity. No single factor sufficiently accounts for the elevated level of these developmental variants or the low probability of finding them in the available paleontological record.

Tripti, M., Gurumurthy, G.P., Lambs, L., Riotte, J., Balakrishna, K., 2018. Water and organic carbon cycles in monsoon-driven humid tropics of the western Ghats Mountain Belt, India: Insights from stable isotope approach. Journal of the Geological Society of India 92, 579-587.

https://doi.org/10.1007/s12594-018-1070-z

The Western Ghats form a major mountain belt, next to the Himalayas, in controlling the flux of water and carbon to the northern Indian Ocean. This study attempts to understand the water and carbon cycles in two humid tropical river basins with its streams originating at higher altitudes of the Western Ghats, India. Water and suspended particulate matter (SPM) were collected on a monthly scale during summer monsoon season (June-September) from Swarna and Nethravati rivers draining into the Arabian Sea. For the source apportionment, samples have been measured for stable isotopes of oxygen (δ18O) and hydrogen (δ2H) in water and stable isotopes of carbon (δ13CPOC) in particulate organic matter (POM) at spatial scale from tributaries and main channel of rivers, and runoff water from agricultural land (dominant paddy field) and forest in the downstream region. The association between δ18O and deuterium-excess in river water and rain water shows that water in these tropical basins depicts rainout effect of marine source moisture during the onset of summer monsoon. As the monsoon intensifies, the fresher rain water replenishes older water stored previously in sub surface soil layer leading to its flushing into the river during summer monsoon season. Stable carbon isotope ratio and elemental ratio of POM (δ13CPOC = -27.1 ± 0.4 ‰ and C/N = 8.1 ± 1.7) in two humid tropical river water during summer monsoon season is an admixture of suspended particulates from runoff water of forest (δ13CPOC = - 27.82 ± 0.4 ‰) and agricultural land (δ13CPOC = -26.29 ± 0.4 ‰). It is found that δ13CPOC shows minimal variability with SPM content and C/N ratio within the same organic carbon pool. The study emphasizes the need to consider the agricultural runoff contribution to the rivers while establishing the global elemental budget and observing the global climate change.

Trubl, G., Jang, H.B., Roux, S., Emerson, J.B., Solonenko, N., Vik, D.R., Solden, L., Ellenbogen, J., Runyon, A.T., Bolduc, B., Woodcroft, B.J., Saleska, S.R., Tyson, G.W., Wrighton, K.C., Sullivan, M.B., Rich, V.I., 2018. Soil viruses are underexplored players in ecosystem carbon processing. mSystems 3, Article e00076-18.


Abstract: Rapidly thawing permafrost harbors ∼30 to 50% of global soil carbon, and the fate of this carbon remains unknown. Microorganisms will play a central role in its fate, and their viruses could modulate that impact via induced mortality and metabolic controls. Because of the challenges of recovering viruses from soils, little is known about soil viruses or their role(s) in microbial biogeochemical cycling. Here, we describe 53 viral populations (viral operational taxonomic units [vOTUs]) recovered from seven quantitatively derived (i.e., not multiple-displacement-amplified) viral-particle metagenomes (viromes) along a permafrost thaw gradient at the Stordalen Mire field site in northern Sweden. Only 15% of these vOTUs had genetic similarity to publicly available viruses in the RefSeq database, and ∼30% of the genes could be annotated, supporting the concept of soils as reservoirs of substantial undescribed viral genetic diversity. The vOTUs exhibited distinct ecology, with different distributions along the thaw gradient habitats, and a shift from soil-virus-like assemblages in the dry palsas to aquatic-virus-like assemblages in the inundated fen. Seventeen vOTUs were linked to microbial hosts (in silico), implicating viruses in infecting abundant microbial lineages from Acidobacteria, Verrucomicrobia, and Deltaproteobacteria, including those encoding key biogeochemical functions such as organic matter degradation. Thirty auxiliary metabolic genes (AMGs) were identified and suggested virus-mediated modulation of central carbon metabolism, soil organic matter degradation, polysaccharide binding, and regulation of sporulation. Together, these

findings suggest that these soil viruses have distinct ecology, impact host-mediated biogeochemistry, and likely impact ecosystem function in the rapidly changing Arctic.

Importance: This work is part of a 10-year project to examine thawing permafrost peatlands and is the first virome-particle-based approach to characterize viruses in these systems. This method yielded >2-fold-more viral populations (vOTUs) per gigabase of metagenome than vOTUs derived from bulk-soil metagenomes from the same site (J. B. Emerson, S. Roux, J. R. Brum, B. Bolduc, et al., Nat Microbiol 3:870–880, 2018, <https://doi.org/10.1038/s41564-018-0190-y>). We compared the ecology of the recovered vOTUs along a permafrost thaw gradient and found (i) habitat specificity, (ii) a shift in viral community identity from soil-like to aquatic-like viruses, (iii) infection of dominant microbial hosts, and (iv) carriage of host metabolic genes. These vOTUs can impact ecosystem carbon processing via top-down (inferred from lysing dominant microbial hosts) and bottom-up (inferred from carriage of auxiliary metabolic genes) controls. This work serves as a foundation which future studies can build upon to increase our understanding of the soil virosphere and how viruses affect soil ecosystem services.

Tushingham, S., Snyder, C.M., Brownstein, K.J., Damitio, W.J., Gang, D.R., 2018. Biomolecular archaeology reveals ancient origins of indigenous tobacco smoking in North American Plateau. Proceedings of the National Academy of Sciences 115, 11742-11747.


Significance: While tobacco is one of the most heavily consumed (and abused) plant substances of the modern era, with profound global health consequences, its early use remains poorly understood. Here we report a substantial direct biomolecular record of ancient tobacco smoking by hunter-gatherers of interior northwestern North America. Nicotine-positive samples demonstrate deep time continuity of indigenous tobacco smoking in a place where tobacco has been depicted as being introduced by early Euro-American traders and explorers. The spread of domesticated trade tobacco seems to have overtaken and obscured ancient indigenous tobacco practices. The information—represented here by the longest continuous biomolecular record of tobacco use from a single region—informs programs designed to combat persistent commercial tobacco use rates among modern Tribal communities.

Abstract: Chemical analysis of residues contained in the matrix of stone smoking pipes reveal a substantial direct biomolecular record of ancient tobacco (Nicotiana) smoking practices in the North American interior northwest (Plateau), in an area where tobacco was often portrayed as a Euro-American–introduced postcontact trade commodity. Nicotine, a stimulant alkaloid and biomarker for tobacco, was identified via ultra-performance liquid chromatography-mass spectrometry in 8 of 12 analyzed pipes and pipe fragments from five sites in the Columbia River Basin, southeastern Washington State. The specimens date from 1200 cal BP to historic times, confirming the deep time continuity of intoxicant use and indigenous smoking practices in northwestern North America. The results indicate that hunting and gathering communities in the region, including ancestral Nez Perce peoples, established a tobacco smoking complex of wild (indigenous) tobacco well before the main domesticated tobacco (Nicotiana tabacum) was introduced by contact-era fur traders and settlers after the 1790s. This is the longest continuous biomolecular record of ancient tobacco smoking from a single region anywhere in the world—initially during an era of pithouse development, through the late precontact equestrian era, and into the historic period. This contradicts some ethnohistorical data indicating that kinnikinnick, or bearberry (Arctostaphylos uva-ursi) was the primary precontact smoke plant in the study area. Early use likely involved the management and cultivation of indigenous tobaccos (Nicotiana quadrivalvis or Nicotiana attenuata), species that are today

exceedingly rare in the region and seem to have been abandoned as smoke plants after the entry of trade tobacco.

Tyner, D.R., Johnson, M.R., 2018. A techno-economic analysis of methane mitigation potential from reported venting at oil production sites in Alberta. Environmental Science & Technology 52, 12877-12885.


The technical and economic potential for reducing methane emissions from reported venting and flaring volumes in 2015 at 9422 upstream oil production sites in Alberta, Canada was evaluated in a comprehensive site-by-site analysis. For each site, up to six different technologies for mitigation were considered, based on conserving gas into pipelines, combusting gas on site, or using gas for on-site fuel. Economic viability of mitigation was calculated using current economic parameters and gas price projections on a net present cost basis. Monte Carlo simulations suggest that a 45% reduction in methane emissions (consistent with current federal and provincial targets) from reported flaring and venting is technically and economically feasible at overall average costs ranging from $–2.98 CAD/tCO2e (i.e., a profit) to $2.51 CAD/tCO2e with no one site paying more than $11.02 CAD/tCO2e. If the reported baseline emissions are augmented to reflect results of recent airborne measurements, overall economics of mitigation generally improve due to larger available gas volumes at many sites. Considering federal carbon price targets of $50 CAD/tCO2e by 2022, there are relevant economic opportunities for mitigating methane from reported venting and flaring volumes well beyond a 45% reduction. This could partially offset the challenge in addressing the additional methane emissions from fugitive and unreported venting sources.

Ulyantsev, A.S., Belyaev, N.A., Bratskaya, S.Y., Romankevich, E.A., 2018. The molecular composition of lignin as an indicator of subaqueous permafrost thawing. Doklady Earth Sciences 482, 1357-1361.

https://doi.org/10.1134/S1028334X1810029X

The concentration and molecular composition of phenols, lignin derivatives, were analyzed. The material for the study was sampled from bottom sediments and subaqueous perennial frozen rocks from a well drilled in the Buor-Khaya Gulf of the Laptev Sea. The analysis was undertaken on the basis of calculation of the molecular factor. The principal difference in the molecular composition of organic matter is shown. This difference is manifested in the decrease in the total concentration of the vanillic lignin derivatives in the thawed formations in comparison with the perennial frozen rocks. This phenomenon is explained by activation of the bacterial transformation of organic matter caused by thawing of the subaqueous permafrost. It was established that the weight percentage of lignin in the organic matter of the analyzed sediments is 17% Corg. Original Russian Text © A.S. Ulyantsev, N.A. Belyaev, S.Yu. Bratskaya, E.A. Romankevich, 2018, published in Doklady Akademii Nauk, 2018, Vol. 482, No. 6.

Umeh, A.C., Duan, L., Naidu, R., Semple, K.T., 2018. Time-dependent remobilization of nonextractable benzo[a]pyrene residues in contrasting soils: Effects of aging, spiked concentration, and soil properties. Environmental Science & Technology 52, 12295-12305.


The environmental and health risks associated with “nonextractable” residues (NERs) of polycyclic aromatic hydrocarbons in soils and their potential for remobilization remain largely unexplored. In

this novel study, sequential solvent extractions were employed to interrogate time-dependent remobilization of benzo[a]pyrene (B[a]P) NERs and associated kinetics after re-equilibration (REQ) periods lasting 30 d in four artificially spiked soils aged for up to 200 days. Following sequential extractions of the re-equilibrated soils, remobilization of B[a]P NERs was observed and further confirmed by decreases in the absolute amounts of B[a]P recovered following methanolic saponification after REQ. Remobilization may occur through slow intercompartmental partitioning of more sequestered into less sequestered B[a]P fractions in soils. The amounts of B[a]P remobilized in soils decreased throughout aging following first-order kinetics, and the rates of decrease were slow but 2 to 4 times faster than those of extractable B[a]P before re-equilibration. Sandy-clay-loam soils with large amounts of hard organic carbon exhibited less NER remobilization compared to sandy soils. The amounts of remobilized B[a]P decreased significantly (p < 0.05) with aging. Specifically, butanol-remobilized B[a]P in soils spiked at 10 mg/kg and 50 mg/kg B[a]P ranged from 0.15 to 0.39 mg/kg and 0.67 to 2.30 mg/kg, respectively, after 200 d of aging.

Van Plantinga, A.A., Grossman, E.L., 2018. Stable and clumped isotope sclerochronologies of mussels from the Brazos River, Texas (USA): Environmental and ecologic proxy. Chemical Geology 502, 55-65.


Oxygen isotope sclerochronology with mollusk shells can provide vital environmental and ecologic information, but is complicated in regulated, subtropical rivers by irregular river water δ18O and consequently irregular shell δ18O patterns. We performed multi-proxy analyses (δ18O, δ13C, clumped isotopes) from serially-sampled freshwater mussels in two specimens each of Amblema plicata and Cyrtonaias tampicoensis from the Brazos River, Texas to age specimens and test whether they accurately record environmental conditions such as river discharge and water source. Oxygen isotopic measurements are similar to predicted aragonite δ18O values based on temperature and water δ18O, but the record is complex and irregular. To better resolve the chronologies, we performed clumped isotope analyses on select shell intervals. Clumped isotope temperatures (T(Δ47)) ranged from 19° to 36 °C. Summer T(Δ47) values were 3–5 °C higher than measured temperatures, suggesting an offset in paleothermometer calibration. Chronologies based on Δ47 and δ18O reveal specimen ages of 3–4 years and winter growth cessation (or dramatic slowing) in both C. tampicoensis and A. plicata, highlighting thermal limitations on growth and potential biases in environmental reconstructions. Compared with modern shells, historical shells collected before intensive damming showed lower δ18O values yet similar clumped temperatures, suggesting enhanced evaporation in modern river water due to impoundment and/or the 2011–12 drought.

Carbon isotope trends were similar between conspecific shells, but differed between species, with substantially higher average values for A. plicata shells (−9‰) than C. tampicoensis shells (−12‰). The correlation between shell δ13C values and the release of 13C-enriched waters from upstream reservoirs demonstrates that δ13C can be used as a proxy for dam release in regulated rivers.

van Zuilen, M.A., 2018. Proposed early signs of life not set in stone. Nature 563, 190-191.

https://www.nature.com/articles/d41586-018-06994-x

Efforts to find early traces of life on Earth often focus on structures in ancient rocks, called stromatolites, that formed by microbial activity. One of the oldest proposed stromatolite discoveries has now been questioned.

In 2016, Nutman et al.1 reported the discovery of cone-shaped structures in 3.7-billion-year-old rocks in the Isua Supracrustal Belt, Greenland, that they identified as being stromatolites — structures that arise as a result of the presence of water-dwelling microorganisms. Previously, the earliest known stromatolites were reported to be those in 3.45-billion-year-old rocks in Australia2. Being able to accurately date the first signs of the emergence of life has important implications for understanding how life on Earth evolved. However, writing in Nature, Allwood et al.3 now report their own independent analysis of these ancient rocks in Greenland, and argue that, in this particular case, the structures that Nutman and colleagues interpreted to be stromatolites instead arose by non-biological processes. This finding shows that a natural process that does not require any input from a living organism can mimic the formation of a structure that normally counts as a strong indication of previous biological activity.

Stromatolites have a laminated (layered) structure (Fig. 1a), formed by sediment trapping, binding and mineral deposition within microbial communities4. They can form in a range of shapes: conical, columnar or dome-like. Whether microorganisms have a role in the formation of certain types of stromatolite shape is unclear. There are models for how stromatolites can arise without input from a living organism5, and various laminated structures that occur naturally without requiring any biological activity can be mistaken for stromatolites, such as silica deposits around geysers4 or laminated carbonate crusts that form when water evaporates6. In well-preserved stromatolite specimens, a biological contribution to such structures can often be confirmed by the presence of complex branching, intricate laminar textures, cavities or, in some rare instances, preserved microfossils and moulds1,7.

Conical stromatolites are a special case, however, because their shape alone can be sufficient to identify them as arising from biological processes. Their steep laminar slopes cannot arise from non-biological processes such as sedimentation or mineral precipitation. From the analysis of present-day stromatolites and laboratory experiments, it is known that conical stromatolites are the preserved remains of motile microbial communities that form vertical cones1,8, and that this cone structure can be preserved by the trapping, binding and precipitation of non-biological material.

When stromatolite structures in the early rock record (which often have a centimetre-scale size) are analysed, their intricate laminations, textures and composition have usually already been partially or completely destroyed through a process called metamorphism, in which rock structure is substantially altered and deformed by heat and pressure, often when the rock is buried deep underground. Stromatolite shape therefore becomes the main way to identify signs of biological input in ancient stromatolite-like structures. In the strongly metamorphosed Early Archean rock record (formed around 3.2 billion to 4 billion years ago), the identification of stromatolites arising from biological processes thus becomes particularly difficult.

However, a convincing case was made for the presence of such biologically arising stromatolites in 3.45-billion-year-old rocks in Australia2. In addition to conical stromatolites, six other stromatolite shapes were found in the samples there; they all existed in specific parts of what was considered to be an ancient, shallow, marine, carbonate-rich environment. This diversity in stromatolite shape convincingly excluded a uniform non-biological formation process and suggested that ecological controls governed the overall stromatolite growth. Evidence of such a clearly defined ancient environmental setting is difficult to find in any older metamorphosed rock on Earth.

Nutman and colleagues reported the identification of ancient stromatolites in a newly described rock outcrop in Greenland, and also interpreted these structures as having arisen in an ancient, shallow, marine environment, on the basis of the textures of interlayered sediments and the distribution patterns of rare-earth elements. Such patterns have previously been interpreted to indicate the deposition of carbonate minerals from seawater9. The entire region in which these rocks are located

was previously found to be metamorphosed rock that had been subjected to high temperature and pressure10. In the Australian rocks with ancient stromatolites2, laminations are clearly visible; in the Greenland samples, however, the proposed laminations are less clear, and the degree of metamorphism is higher than that of the Australian rocks.

The lack of unambiguous, well-preserved laminated structures would preclude the identification of any intricate original textures that might indicate biological input to the structure. However, Nutman et al. identified remnant laminations and conical stromatolite-like shapes that they consistently interpreted as being microbially generated structures. Apart from these conical shapes, Nutman and co-workers also identified some dome-like shapes of proposed stromatolites. However, they did not find the diversity of stromatolite forms described in the Australian study. With few specimens, and a complex history of rock metamorphism, this raised the question of whether non-biological processes might have generated the dome-like and conical shapes in these ancient Greenland rocks.

Allwood et al. argue that the stromatolite-like shapes observed at the Greenland site arise from rock deformation. When they compared the front and side profiles of rock samples that contained stromatolite-like structures, they noted that one side shows a compressional deformation whereas the other shows an extensional deformation. This indicates that the structures are not stromatolite cones, but elongated ridges (Fig. 1b). Furthermore, the folding direction of the stromatolite ridges is parallel to the orientation of pressure-induced mineral textures on smaller scales in the same rock. These observations provide strong evidence for physical rock deformation and therefore offer a non-biological explanation for the observed structures.

In addition, Allwood and colleagues argue that the rock itself did not form in a shallow marine setting, but instead arose when carbonate minerals crystallized from fluids that circulated through an existing rock. If this is true, the observed dome-like and conical structures are definitely not stromatolites. Allwood et al. used a trace-element analysis technique that has high spatial resolution to show that the internal laminations in the conical structures represent the specific replacement of a type of silicate rock by fluid-derived carbonate minerals. The authors found that the rare-earth-element signal associated with the presence of seawater seems to be mainly concentrated in mica minerals in the rock, but is also present in the carbonate areas. Allwood and co-workers suggest that this is possible if the fluids from which the minerals crystallized during later stages of the rock’s existence ultimately derived from seawater as well. So although Nutman et al.1 and Allwood et al.2 report similar patterns of rare-earth elements in the rocks, they offer diverging interpretations of what these patterns mean. This highlights the complexities in discerning primary chemical signatures in such highly deformed rocks.

The biological input to ancient stromatolites is a long-standing controversy. The rocky outcrop on Greenland has not been discovered for long, and few researchers have studied this rock in relation to its geological surroundings. Future research might lead to a firm understanding of the primary versus secondary processes that shaped this rock. Clearly, the work of both Nutman et al. and Allwood et al. will form the basis for the interpretation of other possible stromatolites in the ancient rock record.

References1. Nutman, A. P., Bennett, V. C., Friend, C. R. L., Van Kranendonk, M. J. & Chivas, A. R. Nature

537, 535–538 (2016).2. Allwood, A. C., Walter, M. R., Kamber, B. S., Marshall, C. P. & Burch, I. W. Nature 441, 714–

718 (2006).3. Allwood, A. C. et al. Nature 563, 241–244 (2018).4. Walter, M. R. (ed.) Stromatolites. Developments in Sedimentology 20 (Elsevier, 1976).5. Grotzinger, J. P., Rothman, D. H. Nature 383, 423–425 (1996).6. Pope, M. C., Grotzinger, J. P., Schreiber, B. C. J. Sediment. Res. 70, 1139–1151 (2000).

7. Gotzinger, J. P., Knoll, A. H. Annu. Rev. Earth Planet. Sci. 27, 313–358 (1999).8. Bosak, T. et al. Geobiology 10, 384–401 (2012).9. Bolhar, R., Kamber, B. S., Moorbath, S., Fedo, C. M., Whitehouse, M. J. Earth Planet. Sci. Lett.

222, 43–60 (2004).10. Boak, J. L., Dymek, R. F. Earth Planet. Sci. Lett. 59, 155–176 (1982).

Vandenabeele, P., Edwards, H., 2019. Raman Spectroscopy in Archaeology and Art History, Volume 2. The Royal Society of Chemistry, p. 349.

http://dx.doi.org/10.1039/9781788013475

Ten years after the first volume, this book highlights the important contribution Raman spectroscopy makes as a non-destructive method for characterising the chemical composition of objects with archaeological and historical importance. The original book was ground-breaking in its concept, but the past ten years have seen some advancement into new areas, consolidation of some of the older ones and novel applications involving portable instrumentation, on site in museums and in the field.

This new volume maintains the topic at the cutting edge, the Editors have approached prominent contributors to provide case-studies sorted into themes. Starting with a Foreword from the British Museum Director of Scientific Research and an Introduction from the Editors, which offer general background information and theoretical context, the contributions then provide global perspectives on this powerful analytical tool.

Aimed at scientists involved in conservation, conservators and curators who want to better understand their collections at a material level and researchers of cultural heritage.

Chapter 1 : Analytical Raman Spectroscopy of Inks. Howell G. M. Edwards, 1-15

Chapter 2 : Raman Spectroscopic Analysis of Romano-British Wall Paintings: A Comparison Between Geographically Different Sites at the Northern Fringe of the Roman Empire. Howell G. M. Edwards, Rebecca Widdowson and Jennifer Proctor, 16-30

Chapter 3 : Evidence of Pentimenti for the Authentication of Paintings: A Challenge for Analytical Science at the Interface with Art History. Timothy J. Benoy, William A. Edwards and Howell G. M. Edwards, 31-45.

Chapter 4 : Dancing on Eggshells: A Holistic Analytical Study of a Ballet Dancer on Regency Porcelain. Howell G. M. Edwards, Alexander P. H. Surtees and Richard Telford, 46-60.

Chapter 5 : Pigments and Colourants. Peter Vandenabeele, Anastasia Rousaki, Mafalda Costa, Luc Moens and Howell G. M. Edwards, 61-67.

Chapter 6 : Micro Raman Spectroscopy of Epipalaeolithic Decorated Pebbles from Arroyo Moreras 2 (Parque Darwin, Madrid). A. Hernanz, J. M. Gavira-Vallejo, P. Bueno-Ramírez, R. de Balbín-Behrmann, J. Morín de Pablos and C. de Juana Ortín, 68-80.

Chapter 7 : Raman Microscopy as a Primary Technique for Identifying Micro-residues Related to Tool-use on Prehistoric Stone Artefacts. Linda C. Prinsloo and Luc Bordes, 81-96.

Chapter 8 : Biological Materials of Significance to Cultural Heritage. Elizabeth A. Carter, 97-122.

Chapter 9 : Discrimination of Contraband Ivories Using Long Wavelength Portable Raman Instrumentation. Sarah Kelloway, Howell G. M. Edwards, Brad Swarbrick and Elizabeth A. Carter, 123-140.

Chapter 10 : Micro-Raman and Provenance Studies: The Case of Levantine Ceramics. Laura Medeghini, Danilo Bersani, Silvano Mignardi, Caterina de Vito and Pier Paolo Lottici, 141-156.

Chapter 11 : Raman Spectroscopy for the Identification of Materials in Contemporary Painting. Silvia Bruni and Vittoria Guglielmi, 157-173

Chapter 12 : Application of Micro-spatially Offset Raman Spectroscopy to Street Art Paintings. C. Conti, A. Botteon, C. Colombo, M. Realini and P. Matousek, 174-183

Chapter 13 : Raman Spectroscopy as a Cultural Heritage Forensic Tool. Catarina Miguel and António Candeias, 184-195.

Chapter 14 : Outdoor Bronze and Its Protection. P. Ropret and T. Kosec,196-212.

Chapter 15 : Analysis of the Degradation of Medieval Mural Paintings in the Open Air Abandoned Church of Ribera, North of Spain. Juan Manuel Madariaga, Ilaria Costantini and Kepa Castro, 213-233.

Chapter 16 : Miniaturized Raman Spectrometers Applied to Gemstone Analyses on Works of Art. Jan Jehlička and Adam Culka, 234-253.

Chapter 17 : New Case Studies: Diamonds, Jades, Corundum and Spinel., Lore Kiefert, Pierre Hardy, Klaus Schollenbruch and Wenxing Xu, 254-270.

Chapter 18 : The Cultural Meanings of Color: Raman Spectroscopic Studies of Red, Pink, and Purple Dyes in Late Edo and Early Meiji Period Prints. Anna Cesaratto, Marco Leona and Federica Pozzi, 271-288.

Chapter 19 : Raman Spectroscopy Applied to the Analysis of Typomorphic Minerals in Various Provenance Investigations of Cultural Heritage Objects. B. Łydżba-Kopczyńska, 289-313.

Chapter 20 : Pitfalls in Raman Spectroscopy Applied to Art and Archaeology: A Practical Survival Guide for Non-specialists. D. L. A. de Faria and H. G. M. Edwards, 314-343.

vandenEnden, L., Frey, S.D., Nadelhoffer, K.J., LeMoine, J.M., Lajtha, K., Simpson, M.J., 2018. Molecular-level changes in soil organic matter composition after 10 years of litter, root and nitrogen manipulation in a temperate forest. Biogeochemistry 141, 183-197.

https://doi.org/10.1007/s10533-018-0512-4

With climate change, forests are expected to receive increased inputs of carbon (C) and nitrogen (N) but it is unclear how this will modify forest C cycling and storage at the molecular-level. To investigate the response of forest soil organic matter (SOM) to changes in soil inputs, a study area was established in a Michigan hardwood forest as part of the Detrital Input and Removal Treatments (DIRT) network. Experimental treatments were comprised of both exclusions of detrital inputs (No Litter, No Roots, No Inputs) and additions of C and N (Double Litter, N-Addition, Double Litter + N, Wood). After 10 years of treatment, the soils were characterized using elemental analysis, molecular biomarker techniques, nuclear magnetic resonance spectroscopy, and microbial biomass C measurements. Although manipulation of detrital inputs did not significantly change the soil C and N

content after 10 years, alterations in the cycling and distribution of SOM components were observed. Root exclusion enhanced SOM degradation, while doubling litter favoured the degradation of more labile forms of soil C such as unsaturated n-alkanoic acids and simple sugars. N-Addition and Double Litter + N increased the concentrations of extractable biomarkers, including aliphatic and cyclic lipids and compounds derived from cutin, suberin, and lignin. Microbial biomass C also varied with experimental litter input manipulations and N addition, and these data were consistent with the observed changes in SOM composition. Overall, the observed shifts in SOM chemistry after 10 years of manipulating ecosystem inputs highlight the sensitivity of natural systems to changes in amounts of C and N inputs from roots and litter, and N inputs from external sources.

Vaughn, T.L., Bell, C.S., Pickering, C.K., Schwietzke, S., Heath, G.A., Pétron, G., Zimmerle, D.J., Schnell, R.C., Nummedal, D., 2018. Temporal variability largely explains top-down/bottom-up difference in methane emission estimates from a natural gas production region. Proceedings of the National Academy of Sciences 115, 11712-11717.


Significance: Our results demonstrate that access to high-resolution spatiotemporal activity data and multiscale, contemporaneous measurements is critical to understanding oil- and gas-related methane emissions. Careful consideration of all factors influencing methane emissions—including temporal variation—is necessary in scientific and policy discussions to develop effective strategies for mitigating greenhouse gas emissions from natural gas infrastructure.

Abstract: This study spatially and temporally aligns top-down and bottom-up methane emission estimates for a natural gas production basin, using multiscale emission measurements and detailed activity data reporting. We show that episodic venting from manual liquid unloadings, which occur at a small fraction of natural gas well pads, drives a factor-of-two temporal variation in the basin-scale emission rate of a US dry shale gas play. The midafternoon peak emission rate aligns with the sampling time of all regional aircraft emission studies, which target well-mixed boundary layer conditions present in the afternoon. A mechanistic understanding of emission estimates derived from various methods is critical for unbiased emission verification and effective greenhouse gas emission mitigation. Our results demonstrate that direct comparison of emission estimates from methods covering widely different timescales can be misleading.

Vaziri, S.H., Laflamme, M., 2018. Lithostratigraphy and sedimentary environment of the Precambrian Kushk Series of central Iran. Canadian Journal of Earth Sciences 55, 1284-1296.


The Kushk Series is a distinctive late Ediacaran succession occurring in the Bafq and Behabad regions of central Iran that has yielded an extensive community of diverse Ediacara biota, including several Precambrian (Chuaria) and Ediacaran (Cloudina, Corumbella) index fossils. The Kushk Series reaches a thickness of up to 518 m and consists of shallow to deep subtidal deposits along a homoclinal carbonate ramp during a transgression–regression cycle. These deposits accumulated as part of an extensional rift basin complex resulting from the opening of the Proto–Paleotethys Ocean in northeastern Gondwana. Latest Ediacaran fossils occur in the deep-water calcareous marine shales and represent a thriving community at the dawn of animal life.

Veenaas, C., Linusson, A., Haglund, P., 2018. Retention-time prediction in comprehensive two-dimensional gas chromatography to aid identification of unknown contaminants. Analytical and Bioanalytical Chemistry 410, 7931-7941.

https://doi.org/10.1007/s00216-018-1415-x

Comprehensive two-dimensional (2D) gas chromatography (GC×GC) coupled to mass spectrometry (MS, GC×GC-MS), which enhances selectivity compared to GC-MS analysis, can be used for non-directed analysis (non-target screening) of environmental samples. Additional tools that aid in identifying unknown compounds are needed to handle the large amount of data generated. These tools include retention indices for characterizing relative retention of compounds and prediction of such. In this study, two quantitative structure–retention relationship (QSRR) approaches for prediction of retention times (1tR and 2tR) and indices (linear retention indices (LRIs) and a new polyethylene glycol–based retention index (PEG-2I)) in GC × GC were explored, and their predictive power compared. In the first method, molecular descriptors combined with partial least squares (PLS) analysis were used to predict times and indices. In the second method, the commercial software package ChromGenius (ACD/Labs), based on a “federation of local models,” was employed. Overall, the PLS approach exhibited better accuracy than the ChromGenius approach. Although average errors for the LRI prediction via ChromGenius were slightly lower, PLS was superior in all other cases. The average deviations between the predicted and the experimental value were 5% and 3% for the 1tR and LRI, and 5% and 12% for the 2tR and PEG-2I, respectively. These results are comparable to or better than those reported in previous studies. Finally, the developed model was successfully applied to an independent dataset and led to the discovery of 12 wrongly assigned compounds. The results of the present work represent the first-ever prediction of the PEG-2I.



Volcanic and hydrothermal areas largely contribute to the natural emission of greenhouse gases to the atmosphere, although large uncertainties in estimating their global output still remain. Nevertheless, CO2 and CH4 discharged from hydrothermal fluid reservoirs may support active soil microbial communities. Such secondary processes can control and reduce the flux of these gases to the atmosphere. In order to evaluate the effects deriving from the presence of microbial activity, chemical and carbon (in CO2 and CH4) isotopic composition of interstitial soil gases, as well as diffuse CO2 fluxes, of three hydrothermal systems from Italy were investigated, i.e. (i) Solfatara crater (Campi Flegrei), (ii) Monterotondo Marittimo (Larderello geothermal field) and (iii) Baia di Levante in Vulcano Island (Aeolian Archipelago), where soil CO2 fluxes up to 2400, 1920 and 346 g m−2 day−1 were measured, respectively. Despite the large supply of hydrothermal fluids, 13CO2 enrichments were observed in interstitial soil gases with respect to the fumarolic gas discharges, pointing to the occurrence of autotrophic CO2 fixation processes during the migration of deep-sourced fluids towards the soil-air interface. On the other hand, (i) the δ13C-CH4 values (up to ~48‰ vs. V-PDB higher than those measured at the fumarolic emissions) of the interstitial soil gases and (ii) the comparison of the CO2/CH4 ratios between soil gases and fumarolic emissions suggested that the deep-sourced CH4 was partly consumed by methanotrophic activity, as supported by isotope fractionation modeling. These findings confirmed the key role that methanotrophs play in mitigating the release of geogenic greenhouse gases from volcanic and hydrothermal environments.



In pristine sea ice-covered Arctic waters the potential of natural attenuation of oil spills has yet to be uncovered, but increasing shipping and oil exploitation may bring along unprecedented risks of oil spills.

We deployed adsorbents coated with thin oil films for up to 2.5 month in ice-covered seawater and sea ice in Godthaab Fjord, SW Greenland, to simulate and investigate in situ biodegradation and photooxidation of dispersed oil. GC-MS-based chemometric methods for oil fingerprinting were used to identify characteristic signatures for dissolution, biodegradation and photooxidation. In sub-zero temperature seawater, fast degradation of n-alkanes was observed with estimated half-life times of ∼7 days. PCR amplicon sequencing and qPCR quantification of bacterial genes showed that a biofilm with a diverse microbial community colonised the oil films, yet a population related to the psychrophilic hydrocarbonoclastic gammaproteobacterium Oleispira antarctica seemed to play a key role in n-alkane degradation. Although Oleispira populations were also present in sea ice, we found that biofilms in sea ice had 25 to 100 times lower bacterial densities than in seawater, which explained the non-detectable n-alkane degradation in sea ice. Fingerprinting revealed that photooxidation, but not biodegradation, transformed polycyclic aromatic compounds through 50 cm-thick sea ice and in the upper water column with removal rates up to ∼1% per day.

Overall, our results showed a fast biodegradation of n-alkanes in sea ice-covered seawater, but suggested that oils spills will expose the Arctic ecosystem to bio-recalcitrant PACs over prolonged periods of time.

Verhoeven, A., Giera, M., Mayboroda, O.A., 2018. KIMBLE: A versatile visual NMR metabolomics workbench in KNIME. Analytica Chimica Acta 1044, 66-76.


The problem of reproducibility of scientific research is a serious issue in biomedical sciences. In addition to experimental repeatability, limiting the (pre-) analytical variance is also essential. To address this problem in the field of metabolomics, we have designed KIMBLE, the KNIME-based Integrated MetaBoLomics Environment, a novel platform for the processing and analysis of NMR metabolomics data. It consists of an elaborate NMR metabolomics workflow in the KNIME workflow management system that handles both targeted and untargeted metabolomics. The workflow provides a self-documenting way of transforming raw time-domain NMR data into metabolic insights. Parameters for the quantification of a number of interesting metabolites in urine are included in the workflow, and several useful statistical analysis and visualization tools are incorporated as well. The workflow comes with an interesting sports-induced ketosis dataset so that new users can easily get acquainted with the platform. The user is free to adapt and extend the workflow to his or her personal needs. The KIMBLE workflow, the KNIME software and all the required libraries are installed in a VirtualBox virtual machine that allows for facile installation and use by non-experts.

Vogel, G., 2018. Giant mammal cousin rivaled early dinosaurs. Science 362, 879.


Imagine if you crossed a rhino with a giant turtle and then supersized the result: You might get something like Lisowicia bojani, a newly discovered Triassic mammal cousin that had a body shaped like a rhinoceros, a beak like a turtle, and weighed as much as an African elephant, about 9 tons. Paleontologists say this startling creature offers a new view of the dawn of the age of the dinosaurs. “Who would have ever thought that there were giant, elephant-sized mammal cousins living alongside some of the very first dinosaurs?” marvels Stephen Brusatte, a vertebrate paleontologist at The University of Edinburgh.

Researchers had thought that during the Late Triassic, from about 240 million until 201 million years ago, early mammals and their relatives “retreated to the shadows while dinosaurs rose up and grew to huge sizes,” Brusatte says. “That's the story I tell my students in my lectures. But this throws a wrench into that simple tale,” suggesting the same evolutionary forces that favored giant dinosaurs were at work on other creatures as well.

The new fossil, a partial skeleton described online this week in Science, is an ancient plant eater called a dicynodont; the name means “two dog tooth,” referring to the characteristic tusks on the upper jaw, which resemble oversize canines. Apart from the tusks, dicynodonts were mostly toothless, with a horny beak like modern-day turtles. They're part of the large evolutionary group called synapsids, which includes our mammal ancestors, and they were some of the most abundant and diverse land animals from the mid-Permian period into the Middle Triassic, from 270 million until about 240 million years ago.

Dicynodonts “are the first group of vertebrates that were successfully able to eat plants,” says Tomasz Sulej, a paleontologist at the Polish Academy of Sciences's Institute of Paleobiology in Warsaw.

Dicynodonts evolved a striking range of forms: One burrowed like modern-day moles, another is the first known vertebrate to live in trees. Some grew as large as today's hippos, which weigh about 1.5 tons. However, the fossil record suggests the group was in decline by the time L. bojani lumbered into view. And even in dicynodonts' heyday, they did not come close to early dinosaurs in size.

Sulej, with the Institute of Paleobiology's Jerzy Dzik and Grzegorz Niedźwiedzki, a paleontologist at Uppsala University in Sweden, discovered the new fossil in a clay pit, once quarried for brickmaking, in the village of Lisowice, about 100 kilometers northwest of Krakow in southern Poland. In 2006, the team got a tip that someone had found bone fragments at the site. On their first visit, they found fossils within 15 minutes; during 11 years of fieldwork, they excavated more than 1000 bones.

They didn't immediately recognize the new dicynodont as such—in part because it is so big, Sulej says. “Our first idea was that it was a sauropod,” which were the largest known herbivores in this period, reaching 11 meters long. But skull fragments and limb bones identified the animal as the biggest, most recent dicynodont ever found. The team named it after the village and 18th century comparative anatomist Ludwig Heinrich Bojanus; they estimate it was more than 4.5 meters long and 2.6 meters tall.

Most dicynodonts had a posture that seems awkward to the modern eye: Their hind limbs were straight, like those of today's mammals, but their forelimbs sprawled, lizard-style, with a bend at the elbow. The team suggests that because of the way L. bojani's upper arm bone connected with its shoulder, its front legs must have been oriented vertically, giving it a more erect stance than in modern reptiles. This posture, like that of sauropod dinosaurs and modern mammals, might have helped support its massive weight. But others caution that reconstructing posture without soft tissue can be difficult.

L. bojani's bones also lacked the lines that, in most dicynodont fossils, mark periods when bone growth slowed. The animal may have grown unusually quickly, or wasn't yet full grown when it died. Given the “truly amazing” size of the creature, “it likely grew fast,” says paleontologist Jennifer Botha-Brink of the Bloemfontein Palaeosystems Centre and the National Museum in South Africa. But she adds that lines signaling slower growth might have been erased when the bone was remodeled during adulthood, which happens in elephants today.

Researchers have hypothesized that sauropods grew big to avoid getting eaten. That may have been true for L. bojani, too, Sulej says. The Lisowice bone bed also contains the remains of a 5-meter-long predator—likely a dinosaur—and coprolites (fossilized feces) containing dicynodont bones.

The researchers will seek more specimens farther east in Russia and Ukraine. “There is definitely more to discover,” Niedźwiedzki says. “How many surprises are still waiting for us in the rocks?”

von Gunten, K., Hamilton, S.M., Zhong, C., Nesbø, C., Li, J., Muehlenbachs, K., Konhauser, K.O., Alessi, D.S., 2018. Electron donor-driven bacterial and archaeal community patterns along forest ring edges in Ontario, Canada. Environmental Microbiology Reports 10, 663-672.

https://doi.org/10.1111/1758-2229.12678

Forest rings are 50–1600 m diameter circular structures found in boreal forests around the globe. They are believed to be chemically reducing chimney features, having an accumulation of reduced species in the middle of the ring and oxidation processes occurring at the ring's edges. It has been suggested that microorganisms could be responsible for charge transfer from the inside to the outside of the ring. To explore this, we focused on the changes in bacterial and archaeal communities in the ring edges of two forest rings, the ‘Bean’ and the ‘Thorn North’ ring, in proximity to each other in Ontario, Canada. The drier samples from the methane‐sourced Bean ring were characterized by the abundance of bacteria from the classes Deltaproteobacteria and Gemmatimonadetes. Geobacter spp. and methanotrophs, such as Candidatus Methylomirabilis and Methylobacter, were highly abundant in these samples. The Thorn North ring, centred on an H2S accumulation in groundwater, had wetter samples and its communities were dominated by the classes Alphaproteobacteria and Anaerolineae. This ring's microbial communities showed an overall higher microbial diversity supported by higher available free energy. For both rings, the species diversity was highest near the borders of the 20–30 m broad ring edges.

Vonk, J.E., Drenzek, N.J., Hughen, K.A., Stanley, R.H.R., McIntyre, C., Montluçon, D.B., Giosan, L., Southon, J.R., Santos, G.M., Druffel, E.R.M., Andersson, A.A., Sköld, M., Eglinton, T.I., 2019. Temporal deconvolution of vascular plant-derived fatty acids exported from terrestrial watersheds. Geochimica et Cosmochimica Acta 244, 502-521.


Relatively little is known about the amount of time that lapses between the photosynthetic fixation of carbon by vascular land plants and its incorporation into the marine sedimentary record, yet the dynamics of terrestrial carbon sequestration have important implications for the carbon cycle. Vascular plant carbon may encounter multiple potential intermediate storage pools and transport trajectories, and the age of vascular plant carbon accumulating in marine sediments will reflect these different pre-depositional histories. Here, we examine down-core 14C profiles of higher plant leaf wax-derived fatty acids isolated from high fidelity sedimentary sequences spanning the so-called “bomb-spike”, and encompassing a ca. 60-degree latitudinal gradient from tropical (Cariaco Basin),

temperate (Saanich Inlet), and polar (Mackenzie Delta) watersheds to constrain integrated vascular plant carbon storage/transport times (“residence times”).

Using a modeling framework, we find that, in addition to a “young” (conditionally defined as < 50 y) carbon pool, an old pool of compounds comprises 49 to 78 % of the fractional contribution of organic carbon (OC) and exhibits variable ages reflective of the environmental setting. For the Mackenzie Delta sediments, we find a mean age of the old pool of 28 ky (±9.4, standard deviation), indicating extensive pre-aging in permafrost soils, whereas the old pools in Saanich Inlet and Cariaco Basin sediments are younger, 7.9 (±5.0) and 2.4 (±0.50) to 3.2 (±0.54) ky, respectively, indicating less protracted storage in terrestrial reservoirs. The “young” pool showed clear annual contributions for Saanich Inlet and Mackenzie Delta sediments (comprising 24% and 16% of this pool, respectively), likely reflecting episodic transport of OC from steep hillside slopes surrounding Saanich Inlet and annual spring flood deposition in the Mackenzie Delta, respectively. Contributions of 5–10 year old OC to the Cariaco Basin show a short delay of OC inflow, potentially related to transport time to the offshore basin. Modeling results also indicate that the Mackenzie Delta has an influx of young but decadal material (20–30 years of age), pointing to the presence of an intermediate reservoir.

Overall, these results show that a significant fraction of vascular plant C undergoes pre-aging in terrestrial reservoirs prior to accumulation in deltaic and marine sediments. The age distribution, reflecting both storage and transport times, likely depends on landscape-specific factors such as local topography, hydrographic characteristics, and mean annual temperature of the catchment, all of which affect the degree of soil buildup and preservation. We show that catchment-specific carbon residence times across landscapes can vary by an order of magnitude, with important implications both for carbon cycle studies and for the interpretation of molecular terrestrial paleoclimate records preserved in sedimentary sequences.



On a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks from beneath it. Kjær had 18 hours to find the mineral crystals that would confirm his suspicions.

What he brought home clinched the case for a grand discovery. Hidden beneath Hiawatha is a 31-kilometer-wide impact crater, big enough to swallow Washington, D.C., Kjær and 21 co-authors report this week in a paper in Science Advances. The crater was left when an iron asteroid 1.5 kilometers across slammed into Earth, possibly within the past 100,000 years.

Though not as cataclysmic as the dinosaur-killing Chicxulub impact, which carved out a 200-kilometer-wide crater in Mexico about 66 million years ago, the Hiawatha impactor, too, may have left an imprint on the planet's history. The timing is still up for debate, but some researchers on the discovery team believe the asteroid struck at a crucial moment: roughly 13,000 years ago, just as the world was thawing from the last ice age. That would mean it crashed into Earth when mammoths and other megafauna were in decline and people were spreading across North America.

The impact would have been a spectacle for anyone within 500 kilometers. A white fireball four times larger and three times brighter than the sun would have streaked across the sky. If the object struck an ice sheet, it would have tunneled through to the bedrock, vaporizing water and stone alike in a flash. The resulting explosion packed the energy of 700 1-megaton nuclear bombs, and even an observer hundreds of kilometers away would have experienced a buffeting shock wave, a monstrous thunderclap, and hurricane-force winds. Later, rock debris might have rained down on North America and Europe, and the released steam, a greenhouse gas, could have locally warmed Greenland, melting even more ice.

The news of the impact discovery has reawakened an old debate among scientists who study ancient climate. A massive impact on the ice sheet would have sent meltwater pouring into the Atlantic Ocean—potentially disrupting the conveyor belt of ocean currents and causing temperatures to plunge, especially in the Northern Hemisphere. “What would it mean for species or life at the time? It's a huge open question,” says Jennifer Marlon, a paleoclimatologist at Yale University.

A decade ago, a small group of scientists proposed a similar scenario. They were trying to explain a cooling event, more than 1000 years long, called the Younger Dryas, which began 12,800 years ago, as the last ice age was ending. Their controversial solution was to invoke an extraterrestrial agent: the impact of one or more comets. The researchers proposed that besides changing the plumbing of the North Atlantic, the impact also ignited wildfires across two continents that led to the extinction of large mammals and the disappearance of the mammoth-hunting Clovis people of North America. The research group marshaled suggestive but inconclusive evidence, and few other scientists were convinced. But the idea caught the public's imagination despite an obvious limitation: No one could find an impact crater.

Proponents of a Younger Dryas impact now feel vindicated. “I'd unequivocally predict that this crater is the same age as the Younger Dryas,” says James Kennett, a marine geologist at the University of California, Santa Barbara, one of the idea's original boosters.

But Jay Melosh, an impact crater expert at Purdue University in West Lafayette, Indiana, doubts the strike was so recent. Statistically, impacts the size of Hiawatha occur only every few million years, he says, and so the chance of one just 13,000 years ago is small. No matter who is right, the discovery will give ammunition to Younger Dryas impact theorists—and will turn the Hiawatha impactor into another type of projectile. “This is a hot potato,” Melosh tells Science. “You're aware you're going to set off a firestorm?”

It started with a hole. In 2015, Kjær and a colleague were studying a new map of the hidden contours under Greenland's ice. Based on variations in the ice's depth and surface flow patterns, the map offered a coarse suggestion of the bedrock topography—including the hint of a hole under Hiawatha.

Kjær recalled a massive iron meteorite in his museum's courtyard, near where he parks his bicycle. Called Agpalilik, Inuit for “the Man,” the 20-ton rock is a fragment of an even larger meteorite, the Cape York, found in pieces on northwest Greenland by Western explorers but long used by Inuit people as a source of iron for harpoon tips and tools. Kjær wondered whether the meteorite might be a remnant of an impactor that dug the circular feature under Hiawatha. But he still wasn't confident that it was an impact crater. He needed to see it more clearly with radar, which can penetrate ice and reflect off bedrock.

Kjær's team began to work with Joseph MacGregor, a glaciologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who dug up archival radar data. MacGregor found that NASA aircraft often flew over the site on their way to survey Arctic sea ice, and the instruments were sometimes turned on, in test mode, on the way out. “That was pretty glorious,” MacGregor says.

The radar pictures more clearly showed what looked like the rim of a crater, but they were still too fuzzy in the middle. Many features on Earth's surface, such as volcanic calderas, can masquerade as circles. But only impact craters contain central peaks and peak rings, which form at the center of a newborn crater when—like the splash of a stone in a pond—molten rock rebounds just after a strike. To look for those features, the researchers needed a dedicated radar mission.

Coincidentally, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had just purchased a next-generation ice-penetrating radar to mount across the wings and body of their Basler aircraft, a twin-propeller retrofitted DC-3 that's a workhorse of Arctic science. But they also needed financing and a base close to Hiawatha.

Kjær took care of the money. Traditional funding agencies would be too slow, or prone to leaking their idea, he thought. So he petitioned Copenhagen's Carlsberg Foundation, which uses profits from its global beer sales to finance science. MacGregor, for his part, enlisted NASA colleagues to persuade the U.S. military to let them work out of Thule Air Base, a Cold War outpost on northern Greenland, where German members of the team had been trying to get permission to work for 20 years. “I had retired, very serious German scientists sending me happy-face emojis,” MacGregor says.

Three flights, in May 2016, added 1600 kilometers of fresh data from dozens of transits across the ice—and evidence that Kjær, MacGregor, and their team were onto something. The radar revealed five prominent bumps in the crater's center, indicating a central peak rising some 50 meters high. And in a sign of a recent impact, the crater bottom is exceptionally jagged. If the asteroid had struck earlier than 100,000 years ago, when the area was ice free, erosion from melting ice farther inland would have scoured the crater smooth, MacGregor says. The radar signals also showed that the deep layers of ice were jumbled up—another sign of a recent impact. The oddly disturbed patterns, MacGregor says, suggest “the ice sheet hasn't equilibrated with the presence of this impact crater.”

But the team wanted direct evidence to overcome the skepticism they knew would greet a claim for a massive young crater, one that seemed to defy the odds of how often large impacts happen. And that's why Kjær found himself, on that bright July day in 2016, frenetically sampling rocks all along the crescent of terrain encircling Hiawatha's face. His most crucial stop was in the middle of the semicircle, near the river, where he collected sediments that appeared to have come from the glacier's interior. It was hectic, he says—“one of those days when you just check your samples, fall on the bed, and don't rise for some time.”

In that outwash, Kjær's team closed its case. Sifting through the sand, Adam Garde, a geologist at the Geological Survey of Denmark and Greenland in Copenhagen, found glass grains forged at temperatures higher than a volcanic eruption can generate. More important, he discovered shocked crystals of quartz. The crystals contained a distinctive banded pattern that can be formed only in the intense pressures of extraterrestrial impacts or nuclear weapons. The quartz makes the case, Melosh says. “It looks pretty good. All the evidence is pretty compelling.”

Now, the team needs to figure out exactly when the collision occurred and how it affected the planet.

The Younger Dryas, named after a small white and yellow arctic flower that flourished during the cold snap, has long fascinated scientists. Until human-driven global warming set in, that period reigned as one of the sharpest recent swings in temperature on Earth. As the last ice age waned, about 12,800 years ago, temperatures in parts of the Northern Hemisphere plunged by as much as 8°C, all the way back to ice age readings. They stayed that way for more than 1000 years, turning advancing forest back into tundra.

The trigger could have been a disruption in the conveyor belt of ocean currents, including the Gulf Stream that carries heat northward from the tropics. In a 1989 paper in Nature, Kennett, along with Wallace Broecker, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory, and others, laid out how meltwater from retreating ice sheets could have shut down the conveyor. As warm water from the tropics travels north at the surface, it cools while evaporation makes it saltier. Both factors boost the water's density until it sinks into the abyss, helping to drive the conveyor. Adding a pulse of less-dense freshwater could hit the brakes. Paleoclimate researchers have largely endorsed the idea, although evidence for such a flood has been lacking until recently.

Then, in 2007, Kennett suggested a new trigger. He teamed up with scientists led by Richard Firestone, a physicist at Lawrence Berkeley National Laboratory in California, who proposed a comet strike at the key moment. Exploding over the ice sheet covering North America, the comet or comets would have tossed light-blocking dust into the sky, cooling the region. Farther south, fiery projectiles would have set forests alight, producing soot that deepened the gloom and the cooling. The impact also could have destabilized ice and unleashed meltwater that would have disrupted the Atlantic circulation.

The climate chaos, the team suggested, could explain why the Clovis settlements emptied and the megafauna vanished soon afterward. But the evidence was scanty. Firestone and his colleagues flagged thin sediment layers at dozens of archaeological sites in North America. Those sediments seemed to contain geochemical traces of an extraterrestrial impact, such as a peak in iridium, the exotic element that helped cement the case for a Chicxulub impact. The layers also yielded tiny beads of glass and iron—possible meteoritic debris—and heavy loads of soot and charcoal, indicating fires.

The team met immediate criticism. The decline of mammoths, giant sloths, and other species had started well before the Younger Dryas. In addition, no sign existed of a human die-off in North America, archaeologists said. The nomadic Clovis people wouldn't have stayed long in any site. The distinctive spear points that marked their presence probably vanished not because the people died out, but rather because those weapons were no longer useful once the mammoths waned, says Vance Holliday, an archaeologist at The University of Arizona in Tucson. The impact hypothesis was trying to solve problems that didn't need solving.

The geochemical evidence also began to erode. Outside scientists could not detect the iridium spike in the group's samples. The beads were real, but they were abundant across many geological times, and soot and charcoal did not seem to spike at the time of the Younger Dryas. “They listed all these things that aren't quite sufficient,” says Stein Jacobsen, a geochemist at Harvard University who studies craters.

Yet the impact hypothesis never quite died. Its proponents continued to study the putative debris layer at other sites in Europe and the Middle East. They also reported finding microscopic diamonds at different sites that, they say, could have been formed only by an impact. (Outside researchers question the claims of diamonds.)

Now, with the discovery of Hiawatha crater, “I think we have the smoking gun,” says Wendy Wolbach, a geochemist at DePaul University in Chicago, Illinois, who has done work on fires during the era.

The impact would have melted 1500 gigatons of ice, the team estimates—about as much ice as Antarctica has lost because of global warming in the past decade. The local greenhouse effect from the released steam and the residual heat in the crater rock would have added more melt. Much of that freshwater could have ended up in the nearby Labrador Sea, a primary site pumping the Atlantic

Ocean's overturning circulation. “That potentially could perturb the circulation,” says Sophia Hines, a marine paleoclimatologist at Lamont-Doherty.

Leery of the earlier controversy, Kjær won't endorse that scenario. “I'm not putting myself in front of that bandwagon,” he says. But in drafts of the paper, he admits, the team explicitly called out a possible connection between the Hiawatha impact and the Younger Dryas.

The evidence starts with the ice. In the radar images, grit from distant volcanic eruptions makes some of the boundaries between seasonal layers stand out as bright reflections. Those bright layers can be matched to the same layers of grit in cataloged, dated ice cores from other parts of Greenland. Using that technique, Kjær's team found that most ice in Hiawatha is perfectly layered through the past 11,700 years. But in the older, disturbed ice below, the bright reflections disappear. Tracing the deep layers, the team matched the jumble with debris-rich surface ice on Hiawatha's edge that was previously dated to 12,800 years ago. “It was pretty self-consistent that the ice flow was heavily disturbed at or prior to the Younger Dryas,” MacGregor says.

Other lines of evidence also suggest Hiawatha could be the Younger Dryas impact. In 2013, Jacobsen examined an ice core from the center of Greenland, 1000 kilometers away. He was expecting to put the Younger Dryas impact theory to rest by showing that, 12,800 years ago, levels of metals that asteroid impacts tend to spread did not spike. Instead, he found a peak in platinum, similar to ones measured in samples from the crater site. “That suggests a connection to the Younger Dryas right there,” Jacobsen says.

For Broecker, the coincidences add up. He had first been intrigued by the Firestone paper, but quickly joined the ranks of naysayers. Advocates of the Younger Dryas impact pinned too much on it, he says: the fires, the extinction of the megafauna, the abandonment of the Clovis sites. “They put a bad shine on it.” But the platinum peak Jacobsen found, followed by the discovery of Hiawatha, has made him believe again. “It's got to be the same thing,” he says.

Yet no one can be sure of the timing. The disturbed layers could reflect nothing more than normal stresses deep in the ice sheet. “We know all too well that older ice can be lost by shearing or melting at the base,” says Jeff Severinghaus, a paleoclimatologist at the Scripps Institution of Oceanography in San Diego, California. Richard Alley, a glaciologist at Pennsylvania State University in University Park, believes the impact is much older than 100,000 years and that a subglacial lake can explain the odd textures near the base of the ice. “The ice flow over growing and shrinking lakes interacting with rough topography might have produced fairly complex structures,” Alley says.

A recent impact should also have left its mark in the half-dozen deep ice cores drilled at other sites on Greenland, which document the 100,000 years of the current ice sheet's history. Yet none exhibits the thin layer of rubble that a Hiawatha-size strike should have kicked up. “You really ought to see something,” Severinghaus says.

Brandon Johnson, a planetary scientist at Brown University, isn't so sure. After seeing a draft of the study, Johnson, who models impacts on icy moons such as Europa and Enceladus, used his code to recreate an asteroid impact on a thick ice sheet. An impact digs a crater with a central peak like the one seen at Hiawatha, he found, but the ice suppresses the spread of rocky debris. “Initial results are that it goes a lot less far,” Johnson says.

Even if the asteroid struck at the right moment, it might not have unleashed all the disasters envisioned by proponents of the Younger Dryas impact. “It's too small and too far away to kill off the Pleistocene mammals in the continental United States,” Melosh says. And how a strike could spark

flames in such a cold, barren region is hard to see. “I can't imagine how something like this impact in this location could have caused massive fires in North America,” Marlon says.

It might not even have triggered the Younger Dryas. Ocean sediment cores show no trace of a surge of freshwater into the Labrador Sea from Greenland, says Lloyd Keigwin, a paleoclimatologist at the Woods Hole Oceanographic Institution in Massachusetts. The best recent evidence, he adds, suggests a flood into the Arctic Ocean through western Canada instead.

An external trigger may be unnecessary in any case, Alley says. During the last ice age, the North Atlantic saw 25 other cooling spells, probably triggered by disruptions to the Atlantic's overturning circulation. None of those spells, known as Dansgaard-Oeschger (D-O) events, was as severe as the Younger Dryas, but their frequency suggests an internal cycle played a role in the Younger Dryas, too. Even Broecker agrees that the impact was not the ultimate cause of the cooling. If D-O events represent abrupt transitions between two regular states of the ocean, he says, “you could say the ocean was approaching instability and somehow this event knocked it over.”

Still, Hiawatha's full story will come down to its age. Even an exposed impact crater can be a challenge for dating, which requires capturing the moment when the impact altered existing rocks—not the original age of the impactor or its target. Kjær's team has been trying. They fired lasers at the glassy spherules to release argon for dating, but the samples were too contaminated. The researchers are inspecting a blue crystal of the mineral apatite for lines left by the decay of uranium, but it's a long shot. The team also found traces of carbon in other samples, which might someday yield a date, Kjær says. But the ultimate answer may require drilling through the ice to the crater floor, to rock that melted in the impact, resetting its radioactive clock. With large enough samples, researchers should be able to pin down Hiawatha's age.

Given the remote location, a drilling expedition to the hole at the top of the world would be costly. But an understanding of recent climate history—and what a giant impact can do to the planet—is at stake. “Somebody's got to go drill in there,” Keigwin says. “That's all there is to it.”

Wan, N., Wang, H., Ng, C.K., Mukherjee, M., Ren, D., Cao, B., Tang, Y.J., 2018. Bacterial metabolism during biofilm growth investigated by 13C tracing. Frontiers in Microbiology 9, 2657. doi: 10.3389/fmicb.2018.02657.


This study investigated the metabolism of Pseudomonas aeruginosa PAO1 during its biofilm development via microscopy imaging, gene expression analysis, and 13C-labeling. First, dynamic labeling was employed to investigate glucose utilization rate in fresh biofilms (thickness 40∼60 micrometer). The labeling turnover time of glucose-6-P indicated biofilm metabolism was substantially slower than planktonic cells. Second, PAO1 was cultured in continuous tubular biofilm reactors or shake flasks. Then 13C-metabolic flux analysis of PAO1 was performed based on the isotopomer patterns of proteinogenic amino acids. The results showed that PAO1 biofilm cells during growth conserved the flux features as their planktonic mode. (1) Glucose could be degraded by two cyclic routes (the TCA cycle and the Entner-Doudoroff-Embden-Meyerhof-Parnas loop) that facilitated NAD(P)H supplies. (2) Anaplerotic pathways (including pyruvate shunt) increased flux plasticity. (3) Biofilm growth phenotype did not require significant intracellular flux rewiring (variations between biofilm and planktonic flux network, normalized by glucose uptake rate as 100%, were less than 20%). (4) Transcription analysis indicated that key catabolic genes in fresh biofilm cells had expression levels comparable to planktonic cells. Finally, PAO1, Shewanella oneidensis (as the comparing group), and their c-di-GMP transconjugants (with different biofilm formation

capabilities) were 13C-labeled under biofilm reactors or planktonic conditions. Analysis of amino acid labeling variances from different cultures indicated Shewanella flux network was more flexibly changed than PAO1 during its biofilm formation.



Anomalously low δ13C values of foraminifera in the stratigraphy are usually interpreted to reflect activities of paleo-methane seepage. The application of this proxy, however, requires to understand the cause of anomalously low δ13C signals in foraminifera. Here we present stable carbon and oxygen isotopes (δ13C and δ18O), Mg/Ca ratios and accelerator mass spectrometry (AMS) radiocarbon data from Cores GMGS2-08B (∼0–5.5 m below the seafloor [mbsf]) and 08C (2–23 mbsf) at ∼798 m water depth, recovered from the gas hydrate-bearing sediments in the northeastern South China Sea (SCS). The main objectives are to investigate the primary versus secondary signals of extremely negative δ13C values of foraminifera and further recognize the methane emission events (MEEs). The δ13C values of benthic (Uvigerina peregrina and Cibicidoides spp.) and planktonic (Globigerinoides ruber and Pulleniatina obliquiloculata) foraminifera in these two cores show distinct intervals with negative values (as low as −15.85‰) that indicate the shift of the sulfate methane transition zone (SMTZ) and the change in methane release flux in the past. The δ13C records of U. peregrina by a more exhaustive cleaning procedure designed to remove authigenic carbonate coatings show that most δ13C values are still lower relative to those in the normal marine environment. The Mg/Ca ratios of Uvigerina spp. by this exhaustive cleaning procedure display higher values and more variable for anomalous tests (as high as 13.40 mmol/mol) than normal ones. These observations indicate the 13C-depleted signals of foraminifera are mainly originated from diagenetic alteration of authigenic carbonate precipitates with extremely negative δ13C values. Furthermore, the mass-balance approach is adopted to assess the relative contribution of methane-derived authigenic carbonate in the low-δ13C signals in foraminifera and reveals the maximum contribution can be as high as ∼30% among the δ13C anomalies. Additionally, several major MEEs with distinct characteristics can be recognized according to remarkable δ13C excursions of foraminifera in these two cores.



Nanofluids, which are dispersed nanoparticles (NPs) in aqueous or organic fluids, are effective in enhanced oil recovery. In this paper, different hydrophobic and hydrophilic silica NPs were dispersed in water to prepare nanofluids with the help of surfactants (CTAB, AOT, and TX-100). The contact angle of the model oil on the solid surface increased obviously when using the oil drop on a quartz plate immersed in nanofluids. Core flooding experiments showed that nanofluids displaced more oil from the core than the surfactant solution without NPs. Finally, we investigated the nanofluid effect mechanism on the separation of model oil from the solid surface by an adhesion work evaluation and the force–distance curve measurement with an atomic force microscope. We found that hydrophobic NPs were more easily adsorbed on the solid surface than hydrophilic NPs. Hydrophilic NPs were more easily adsorbed on the model oil surface than hydrophobic NPs. These results may provide a

better understanding of the complex phenomena involved in the enhanced spreading of nanofluids on solid surfaces.


https://doi.org/10.1111/1755-6724.13688

Heavy biodegraded crude oils have larger numbers of coeluting compounds than non‐ biodegraded oils, and they are typically not resolved with conventional gas chromatography (GC). This unresolved complex mixture (UCM) has been investigated using comprehensive two‐ dimensional gas chromatography–time‐of‐flight mass spectrometry (GC×GC‐ToFMS) within a set of biodegraded petroleums derived from distinct sedimentary basins, including northwestern Sichuan (Neoproterozoic, marine), Tarim (Early Paleozoic, marine), Bohai Bay (Eocene, saline/brackish) and Pearl River Mouth (Eocene, freshwater). In general, the hydrocarbons that constitute the UCM in petroleum saturate fractions can be classified into three catalogues based on the distributions of resolved compounds on two dimensional chromatograms. Group 1 is composed mainly of normal and branched alkanes, isoprenoid alkanes and monocyclic alkanes; Group 2 comprises primarily terpanes ranging from two to five rings, and Group 3 is dominated by monoaromatic hydrocarbons such as tetralins and monoaromatic steranes. In addition, the UCM is source dependent and varies between oil populations. i.e., the UCM of petroleum derived from Precambrian and Early Paleozoic marine, Eocene saline/brackish and freshwater source rocks is specifically rich in higher homologues of A‐norsteranes, series of 1,1,3‐trimethyl‐2‐ alkylcyclohexanes (carotenoid‐derived alkanes), and tetralin and indane compounds, respectively.

Wang, H., Hu, X., Rabalais, N.N., Brandes, J., 2018. Drivers of oxygen consumption in the Northern Gulf of Mexico hypoxic waters—a stable carbon isotope perspective. Geophysical Research Letters 45, 10,528-10,538.

https://doi.org/10.1029/2018GL078571

Abstract: We examined the stable carbon isotopic composition of remineralized organic carbon (δ13COCx) in the northern Gulf of Mexico (nGoM) using incubations (sediment and water) and a three‐end‐member mixing model. δ13COCx in incubating sediments was −18.1‰ ± 1.3‰, and δ13COCx in incubating near‐surface and near‐bottom waters varied with salinity, ranging from −30.4‰ to −16.2‰ from brackish water to full‐strength Gulf water. The average δ13COCx was −18.6‰ ± 1.8‰ at salinity >23. A three‐end‐member mixing model based on a multiyear data set collected in previous summer hypoxia cruises (2011, 2012, 2014, 2015, and 2016) suggested that δ13COCx in near‐bottom waters across the nGoM (5–50 m) was −18.1‰ ± 0.6‰. The close agreement of δ13COCx obtained from the three independent approaches, that is, incubations of water column, surface sediments, and mixing model, suggests that 13C‐enriched organic matter of marine origin played the dominant role in near‐bottom water and benthic oxygen consumption in the nGoM shelf in summer.

Plain Language Summary: Bottom water hypoxia, that is, dissolved oxygen concentration < 2 mg/L, has been increasingly disrupting important coastal ecosystems. The ultimate reasons for causing the low oxygen levels include stratified physical conditions that isolate bottom water from oxygen‐rich surface water and rapid respiration in the bottom water, where microbes feed on organic matter (OM) and at the same time consume oxygen. In complex coastal environments, OM can be supplied from multiple sources, including river delivery, coastal erosion, and primary production enhanced by

terrestrial nutrient loading. On the Louisiana shelf of the northern Gulf of Mexico, where extensive summer hypoxia has been frequently observed, the type of OM that fuels bottom water oxygen consumption on a broad scale has not been systematically examined. Using field data and lab experiments, we address the question regarding the OM source issue on the Louisiana shelf. Our findings suggest that respiration of terrestrial OM is restricted to a low‐salinity zone where river influence is significant, while marine‐generated OM is dominant in the much broader Louisiana shelf. As the marine production is closely associated with land‐derived nutrients, curbing the hypoxia problem requires unambiguous and persistent management in fertilizer usage upstream.

Wang, H., Pu, Y., Ragauskas, A., Yang, B., 2019. From lignin to valuable products–strategies, challenges, and prospects. Bioresource Technology 271, 449-461.


The exploration of effective approaches for the valorization of lignin to valuable products attracts broad interests of a growing scientific community. By fully unlocking the potential of the world’s most abundant resource of bio-aromatics, it could improve the profitability and carbon efficiency of the entire biorefinery process, thus accelerate the replacement of fossil resources with bioresources in our society. The successful realization of this goal depends on the development of technologies to overcome the following challenges, including: 1) efficient biomass pretreatment and lignin separation technologies that overcomes its diverse structure and complex chemistry challenges to obtain high purity lignin; 2) advanced chemical analysis for precise quantitative characterization of the lignin in chemical transformation processes; 3) novel approaches for conversion of biomass-derived lignin to valuable products. This review summarizes the latest cutting-edge innovations of lignin chemical valorization with the focus on the aforementioned three key aspects.

Wang, H., van Hunen, J., Pearson, D.G., 2018. Making Archean cratonic roots by lateral compression: A two-stage thickening and stabilization model. Tectonophysics 746, 562-571.


Archean tectonics was capable of producing virtually indestructible cratonic mantle lithosphere, but the dominant mechanism of this process remains a topic of considerable discussion. Recent geophysical and petrological studies have refuelled the debate by suggesting that thickening and associated vertical movement of the cratonic mantle lithosphere after its formation are essential ingredients of the cratonization process. Here we present a geodynamical study that focuses on how the thick stable cratonic lithospheric roots can be made in a thermally evolving mantle. Our numerical experiments explore the viability of a cratonization process in which depleted mantle lithosphere grows via lateral compression into a >200-km thick, stable cratonic root and on what timescales this may happen. Successful scenarios for craton formation, within the bounds of our models, are found to be composed of two stages: an initial phase of tectonic shortening and a later phase of gravitational self-thickening. The initial tectonic shortening of previously depleted mantle material is essential to initiate the cratonization process, while the subsequent gravitational self-thickening contributes to a second thickening phase that is comparable in magnitude to the initial tectonic phase. Our results show that a combination of intrinsic compositional buoyancy of the cratonic root, rapid cooling of the root after shortening, and the long-term secular cooling of the mantle prevents a Rayleigh-Taylor type collapse, and will stabilize the thick cratonic root for future preservation. This two-stage thickening model provides a geodynamically viable cratonization scenario that is consistent with petrological and geophysical constraints.



The active Haima cold seep sites were discovered by the remotely operated vehicle on the western part of the northern slope of South China Sea in 2015 and 2016. However, the subsurface structures in the seep area are not well studied, which prevents the further understanding of the evolution of fluid venting system in the active cold seep area. In 2017, a high-resolution 2D seismic line transecting the two main seep sites was acquired and processed. In this study, the subsurface structures were well resolved on the seismic profile. The new observations include the widespread subsurface fluid flow features (i.e., chimney structures and pockmarks) and the pervasively distributed magmatic activities. Seismic indicators for hydrothermal vents were also observed on the seismic section. This new discovery confirms the contribution of magmatic activities to the evolution of subsurface fluid flow in the study area. Minor faults under the recognizable resolution of seismic profile, which can act as conduits for the subsurface fluid flow, were also identified in the fine-grained sediment sequences. Overall, these results provide new insights into the evolution of subsurface fluid flow in the study area.

Wang, J., Wu, S., Yao, Y., 2018. Quantifying gas hydrate from microbial methane in the South China Sea. Journal of Asian Earth Sciences 168, 48-56.


Methane hydrate has been confirmed to be present in the South China Sea (SCS) based on drilling expeditions and geophysical indications. It is necessary to access the methane hydrate inventory because of its role in the energy resources and climate change. The aim of this study is to constrain the inventory of methane hydrates in the SCS formed by the microbial degradation of organic matter within the gas hydrate stability zone (GHSZ). Bathymetry, seafloor temperature, and geothermal gradient datasets enabled us to estimate the GHSZ at a resolution of 30″×30″ for the SCS. We conclude that the GHSZ occurs at water depths of >500 m in most areas of the SCS. The methane hydrate distribution formed by microbial methane production in the SCS was computed using the parameterized transfer function recently proposed by Wallmann et al. (2012). The result indicates widespread accumulations of methane hydrate along the continental slopes in the SCS. The microbial methane hydrate is distributed over a 7.69 × 1011 m2 area and the total abundance of methane hydrate in the SCS is estimated to be 42.8 Gt C.

Wang, J., Xu, Y., Zhou, L., Shi, M., Axia, E., Jia, Y., Chen, Z., Li, J., Wang, G., 2018. Disentangling temperature effects on leaf wax n-alkane traits and carbon isotopic composition from phylogeny and precipitation. Organic Geochemistry 126, 13-22.


Leaf wax n-alkanes are terrestrial plant biomarkers that have characteristics that are widely employed as proxies for climatic conditions. Understanding the relationship between different environmental factors to the amounts and types of leaf wax n-alkanes in modern plants is crucial for the application of these proxies to paleoenvironmental reconstructions. However, the effects of climate conditions on plant wax characteristics remain complicated due to the interactions among temperature, precipitation and phylogeny. To evaluate the effect of temperature with minimized interfering factors, we collected

106 Artemisia plants across a 15 °C mean annual temperature gradient along the 400 mm isohyet in China. Both total n-alkane concentration (∑alk) and carbon preference index (CPI) varied greatly but did not correlate with temperature. Average chain length (ACL) increased with temperature, especially summer temperature (TJJA, June–August), indicating that ACL could be used as proxy for temperature. The stable carbon isotope compositions of n-C27, n-C29 and n-C31 were very similar in each plant (−38.2‰ to −30.0‰, −39.0‰ to −30.2‰, −38.7‰ to −30.5‰, respectively), which reflects a similar biosynthetic process for all three n-alkane homologues of Artemisia. There was a positive relationship between δ13C of bulk leaf tissues (δ13Cbulk) and of n-alkanes (δ13Calk), and the average offset of δ13C29 relative to δ13Cbulk (εC29/bulk) was −7.1‰. Increasing trends in both δ13Cbulk and δ13C29 were found with temperature. However, correlation of δ13Cbulk with temperature (R2 = 18%) was much weaker than that of δ13C29 with temperature (R2 = 60%). Therefore, δ13C29 appears to be a better proxy of paleotemperature than δ13Cbulk.

Wang, L., Jiang, B., Chen, R., Li, Y., 2018. Evolutions of nanoscale pore and chemical structures of tectonically deformed coals after supercritical CO2 treatment. International Journal of Oil, Gas and Coal Technology 19, 477-500.


Supercritical CO2 treatments were carried out for four coal samples with different deformation degrees at around 35°C and 10 MPa for 5 h. Nanoscale pore and chemical structures of coals before and after treatments were studied via liquid nitrogen adsorption and X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) tests. The results showed that coal deformation induced more spaces and contact areas, and thus supercritical CO2 treatment presents improved effects on pore volume and specific surface area with increasing coal deformation degree. Moreover, supercritical CO2 treatment mainly induced increased pore volumes of pore types I (< 10 nm) and II (10-50 nm) and specific surface area of pore type I. In addition, supercritical CO2 treatment exerts substantial effects on chemical structures, including increased aromatic layer spacing, decreased the aliphatic compound or ethers, alcohols, and lipids, which is also related to coal deformation degrees. The experiments revealed that treated tectonically deformed coals present greater growths in gas adsorption and diffusion spaces and more obvious changes in chemical structure than the undeformed coal, which can improve CO2 storage and seepage.



Current US unconventional resource revolution has more than doubled US oil production and made US the largest oil production country in the world recently. Although the industry is trying all means including screening sweet spots, conducting infill drillings and optimizing the well spacing to improve recovery factor (RF) from primary production, unconventional reservoirs will encounter what the past conventional reservoir production experienced: difficult to explore new giant resource, run out of ‘easy oil’ (sweet spot), production comes to a plateau and declines. Therefore, it is time to implement enhanced oil recovery for unconventional resources. The goal of this work is to improve oil recovery by implementing and optimizing gas Huff and Puff method for one of the US major tight oil reservoirs-Bakken formation. Pressure dependent permeability and porosity are implemented into the compositional reservoir simulation to represent geomechanics effects. Gas diffusion effects is systematically analyzed to quantify the importance comparing with the natural fracture system in tight oil fractured reservoirs. Alternative gas composition instead of using CO2 in the Huff and Puff

process is investigated and the recovered oil components is analyzed. The complex natural fracture structure and natural fracture permeability proved to be important affecting factors to oil production of Bakken reservoirs.

Wang, N., Luo, Y.-W., Polimene, L., Zhang, R., Zheng, Q., Cai, R., Jiao, N., 2018. Contribution of structural recalcitrance to the formation of the deep oceanic dissolved organic carbon reservoir. Environmental Microbiology Reports 10, 711-717.

https://doi.org/10.1111/1758-2229.12697

The origin of the recalcitrant dissolved organic carbon (RDOC) reservoir in the deep ocean remains enigmatic. The structural recalcitrance hypothesis suggests that RDOC is formed by molecules that are chemically resistant to bacterial degradation. The dilution hypothesis claims that RDOC is formed from a large diversity of labile molecules that escape bacterial utilization due to their low concentrations, termed as RDOCc. To evaluate the relative contributions of these two mechanisms in determining the long‐term persistence of RDOC, we model the dynamics of both structurally recalcitrant DOC and RDOCc based on previously published data that describes deep oceanic DOC degradation experiments. Our results demonstrate that the majority of DOC (84.5 ± 2.2%) in the deep ocean is structurally recalcitrant. The intrinsically labile DOC (i.e., labile DOC that rapidly consumed and RDOCc) accounts for a relatively small proportion and is consumed rapidly in the incubation experiments, in which 47.8 ± 3.2% of labile DOC and 21.9 ± 4.6% of RDOCc are consumed in 40 days. Our results suggest that the recalcitrance of RDOC is largely related to its chemical properties, whereas dilution plays a minor role in determining the persistence of deep‐ocean DOC.



Large-scale exploration and development of shale gas in Lower Cambrian Niutitang Formation of South China has been carried out in recent years, but the result is not good, only except some drilling wells in Jingyan-Qianwei area of Sichuan Basin and Yichang of Hubei obtain some commercial gas flows. In order to clarify reasons for failure of shale gas exploration and development in Niutitang Formation around Sichuan Basin and to provide reservoir geological parameters for subsequent efficient exploration and development, taking a case of shale gas reservoirs in Lower Cambrian Niutitang Formation in northeast Chongqing around Sichuan Basin, some experimental methods, such as analysis of organic carbon pyrolysis, determination of equivalent vitrinite reflectance, focused ion beam scanning electron microscope (FIB-SEM) and other are adopted in this study. The results show that the average TOC of shale samples in Niutitang Formation in northeast Chongqing is 3.1%, the equivalent vitrinite reflectance ranges from 3.0% to 4.0%, and the degree of thermal evolution reaches the post-mature–metamorphic stage. Due to excessively high degree of the thermal evolution, organic pores in shale samples are not developed in Lower Cambrian Niutitang Formation in the study area, instead, micro-nano pores dominated by intergranular pores and intragranular pores are developed in the shale. The degree of the thermal evolution controls the sustaining gas generation of kerogen and retained liquid hydrocarbons in the shale, it also controls the development of organic pores of the shale. The evolution of organic pores and hydrocarbon generation in the shale of Niutitang Formation in northeast Chongqing around Sichuan Basin do not match best with each other, that is, during development period of a large number of organic pores, thermal evolution degree of reservoirs is further enhanced because the strata are not uplifted in time, therefore, the quantity of

organic pores is decreased sharply, the shale gas would be escaped due to the absence of organic pores as effective storage space after the shale gas generation. Therefore, the efficient exploration and development of the shale gas in Lower Cambrian Niutitang Formation in South China should be focused on the shale development area where the shale is characterized by moderate thermal evolution degree (2.0% < Ro < 3.0%) and shallow buried depth, that is, the shale distribution area with paleo-uplift or paleo-buried hill.



A comprehensive investigation of oil composition is important for the petroleum industry as well as the understanding of natural science. Ketones commonly exist in petroleum; however, as a result of the low concentrations and limitations inherent in the analytical technique, the molecular composition of these compounds is rarely studied. In this study, ketones in a source rock were characterized by gas chromatography–mass spectrometry, Fourier transform ion cyclotron resonance mass spectrometry, and Orbitrap mass spectrometry. Ketones were derivatized with the Girard T reagent under weakly acidic conditions to enhance their detectability by electrospray ionization mass spectrometry (ESI MS) analysis. Atmospheric pressure photoionization mass spectrometry (APPI MS) was also used for the molecular characterization of ketones without chemical derivatization. The characterization techniques were complementary to each other, and the results were consistent in general. The chemical derivatization followed by positive-ion ESI MS analysis is suitable for the analysis of ketones in a trace amount, but it had discrimination on high double bond equivalent (DBE) species (DBE ≥ 9). Direct analysis with positive-ion APPI MS showed comparable ionization efficiency throughout the DBE range and could distinguish aliphatic ketones from aromatic ketones according to different ionization pathways.

Wang, Q., Chen, D., Peckmann, J., 2019. Iron shuttle controls on molybdenum, arsenic, and antimony enrichment in Pliocene methane-seep carbonates from the southern Western Foothills, Southwestern Taiwan. Marine and Petroleum Geology 100, 263-269.


Certain trace metals are anomalously enriched in sediments and pore fluids at cold hydrocarbon seeps. Recent studies ascribed such anomalies, particularly those of molybdenum (Mo), arsenic (As), and antimony (Sb), to so-called particulate shuttle processes by manganese and iron oxyhydroxides. However, there are still some uncertainties about the prevalence of this mechanism, and it is difficult to generally rule out an influence of deep ascending fluids on trace metal enrichments. The Pliocene Chiahsien seep carbonates from the southern Western Foothills of Southwestern Taiwan were precipitated through anaerobic oxidation of methane contained in fluids that yielded no evidence for an admixture of deep ascending fluids. These authigenic carbonates consequently represent a good example to explore the role of particulate shuttle processes on the enrichments of trace metals. The Chiahsien seep carbonates reveal strong enrichment of authigenic Mo relative to uranium (U), reflected in high Mo/U ratios that are much higher than those of seawater. Such a pattern of Mo–U covariation is best explained by a weak particulate shuttle process that operated during the formation of the Chiahsien seep carbonates. Furthermore, the seep carbonates show exceptional Mo, As, and Sb enrichments with no U enrichment and strong covariations between the former three trace metals and reactive iron. These findings indicate that iron oxyhydroxide particulate shuttles indeed played an intrinsic role in the enrichments of Mo, As, and Sb at the Pliocene seeps. Our findings confirm the

potential importance of iron particulate shuttles on the biogeochemistry of marine cold seeps, but the factors governing the presence or absence of particulate shuttles are insufficiently understood and require more research on trace metal sequestration at seeps in the future.

Wang, Q., Huang, L., 2019. Molecular insight into competitive adsorption of methane and carbon dioxide in montmorillonite: Effect of clay structure and water content. Fuel 239, 32-43.


The microscopic competitive adsorption mechanism of methane (CH4) and carbon dioxide (CO2) is of fundamental significance for CO2 sequestration with enhanced gas recovery (CS-EGR) in clay-rich shale gas reservoirs, which is still in a preliminary research stage. In this study, the Na-montmorillonite models with various pore sizes and water densities were generated to gain insights into the CO2/CH4 competitive adsorption behaviors using the combined molecular dynamics and grand canonical Monte Carlo simulations. The effects and corresponding mechanisms of clay pore size, structure heterogeneity and water content on CO2/CH4 adsorption capacity, contribution of selectivity and isosteric adsorption heat were discussed in detail. Simulation results show that the Na-montmorillonite clay favors the preferential adsorption of CO2 over CH4, and the preferential adsorption of CO2 reduces with increasing clay pore size and pressure. Adsorbility factor is the major contribution for the CO2/CH4 adsorption selectivity in dry clay models, while the contribution of volumetric factor enhances with rising pore heterogeneity caused by increasing water content and decreasing pore size. The physical pore heterogeneity in the upper near-wall region resulted from Na+

distribution, associated with the difference of CO2/CH4 dynamic diameter is one reason for the asymmetrical CO2/CH4 density profiles, while the strong affinity between CO2/Na+ and substituted Al atoms in the upper tetrahedron is the other reason. Interestingly, a later increase of CO2/CH4 adsorption selectivity with further rising water density is observed, which is due to the solvation of Na+ in interlayer water phase, re-exposing some high energy adsorption sites for CO2 adsorption. This result provides implication that the CS-EGR efficiency can be potentially improved by increasing the water content in clay. This study gains deep insights into the CO2/CH4 competitive adsorption mechanism in montmorillonite clay at microscopic scale, and can open new potentials for tuning the application of CS-EGR in clay-rich shale gas reservoirs.

Wang, Q., Song, J., Yuan, H., Li, X., Li, N., Wang, Y., 2018. Sources and burial of particulate organic matter in the Kuroshio mainstream and its response to climate change over the past millennium. Geo-Marine Letters 38, 497-511.

https://doi.org/10.1007/s00367-018-0551-9

Sedimentation rate and biogenic elements of a sediment core KET-1 recovered from Kuroshio Mainstream, east of Taiwan, were determined to investigate variation of organic carbon burial and its response to climate fluctuations. The results showed that the organic carbon burial flux was mainly depended on the sedimentation rate and the input of river particles had a dilution effect on total organic carbon (TOC) content of the sediment. Based on the organic carbon burial flux, the entire depositional process could be divided into three stages, which exactly corresponded to three specific climate periods over the past millennium. During the Medieval Warm Period (MWP, ad 1150–1250), the strong East Asian summer monsoon (EASM) caused more river input to the sea, resulting in high sedimentation rate and high organic carbon burial flux, meanwhile the dilution effect of river particles as well as low marine primary productivity resulted in relatively low proportion of marine organic matter (MOM) in the sediment, which was reflected by low TOC content. During the Little Ice Age (LIA, ad 1400–1835), lower organic burial flux and higher marine primary productivity as well as

higher TOC content in the sediment were accompanied by weakened EASM. In the Modern Period (MP, ad 1835–present), however, the correlation between organic carbon burial and climate fluctuations that was found to be significant during the MWP and LIA had been greatly changed, and anthropogenic forcing was thought to be the primary driving factor. Overall, the climate variability and anthropogenic activities over the past millennium dominated the organic carbon burial in the sediment along the Kuroshio mainstream.

Wang, Q., Tong, H., Huang, C.-Y., Chen, D., 2018. Tracing fluid sources and formation conditions of Miocene hydrocarbon-seep carbonates in the central Western Foothills, Central Taiwan. Journal of Asian Earth Sciences 168, 186-196.


Hydrocarbon-seep carbonates were discovered to be hosted within Miocene marine mudstone in the central Western Foothills near the Kuohsing area, Central Taiwan. Here, we present field observations, petrography, mineralogy, stable carbon isotope data, as well as rare earth element compositions. We evaluate the role of diagenetic alteration on the Kuohsing seep carbonates and constrain their fluid sources and formation conditions. Four main morphologies in the field were observed, including cylindrical columns, massive forms, lenticular nodules, and stratiform bodies. Petrographically, the carbonates are predominantly composed of partially recrystallized calcite and dolomite, with abundant amounts of biogenic detritus, pyrite aggregations and unidentified filaments. Isotopic analyses show that carbon isotope values inversely vary with oxygen isotope values, indicating substantial modification of the carbon isotope compositions of the carbonates by diagenetic processes. Extremely negative δ13C values as low as −47.6‰ recognized as a near-primary isotopic signature recorded in the carbonates, an end member of the trend, reveals that methane was incorporated during the carbonate precipitation. On the other hand, the carbonates have well preserved primary REE compositions, exhibiting MREE enrichment, no La and Ce anomalies, and supra-chondritic Y/Ho ratios. These REE patterns suggest that the Kuohsing authigenic carbonates were precipitated from reducing seep fluids with limited admixture of seawater.

Wang, S., Liu, G., Zhang, J., Zhou, L., Lam, P.K.S., 2019. An effective method for reconstructing the historical change in anthropogenic contribution to sedimentary organic matters in rivers. Science of The Total Environment 655, 968-976.


Surface water quality has been greatly affected by anthropogenic activities around the world in the past decades. Scientists and policymakers should pay close attention to quantify historical change in human impacts on aquatic environment. An effective method for reconstructing the historical input of anthropogenic organic matters in aquatic environment is urgently required. Here, five sediment cores from the Huaihe River were analyzed for n-alkanes (C8–C40) and isoprenoid alkanes (pristane and phytane) using gas chromatography–mass spectrometry (GC–MS). Sixty years (1955–2014) sedimentary history of n-alkanes was reconstructed using 210Pb method. The evaluation of wax n-alkanes percentage (WNA) indicated that the terrestrial higher plant input was predominant in most samples. The main anthropogenic sources were the petroleum hydrocarbon, fossil fuel combustion and the discharge of industrial wastewater and domestic sewage. The results of principal component analysis-multiple linear regression (PCA-MLR) indicated that the respective contributions of anthropogenic and biogenic sources to sedimentary organic matters were 47.8% and 48.1% in the Huaihe River. Furthermore, the anthropogenic contribution displayed a decrease trend from 1991 to 2014, which probably attributed to the effective pollution control measures taken by the local

government. However, the anthropogenic contribution was still considerable during this period. Thus, the government should pay attention to organic pollution control in the Huaihe River sediments continuously. In summary, this study provides an effective method for reconstructing the historical change in anthropogenic contribution to sedimentary organic matters in rivers, which can probably be applied to other aquatic environment around the world.

Wang, X., Li, N., Feng, D., Hu, Y., Bayon, G., Liang, Q., Tong, H., Gong, S., Tao, J., Chen, D., 2018. Using chemical compositions of sediments to constrain methane seepage dynamics: A case study from Haima cold seeps of the South China Sea. Journal of Asian Earth Sciences 168, 137-144.


Cold seeps frequently occur at the seafloor along continental margins. The dominant biogeochemical processes at cold seeps are the combined anaerobic oxidation of methane and sulfate reduction, which can significantly impact the global carbon and sulfur cycles. The circulation of methane-rich fluids at margins is highly variable in time and space, and assessing past seepage activity requires the use of specific geochemical markers. In this study, we report multiple sedimentary proxy records for three piston gravity cores (QDN-14A, QDN-14B, and QDN-31) from the Haima seep of the South China Sea (SCS). By combining total organic carbon (TOC), total inorganic carbon (TIC), total nitrogen (TN), total sulfur (TS), acid insoluble carbon and sulfur isotope (δ13Corganic carbon and δ34Sacid-insoluble), and δ34S values of chromium reducibility sulfur (δ34SCRS), as well as carbon isotopes of TIC (δ13CTIC) in sediments, our aim was to provide constraints on methane seepage dynamics in this area. We identified three sediment layers at about 260–300 cm, 380–420 cm and 480–520 cm sediment depth, characterized by particular anomalies of low δ13CTIC values and high TS content, high TS and CRS contents, and high δ34Sacid-insoluble and δ34SCRS values, respectively. On this basis, we propose that these sediment horizons correspond to distinct methane release events preserved in the sediment record. While the exact mechanisms accounting for the presence (or absence) of these particular geochemical signals in the sediment are not known, we propose that they correspond to variations in methane flux and their duration through time. Overall, our results suggest that sedimentary carbon and sulfur and their isotopes are useful tracers for better understanding of methane seepage dynamics over time.

Wang, X., Li, X., Yu, L., Huang, L., Xiu, J., Lin, W., Zhang, Y., 2019. Characterizing the microbiome in petroleum reservoir flooded by different water sources. Science of The Total Environment 653, 872-885.


Petroleum reservoir is an unusual subsurface biosphere, where indigenous microbes lived and evolved for million years. However, continual water injection changed the situation by introduction of new electron acceptors, donors and exogenous microbes. In this study, 16S-rRNA gene sequencing, comparative metagenomics and genomic bins reconstruction were employed to investigate the microbial community and metabolic potential in three typical water-flooded blocks of the Shen84 oil reservoir in Liaohe oil field, China. The results showed significant difference of microbial community compositions and metabolic characteristics existed between the injected water and the produced water/oil mixtures; however, there was considerable uniformity between the produced samples in different blocks. Microbial communities in the produced fluids were dominated by exogenous facultative microbes such as Pseudomonas and Thauera members from Proteobacteria phylum. Metabolic potentials for O2-dependent hydrocarbon degradation, dissimilarly nitrate reduction, and thiosulfate-sulfur oxidation were much more abundant, whereas genes involved in dissimilatory sulfate reduction, anaerobic hydrocarbon degradation and methanogenesis were less

abundant in the oil reservoir. Statistical analysis indicated the water composition had an obvious influence on microbial community composition and metabolic potential. The water-flooding process accompanied with introduction of nitrate or nitrite, and dissolved oxygen promoted the alteration of microbiome in oil reservoir from slow-growing anaerobic indigenous microbes (such as Thermotoga, Clostridia, and Syntrophobacter) to fast-growing opportunists as Beta- and Gama- Proteobacteria. The findings of this study shed light on the microbial ecology change in water flooded petroleum reservoir.



Seafloor features, seismic amplitude anomaly, geophysical attributes, and chemosynthetic community are different in the methane seepage areas of Taixinan Basin, South China Sea. We integrate the new acquired seafloor images with seismic data to present the differences of three cold seeps which are associated with fluid flows. These three cold seeps include two inactive sites (CS02-8 and CS02-9) and one active site (Site F). At site CS02-8 area, the seafloor carbonate and buried carbonate layer are identified from core samples at Site GMGS2-08. BSR is interrupted by the upward migration of fluids from the base of gas hydrate stability zone (BGHSZ) and gas hydrate-bearing sediments show pull-up seismic reflections below the buried carbonate layer. At site CS02-9 area, near seafloor carbonate was found at hole GMGS2-09B where a 62 m-high pinnacle and gas hydrate were also found from the core samples. The LWD data at hole 09A indicate that free gas is present below the depth of 64 m without gas hydrate. The average saturations of free gas estimated from P-wave velocity are about 3% with a patchy distribution and 0.3% with homogenous distribution respectively, which is accord with the enhanced reflection below BGHSZ. At Site F area, the exposed gas hydrate, carbonate and flourishing chemosynthetic communities are detected using ROV with a high amplitude seismic reflection at seafloor. The BSR is interrupted by a chimney structure from the seismic data which indicates that the fluids are migrating vertically and rise to the seafloor as gas bubbles. The geophysical evidence at these three seep sites show that pore-filling gas hydrates with saturations ranging from 10% to 40% are widely distributed above the BSR. However, massive or vein gas hydrates only occur around cold seeps.

Wang, X., Nie, J., Yu, G., Wang, P., Li, Z., Lee, M., 2018. Microwave-assisted-demulsification–dispersive liquid–liquid microextraction coupled with gas chromatography–mass spectrometry for the determination of PAHs in water. Analytical Methods 10, 5105-5111.

http://dx.doi.org/10.1039/C8AY01794H

IIn this study, a novel technology of microwave-assisted-demulsification–dispersive liquid-liquid microextraction (MAD–DLLME) was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples, which was followed by gas chromatography–mass spectrometry (GC–MS). The key to MAD–DLLME is based on the formation of an emulsion, where target analytes can partition between two phases, and subsequently employing microwave irradiation to achieve phase separation. To the best of our knowledge, it's the first time that microwave-assisted-demulsification has been introduced into sample preparation technology. Under the optimal conditions, the response of the proposed method was found to be linear in the concentration range of 0.05–10.0 μg L−1 for most target analytes. The limits of detection for S/N = 3 ranged between 0.3 and 7.1 ng L−1, and relative standard deviations (RSDs) were in the range of 1.1–

6.7%. Finally, water samples collected from West Lake and the Qiantang River (Hangzhou, China) were used for verification of the applicability of the developed method, which was demonstrated to be rapid, simple, efficient, reliable, and environmentally friendly.



Significance: Archaeorhynchus spathula is a basal member of the Ornithuromorpha, the lineage that includes neornithines. Although this is the fifth reported specimen, unlike the others it preserves significant soft tissue, revealing a tail morphology previously unknown in Mesozoic birds and an exceptional occurrence of fossilized lung tissue. This identification is based on topographical location and anatomical features revealed mainly by scanning electron microscopy. A structure similar to that in neornithines indicates that the 120-Ma-old Archaeorhynchus may have been capable of acquiring the large quantities of oxygen needed to support powered flight. Skeletal features related to respiration remain primitive, supporting inferences that many physiological adaptations preceded skeletal changes during the evolution of the anatomically modern bird.

Abstract: We describe a specimen of the basal ornithuromorph Archaeorhynchus spathula from the Lower Cretaceous Jiufotang Formation with extensive soft tissue preservation. Although it is the fifth specimen to be described, unlike the others it preserves significant traces of the plumage, revealing a pintail morphology previously unrecognized among Mesozoic birds, but common in extant neornithines. In addition, this specimen preserves the probable remnants of the paired lungs, an identification supported by topographical and macro- and microscopic anatomical observations. The preserved morphology reveals a lung very similar to that of living birds. It indicates that pulmonary specializations such as exceedingly subdivided parenchyma that allow birds to achieve the oxygen acquisition capacity necessary to support powered flight were present in ornithuromorph birds 120 Mya. Among extant air breathing vertebrates, birds have structurally the most complex and functionally the most efficient respiratory system, which facilitates their highly energetically demanding form of locomotion, even in extremely oxygen-poor environments. Archaeorhynchus is commonly resolved as the most basal known ornithuromorph bird, capturing a stage of avian evolution in which skeletal indicators of respiration remain primitive yet the lung microstructure appears modern. This adds to growing evidence that many physiological modifications of soft tissue systems (e.g., digestive system and respiratory system) that characterize living birds and are key to their current success may have preceded the evolution of obvious skeletal adaptations traditionally tracked through the fossil record.

Wang, Y., Liao, B., Kong, Z., Sun, Z., Qiu, L., Wang, D., 2018. Oscillating electric field effects on adsorption of the methane–water system on kaolinite surface. Energy & Fuels 32, 11440-11451.


A quantitative understanding of oscillating electric field effects on adsorption of the methane–water system on kaolinite surfaces is vital for enhancing methane desorption and forecasting gas production. We have performed nonequilibrium molecular dynamics simulations to investigate the adsorption behaviors of methane–water on the kaolinite (0 0 1) surface applying oscillating electric fields in the frequency range of 0–100 GHz and amplitudes of 0–0.25 V/Å. The simulated results demonstrate that water will preferentially adsorb onto the surface, forming a water layer and

preventing the adsorption of methane and thus leading to the reduced adsorption of methane. The applied oscillating electric fields contribute to a thicker water layer and a smaller amount of adsorbed methane for the water–methane system on kaolinite surfaces. Furthermore, higher oscillating frequency and stronger intensity of the applied electric fields facilitate the desorption of methane. These phenomena associate with the fact that the applied oscillating fields reduce hydrogen bond amounts on the interface of kaolinite, and higher frequencies or stronger intensities further break hydrogen bonds. Meanwhile, the interaction energy of water–kaolinite and the self-diffusion coefficient of water increase with the frequency and intensity of the applied electric fields. This study helps us to understand the mechanism of how oscillating electric fields affect the adsorption behaviors of the methane–water system on kaolinite surfaces and is of applicable importance to boost gas production.

Wang, Y., Liu, H., Song, G., Hao, X., Zhu, D., Zhu, D., 2018. Formation mechanism of carbonates in the lacustrine muddy shale and it implication for shale oil and gas: A case study of source rocks in Member 4 and Member 3 of Shahejie Formation, Dongying sag. Petroleum Research 3, 248-258.


Through analysis of microscopic characteristics, mineral components, elements and isotopes, the genetic mechanism of carbonates in the deep lacustrine source rocks in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag, is well investigated. The results show that four types of carbonates in the deep lake, i.e., lenticular coarse crystalline carbonate, lamellar micro-fine crystalline carbonate, lamellar cryptocrystalline carbonate and massive cryptocrystalline carbonate. Of which, the lenticular coarse crystalline carbonate is formed by diagenetic recrystallization. For the lamellar micro-fine crystalline carbonate and the lamellar cryptocrystalline carbonate, through the alga photosynthesis, the carbon dioxide (CO2) is constantly extracted from water, thus the concentration of CO3

−2 ion in water increases, and then the CO3

−2 ion reacts with Ca2+ ion in lake water surface to form the carbonates; the saline water environment is favorable for preservation of carbonate particles which mostly occur in lamellar micro-fine crystalline; in the brackish water environment, the water is deep, and the carbonate crystalline beneath the carbonate compensation depth surface is usually is dissolved, and most of lamellar cryptocrystalline are preserved. The massive cryptocrystalline carbonate is formed by the sedimentary carbonate which transport from shallow water to deep water by gravity flow. To some extent, the carbonates control reservoir property and compressibility of muddy shale in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag, and provide important information for reconstruction of sedimentary environment of the ancient lake.

Wang, Y., Qian, X., Cawood, P.A., Liu, H., Feng, Q., Zhao, G., Zhang, Y., He, H., Zhang, P., 2018. Closure of the East Paleotethyan Ocean and amalgamation of the Eastern Cimmerian and Southeast Asia continental fragments. Earth-Science Reviews 186, 195-230.


The Phanerozoic record of Southeast Asia preserves the history of opening and subsequent consumption of the Paleotethyan Ocean and the assembly of continental fragments into Asia as part of the broader-scale reconstruction of Pangea. However, uncertainty remains as to which of the many suture zones in Southeast Asia represents the relict of the main ocean, when final ocean closure occurred, and the assembly history of the Eastern Cimmerian and Southeast Asia continental fragments. Our overview of the geological features of the suture zones, the bounding continental

fragments and their magmatic, metamorphic and sedimentary records resolves many of these key issues. The sedimentary, biogeographical, structural, lithological, geochemical and geochronological data from the Changning-Menglian, Inthanon and Bentong-Raub suture zones argue for their linkage with the Longmu Co-Shuanghu suture zone in Central Tibet, and together constitute the main East Paleotethyan Ocean relict. The eastward subduction of the ocean resulted in the development of a series of magmatic arc-back-arc basin and continental fragments in Southeast Asia, including, from west to east, the Lincang-Sukhothai-East Malaya arc, the Jinghong-Nan-Sa Kaeo back-arc basin, the Simao/west Indochina fragment, the Luang Prabang-Loei back-arc basin, the south Indochina fragment, the Wusu and Truong Son back-arc basins, the north Indochina fragment, the Jinshajiang-Ailaoshan-Song Ma branch/back-arc basin and the South China Block. Assembly of these fragments resulted in Indosinian high temperature and high pressure metamorphism and related tectonothermal event. Available data indicate a switch from subduction of the main East Paleotethyan Ocean to the collision of the Sibumasu with Simao/Indochina blocks at ~237Ma, with subsequent syn- and post-collisional events at ~237–230Ma and ~230–200Ma, respectively, along the Changning-Menglian, Inthanon and Bentong-Raub suture zones. The timing of initial-, syn- and post-collision events along the Jinshajiang-Ailaoshan-Song Ma suture zone with its record of back-arc basin closure is at ~247Ma, ~247–237Ma and ~237–200Ma, generally ~10Ma older than that along the Changning-Menglian, Inthanon and Bentong-Raub suture zones. Our synthesis of all available data enables establishment of a comprehensive geodynamic model for the East Paleotethyan evolution. This model links the spatial-temporal pattern across Southeast Asia into a series of tectonic events including ocean/back-arc basin opening, subduction/closure, subsequent assemblage and orogenic collapse, along with associated igneous, metamorphic and sedimentary activities.

Wang, Z., 2018. Reservoir forming conditions and key exploration and development technologies for marine shale gas fields in Fuling area, South China. Petroleum Research 3, 197-209.


Although shale gas resources are abundant in China, commercial discoveries have not been made before the discovery of Fuling Shale Gas Field. SINOPEC has done lots of theoretical and technological studies on marine shale gas development in China. Research shows shale gas has dynamic accumulations with early preservation and late reconstruction and proposes high-quality shale developed in deep-water shelf as the base and good preservation conditions as the key factor for shale gas accumulation. Key technologies and facilities were developed for geophysical survey of shale gas, design and optimization of shale gas development, drilling and completion of horizontal wells, and fracturing stimulation. As the first and largest shale gas field in China, the discovery and successful development of Fuling Shale Gas Filed has made China the first country to achieve large-scale development of shale gas after North America. By August 2017, Fuling Shale Gas Field had declared 6008.14 × 108 m3 proven reserves, 76.8 × 108 m3 production capacity and 133.9 × 108 m3 cumulative production. The construction of Fuling Shale Gas Field with high level, high speed and high quality has been a good example of shale gas development in China. Its successful experiences can be used to other fields and play an important role in optimizing energy structure and improving environment.

Wang, Z., Yin, H., Fu, G.C., 2018. Catalytic enantioconvergent coupling of secondary and tertiary electrophiles with olefins. Nature 563, 379-383.

https://doi.org/10.1038/s41586-018-0669-y

Carbon–carbon bonds, including those between sp3-hybridized carbon atoms (alkyl–alkyl bonds), typically comprise much of the framework of organic molecules. In the case of sp3-hybridized carbon, the carbon can be stereogenic and the particular stereochemistry can have implications for structure and function. As a consequence, the development of methods that simultaneously construct alkyl–alkyl bonds and control stereochemistry is important, although challenging. Here we describe a strategy for enantioselective alkyl–alkyl bond formation, in which a racemic alkyl electrophile is coupled with an olefin in the presence of a hydrosilane, rather than via a traditional electrophile–nucleophile cross-coupling, through the action of a chiral nickel catalyst. We demonstrate that families of racemic alkyl halides—including secondary and tertiary electrophiles, which have not previously been shown to be suitable for enantioconvergent coupling with alkyl metal nucleophiles—cross-couple with olefins with good enantioselectivity and yield under very mild reaction conditions. Given the ready availability of olefins, our approach opens the door to developing more general methods for enantioconvergent alkyl–alkyl coupling.



Interpretation of environmental DNA (eDNA) is a major problem hindering the application of this emerging technology for environmental monitoring. The decay characteristics and bioabundance estimation of different DNA fragment lengths are largely unknown, especially for eDNA captured from surface sediments. An estuarine amphipod, Grandidierella japonica, was used as the target species in this study. We conducted a lab-scale experiment using DNA extraction to clarify the effect of bacteria on eDNA decay. We also conducted a microcosm experiment using amphipods to clarify interpretations of information regarding eDNA decay and bioabundance estimation by using two fragments with different lengths (126 and 358 bp). It was found that the bacteria concentration accelerated eDNA decay, and long fragments were more susceptible to bacteria, thus decaying faster, than short fragments in the exponential decay period. The fresh eDNA (collected within 24 h of removing the amphipods) was more indicative of bioabundance than old eDNA (collected 240–480 h after removing amphipods), and short fragments better reflected bioabundance than long fragments. Finally, we compared the half-life of eDNA in surface sediment with that in a water sample and found that the temporal scales of surface sediment and water are similar (days to weeks). Our results suggest that surface sediment also has the potential to monitor the environment at a temporal scale similar to water.



The characteristics and influence on methane adsorption capacity of the pore structure of coals was investigated through an approach that integrates mercury intrusion porosimetry, low pressure N2/CO2 adsorption, and field emission scanning electron microscopy. Shihezi Formation coal samples from the Panji Deep Area in Huainan Coalfield in Southern North China were adopted as the study subjects. The fractal features of heterogeneous coal pore structures were quantified on the basis of N2 adsorption isotherms by using the Frenkel−Halesy−Hill (FHH) model. Pore structure and morphology

characterizations confirm that Shihezi Formation coals developed with multiple pore types and heterogeneous pore structures, and the slit-shaped and ink-bottle-shaped pores are mainly distributed at the pore size interval of 3.3–10 nm. Our coal samples present uni-modal and multi-modal pore size distributions, wherein multiple peaks are concentrated in the intervals of 0.45–0.55 nm and 2–20 μm. The major volumes from mesopores (2 nm < pore diameter < 50 nm) and macropores (pore diameter > 50 nm) occur in the full-scale pore size distributions, revealing Shihezi Formation coals are mesopores and macropores rich. Micropores (pore diameter < 2 nm) provide the majority of pore specific surface area, whereas pore volume is mostly contributed by mesopores and macropores. The volumes and specific surface areas of mesopores and macropores are positively correlated with ash yield and inertinite contents but are negatively correlated with maximum vitrinite reflectance (Ro,max). The methane adsorption capacity of Shihezi Formation coals is largely independent of mesopores and macropores but is positively correlated with the pore volume and specific surface area of micropores. This correlation suggests that micropores provide the predominant sites for methane adsorption. The calculated values of pore surface fractal dimension D1 and spatial fractal dimension D2 are 2.440–2.610 (avg. 2.515) and 2.542–2.761 (avg. 2.650), respectively, suggesting that the pore structures of Shihezi Formation coals are highly complex and heterogeneous. The positive correlation between D1 and methane adsorption capacity reveals that high surface roughness of the pore structure is associated with high methane adsorption capacity. However, the irregular pore structure does not influence methane adsorption capacity.

Wei, W., Frei, R., Klaebe, R., Li, D., Wei, G.-Y., Ling, H.-F., 2018. Redox condition in the Nanhua Basin during the waning of the Sturtian glaciation: A chromium-isotope perspective. Precambrian Research 319, 198-210.


The Neoproterozoic oxygenation event (NOE) is often considered to be synchronously and possibly causally associated with the Cryogenian glaciations. Reconstructing early Cryogenian redox conditions is therefore essential for understanding the onset of the NOE. We analyzed Cr-isotope compositions (δ53Cr) as well as major and rare earth element (REE) concentrations of the banded iron formations (BIFs) in the basal Fulu Formation of the Xiajiajiang section (Nanhua Basin), which are thought to have been deposited during the waning stage of the Sturtian glaciation. Strongly positively fractionated authigenic δ53Cr values were obtained after detrital correction, ranging from 0.64 to 1.22‰ and averaging at 0.91 ± 0.40‰ (2σ, n = 10) or after detrital evaluation, ∼0.71‰. This suggests extensive oxidative Cr cycling occurred at the Earth’s surface and implies that the pO2 was probably higher than 1% PAL during this period. The lack of Ce anomalies (0.90 < Ce/Ce∗ < 1.02) suggests that during this period the seawater in which the BIFs were deposited was at a redox state under which the oxidation of Fe2+ to Fe3+ could occur but the oxidation of Ce3+ to Ce4+ could not. A compilation of published δ53Cr data from BIFs, ironstones, and shales deposited from the late Paleoproterozoic to early Cryogenian (1.8–0.7 Ga) suggests that the early increase in atmospheric O2 related to the NOE probably first took place during the late Tonian Period (ca. 800–720 Ma). This was temporally coincident with the first appearance of several eukaryotic groups, and the estimated initial divergence of early animals.

Wen, X., Unger, V., Jurasinski, G., Koebsch, F., Horn, F., Rehder, G., Sachs, T., Zak, D., Lischeid, G., Knorr, K.-H., Böttcher, M.E., Winkel, M., Bodelier, P.L.E., Liebner, S., 2018. Predominance of methanogens over methanotrophs in rewetted fens characterized by high methane emissions. Biogeosciences 15, 6519-6536.

https://doi.org/10.5194/bg-15-6519-2018

The rewetting of drained peatlands alters peat geochemistry and often leads to sustained elevated methane emission. Although this methane is produced entirely by microbial activity, the distribution and abundance of methane-cycling microbes in rewetted peatlands, especially in fens, is rarely described. In this study, we compare the community composition and abundance of methane-cycling microbes in relation to peat porewater geochemistry in two rewetted fens in northeastern Germany, a coastal brackish fen and a freshwater riparian fen, with known high methane fluxes. We utilized 16S rRNA high-throughput sequencing and quantitative polymerase chain reaction (qPCR) on 16S rRNA, mcrA, and pmoA genes to determine microbial community composition and the abundance of total bacteria, methanogens, and methanotrophs. Electrical conductivity (EC) was more than 3 times higher in the coastal fen than in the riparian fen, averaging 5.3 and 1.5mS cm−1, respectively. Porewater concentrations of terminal electron acceptors (TEAs) varied within and among the fens. This was also reflected in similarly high intra- and inter-site variations of microbial community composition. Despite these differences in environmental conditions and electron acceptor availability, we found a low abundance of methanotrophs and a high abundance of methanogens, represented in particular by Methanosaetaceae, in both fens. This suggests that rapid (re)establishment of methanogens and slow (re)establishment of methanotrophs contributes to prolonged increased methane emissions following rewetting.


https://doi.org/10.5194/bg-2018-442

In drylands, microbes that colonise rock surfaces were linked to erosion because water scarcity excludes traditional weathering mechanisms. We studied the origin and role of rock biofilms in geomorphic processes of hard lime and dolomitic rocks that feature comparable weathering morphologies though originating from arid and hyperarid environments, respectively. We hypothesised that weathering patterns are fashioned by salt erosion and mediated by the rock biofilms that originate from the adjacent soil and dust. We used a combination of microbial and geological techniques to characterise rocks morphologies and the origin and diversity of their biofilm. Amplicon sequencing of the SSU rRNA gene suggested that bacterial diversity is low and dominated by Proteobacteria and Actinobacteria. These phyla formed laminar biofilms only on rock surfaces that were exposed to the atmosphere and burrowed up to 6mm beneath the surface, protected by sedimentary deposits. Unexpectedly, the microbial composition of the biofilms differed between the two rock types and was also distinct from the communities identified in the adjacent soil and settled dust, showing a habitat-specific filtering effect. Moreover, the rock bacterial communities were shown to secrete extracellular polymeric substances that form an evaporation barrier, reducing water loss rates by 65–75%. The reduced water transport rates through the rock also limit salt transport and its crystallisation in surface pores, which is thought to be the main force for weathering. Concomitantly, the biofilm layer stabilises the rock surface via coating and protects the weathered front. Our hypothesis contradicts common models, which typically consider biofilms as weathering-promoting agents. In contrast, we propose the microbial colonisation of mineral surfaces acts to mitigate geomorphic processes in hot, arid environments.

Wiemann, J., Yang, T.-R., Norell, M.A., 2018. Dinosaur egg colour had a single evolutionary origin. Nature 563, 555-558.

https://doi.org/10.1038/s41586-018-0646-5

Birds are the only living amniotes with coloured eggs, which have long been considered to be an avian innovation. A recent study has demonstrated the presence of both red-brown protoporphyrin IX and blue-green biliverdin—the pigments responsible for all the variation in avian egg colour—in fossilized eggshell of a nonavian dinosaur. This raises the fundamental question of whether modern birds inherited egg colour from their nonavian dinosaur ancestors, or whether egg colour evolved independently multiple times. Here we present a phylogenetic assessment of egg colour in nonavian dinosaurs. We applied high-resolution Raman microspectroscopy to eggshells that represent all of the major clades of dinosaurs, and found that egg colour pigments were preserved in all eumaniraptorans: egg colour had a single evolutionary origin in nonavian theropod dinosaurs. The absence of colour in ornithischian and sauropod eggs represents a true signal rather than a taphonomic artefact. Pigment surface maps revealed that nonavian eumaniraptoran eggs were spotted and speckled, and colour pattern diversity in these eggs approaches that in extant birds, which indicates that reproductive behaviours in nonavian dinosaurs were far more complex than previously known. Depth profiles demonstrated identical mechanisms of pigment deposition in nonavian and avian dinosaur eggs. Birds were not the first amniotes to produce coloured eggs: as with many other characteristics this is an attribute that evolved deep within the dinosaur tree and long before the spectacular radiation of modern birds.

Wilmeth, D.T., Corsetti, F.A., Beukes, N.J., Awramik, S.M., Petryshyn, V., Spear, J.R., Celestian, A.J., 2019. Neoarchean (2.7 Ga) lacustrine stromatolite deposits in the Hartbeesfontein Basin, Ventersdorp Supergroup, South Africa: Implications for oxygen oases. Precambrian Research 320, 291-302.


The Hartbeesfontein Basin contains the most extensive deposits of Archean lacustrine stromatolites on the Kaapvaal Craton, with stromatolitic facies occurring over ∼100 km2 in beds up to 7 m thick. Stromatolitic dolostones and cherts both preserve evidence of microbial processes. Dolomitic stromatolites have grumelous microspar textures between organic-rich laminae, suggestive of carbonate precipitation within microbial mats. Stromatolitic laminae within chert preserve detrital material beyond the angle of repose, indicating the trapping and binding of grains by microbial mats. Stromatolitic cherts also preserve fenestral textures and filamentous microfossils. Many fenestrae have rounded shapes surrounded by filamentous laminae and appear to have formed in situ within stromatolite fabrics before lithification. Fenestrae within stromatolitic chert resemble “hourglass-associated fenestrae” noted from recent silica stromatolites from Yellowstone National Park, and are interpreted to originate from gas bubbles forming within stromatolite-building mats. The preservation of delicate structures in Hartbeesfontein stromatolitic chert (e.g., filamentous microfossils and gas-related fenestrae) implies rapid lithification of microbial mats, while the mm to cm scale of fenestrae indicate equally rapid rates of microbial gas production. Textural and mineralogical evidence associated with gas-related fenestrae support the presence of oxygenic photosynthesis, which in turn strengthens previous hypotheses on Archean lakes as potential oxygen oases before the Great Oxidation Event.


https://pubs.geoscienceworld.org/cspg/bcpg/article-abstract/66/2/499/565803/organic-petrography-and-scanning-electron

Organic petrography and field emission scanning electron microscopy (FESEM) images of drill-core samples from five wells comprising a thermal maturity series through the Montney Formation are used to document and interpret the thermal evolution of migrated secondary organic matter (bitumen and oil) from the late oil window into the dry gas window. The present-day organic matter (OM) consists almost entirely of pore-filling secondary OM that migrated into the organic-lean siltstones of the Montney Formation as liquid hydrocarbons. With increasing burial depth and changing temperature, pressure and compositional conditions, the originally introduced oil became unstable and dissociated into different fractions. These dissociated hydrocarbon fractions underwent secondary cracking resulting in a range of solid and fluid hydrocarbon products including: natural gas, condensate, light oil, fluid-like hydrocarbon residue (FHR) and solid bitumen and pyrobitumen. The solid to semi-solid secondary OM products have distinct characteristics in each of the late oil, wet gas and dry gas windows. The wide range of OM textures observed undoubtedly reflect a complex interplay of many organic maturation mechanisms: however, petrographic observations in this study suggest important distinctions in how the different dissociated fractions of the original oil matured. The dissociated asphalt-rich fraction, which precipitated as globular or granular aggregates in the central portions of large open pores, matured and consolidated into solid bitumen (oil and wet gas windows) and pyrobitumen (dry gas window). Solid bitumen/pyrobitumen accumulations have different degrees of organic porosity that partially reflect the variable composition of the precursor asphalt fraction. The early paraffin-rich heavy oil fraction matured into paraffin wax (late oil window), FHR (wet gas window) and carbon residue (dry gas window) that coats grain surfaces and fills the finer interstices of the original pore network. Differences in OM maturity operated at the micrometer scale such that, in the dry gas window, non-porous pyrobitumen in large pores is commonly observed next to highly porous pyrobitumen associated with clays in smaller pores.

Wu, C., Yang, Z., Qin, Y., Chen, J., Zhang, Z., Li, Y., 2018. Characteristics of hydrogen and oxygen isotopes in produced water and productivity response of coalbed methane wells in western Guizhou. Energy & Fuels 32, 11203-11211.


The characteristics of hydrogen (H) and oxygen (O) isotopes in produced water of coalbed methane (CBM) wells have abundant geochemical indication information. On the basis of the tests of conventional ions and H and O isotopes of 20 water samples produced from CBM wells in western Guizhou, the characteristics of H and O isotopes and productivity response of the wells in the study area have been analyzed in combination with the geological background. The research shows that, if the H and O isotopic compositions of produced water from a CBM well have obvious D drift (D drift means that, when δ18O takes the same value, the measured value of δD that is higher than the theoretical value of δD is obtained from the regional atmospheric precipitation line equation), the well is likely to obtain high production, and if the H and O isotopic compositions have O drift (O drift means that, when δD takes the same value, the measured value of δ18O that is higher than the theoretical value of δ18O is obtained from the regional atmospheric precipitation line equation), the well is not likely to obtain high production. As drainage continues, the water–rock interaction gradually strengthens and the H and O isotope compositions tend to become heavier, but seasonal rainfall can cause their values to decrease. From shallow to medium-deep formations, δD and δ18O values increase continuously, and the wells with the lowest δD and δ18O values in the shallow formation have the highest average daily gas production. d′, D drift comprehensive index, is proposed, which is of universal significance. With the increase of d′, the average daily gas production decreases, and in combination with the productivity performance, the high production wells and low production wells can be distinguished. d′ of less than 0 indicates high production, which can be used as a geochemical index to evaluate potential productivity. It is proposed that δD = −50‰, d′ = 0, and

Cl– = 2000 mg/L can be used as a criterion for judging whether produced water of the CBM well is polluted and δD = −25‰ and Cl– = 4000 mg/L can be used to distinguish the degree of formation of water pollution. Moreover, the identification template of the produced water source based on δD, d′, and Cl– has been established preliminarily, and three ranges, coal seam water, light polluted water, and severe polluted water, can be identified according to the template. Moreover, it is considered that the CBM production will drop as the pollution degree of produced water increases.

Wu, F., Owens, J.D., Huang, T., Sarafian, A., Huang, K.-F., Sen, I.S., Horner, T.J., Blusztajn, J., Morton, P., Nielsen, S.G., 2019. Vanadium isotope composition of seawater. Geochimica et Cosmochimica Acta 244, 403-415.


The speciation, burial, and isotopic composition of vanadium (V) in seawater is predicted to be closely coupled to the redox state of the oceans. While the speciation and burial terms are reasonably constrained, the V isotopic composition of seawater has remained elusive owing to significant analytical challenges. To this end, for the first time we have developed and validated a new method to purify V from large volume (≥500 mL) seawater samples that we used to determine the V isotopic composition of seawater. Our method comprises four discrete V-purification steps that exploit ion-exchange chromatography including Nobias chelate and anion exchange resin(s) and measurement by multi-collector inductively-coupled plasma mass spectrometry. Results from several samples with addition of standard V solution with known isotope composition show no isotopic deviation in the chemical and/or analytical procedures and our reproducibility is within typical analytical error for vanadium isotopes measurements. Though V yields were non-quantitative (averaging ≈ 70%) for natural seawater samples, our approach was nonetheless validated with additional experiments. Therein, synthetic seawater solutions of known V isotopic composition with concentration similar to natural seawater were used to confirm that there is limited isotope fractionation during analytical procedures with similar yields. We further tested seawater samples using UV radiation, HNO3/HCl oxidation, and High-Pressure Asher treatments to ensure there was limited effects from potential non-dissolved phases or variable V speciation such as organic ligand binding of V. All tests except the High-Pressure Asher samples had similar recoveries (i.e. >70%) and all recorded similar isotopic values within error which suggest our method is robust and reliable for V isotopic measurement of seawater. Using our most optimal method, we report V isotope data for several seawater samples from surface and subsurface Atlantic Ocean and deep Pacific Ocean for the first time. Inter-laboratory sample comparison shows that the data was within analysis error (∼0.15‰, 2SD). Initial results imply that the deep ocean is isotopically homogeneous with respect to V, and the uptake of V in surface waters appear to cause very limited, if any, isotope fractionation as it is within analytical uncertainties. Thus, our results suggest a reference seawater V isotope composition of +0.20 ± 0.15‰ relative to V isotope standard AA solution. This work analyzes the first V isotope value of seawater which provides a key foundation for future work to constrain the modern marine V isotope cycle and budget and application for paleoceanographic research.

Wu, M., Zhuang, G., Hou, M., Miao, Y., 2019. Ecologic shift and aridification in the northern Tibetan Plateau revealed by leaf wax n-alkane δ2H and δ13C records. Palaeogeography, Palaeoclimatology, Palaeoecology 514, 464-473.


Two competing factors, the global cooling and the uplift of Tibetan Plateau, have been proposed to drive the central Asian aridification, but their relative role has seldom been discriminated in

paleoclimate and paleoenvironment records. Here, we reconstruct a 14-million-year-long record of paleohydrology and paleoecology in the western Qaidam Basin by applying the compound-specific hydrogen (δ2H) and carbon (δ13C) isotope analyses to terrestrial leaf wax long-chain n-alkanes. The δ2H values are low during the interval of 14.6 to 13.0 Ma. Then the δ2H increases from 13.0 to 12.2 Ma and maintains high values from 12.2 to 3.2 Ma with a peak high value of −156.1‰ at 8.0 Ma. After 3.2 Ma, the δ2H values are low and vary larger than 30‰. The δ13C values decrease from 14.6 to 13.0 Ma and are low from 13.0 to 3.2 Ma except a high value at 3.8 Ma. Then they decrease slightly after 3.2 Ma. Low δ2H values indicate relatively wet climate between 14.6 and 13.0 Ma. The decreasing δ13C values during the same time period support the ecologic shift with the decline of warm component of conifers after the Mid-Miocene Climatic Optimum. High δ2H values since 13.0 Ma are synchronous with the uplift of northern Tibetan Plateau, implying tectonics-driven aridity. Large-amplitude variation in δ2H values since ca. 3.2 Ma seen in East and West Qaidam and lower δ13C values reveal the climatic cyclic responses to the Northern Hemisphere Glaciation.

Wu, Y., Zhang, J., 2018. Geochemical characteristics and identification criteria of effective source rock in Mesozoic Yanchang Formation, southern margin of Ordos Basin. International Journal of Oil, Gas and Coal Technology 19, 379-395.


The geochemical characteristics of source rock in Mesozoic Yanchang Formation, southern margin of Ordos Basin have not been introduced in literature. In this study, a number of geochemical experiments were conducted to discuss the geochemical characteristics and to establish the identification criteria. It is shown that source rock in the study area can be divided into five types: A1, A2, A3, A4 and B. Based on the detailed oil source correlation, the source rock types in the study area can be identified as: 1) A1, Chang 7 oil shale, is the excellent source rock with large hydrocarbon-generation potential; 2) A2 and A3, mainly Chang 7 dark mudstone, are the effective source rocks with medium hydrocarbon-generation potential; 3) A4 and B, mainly the thin mudstone or carbonaceous mudstone intervals, are the potential source rock with small hydrocarbon-generation potential.

Wulf, G., Hergarten, S., Kenkmann, T., 2019. Combined remote sensing analyses and landform evolution modeling reveal the terrestrial Bosumtwi impact structure as a Mars-like rampart crater. Earth and Planetary Science Letters 506, 209-220.


We combine remote sensing and geomorphological analyses with landform evolution modeling to investigate whether or not terrestrial impact crater morphologies are comparable with martian impact craters formed in volatile-rich environments. We conduct a detailed remote sensing analysis of the terrestrial Bosumtwi crater in Ghana (10.5 km, 1.07 Ma) investigating its geology and geomorphology. This includes a morphometric analysis of the drainage pattern from digital elevation models and the interpretation of multi-spectral image data. The results are compared with a fresh martian impact crater of similar size for which a hypothetical drainage network and catchment areas are derived. We investigate whether the current morphology of Bosumtwi crater results from erosion of a typical martian-type or lunar-type impact crater morphology using landform evolution modeling. Our results reveal that the morphology of Bosumtwi crater cannot be explained by erosion of a lunar-like impact crater. In contrast, the morphological and spectral characteristics of Bosumtwi crater exhibit striking similarities to those of martian rampart craters, especially double-layered ejecta

craters. We therefore suggest that Bosumtwi crater was originally built as a Mars-like rampart crater, and that the current morphology is the result of weakly eroded ejecta ramparts.

Wünsch, U.J., Geuer, J.K., Lechtenfeld, O.J., Koch, B.P., Murphy, K.R., Stedmon, C.A., 2018. Quantifying the impact of solid-phase extraction on chromophoric dissolved organic matter composition. Marine Chemistry 207, 33-41.


Advancing our understanding of the behaviour of dissolved organic matter (DOM) in aquatic environments necessitates efforts to combine complementary analytical data sets. However, some analytical measurements require sample pre-treatment, while others are carried out on bulk water samples, and it remains unclear if the resulting data sets can be compared. Here, we investigated the impact of solid-phase extraction with PPL resins on DOM optical properties. In samples from contrasting Arctic fjords, extraction efficiencies based on optical properties varied spectrally with averages between 31 ± 13% at 411 nm and 40 ± 12% at 363 nm for chromophoric DOM. Similarly, the extraction efficiency for specific fluorescence components varied between 37 ± 16% and 58 ± 18%. Solid-phase extraction also decreased S275–295, fluorescence index, and the freshness index, but increased S350–400, and apparent fluorescence quantum yields, indicating that the extraction process was qualitatively selective. Six fluorescence components identified independently in bulk water samples and extracted DOM using parallel factor analysis exhibited different behaviours. Three had identical spectral properties before and after extraction, although their extraction efficiencies varied with water mass characteristics and DOM composition, whereas three other components appeared to change after extraction. With the exception of one fluorescence component, the dynamics of optical properties in bulk water samples were not accurately reflected by DOM extracts. These results indicate that solid-phase extraction imparts a qualitative selectivity that leads to the homogenization of DOM extracts relative to their original samples. Efforts to integrate chemical information from different analytical methods should prioritize comparisons of measurements obtained on the same samples.


https://pubs.geoscienceworld.org/cspg/bcpg/article/66/2/436/565810/chemostratigraphy-petrography-and-sem

High resolution chemostratigraphy of the Montney Formation across Alberta identifies three unique and distinct chemostratigraphic units, referred to as CS1-3, with several subunits (i.e. CS1a, 1b, 3a, 3b). The lowermost two units (CS1-2) are mostly monotonous, finely laminated dolomitic “siltstones” with low geochemical (e.g. element, ratio, factor) variability except for CS1b, where both sedimentary and geochemical variability is present. The overlying units (i.e. CS3a-3b) contains dolomitic siltstones with sandy beds that show abundant sedimentary variability, pervasive bioturbation and abundant geochemical variability. This study focuses on the lowermost units (CS1a, 1b, 2) of the Montney Formation in Alberta, deposited during the Triassic Induan Period and proposes a new depositional model that largely contradicts the current depositional models of a basinal turbidite system. Evidence for a new model are derived from geochemical, petrographic and SEM data. Geochemical data (i.e. Si/Ti, As/Zr ratios, etc) suggest that the lower chemostratigraphic units (CS1-2) had minimal terrestrial influx and geostatistical analysis infers three distinct sources

during the time of deposition, i.e. 1) marine benthic carbonates; 2) planktonic siliceous ooze; and 3) terrestrial material. Petrographic/SEM analyses of CS1-2 corroborate the geochemical findings revealing the dominance of authigenic minerals of quartz, dolomite, feldspars and pyrite, with few detrital grains of quartz, mica, feldspars and clay. Hence, the depositional model for the Lower Triassic Montney Formation in Alberta proposes a back-arc, semi-restricted shallow carbonate shelf with prolific benthic/planktonic shell productivity due to limited species diversity following the Permian-Triassic extinction event and limited terrestrial influx (varies locally). High benthic biogenic productivity suggests oxic bottom water conditions and possibly elevated salinity (to limit species diversity) that led to excess NaCl in the pore waters after deposition. Trace elements and total organic carbon (TOC) contents support oxic to sub-oxic sea water conditions, contradicting previous hypotheses of bottom water anoxia. Mineralogical, geochemical and organic carbon data also suggest limited influx of terrestrial and volcanic material. Since the majority of the CS1-2 sediments examined in Alberta display finely laminated dolomitic siltstones, diagenetic processes that generate dolomitic quartz-feldspar laminae from initial bedded shell debris are elaborated upon. A new proposal for the diagenetic pathway is based on findings from isolated carbonate concretions that demonstrate how in-situ porous biogenic debris (metastable aragonite, high Mg-calcite, biogenic silica and rare detrital and organic matter) can transform diagenetically during burial to “pseudo-laminated dolomitic siltstones”.

Xi, S., Zhang, X., Du, Z., Li, L., Wang, B., Luan, Z., Lian, C., Yan, J., 2018. Laser Raman detection of authigenic carbonates from cold seeps at the Formosa Ridge and east of the Pear River Mouth Basin in the South China Sea. Journal of Asian Earth Sciences 168, 207-224.


Laser Raman spectroscopy has been successfully applied for the in situ detection of gases and liquids, but has not yet been extensively applied to rocks in the deep sea. Authigenic carbonate rocks are widely distributed at the Formosa Ridge (Site F) and the eastern region of the Pear River Mouth basin (Site P) in the South China Sea (SCS). Considerable Raman spectral information on authigenic carbonates was obtained from laboratory measurements of slices of authigenic carbonate, direct measurements in a simulation environment, and in situ measurements in the deep sea. The dominant band of authigenic carbonate from Site F ranges from 1084 to 1087 cm−1 while the dominant band from Site P ranges from 1088 to 1091 cm−1, suggesting that compositional differences exist between the samples from the two cold seep areas. The results of the point-counting method indicates that the aragonite content in Site F is higher than that at Site P. The wider peak width of the aragonites at Site P shows the aragonites at Site P have lower degree of crystallinity, which suggests that aragonite is likely to be destroyed when the cold seep weakens or dies. The above information obtained via the Raman spectroscopy can guide sample collection in the deep sea and can be used in conjunction with other analysis methods to better understand environmental changes or the geological processes.

Xi, Z., Tang, S., Wang, J., Yang, G., Li, L., 2018. Formation and development of pore structure in marine-continental transitional shale from northern China across a maturation gradient: insights from gas adsorption and mercury intrusion. International Journal of Coal Geology 200, 87-102.


The evolutionary characteristics of pore structure from Permian marine-continental transitional shale were examined based on a suite of natural shale samples from the Ningwu and Qinshui Basins in northern China, which ranged in maturity from immature (vitrinite reflectance, Ro = 0.44%) to over-mature (Ro = 1.85%). Experiments included mercury intrusion, nitrogen adsorption, and carbon

dioxide adsorption, and were conducted to quantify pore volume and pore size distributions. Samples with different thermal maturity had large differences in micropore, mesopore, and macropore volume and pore size distributions. Mesopore and macropore volumes were the largest in immature shale and declined with increasing maturity to intermittent minima in the mature shale, continuing to increase to the over-mature shale. However, micropore volume gradually increased during maturation. The pore-related variances may be primarily controlled by maturity, whose effect was stronger than other factors (total organic carbon and mineral composition). During maturation, changes in pore size distribution and relative proportions of micropores, mesopores, and macropores were related to both chemical (transformation of organic matter into hydrocarbons) and mechanical (compaction) processes. Pore volume was reduced during the transition from immature to mature stage, likely mainly due to compaction instead of liquid hydrocarbon filling the pores, whereas the increase in pore volume during the transition from the mature to over-mature stage was mainly associated with the transformation of organic matter.

Xiao, L., Hu, S., Song, Y., Zhang, L., Han, H., Liu, C., Jiang, L., Xu, K., Su, S., Wang, Y., Xiang, J., 2019. The formation mechanism for OPAHs during the cellulose thermal conversion in inert atmosphere at different temperatures based on ESI(−) FT-ICR MS measurement and density functional theory (DFT). Fuel 239, 320-329.


Oxygenated polycyclic aromatic hydrocarbons (OPAHs) are an important group of components produced from the thermal conversion of cellulose. Through using gas chromatography mass spectrometry (GC–MS), Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) and ultraviolet fluorescence spectroscopy (UV-F), the information for the evolution of OPAHs is obtained in this study. The tar produced at low temperature mainly contains light components such as homologues of pyran and furan, while the components in the tars at 700 °C and 900 °C show high double bond equivalent (DBE) values, indicating the existence of large aromatic structures.

High temperature promote condensation reactions during cellulose thermal conversion, thus leading to a higher percentage of OPAHs in the tar at higher temperature process. According to Density Functional Theory (DFT) calculation, the energy barrier of Diels-Alder reaction (302.65 kJ/mol) is lower than the dehydration (583.26 kJ/mol), which means that Diels-Alder reaction could be the main route for OPAH formation rather than dehydration reaction. High reaction temperature is calculated to be favorable for the formation of naphthol during the cellulose thermal conversion because of the high energy barrier of dehydration between phenol and furan. It is consistent with the ESI FT-ICR MS result that there is a higher content of naphthol in the tar at 700 °C than that at 500 °C.

Xie, J., Zhang, X., Xie, J., Xu, J., Pan, L., Zou, J.-J., 2019. Acid-catalyzed rearrangement of tetrahydrotricyclopentadiene for synthesis of high density alkyl-diamondoid fuel. Fuel 239, 652-658.


Alkyl-diamondoid fuels are attractive for aerospace vehicles due to their high energy density and supreme low-temperature performance. Here we reported a facile route to synthesize alkyl-diamondoids via solvent-free rearrangement of tetrahydrotricyclopentadiene simply catalyzed by acid. The reaction conditions including catalysts, temperature, catalyst dosage, and solvent were optimized. Notably, under the optimal conditions (10.7 wt% cat., 180 °C, 20 h) an extremely high content of alkyl-diamondoids (85.6%) was found in liquid phase, with high carbon yield of alkyl-diamondoids (60.0%) was obtained. The reaction kinetics of rearrangement has been investigated,

and the reaction rate constants and apparent activation energies were calculated based on the experimental kinetic data. The resultant diamondoid-based product shows excellent low-temperature performance and a higher energy content than reported diamondoids and widely used JP-10 fuel, thus is superior as a high-energy-density fuel.



In order to examine the mobility of hydrocarbons in a lacustrine shale oil system, three cylindrical core plugs from the Eocene Shahejie Formation lacustrine shale oil system in the Jiyang Depression were sequentially extracted with dichloromethane (DCM) in flow-through experiments under controlled stress conditions in a tri-axial flow cell. Orientations of the three sample plugs were perpendicular to bedding (#1) and parallel to bedding (#2 and #3). Post-experiment Micro-CT analysis confirmed three different flow patterns: Cross bedding flow (#1), minor bedding-parallel flow (#2), and extensive bedding-parallel flow along open fractures (#3). Extraction times were 28 days, 7 days and 3 days, for samples #1, #2 and #3, respectively. Sequential series of extracts from the samples were analyzed using gas chromatography. For comparison, hydrocarbon compositions were also determined on bulk extracts of powdered original sister-sample material and the residues after flow-through experiments.

The mobilities of hydrocarbons are controlled by the flow direction and fracture intensity and orientations. For sample #1, DCM flow-through extraction yielded mostly hydrocarbons associated with matrix kerogen. This flow-extracted bitumen was found to be much heavier than that extracted from the other two samples, and to have a lower mobility. The hydrocarbons extracted from the sample #2 were the lightest. For sample #3, containing micro-fractures along the bedding planes, the extraction process was apparently very effective, not only dissolving HC from the fractures but also some HC from the kerogen.

The characteristic hydrocarbon compositions of the samples were essentially retained in all extracts, although lighter hydrocarbons (<C19) were extracted somewhat preferentially. After the flow-through experiments the Rock-Eval S1 values had decreased by 81%, 56% and 84%, respectively, for all three samples, indicating that the hydrocarbons were extracted to different extents during the flow-through tests. Additionally, the Rock-Eval S2 values decreased by 29%, 0.4%, and 16%, for the three samples, respectively, showing that the flow-through tests on two of the samples also extracted significant amounts of organic material commonly interpreted as “heavy-hydrocarbons”. The free hydrocarbons in micro-fractures, especially fractures along the bedding, could be very important for shale oil mobilization and the intervals with well-developed laminae provide horizontal fracturing intervals that are most favorable.

Xie, Z., Zhang, B., Yang, C., Dong, C., Pei, S., Zhao, J., Guo, J., Zhang, L., 2018. Geochemical characteristics and source trace of the Devonian natural gas and bitumen in Northwest Sichuan Basin. Acta Petrolei Sinica 39, 1103-1113.

http://www.syxb-cps.com.cn/EN/abstract/abstract5555.shtml

Industrial gas flows have recently been discovered for the first time in the dolomite reservoirs from Mid-Devonian Guanwushan Formation, Northwest Sichuan Basin, and its natural gas sources have attracted much attention. Based on geochemical analysis, a comprehensive study is conducted on the geochemical characteristics of Devonian natural gas, bitumen, oil sand and source rocks. The results show that the Devonian natural gas is secondary cracking dry gas dominated by hydrocarbon gases, including more than 94% of methane content, trace ethane, propane, and a small amount of non-hydrocarbon gas such as nitrogen and carbon dioxide. The δ13C1 value of nature gas is ranged from -32.3‰ to -31.9‰, δ13C2 values is from -28.6‰ to -28.4‰, and δ2H1 values is from -141‰ to -138‰, indicating the hybrid gas dominated by sapropelic type. The n-alkanes and alkyl cyclohexane of Devonian downhole bitumen are characterized by two main peaks, and the biomarkers are distributed normally. The bitumen and oil sands in the outcrop section are subjected to strong biodegradation. The comparison in the biomarkers characteristics of saturated hydrocarbon and aromatic hydrocarbons between bitumen, oil sands and source rocks show that the Devonian oil and gas is sourced from the Lower Cambrian Qiongzhusi Formation and Lower Permian source rocks, dominated by Qiongzhusi Formation. The research results have important guiding significance for developing exploration and deployment solutions for natural gas in Northwest Sichuan Basin.



The knowledge about the formation of the heavy tars of bio-oil during pyrolysis is of great importance for the further utilization of bio-oil. This work focuses on the formation of the heavy tars during pyrolysis of bio-oil at various temperatures and heating rates in a fixed-bed reactor. In order to investigate the detailed composition of the heavy tar, the bio-oil and tars were characterized with a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS). Our results indicate that low temperature promotes the formation of heavy tars via the polymerization of bio-oil components, especially at slow heating rates, therein the condensed aromatics are formed via the polymerization of small aromatics with one or two rings. High temperature promotes the breakage of the oxygen-containing functional groups, meanwhile the highly condensed aromatics with more than 4 rings are formed at 800 °C via the strong secondary reactions (e.g. recombination), especially at fast heating rates.

Xu, K., Agrawal, D., Darugar, Q., 2018. Hydrophilic, nanoparticle-based enhanced oil recovery: Microfluidic investigations on mechanisms. Energy & Fuels 32, 11243-11252.


We discovered a novel nanoparticle (NP)–crude oil interaction and propose a mechanism of NP-based enhanced oil recovery. This NP–crude oil interaction and its effects on oil recovery are systematically investigated by conducting microfluidic experiments in both single-pore scale and “reservoir-on-a-chip” scale. It is confirmed that hydrophilic silica NPs in an aqueous phase could lead to dramatic swelling, dewetting, and disjoining of crude oil. The swelling ratio increased with decreased aqueous phase salinity and with increased concentrations of negative charging of NPs. Natural polar components in crude oil is shown to play a very important role. From a pore-scale perspective, this oil swelling and dewetting increased the flow resistance in the swept region and redirected flooding liquid toward the unswept region. From a reservoir perspective, the mobility ratio was reduced because oil swelling and dewetting modified the relative permeabilities. This

improvement in sweep efficiency resulted in approximately 11% incremental oil recovery in a completely homogeneous porous micromodel, with 2000 ppm of NPs suspended in seawater.

Xu, Q., Xu, F., Jiang, B., Zhao, Y., Zhao, X., Ding, R., Wang, J., 2018. Geology and transitional shale gas resource potentials in the Ningwu Basin, China. Energy Exploration & Exploitation 36, 1482-1497.

https://doi.org/10.1177/0144598718772316

We analyzed the tectonic evolution characteristics, sedimentary environment, geochemical characteristics, petrological characteristics, and gas-bearing properties of three mudstone sections of the Lower Paleozoic in Ningwu Basin, NE China, and determined the geologic characteristics and resource potential of the transitional facies shale gas. Geochemical analysis of the organic carbon content, kerogen macerals, and vitrinite reflectance of the shale samples showed that the total organic content was generally over 2.0%, the main organic type was type III, and the vitrinite reflectance values (Ro) were between 1.20 and 1.90%. Thus, the mudstones are good shale gas source rocks. The thickness of the three mudstone sections was approximately 30–70 m, and the average porosity was 3.10%. The pore types were diverse with good reservoir capacity. The shale gas resources of the Carboniferous-Permian transitional facies estimated by the volumetric method were approximately 2798.97 × 108–4643.09 × 108 m3. Through a comparison with shales in SW China, where shale gas has been successfully exploited, we determined the preferred criteria for favorable shale gas areas, as well as favorable areas for shale gas enrichment.



Chemical oxidation and microbial degradation are promising treatments to remediate soils contaminated with persistent organic pollutants. Moderate pre-oxidation is able to enhance the subsequent bioremediation of organic pollutants in soil. In this study, the effects of pre-oxidation on the subsequent biodegradation of benzo[a]pyrene (BaP) were evaluated. The tested oxidants included potassium permanganate (PP) and iron-activated sodium persulfate (PS) at the concentration of 1–40 mmol L−1. The results showed that 20 mmol L−1 PS and 10 mmol L−1 PP treatments had the highest degradation efficiency of BaP in soil, up to 98.7% and 84.2%, without inhibiting subsequent microbial degradation. 10–20 mmol L−1 of the two oxidants significantly promoted viability of microbial community. Especially, PS facilitated the occurrence of more PAHs-degrading microorganisms. The expression of PAH-degradation gene in PS treatment was significantly higher than that in PP treatment (P < 0.05), leading to 12.0–18.4% higher degradation efficiencies of BaP. In general, proper oxidants of moderate dosages were able to promote microbial bioremediation of persistent organic pollutants in soil.

Xu, X., Huang, H., Zhang, S., Hu, S., 2019. Gas generation potential and processes of Athabasca oil sand bitumen from gold tube pyrolysis experiments. Fuel 239, 804-813.


Gold-tube pyrolysis experiments were conducted on two oil sand bitumens (OSBs) from the top and bottom of the McMurray Formation in the Athabasca oil sand region of Alberta, Canada. Temperatures ranging from 300 °C to 650 °C and a pressure of 50 MPa with heating rates of 2 °C/h were used to investigate the gas generation behavior of OSB. The extractable residual bitumen

content decreased systematically with increasing heating temperatures resulting in a continuous increase in total hydrocarbon gas yields with the highest value of about 480 mg/g bitumen at 650 °C. Among hydrocarbon gases, the yields of methane (C1) increased consistently with experimental temperatures, while the yields of ethane (C2), propane (C3), butanes (i + n-C4) and pentanes (i + n-C5) increased initially to a critical pyrolysis temperature and then decreased at higher temperatures. Molecular indices (C1/C2, C2/C3, C2/i-C4, C3/C4, i-C4/n-C4, i-C5/n-C5 and C1/ΣC1-5) obtained in this work are different from typical primary thermogenic gases generated from kerogen or secondary thermogenic gases derived from thermal cracking of oil. Three stages of OSB thermal evolution were identified over a wide range of heating temperatures. The first stage (300–425 °C) reflects initial decomposition of thermally unstable moieties in resins and asphaltenes. Gas generated at this stage was dominated by carbon dioxide and hydrogen sulfide with minor amounts of hydrocarbon. Hydrocarbon gases were enriched in wet gas components with increasing heating temperatures. The second stage (425–525 °C) corresponds to liquid oil cracking and wet gas generation. While the yields of methane and ethane still increased with heating temperatures, yield of propane reached a maximum and yields of butane and pentane started to decline. The third stage (525–650 °C) reflects wet gas cracking and dry gas generation as indicated by the dramatic decrease of wet gas components and increase in gas dryness. Variations of gas yields and chemical compositions from two OSBs were partially caused by different levels of biodegradation. The top OSB has experienced less biodegradation influence than the bottom one as indicated by higher saturated and aromatic hydrocarbon contents and intact alkylphenanthrene distribution. Increased biodegradation of OSB yielded a higher concentration of polar compounds and an overall lower hydrogen content, which reduced the hydrocarbon gas generation potential. Slightly higher amounts of wet gas components were generated from the top OSB because of the relatively higher content of reactive moieties (mainly alkyl groups) at a lower biodegradation level, while a higher proportion of methane was observed from the bottom, severely biodegraded OSB that was enriched in cross linked ring structures.

Xu, Y., Chang, X., Shi, B., Wang, Y., Li, Y., 2018. Geochemistry of severely biodegraded oils in the Carboniferous volcanic reservoir of the Chepaizi Uplift, Junggar Basin, NW China. Energy Exploration & Exploitation 36, 1461-1481.

https://doi.org/10.1177/0144598718770692

A substantial amount of petroleum was recently discovered in the Carboniferous volcanic reservoir of the Chepaizi Uplift in the western Junggar Basin, yet the source is still indefinitive. Geochemical investigation indicates that the Carboniferous oils from the eastern and western Chepaizi Uplift are characterized by different source facies, although they are all typically of lacustrine origin. The eastern oils exhibit a restricted, clastic starved, highly reducing hypersaline condition during source rock deposition, which is distinct from the western oils. The Carboniferous oils were subjected to biodegradation ranging from rank 6 to rank 9, as indicated by the presence of 25-norhopane, evident depletion of hopanes and regular steranes, and even selective reduction of tricyclic terpanes. The maturities for the Carboniferous oils correspond to the onset of oil generation. The eastern oils contain lower (C19 + C20)TT/(C23 + C24)TT and C19TT/C21TT, and lighter stable carbon isotopes than the western ones, correlating well with the Middle Permian Wuerhe (P2w) source rocks and the Jurassic source rocks, respectively. The good correlation of tricyclic terpanes source-related parameters further implies less contribution to the eastern oils by the Carboniferous source rocks.

Xu, Y., Ge, H., Fang, J., 2018. Biogeochemistry of hadal trenches: Recent developments and future perspectives. Deep Sea Research Part II: Topical Studies in Oceanography 155, 19-26.


Hadal trenches with water depth ranging from 6000 to 11,000 m are the deepest biogeochemical province in the world's oceans. Due to technological challenges of sampling and observation at such extreme depths, these trenches are one of the least exploited habitats on our planet. Recent findings show high sedimentation rates, high biomass, intense microbial activity and chemosynthetic communities in hadal trenches, suggesting that they may play a more important role in global ocean biogeochemical cycles than previously recognized. Here we review the hadal biogeochemistry in four aspects: food supply and its effect on hadal life; hadal carbon cycle; microbial-mediated stable carbon isotope fractionation in biosynthesis of lipids under high hydrostatic pressures; and pollution in the hadal trenches. Our current knowledge of hadal biogeochemistry is rudimentary and many fundamental questions remain to be answered. However, with the rapid development of the full-ocean-depth exploration and sampling technologies, it is very likely hadal scientists will make significant breakthroughs in hadal biogeochemistry research in the coming decades.

Xu, Z., Jiang, S., Yao, G., Liang, X., Xiong, S., 2019. Tectonic and depositional setting of the lower Cambrian and lower Silurian marine shales in the Yangtze Platform, South China: Implications for shale gas exploration and production. Journal of Asian Earth Sciences 170, 1-19.


Marine shales of the Lower Cambrian Qiongzhusi and Lower Silurian Longmaxi formations are extensively distributed in the Yangtze Platform. Detailed depositional and tectonic analyses and regional mapping indicated that the organic-rich Qiongzhusi-equivalent shale was deposited in an intra-shelf low-slope environment in a passive margin setting. The Longmaxi-equivalent shale was mainly deposited in a widely-distributed intra-shelf low setting in the Upper and Middle Yangtze, and in a distal foredeep area away from clastic dilution in the Lower Yangtze Platform. The transgressive and early highstand system tracts in both Qiongzhusi and Longmaxi shales produced the best-quality shale reservoirs, with high total organic matter (TOC) content (>2%) and high quartz content (>45%). Tectonics has substantial effects on coeval deposition of organic-rich shale and its hydrocarbon accumulation and production. Later tectonism deformed the shales and disrupted early shale gas accumulation. Recent shale gas resource exploration and geologic analysis suggested that the high rate of shale gas production is due to overpressured marine shale reservoirs with high TOC and high gas content in the tectonically-stable area. Shale gas production occurred at reduced rates in slightly underpressured shale reservoirs with lower gas content in the syncline of the tectonically-transitional area deformed by three tectonic movements. There was no gas production from shales in the tectonically-active area disrupted by at least four tectonic movements and complex faults. The results of this analysis indicate that local tectonically-stable areas in the Middle and Lower Yangtze platforms may have shale gas accumulation and production potential.

Yakubova, S.G., Tazeeva, E.G., Abilova, G.R., Milordov, D.V., Yakubov, M.R., 2018. Relationship of light absorption and vanadium content in asphaltenes and resins of heavy oils. Petroleum Science and Technology 36, 1657-1662.

https://doi.org/10.1080/10916466.2018.1501391

The relationship of the light absorption of asphaltenes and resins with vanadium content has been investigated on the example of heavy oils of various deposits. In the oils of various deposits in Permian and Carboniferous producing complexes of Volga?Ural oil-and-gas bearing basin, the asphaltene content varies from 5.3 to 21.2?wt %, while the vanadium content is from 0.009 to 0.165?

wt %. It has been shown that there is a direct correlation of the light absorption of asphaltenes and vanadium content with the correlation coefficient of higher than 0.96 in the case of each producing complex. There is also a direct relationship between the light absorption of resins and vanadium content in the HOs under study with the correlation coefficient of higher than 0.92 in the case of each producing complex.


https://doi.org/10.1007/s13202-018-0489-5

In this study, Karadere oil seep (solid bitumen) and Late Cretaceous shales and carbonate levels of the Hekimhan Formation in Hekimhan Basin are compared genetically by means of organic-geochemical data. Investigated shale samples have generally low (< 0.5%) the total organic carbon values (TOC, wt%) and there is no petroleum and gas source-rock potential; however, the amount (0.11–5.92%) and type (type II–III kerogen) of organic matter within limestone are consistent for source-rock potential. On the basis of average Tmax (433 °C) and 0.53% R0 values, the investigated samples are at the immature and early mature level for hydrocarbon generation. According to biomarker data, the bitumen is pre-Cretaceous in age, highly reducing conditions, formed in a marine depositional environment at normal salinity, and under the influence of high bacterial activity, and was originate from an immature carbonate source rock. These geochemical data are highly in agreement with the late Cretaceous limestone of the Hekimhan Formation, and these rocks may be considered the source rock of the solid bitumen. However, these organic richness zones formed from non-indigenous organic material, and therefore, it is concluded that this seepage which generates from non-indigenous organic materials cannot be due to the limestone at the evaluated level. On the basis of organic-geochemical evaluations, it has been concluded that, in Hekimhan Basin, some hydrocarbons developed in deeper, more mature intervals of the limestone, and that these were migrated probably only a short distance within the basin and became really surfaced in relation to tension fractures.

Yamagishi, A., Kawaguchi, Y., Hashimoto, H., Yano, H., Imai, E., Kodaira, S., Uchihori, Y., Nakagawa, K., 2018. Environmental data and survival data of Deinococcus aetherius from the exposure facility of the Japan Experimental Module of the International Space Station obtained by the Tanpopo Mission. Astrobiology 18, 1369-1374.

https://www.liebertpub.com/doi/abs/10.1089/ast.2017.1751

The Tanpopo mission has two objectives: (1) test the panspermia hypothesis and (2) test whether organic compounds may have been transferred to Earth before the origin of life. We developed an exposure panel (EP) designed to expose microbes and organic compounds to the space environment and a capture panel designed to capture high-velocity particles on the International Space Station (ISS) using aerogel contained in an aluminum container. The panels returned after 1 year of exposure at the Exposure Facility of the Japan Experimental Module, ISS. In this communication, we report the measurements of temperature, radiation dosimeter and vacuum ultraviolet dosimeter in the EP, and survival data of Deinococcus aetherius. The environmental data are consistent with survival data of microbes and organic compounds, which will be presented elsewhere in detail.



Methane-derived carbonates with blocky and chimney morphologies were collected on the northern slope of the South China Sea. The studies of petrography, geochemistry and chronology show that the blocky carbonate has a microcrystalline structure with numerous of biogenic tests, whereas the carbonate chimney has a cryptocrystalline structure with scarce biogenic tests. Aragonite can be detected in the carbonate chimney, which indicates that it formed at the shallow sediments or on the seafloor. The δ13C and δ18O values of the blocky carbonate range from −46.8‰ to −28.8‰ VPDB and 2.2‰ to 3.5‰ VPDB, respectively. The δ13C and δ18O values of the carbonate chimney range from −45.0‰ to −22.9‰ VPDB and −2.8‰ to 3.1‰ VPDB, respectively. The carbon isotopic values indicate that these carbonates are related to the anaerobic oxidation of methane (AOM). The oxygen isotopic values show that the gas hydrate dissociation contributed the 18O-enrich fluid to a certain degree during the authigenic carbonate formation. According to the rare earth element results, the carbonate chimney precipitated in stable anoxic conditions. Because of the La-enriched influence, the formation environment of the blocky carbonate is ambiguous. The U/Th chronology results indicate that these authigenic carbonates precipitated during the last glacial period (primarily Marine Isotopic Stage 3) of low sea level stand.

Yang, S., Wu, W., Xu, J., Ji, D., Chen, Z., Wei, Y., 2018. Modeling of methane/shale excess adsorption under reservoir conditions. SPE Reservoir Evaluation & Engineering 21, 1027-1034.

https://doi.org/10.2118/180076-PA

Micropores and mesopores are the main storage volumes in shale matrix. Because of their small pore sizes, the force between pore boundary and gas molecules is significant. A larger amount of adsorbed gas is in a shale gas reservoir than in a conventional gas reservoir. People usually measure adsorption through volumetric methods under an isothermal condition. Because of a limitation of volumetric methods, only excess adsorption data are directly measured; then, a chosen model is applied to calculate an absolute adsorption through fitting the measured data.

An adsorption process induces changes in free-gas volume. However, the changes in absorbent volume and methane absorption into organic matter also alter the measured gas volume, which is widely neglected in previous studies. In this study, one volume term, which accounts for the unexpected changes in gas volumes caused by the other mechanisms except adsorption, is added to the Dubinin-Astakhov (DA) model (pore-filling theory). The in-situ methane is in a supercritical condition under reservoir conditions. Because of the lack of a saturation pressure of a supercritical fluid, an adsorbed-phase gas density is used to replace the saturation pressure in the DA model.

The modified model is validated by the isothermal adsorption data from four different shale plays. The calculated data by the proposed model have a better match with the measured data than those by the DA model. All shale samples demonstrate a nonmonotonic deformation of adsorbent (volume shrinkage in the low-pressure region, then swelling as pressure increases), which coincides with the results of previous molecular simulation. The key parameters of the proposed model such as a maximum adsorption capacity are more accurate and reasonable than the ones of the DA model. The proposed model provides a good approach to quantify absolute adsorption through experimental data, especially under reservoir conditions, and to emphasize the important effects of volume on methane/shale adsorption.

Yang, X., Chen, Q., Ma, Y., Li, Z., Hung, H.-c., Zhang, Q., Jin, Z., Liu, S., Zhou, Z., Fu, X., 2018. New radiocarbon and archaeobotanical evidence reveal the timing and route of southward dispersal of rice farming in south China. Science Bulletin 63, 1495-1501.


The origins and spreads of rice agriculture have been enduring topics, yet the timing and southward dispersal from the Yangtze River Basin have been difficult to trace, due to the scarcity of archaeobotanical data, especially systematic macro-plant remains examination, combined with the poor preservation in the humid climate and acidic soils of China’s southern provinces. Here, we report new radiocarbon dating and preserved rice phytolith evidence, derived from three Late Neolithic archaeological sites in south China, dated about 5,000–4,100 cal a BP. Our results demonstrate that rice farming had spread southward through the mountainous regions of Wuyi and Nanling, then entered the areas of Western Fujian and North Guangdong by 5,000 cal a BP, followed by continued expansion into coastal areas of East China Sea and South China Sea, also crossing the Taiwan Strait, around 4,500–4,000 cal a BP. The North River, East River, Min River, and possibly other river systems likely were influential as pathways or conduits.

Yang, Y., Chen, J., Li, B., Liu, Y., Xie, S., 2018. Anaerobic methane oxidation potential and bacteria in freshwater lakes: Seasonal changes and the influence of trophic status. Systematic and Applied Microbiology 41, 650-657.


Nitrite-dependent anaerobic methane oxidation (n-damo), mainly carried out by n-damo bacteria, is an important pathway for mitigating methane emission from freshwater lakes. Although n-damo bacteria have been detected in a variety of freshwater lakes, their potential and distribution, and associated environmental factors, remain unclear. Therefore, the current study investigated the potential and distribution of anaerobic methanotrophs in sediments from Erhai Lake and Dianchi Lake, two adjacent freshwater lakes in the Yunnan Plateau with different trophic status. Both lakes showed active anaerobic methane oxidation potential and harbored a high density of n-damo bacteria. Based on the n-damo pmoA gene, sediment n-damo bacterial communities mainly consisted of Candidatus Methylomirabils oxyfera and Candidatus Methylomirabils sinica, as well as novel n-damo organisms. Sediment anaerobic methane oxidation potential and the n-damo bacterial community showed notable differences among seasons and between lakes. The environmental variables associated with lake trophic status (e.g. total nitrogen, ammonia nitrogen, nitrate nitrogen, and total organic carbon) might have significant impacts on the anaerobic methane oxidation potential, as well as the abundance and community structure of n-damo bacteria. Therefore, trophic status could determine the n-damo process in freshwater lake sediment.

Yang, Y., Mavko, G., 2018. Mathematical modeling of microcrack growth in source rock during kerogen thermal maturation. American Association of Petroleum Geologists Bulletin 102, 2519-2535.


The success of hydraulic fracturing and increasing use of basin-modeling packages drive the need to understand the effects of hydrocarbon (HC) generation on the mechanical properties of source rocks. A better understanding of relationships among geological, geochemical, and geomechanical

parameters can potentially reduce the uncertainties associated with conventional and unconventional prospect evaluation.

We present a simulation of microcrack growth based on a three-dimensional source-rock system. Upon thermal maturation, the kerogen transforms into lighter products, most of which are HCs. The generated products exert excessive pore pressure to the system resulting from the effect of volume expansion; this pressure is released through the expansion of pore space and formation of microcracks. Using linear elasticity and linear elastic fracture mechanics, our model calculates microcrack sizes (surface areas, lengths, apertures, and volumes) and the amount of overpressure throughout the maturation process. We validated this model with experimental data from Kobchenko et al. (2011), and performed sensitivity analysis for both laboratory and geological settings. Much larger microcracks are generated in laboratory settings compared to the subsurface because of the lack of overburden, resulting in secondary porosity over 100 times larger than the original organic porosity and crack lengths obtaining millimeter scale. In contrast, microcracks are much smaller in geological settings because of the presence of significant overburden and stiffer rock frames: the crack apertures are in the submicron regime with a crack length ranging from 100 to 300 μm. The formation of microcracks connects isolated microscale HC pockets, providing pathways for primary migration.

Yang, Y., Qi, M., Wang, J., 2018. Separation performance of a star-shaped truxene-based stationary phase functionalized with peripheral 3,4-ethylenedioxythiophene moieties for capillary gas chromatography. Journal of Chromatography A 1578, 67-75.


This work describes the separation performance of a star-shaped truxene-based material (denoted as EDOTT) as the stationary phase for capillary gas chromatography (GC). The EDOTT capillary column achieved the column efficiency of 5920 plates/m by n-dodecane, 4890 plates/m by naphthalene and 3960 plates/m by 1-octanol at 120 . Its selectivity and retention behaviour were ℃investigated by a number of mixtures of diverse analytes and their isomers. As a result, it showed advantageous performance for separations of apolar to polar analytes, especially phenols and alcohols, over its analogous TTT, TDT and TFT stationary phases. In addition, the EDOTT capillary column was investigated for its column loadability, repeatability and thermal stability, and was finally applied for the determination of isomer impurities in real samples. This work provides an alternative truxene-based stationary phase with high selectivity for polar analytes and demonstrates the key role of structural modification in developing a family of stationary phases with specific selectivity for targeted analytes.

Yang, Z., Li, M., Cheng, D., Xiao, H., Lai, H., Chen, Q., 2019. Geochemistry and possible origins of biodegraded oils in the Cretaceous reservoir of the Muglad Basin and their application in hydrocarbon exploration. Journal of Petroleum Science and Engineering 173, 889-898.


The Muglad Basin is one of the largest petroliferous basins within the Central and Western African Rift System (WCARS). A total of 42 oil samples including light, normal and heavy crude oils from the Cretaceous reservoirs of the Muglad Basin were systematically analyzed to fully understand their geochemical characteristics and possible origins. The results of oil–oil correlation show that these Cretaceous crude oils are genetically identical and derive from the same source kitchen. Differences in physical properties and geochemical compositions may be attributed to secondary alteration, such as biodegradation. Lightly, moderately and severely biodegraded oils can be divided on the basis of

the relative abundance of n–alkanes and acyclic isoprenoids in the oils and the presence of “humps” on gas chromatogram baselines, as well as of the relative abundance of 25–norhopanes. The biodegradation degree of Cretaceous oils in the Muglad Basin is closely related to the burial depth of oil reservoirs and the distance between the locations of oil reservoirs and adjacent faults. This study may have practical application for further petroleum exploration and development in the Muglad Basin.

Yi, F., Yi, H., Xia, G., Cai, Z., 2018. Atmospheric carbon dioxide reconstruction and ocean acidification deduced from carbon isotope variations across the Triassic–Jurassic boundary in the Qiangtang area, Tibetan Plateau. Acta Geologica Sinica - English Edition 92, 2055-2057.

https://doi.org/10.1111/1755-6724.13706

The end-Triassic mass extinction was one of the five most profound Phanerozoic extinction events. This event was accompanied by a series of significant environmental changes, of which the most notable is the emergence of warm climate and the world-wide disappearance of carbonate platform. C isotope is one of the main means of reconstructing palaeoenvironment, however, there are very limited studies on Asia and Oceania in the East Tethys region. In China, continuous marine strata through the J/Tboundary are widespread in the Qiangtang area of Tibet (Chen Lan et al., 2017), which provide us abundant research materials to study the environmental geological evolution during the T–J transition in Asian and even eastern Tethys.

Yu, J., Maliutina, K., Tahmasebi, A., 2018. A review on the production of nitrogen-containing compounds from microalgal biomass via pyrolysis. Bioresource Technology 270, 689-701.


Nitrogen-containing compounds (NCCs) which may be produced from nitrogen-rich biomass such as microalgae, may find important biochemical and biomedical applications. This review summarizes the recent knowledge about the formation mechanism of NCCs during pyrolysis of microalgae. The key technical and biological aspects of microalgae and pyrolysis process parameters, which influence the formation of NCCs, have been analyzed. The mechanism of formation of NCCs such as indole, pyridine, amides, and nitriles during primary and secondary pyrolysis reactions are elaborated. It has been emphasized that the pyrolysis conditions and the use of catalysts had significant impacts on the yields and compositions of NCCs. The available information shows that the transformation of nitrogen and nitrogen functionalities during pyrolysis are strongly associated with the formation process of NCCs. The challenges in the development of pyrolysis technologies for the production of NCCs from microalgae are identified with future research needs identified.

Yu, T., Chen, Y., 2019. Effects of elevated carbon dioxide on environmental microbes and its mechanisms: A review. Science of The Total Environment 655, 865-879.


Before the industrial revolution, the atmospheric CO2 concentration was 180–330 ppm; however, fossil-fuel combustion and forest destruction have led to increased atmospheric CO2 concentration. CO2 capture and storage is regarded as a promising strategy to prevent global warming and ocean acidification and to alleviate elevated atmospheric CO2 concentration, but the leakage of CO2 from storage system can lead to rapid acidification of the surrounding circumstance, which might cause negative influence on environmental microbes. The effects of elevated CO2 on microbes have been

reported extensively, but the review regarding CO2 affecting different environmental microorganisms has never been done previously. Also, the mechanisms of CO2 affecting environmental microorganisms are usually contributed to the change of pH values, while the direct influences of CO2

on microorganisms were often neglected. This paper aimed to provide a systematic review of elevated CO2 affecting environmental microbes and its mechanisms. Firstly, the influences of elevated CO2 and potential leakage of CO2 from storage sites on community structures and diversity of different surrounding environmental microbes were assessed and compared. Secondly, the adverse impacts of CO2 on microbial growth, cell morphology and membranes, bacterial spores, and microbial metabolism were introduced. Then, based on biochemical principles and knowledge of microbiology and molecular biology, the fundamental mechanisms of the influences of carbon dioxide on environmental microbes were discussed from the aspects of enzyme activity, electron generation and transfer, and key gene and protein expressions. Finally, key questions relevant to the environmental effect of CO2 that need to be answered in the future were addressed.

Yuan, H.-Y., Ding, L.-J., Zama, E.F., Liu, P.-P., Hozzein, W.N., Zhu, Y.-G., 2018. Biochar modulates methanogenesis through electron syntrophy of microorganisms with ethanol as a substrate. Environmental Science & Technology 52, 12198-12207.


Biochar has the potential to influence methanogenesis which is a key component of global carbon cycling. However, the mechanisms governing biochar’s influence on methanogenesis is not well understood, especially its effects on interspecies relationships between methanogens and anaerobic bacteria (e.g., Geobacteraceae). To understand how different types of biochar influence methanogenesis, biochars derived from rice straw (RB), wood chips (WB), and manure (MB) were added to the methanogenic enrichment culture system of a paddy soil. Compared to the nonbiochar control, RB and MB additions accelerated methanogenesis remarkably, showing 10.7 and 12.3-folds higher methane production rate, respectively; while WB had little effect on methanogenesis. Using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical methods, RB and MB also had higher redox-active properties or charging and discharging capacities than WB, and the functional groups, mainly quinones, on the biochar surface played an important role in facilitating methanogenesis. Quantitative polymerase chain reaction results demonstrated that electronic syntrophy did exist between methanogens and Geobacteraceae. RB and MB stimulate methanogenesis by facilitating direct interspecies electron transfer between methanogens and Geobacteraceae. Our findings contribute to a better understanding of the effects of biochars from different feedstocks on methanogenesis and provide new evidence to the mechanisms of stimulating methanogenesis via biochar.

Yuan, T., Yi, H., Zhang, S., Cai, Z., Li, G., 2018. Carbon isotope excursions and paleo-oceanography of the Ordovician–Silurian boundary carbonate rocks from the Xainza Area, Tibet. Acta Geologica Sinica - English Edition 92, 2052-2054.

https://doi.org/10.1111/1755-6724.13705

The Ordovician–Silurian transitional period is a special time when the global paleo-environment changed greatly. It witnessed the first mass extinction as of Phanerozoic period and glaciations that occurred frequently at a large scale in a very short time, which has thus attracted much attention among geoscientists at home and abroad. The most complete and continuous development of Paleozoic strata occurs in the Xainza area, Tibet, which are dominated by carbonate sediments during the Ordovician-Silurian period and provide good materials

for research on carbon isotopes. This work focused on the carbon isotope excursion of the Ordovician–S

ilurian marine carbonates in the Xainza area, Tibet, which is the key to studying the glaciations and mass extinction of the Ordovician–Silurian period of East Paleo-Tethys, as well as the changes of paleo-climate environment and paleo-ocean environments.

Zammuto, V., Fuchs, F.M., Fiebrandt, M., Stapelmann, K., Ulrich, N.J., Maugeri, T.L., Pukall, R., Gugliandolo, C., Moeller, R., 2018. Comparing spore resistance of Bacillus strains isolated from hydrothermal vents and spacecraft assembly facilities to environmental stressors and decontamination treatments. Astrobiology 18, 1425-1434.

https://doi.org/10.1089/ast.2017.1715

Submarine hydrothermal vents are inhabited by a variety of microorganisms capable of tolerating environmental extremes, making them ideal candidates to further expand our knowledge of the limitations for terrestrial life, including their ability to survive the exposure of spaceflight-relevant conditions. The spore resistance of two Bacillus spp. strains, APA and SBP3, isolated from two shallow vents off Panarea Island (Aeolian Islands, Italy), to artificial and environmental stressors (i.e., UVC radiation, X-rays, heat, space vacuum, hydrogen peroxide [H2O2], and low-pressure plasma), was compared with that of two close phylogenetic relatives (Bacillus horneckiae and Bacillus oceanisediminis). Additional comparisons were made with Bacillus sp. isolated from spacecraft assembly facilities (B. horneckiae, Bacillus pumilus SAFR-032, and Bacillus nealsonii) and the biodosimetry strain and space microbiology model organism Bacillus subtilis. Overall, a high degree of spore resistance to stressors was observed for the strains isolated from spacecraft assembly facilities, with an exceptional level of resistance seen by B. pumilus SAFR-032. The environmental isolate SBP3 showed a more robust spore resistance to UVC, X-rays, H2O2, dry heat, and space vacuum than the closely related B. horneckiae. Both strains (SBP3 and APA) were more thermotolerant than their relatives, B. horneckiae and B. oceanisediminis, respectively. SBP3 may have a novel use as a bacterial model organism for future interrogations into the potential of forward contamination in extraterrestrial environments (e.g., icy moons of Jupiter or Saturn), spacecraft sterilization and, broadly, microbial responses to spaceflight-relevant environmental stressors.

Zare, A., Hamouda, A.A., 2019. Coinjection of C6, C7, and CO2 with steam to improve low-pressure SAGD process. Fuel 238, 394-401.


Steam assisted gravity drainage (SAGD) is one of the most widely used processes of thermal recovery for heavy oil. Investigating the effectiveness of solvent coinjection with steam is an important aspect in the optimisation of SAGD process. So far, however, the effects of using CO2 have not been closely examined. This study sheds light on the addition of hydrocarbon solvents with CO2 which reached earlier maximum ultimate oil recovery (90%) than that for other solvents coinjection. This study shows that solubility of C6, heat loss reduction and CO2 diffusion, are the main recovery mechanism in enhancing oil recovery. The present study highlights the steam propagation in the presence of C6 and CO2 and its relation to enhancing oil recovery. It is interesting to observe that physical properties of the injected fluid reduce the energy consumption. Another finding is that solvent coinjection leads to stable subcool, hence increase oil recovery.

Zarrillo, S., Gaikwad, N., Lanaud, C., Powis, T., Viot, C., Lesur, I., Fouet, O., Argout, X., Guichoux, E., Salin, F., Solorzano, R.L., Bouchez, O., Vignes, H., Severts, P., Hurtado, J., Yepez, A., Grivetti, L., Blake, M., Valdez, F., 2018. The use and domestication of Theobroma cacao during the mid-Holocene in the upper Amazon. Nature Ecology & Evolution 2, 1879-1888.

https://doi.org/10.1038/s41559-018-0697-x

Cacao (Theobroma cacao L.) is an important economic crop, yet studies of its domestication history and early uses are limited. Traditionally, cacao is thought to have been first domesticated in Mesoamerica. However, genomic research shows that T. cacao’s greatest diversity is in the upper Amazon region of northwest South America, pointing to this region as its centre of origin. Here, we report cacao use identified by three independent lines of archaeological evidence—cacao starch grains, absorbed theobromine residues and ancient DNA—dating from approximately 5,300 years ago recovered from the Santa Ana-La Florida (SALF) site in southeast Ecuador. To our knowledge, these findings constitute the earliest evidence of T. cacao use in the Americas and the first unequivocal archaeological example of its pre-Columbian use in South America. They also reveal the upper Amazon region as the oldest centre of cacao domestication yet identified.

Zeng, Y., Khodadadi, J.M., 2018. Molecular dynamics simulations of the crystallization process of n-alkane mixtures and the resulting thermal conductivity. Energy & Fuels 32, 11253-11260.


To elucidate the underlying mechanism of crystallization processes of n-alkane mixtures, molecular dynamics simulation is used to assess the effect of the morphology on thermal conductivity. Binary mixtures of n-eicosane and n-triacontane with different molecular number ratios are solidified following two approaches: the surface potential route and the free surface route. There exists a marked discrepancy of the orientation factor of the resulting solid n-alkane molecules following the imposed surface potential and the free surface routes corresponding to observed layered systems and random ordering of molecular chains, respectively. In addition, the thermal conductivities of the n-alkane mixtures are evaluated using non-equilibrium molecular dynamics. The results suggest that the orientation factor of the molecular system greatly impacts the thermal transport of n-alkane mixtures at the nanometer scale, with a negligible influence of the number ratio of n-triacontane. Moreover, the solid ratio plays a significant role on the thermal conductivity for low orientation factor systems by adjusting the number of thermal interfaces of the entire molecular system.

Zhan, Z.-W., Lin, X.-H., Zou, Y.-R., Li, Z., Wang, D., Liu, C., Peng, P.a., 2019. Chemometric differentiation of crude oil families in the southern Dongying Depression, Bohai Bay Basin, China. Organic Geochemistry 127, 37-49.


Fifty-seven crude oil samples from the southern Dongying Depression were selected for detailed geochemical analysis. High C26/C25 tricyclic terpanes (0.81–1.26) and low C31 homohopane (R)/C30 hopane (0.15–0.26) ratios indicate that the oils are from lacustrine source rocks. The presence of C30 4α-methyl-24-ethylcholestanes and C30 tetracyclic polyprenoids imply the contribution of microalgal organic matter. Large variations of depositional environment-related biomarker parameters suggest differences in organofacies and water environment. Four genetically distinct oil families were differentiated by chemometrics of hierarchical cluster and principal component analyses using the parameter dataset of three isotope ratios and 15 molecular parameters, all related to source and

depositional environment. Family I is mature and does not match any available source rocks. The inferred source rock contains microalgal material that could produce large quantities of wax, C29 steranes and tricyclic terpenoids in a reducing, salinity stratified water column. Family II is characterized by a strong phytane dominance, relatively high gammacerane and C35 homohopanes, and low diasterane and 4-methyl sterane contents. It has high values of sterane/hopane (S/H = 1.67–4.14), C35/C34 homohopane (C35H/C34H = 0.81–1.66) and gammacerane/C30 hopane (G/C30H = 0.57–1.13) and low pristane/phytane (Pr/Ph = 0.30–0.59), suggesting that the inferred source rock is the upper Es4 interval. Family III has characteristics distinct from families I and II: low S/H (0.15–0.27), C35H/C34H (0.39–0.49) and G/C30H (0.03–0.12) ratios and high Pr/Ph (0.48–1.90), C30-4M/C29 ααα20R (0.54–1.18) and C30 tetracyclic polyprenoid (0.54–0.66) ratios, suggesting that the source rock is the lower Es3 interval. The family IV oils are compositionally in-between the ranges of families II and III oils, and in line with them in plots of geochemical parameters. We suggest that family IV consists of mixed oils derived from the upper Es4 and lower Es3 intervals. Family II has a relatively low thermal maturity and the inferred source rock may be located in the Niuzhuang Sag and/or the southern gentle slope zone. Family III is mature and its inferred source rock may be situated in the Lijin and Boxing sags. The upper Es4 and lower Es3 source rocks in the three sags contribute the crude oils of family IV that occurs in the middle and eastern parts of the southern Dongying Depression.

Zhang, B., Pan, M., Wu, D., Wu, N., 2018. Distribution and isotopic composition of foraminifera at cold-seep Site 973-4 in the Dongsha area, northeastern South China Sea. Journal of Asian Earth Sciences 168, 145-154.


A 1375-cm-long gravity core (Site 973-4) was acquired from the Dongsha cold seep area of the northeastern South China Sea (SCS). We measured its stable isotopes of planktonic foraminifera and investigated benthic foraminiferal assemblage compositions. Accelerator mass spectrometry 14C analysis of planktonic foraminifera shows that some intervals are dated to Marine Isotope Stage (MIS) 3. Pulleniatina obliquiloculata has positive δ13C (0.25–1.25‰) except for a negative carbon isotopic excursion (up to δ13C = −1.15‰), but its light-carbon sources remain elusive. The benthic δ13C values (Uvigerina) of non-seep and cold-seep boreholes from the SCS have no systematic difference. Therefore, the benthic δ13C at Site 973-4 did not record the enhanced seepage activities (if occurred) during the last sea-level lowstand in the Dongsha area. In the pre-Holocene sediments, the foraminiferal assemblages have lower diversities, Shannon-Wiener indices, evenness indices, Simpson indices and higher calcareous proportions like typical cold-seep settings. The changes in oxygen levels (lower in the glacial period than those in the Holocene) indicated by foraminiferal indices reflect either bottom-water oxygen variations on the glacial-interglacial scale or enhanced seepage activities during the last glacial period.

Zhang, F., Zhang, Q., Gardner, R.P., Liu, J., Zhang, X., Qiu, F., Chen, Q., Tian, L., Wang, Y., 2018. Quantitative monitoring of CO2 sequestration using thermal neutron detection technique in heavy oil reservoirs. International Journal of Greenhouse Gas Control 79, 154-164.


CO2 enhanced oil recovery (CO2-EOR) project is of significance for CO2 sequestration and heavy oil recovery. Quantitative monitoring of CO2 saturation (SCO2) is essential to recognizing and understanding the migration and distribution of CO2 injected into the geological formations. In this paper, based on the difference in the neutron moderation ability of CO2, water and heavy oil, thermal

neutron detection technique is applied in heavy oil reservoirs to monitor CO2 sequestration. By Monte Carlo simulation, the responses of thermal neutron count ratio versus different porosities and CO2 saturation were studied. Then, a mathematical model of CO2 saturation versus thermal neutron count ratio and formation porosity was established to quantitatively calculate CO2 saturation. Besides, the effects of formation pressure and temperature, heavy oil density, lithology, and other factors on the method were studied. Results show that variations of formation pressure, formation temperature, and density of heavy oil have little impact on the CO2 saturation measurement. However, the change of formation lithology results in larger CO2 saturation errors and needs corrections. In addition, the method has a low discrimination between CO2 and CH4 gas, and the results are easily affected by the CH4 content. Finally, a simulated case demonstrates the application of the method. For the heavy-oil sandstone with different porosities, the method shows a perfect performance: the SCO2 errors are less than 1% for the high and low gas saturated formation. This research provides an effective strategy to monitor CO2 storage and residual oil saturation in CO2-EOR reservoirs.



A large amount of polycyclic aromatic hydrocarbons (PAHs) and their heterocyclic analogues (N, S, O) are released to the marine environment from natural oil seeps, oil spills, bilge discharges and input of land-based sources. Many of these compounds are toxic and have a deleterious effect on marine biota. Nitrogen-containing compounds in crude oils are typically present as cyclic compounds such as polycyclic aromatic nitrogen heterocycles (PANHs) and are generally classified into the two categories of nonbasic (N-PANHs) and basic compounds (B-PANHs). Chromatographic analyses of PANHs are easily to be interfered by other oil components without proper sample preparation prior to instrumental analysis. In this work, dual solid phase extraction columns of 3-(isocyanato)propyl-functionalized silica gel (Si-NCO) and silica gel were employed to efficiently separate both N-PANHs and B-PANHs from saturated and aromatic petroleum hydrocarbons, which enable simultaneous accurate analyses of these groups with single sample preparation. Crude oils studied contain various concentrations of N-PANHs including carbazole, benzocarbazole and B-PANHs including quinolone, acridine and benzoacridine as well as their alkylated homologues. These compounds in light fuel and lubricating oil are generally not detected or are only in trace concentration, but have considerable abundance in heavy fuel oils. Crude oils from different sources and various petroleum products have their unique absolute concentrations and relative distribution patterns of PANHs. Chemical fingerprints of PANHs can provide valuable information for forensic oil spill identification and improve the understanding of the fate, behaviour and chemical degradation of spilled crude oil.

Zhang, H., Shi, J.-T., Li, X.-F., 2018. Optimization of shale gas reservoir evaluation and assessment of shale gas resources in the Oriente Basin in Ecuador. Petroleum Science 15, 756-771.

https://doi.org/10.1007/s12182-018-0273-7

The petroleum geological features of hydrocarbon source rocks in the Oriente Basin in Ecuador are studied in detail to determine the potential of shale gas resources in the basin. The favorable shale gas layer in the vertical direction is optimized by combining logging identification and comprehensive geological analysis. The thickness in this layer is obtained by logging interpretation in the basin. The favorable shale gas accumulation area is selected by referring to thickness and depth data.

Furthermore, the shale gas resource amount of the layer in the favorable area is calculated using the analogy method. Results show that among the five potential hydrocarbon source rocks, the lower Napo Formation is the most likely shale gas layer. The west and northwest zones, which are in the deep-sea slope and shelf sedimentary environments, respectively, are the favorable areas for shale gas accumulation. The favorable sedimentary environment formed thick black shale that is rich in organic matter. The black shale generated hydrocarbon, which migrated laterally to the eastern shallow water shelf to form numerous oil fields. The result of the shale gas resource in the two favorable areas, as calculated by the analogy method, is 55,500 × 108 m3. This finding shows the high exploration and development potential of shale gas in the basin.

Zhang, J.-F., Dennell, R., 2018. The last of Asia conquered by Homo sapiens. Science 362, 992-993.


By 30,000 years ago, humans had colonized almost every part of Asia that was not covered by ice sheets and may even have settled on the shores of the Arctic Ocean (1). One of the last places in Asia that was colonized was the Tibetan Plateau, one of the most challenging and hostile environments of the Northern Hemisphere (2). With an average elevation of about 4000 m above sea level and an average annual temperature close to the freezing point of water, and with only half the concentration of oxygen as at sea level, it is not hard to see why it was such a challenge. Many researchers maintain that it was only colonized in the Holocene (the current epoch, which began approximately 12,000 years ago) with the adoption of agriculture, and the domestication of barley and yak (3). Others suggest that it might have been initially colonized at the end of the last ice age after about 15,000 years ago, when hunter-foragers began to hunt at higher altitudes during the summer months and gradually learned how to acclimatize to such harsh surroundings (4). Some genetic evidence from modern Tibetans suggests that the Plateau might have been colonized 30,000 years ago before the last glacial maximum (5), but archaeological evidence for this is lacking. On page 1049 of this issue, Zhang et al. (6) report that the Tibetan Plateau shows not only the earliest occupation of the “roof of the world” but the earliest record worldwide for humans living at high altitude (see the first photo).

Zhang et al. report the excavation of a site called Nwya Devu, which lies at 4600 m in eastern Tibet (see the second photo). The site is positioned on the edge of a former lake and near a low ridge of black slate that provided an ample high-quality source of flakable stone for making stone tools. Unlike almost all other sites on the Tibetan Plateau that may have paleolithic-looking stone tools, this one is stratified and has almost 2 m of deposits. The site has three strata, of which the lowest is a layer of fine-grained sands denoting gentle deposition. Over 3600 stone artifacts were found, of which 300 are in the lowest layer, and 200 in a middle layer of sands and gravels; the rest were found in the top-most layer of sand and silt. There are no obvious typological, technological, or morphological differences in the assemblages from each layer, and Zhang et al. argue that all the artifacts can be regarded as part of the same assemblage. They also argue that the artifacts were primarily associated with the lowest layer but that geological processes such as freeze-thawing and gelifluction moved some of the artifacts upwards through the strata.

Dating is clearly critical here. Because there was not enough material for radiocarbon dating, the layers were dated primarily by optically stimulated luminescence (OSL). This technique measures the time that has lapsed since the dated sediment was last exposed to sunlight. It is now widely used to establish chronologies for human evolution and dispersals during the past 500,000 years on the basis of ubiquitous dating material (quartz and feldspar) within sediments (7). The 24 OSL dates are largely internally consistent (6). The topmost layer is OSL- and radiocarbon-dated to about 4000 to 13,000 years ago and is largely Holocene in age, and the middle layer dates from 18,000 to 25,000 years ago, indicating deposition during the last glacial maximum when conditions were at their most severe. The

oldest dates of 30,000 to 45,000 years ago are from the bottom layer in the deepest part of the stratigraphy and indicate the likely age of the stone tool assemblage. This estimate is consistent with a radiocarbon date on a shell from that layer of 44,000 calibrated years before the present. Paleoenvironmental evidence from the Tibetan Plateau indicates that during this period, the climate was less severe than it is today.

It is obvious from the stone tool assemblage that a primary aim of those who stayed there was to produce long, parallel-sided blades that could be used as knives or scrapers that were most likely hafted onto a bone or wooden handle. Some of these blades were over 20 cm long, which testifies both to the quality of the raw material and the skill of the person flaking it. Because of the proximity of the site to a large source of flakable stone, the site is likely a workshop where tools were made that were then used on hunting expeditions at other locations. For paleolithic hunters, the attractions of the Tibetan Plateau must have been the herds of gazelles, horses, and yaks (and perhaps other herbivores such as woolly rhinoceros); the Plateau was undoubtedly harsh, but it was not barren. The stone tool assemblage is more or less unique in East Asia. The best-known assemblage from this period is that from the site of Shuidonggou locality 1 in Ninxia Province, north China. There, the earliest blades (dated to about 40,000 years ago) were made on a type of flake known as Levallois, followed by assemblages from Shuidonggou locality 2 that have smaller blades (8). It should be remembered that the paleolithic record of the vast area of northern China, Tibet, and Mongolia is very poorly known, so it is not surprising that there are no obvious parallels for the Nwya Devu assemblage.

We know from the cave site of Tianyuandong near Beijing that Homo sapiens were already in northern China by 40,000 years ago (9), so the first Tibetans were also likely H. sapiens. An interesting perspective on the colonization of the Tibetan Plateau is that the high-altitude adaptation that may have enabled humans to live at such a location may have come from a now-extinct type of humanity known as Denisovan, named after the cave of Denisova in the Altai Mountains of Siberia where it was first discovered. Denisovans are known only from their ancient DNA preserved in a few fossils. They appear to have been a sister taxon of the better-known Neanderthals. Denisovans may have contributed to adaptation of H. sapiens to high-altitude hypoxia (10). Denisovans interbred with Neanderthals (11), and Neanderthals interbred with H. sapiens, and therefore it is very likely that Denisovans interbred with H. sapiens as well. In fact, present-day human genetic makeup reflects that varied background, as in modern Melanesian populations, in that about 4 to 6% of our DNA is derived from Denisovans.

Unfortunately, no bone was preserved at Nwya Devu, so there is no direct skeletal evidence of the first Tibetans, nor of the animals that they hunted. Nevertheless, the evidence from Nwya Devu that humans were living at 4600 m above sea level 30,000 to 40,000 years ago provides a graphic example of how successful our species has been as a colonizing animal.

References and Notes1. C. J. Bae et al., Science 358, eaai9067 (2017)2. L. Barton, Archaeol. Res. Asia 5, 4 (2016).3. F. H. Chen et al., Science 347, 248 (2015).4. B. Madsen, Archaeol. Res. Asia 5, 24 (2016).5. D. S. Lu et al., Am. J. Hum. Genet. 99, 580 (2016).6. X. L. Zhang et al., Science 362, 1049 (2018).7. R. G. Roberts, Z. Jacobs, Elements 14, 27 (2018).8. F. Li et al., Sci. China Earth Sci. 59, 1540 (2016).9. M. A. Yang et al., Curr. Biol. 27, 3202 (2017).10. E. Huerta-Sánchez et al., Nature 512, 194 (2014).11. V. Slon et al., Nature 561, 113 (2018).

Zhang, J., Wei, C., Ju, W., Yan, G., Lu, G., Hou, X., Kai, Z., 2019. Stress sensitivity characterization and heterogeneous variation of the pore-fracture system in middle-high rank coals reservoir based on NMR experiments. Fuel 238, 331-344.


Five groups of middle to high rank coal samples (Ro, max value between 1.87 and 3.01%) were tested under different confine pressures using nuclear magnetic resonance (NMR) technology. Stress sensitivities of adsorption pore, seepage pore and fracture were calculated to investigate the relationship between the compressibility of pore-fracture system and its effective stress. The heterogeneous variation of pore and fracture caused by the effect of stress was discussed based on the T2 spectrum by using the NMR method. The conclusions are as follows. 1) The overall compressibility (OC) of the middle rank coal samples is mainly controlled by seepage pore and fracture. Adsorption pore are generally well developed in high-rank coal samples and the pores are primarily responsible for the stress sensitivity of these kinds of samples. 2) The compressibility shows a trend of decrease with increase of coal rank and there exists a good logarithmic relationship between OC and effective stress. 3) With the decrease of OC, the pore and fracture heterogeneity tends to become more complex. The variation of the heterogeneity of middle rank coal sample is higher than that of a high rank coal sample, and the heterogeneity variation of adsorption pore is greater than that of seepage pore and fracture. 4) The effect of stress on the heterogeneity of pore-fracture system has a two-stage characteristic. At the initial stage that the confine pressure is less than 9 MPa, the heterogeneity of pore-fracture system becomes more complicated. And when the stress is higher than 9 MPa, it moves to the stable stage that the heterogeneity tends to be stable. 5) Compared to the middle rank coal samples, the OC of high rank coal reveals a significant negative linear correlation with the (total fractal dimension) DR, indicating the simultaneity of pore structure and strain variation under the action of stress. The above results can provide theoretical guidance for increased understanding of the changes in a coal reservoir’s permeability during coalbed methane drainage.

Zhang, K., Meng, Z., Wang, X., 2019. Distribution of methane carbon isotope and its significance on CBM accumulation of No.2 coal seam in Yanchuannan CBM block, Ordos Basin, China. Journal of Petroleum Science and Engineering 174, 92-105.


Distribution and origins of methane isotope (δ13C(CH4)) in coalbed methane (CBM) block of southeast-Ordos Basin are related to the accumulation and distribution of CBM in Yanchuannan CBM block, which is of great significance for the evaluation of CBM resources. In this paper, the stable isotope ratios of coalbed gases (δ13C(CH4), δD(CH4) and δ13C(CO2)) of the No.2 coal seam associated with water samples collected from Permian Shanxi Formation in southeast of Ordos Basin were investigated. The data set reveals that stable isotope ratios vary within the following ranges: δ13C(CH4) from −54.1‰ to −29.6‰ with an average of −37.73‰, δD(CH4) from −230‰ to −158‰ with an average of −188.39‰, and δ13C(CO2) from −20.6‰ to +2.2‰ with an average of −14.47‰. There are four dominant factors that decides the distribution of methane carbon isotope, including burial depth, Ro,max, hydrodynamic conditions and biogenic gases. The values of δ13C(CH4) naturally desorbed from No.2 coal seam increase with an increase with burial depth, Ro,max and reservoir pressure, which indicates that δ13C(CH4) of almost the whole studied area is controlled by the thermodynamic equilibrium fractionation, except the Xibaigou gentle slope belt (A4). The stable isotope compositions in Xibaigou gentle slope belt (A4) characterized by shallow and up-dip areas suggest that late-stage biogenic methane was generated via CO2-reduction associated with meteoric water recharge, which significantly contributes to δ13C(CH4) stripping and higher gas saturation than

expected. Furthermore, it is summarized a variation model of gas-bearing properties andδ13C(CH4) values in Yanchuannan CBM block, which shows that the geological controls on gas-bearing properties are consistent with that on stable carbon isotope of methane, and normally lighter δ13C(CH4) ratios corresponds to lower gas-bearing properties domain. Significantly, this result can be used to evaluate and instruct the enrichment law of CBM and benefit its exploration and development in research area.

Zhang, K., Song, Y., Jiang, S., Jiang, Z., Jia, C., Huang, Y., Wen, M., Liu, W., Xie, X., Liu, T., Wang, P., Shan, C.a., Wu, Y., 2019. Mechanism analysis of organic matter enrichment in different sedimentary backgrounds: A case study of the Lower Cambrian and the Upper Ordovician-Lower Silurian, in Yangtze region. Marine and Petroleum Geology 99, 488-497.


In order to meet the demand of shale oil and gas exploration, it is more and more important to study the controlling effect of sedimentary environment on the enrichment of organic matter. In this paper, the Lower Cambrian and Upper Ordovician-Lower Silurian shales in the Yangtze region are studied. Firstly, according to the content of Mo and TOC, the water closure property of the shale depositional period is judged. Then this study selected typical wells, and calculated quantitatively whether there was excess siliceous minerals in shale and the content of it. The origin of excess siliceous minerals is determined by Al, Fe and Mn element. The results show that the Lower Cambrian shale is deposited in a weak to moderate restricted water environment, and the Upper Ordovician and Lower Silurian shales are deposited in a strong restricted water environment in the Yangtze region. Excess siliceous minerals in the Lower Cambrian shale is of hydrothermal origin. On the one hand, hydrothermal activity can enhance the reductivity of the water bottom. On the other hand, it can improve the biological productivity, so that the sedimentary organic matter can be enriched. Excess siliceous minerals in Upper Ordovician and Lower Silurian shale is biogenic. The strong restriction of the water leads to stratification. The oxygen content in the upper layer makes the biological productivity higher and the lower layer more reductive, which is beneficial to the preservation of sedimentary organic matter.

Zhang, M., Dai, S., Du, B., Ji, L., Hu, S., 2018. Mid-Cretaceous hothouse climate and the expansion of early angiosperms. Acta Geologica Sinica - English Edition 92, 2004-2025.

https://doi.org/10.1111/1755-6724.13692

The remarkable transition of early angiosperms from a small to a dominant group characterized the terrestrial ecosystem of the Cretaceous. This transition was instigated and promoted by environmental changes. Mid‐Cretaceous is characterized by major geological events that affected the global environment. δ18O, palaeothermometer TEX86, and other climatic indices from marine sediments suggest rapid temperature increase during mid‐Cretaceous despite occasional short cooling events. Simultaneously, terrestrial deposits in East Asia changed from coal‐bearing to shale, then to red beds and evaporites. Plant assemblages and other paleoclimate indicators point to rapid aridification for mid‐Cretaceous terrestrial environments. In addition, the wildfires were frequently spread all over the earth by the numerous charcoal evidence during the Mid‐Cretaceous. Thus, we speculate that the seasonally dry and hot conditions of mid‐Cretaceous created a fiery hothouse world. Early angiosperms increased in abundance and diversity and evolved from a few aquatic species to terrestrial herbaceous and then to the diversified flora of today. Angiosperms showed rapid physiological evolution in vein density and leaf area that improved photosynthesis and water absorption. These ecophysiological changes made early angiosperms well adapted to the hot and dry

environment in mid‐Cretaceous. Moreover, these physiological changes facilitated the fire–angiosperm cycles in mid‐Cretaceous that likely further stimulated the early angiosperm evolution.

Zhang, M., Fu, X., Zhang, Q., Cheng, W., 2019. Research on the organic geochemical and mineral composition properties and its influence on pore structure of coal-measure shales in Yushe-Wuxiang Block, South Central Qinshui Basin, China. Journal of Petroleum Science and Engineering 173, 1065-1079.


This paper uses coal-measure shales from Carboniferous-Permian in Yushe-Wuxiang Block as an example to study the physical properties of transitional coal measure shales, including geochemical properties (e.g. total organic carbon content (TOC), organic matter maturity and hydrocarbon generation potential); mineral composition determined by X-ray diffraction (XRD) and pore structure characteristics determined by gas adsorption methods. The results indicated that the transitional coal measure shales in Yushe-Wuxiang area mostly comprise type III kerogen and are mostly in the over-mature stage, with shales in the range of 1.86%–3.36%Ro. The TOC of transitional shales varied significantly, ranging from 0.10% to 34.37%. Clay minerals and quartz are major minerals in transitional shales, while the predominant clay minerals are illite-smectite mixed clay (I/S) and kaolinite. The total pore volume (TPV) and pore specific surface area (SSA) of investigated mud shales varies from 0.0071 to 0.023 cm3/g and 8.4059–18.2888 m2/g, respectively. The transitional shales mostly provide mesopores and macropores, whereas the micropores provide the main SSA. The TOC content has a distinct effect on the porosity and micropores volume but contributes little to the TPV and volumes of macropores and mesopores. Clay minerals are positively correlated with porosity, TPV and volumes of each class of pores, while quartz has an opposite effect. In the over-maturity stage, the increase of organic matter maturity will inhibit the development level of pores in shale. For the coal measure shales, I/S and illite contribute most to the pore development.



Biofilm-sediment aggregate (BSA) contains a high water content, either within internal pores and channels or bound by extracellular polymeric substances (EPS) forming a highly hydrated biofilm matrix. Desiccation of BSAs alters the biofilm morphology and thus the physical characteristics of porous media, such as the binding matrix within BSA and internal pore geometry. Observing BSAs in their naturally hydrated form is essential but hampered due to the lack of techniques for imaging and discerning hydrated materials. Generally, imagery techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and focused ion beam nanotomography (FIB-nt)) involve the desiccation of BSAs (freeze-drying or acetone dehydration) or prevent differentiation between BSA components such as inorganic particles and pore water (confocal laser scanning microscopic (CLSM)). Here, we propose a novel methodology that simultaneously achieves the 3D visualization and quantification of BSAs and their components in their hydrated form at a submicron resolution using X-ray microcomputed tomography (μ-CT). It enables the high-resolution detection of comparable morphology of multiphase components within a hydrated aggregate: each single inorganic particle and the hydrated biofilm matrix. This allows the estimation of aggregate density and the illustration of biofilm-sediment binding matrix. This information provides valuable insights into investigations of the transport of BSAs and aggregate-associated sediment particles,

contaminants (such as microplastics), organic carbon, and their impacts on aquatic biogeochemical cycling.



Shale oil reservoirs characterized by complex pore structures typically contain a wide pore size range from nanometers to millimeters. The pore size distribution (PSD) is one of the most critical parameters affecting fluid storage and transport properties in shale oil reservoirs. Quantitatively and accurately determining PSD is of great importance for evaluating the shale oil occurrence state and movable fluid volume. In this study, four major techniques, including nitrogen adsorption (NA), scanning electron microscopy (SEM), mercury injection capillary pressure (MICP) and nuclear magnetic resonance (NMR), were adopted to determine pore sizes in ten shale oil reservoir samples from Dongying sag, Bohai Bay basin, China. NMR T2 spectra were converted to PSDs by using a new subsection calibration method based on the NA and SEM measurements; using the linear and power exponent conversion models, these two models are compared. The results show that the subsection calibration is an effective method for shale NMR T2 spectrum conversion. Shale oil reservoir T2 spectra can be converted to full-scale PSDs by combining NA micropore (<100 nm) PSDs and SEM mesopore (100 nm–1000 nm) PSDs using linear and power exponent models. The power exponent model is more useful for determining the approximate initial transverse surface relaxivity (ρ2,0) values for the shale samples. However, if the calibration PSDs are not sufficient, the average conversion coefficient (51.295, in this study) of the linear model is recommended to determine an approximate NMR PSD. The results also indicate that there is a wide range of pore sizes from micropores to macropores (>1000 nm) in shale oil reservoirs; however, they are mainly connected by small-scale throats. Therefore, the comprehensive characterization of shale oil reservoir pore structures may be efficiently and accurately determined by a combination of NMR and MICP.

Zhang, Q., Liang, F., Pang, Z., Jiang, S., Zhou, S., Zhang, J., 2019. Lower threshold of pore-throat diameter for the shale gas reservoir: Experimental and molecular simulation study. Journal of Petroleum Science and Engineering 173, 1037-1046.


Low-field nuclear magnetic resonance (LF-NMR), high-speed centrifuge and low-pressure nitrogen adsorption (LPNA) experiments were conducted on shale samples from the Lower Silurian Longmaxi Formation to measure pore-throat parameters of the shale reservoir. We measured bound water saturation, helium porosity, bulk density, specific surface area, and pore-size distribution to evaluate reservoir quality. The thickness of the bound water film was calculated based on the equation established from these parameters, showing that its thickness ranges from 1.07 nm to 2.73 nm, with a mean of 1.72 nm. In addition, Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were carried out to estimate the methane adsorption capacity and the number of the adsorbed layers in pores with different sizes at the given temperature and pressure (393.15 K, 65 MPa). The simulation results demonstrate that methane is unanimously adsorbed into pores <1.52 nm in diameter. Shale gas was present in both free and adsorbed states when the pore size was larger than 1.52 nm, and two layers were adsorbed on each pore wall. By combining the thicknesses of bound water film and adsorbed layers, the pore-throat lower limit for the shale gas reservoir was calculated to be about 4.96 nm.

Zhang, S.-H., Ernst, R.E., Pei, J.-L., Zhao, Y., Zhou, M.-F., Hu, G.-H., 2018. A temporal and causal link between ca. 1380 Ma large igneous provinces and black shales: Implications for the Mesoproterozoic time scale and paleoenvironment. Geology 46, 963-966.

http://dx.doi.org/10.1130/G45210.1

Phanerozoic large igneous provinces (LIPs) have a significant influence on global climate changes and mass extinction events (MEEs). Most of the Global Boundary Stratotype Section and Points in the Phanerozoic international chronostratigraphic scale are coeval with LIPs and are marked in the sedimentary record by global-scale MEEs and/or by ocean anoxic events represented by black shales. However, due to limited knowledge on atmospheric oxygen concentrations, ocean redox conditions, and early fossils during the Meso-Neoproterozoic Eras prior to the Ediacaran period, little is known on the climate and environmental effects of LIPs during this period of a billion years, the so-called “Boring Billion” (1.8–0.8 Ga). Here we provide geochronological and geological evidence for a temporal and genetic link between the intense ca. 1380 Ma LIP activity (found on many crustal blocks) and coeval black shales in the Nuna (Columbia) supercontinent. We further propose that the ca. 1380 Ma LIPs and black shales widely distributed in the Nuna supercontinent represent a global-scale geological event and provide a robust natural marker for the Calymmian-Ectasian boundary at 1383 Ma. Further investigation of the temporal and genetic link between the LIPs and black shales at other times can contribute to understanding the variations in atmospheric oxygen concentrations and ocean redox conditions during the Boring Billion, during which virtually nothing of Earth’s climate and MEEs is known.

Zhang, S., Cao, Y., Liu, K., Jahren, J., Xi, K., Zhu, R., Yang, T., Cao, X., Wang, W., 2019. Characterization of lacustrine mixed fine-grained sedimentary rocks using coupled chemostratigraphic-petrographic analysis: A case study from a tight oil reservoir in the Jimusar Sag, Junggar Basin. Marine and Petroleum Geology 99, 453-472.


Mixed deposits are sediments consisting of external clastic (epiclastic or terrigenous), intrabasinal components and pyroclastic components. The mixture, comprising variable amounts of the three components, is defined as “mixed sedimentary rocks”. The Permian Lucaogou Formation (P2l) in the Jimusar Sag of the Junggar Basin is a promising tight oil target in western China, the fine-grained mixed sedimentary rocks of which are rich in organic matter (OM) and two sweet spot intervals with relatively high porosity. However, the sediment composition, provenance and deposition environmental settings have not been studied in detail. In this study coupled chemostratigraphic-petrographic analysis were used to reconstruct their depositional environments. The results show that the fine-grained sedimentary rocks have three major sediment sources, external clastic input (terrigenous clastics), intrabasinal autochthonous to parautochthonous components (carbonates, siliceous skeletal debris and OM) and pyroclastic input. Main lithofacies include siltstone/fine sandstone, mudstone, dolomite and tuffite. The silt/sandstones were mainly sourced from rocks with calc-alkaline composition, while the tuffaceous sedimentary rocks were sourced from high-K calc-alkaline rocks. Elemental proxies suggest that the carbonate rocks were generally deposited under warm and arid conditions, whereas the fine-grained clastic sediments were deposited under relatively humid conditions. The muddy or silty tuffaceous mixed rocks were deposited under relatively reducing conditions compared with carbonates and sandstones. Variations of lithofacies and OM accumulation of different intervals reflect changing deposition environmental settings, and the frequently altered high TOC content rocks and good reservoirs are benefit for tight oil formation. The work may provide some useful insights and serve as a reference for studying other mixed fine-grained sedimentary rocks and tight oil plays in similar lacustrine basins elsewhere.



Of particular importance for shale reservoirs is the evaluation of pore structure characteristics that significantly influence a reservoir's storage capacity and flow mechanisms. Due to the presence of multiscale pore sizes in shale reservoirs, a series of experiments, including total organic carbon (TOC), Rock-Eval analysis, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and nuclear magnetic resonance (NMR), were conducted on shale samples from the lower submember of the third member (Es3

L) and upper submember of the fourth member of the Eocene Shahejie Formation (Es4

U) in the Dongying Depression, Bohai Bay Basin. The results indicate that calcite (averaging 30.5%) and clay (averaging 29.1%) are the dominant minerals. Based on analysis of geochemistry data, the organic matter type of LY1 is I and II. Four main types of reservoir spaces are observed in LY1: intercrystalline pores, dissolved pores, intergranular pores, and microfractures. Shale samples in the study area have a wide range of pore size distributions and complex pore structures because of the wide range of transversal relaxation time (T2) distributions and messy T2 curves of the NMR experiment. Per the NMR results, the percentage of micropores, mesopores and macropores (MS1, MS2, and MS3) were calculated, and the relationships between these proportions and pore structure parameters (porosity, permeability, T2 cutoff value, T2 geometric mean value) and structural characteristics were investigated. MS1 increased with a decrease of T2 cutoff values and geometric mean values, suggesting that shale samples with higher MS2 and MS3 have better pore structures and strong percolation potential. Under similar porosity conditions, samples with high permeability have a larger MS3 value. Laminated and layered shale samples have larger values of MS2

and MS3 than massive shale. Therefore, MS1, MS2 and MS3 are useful to indicate the quality of pore structures; the smaller the MS1, the better the pore structure. Finally, taking three representative shale samples as an example, the relationships between MS1, MS2 and MS and the effectiveness of the reservoir were discussed using the logging profile of LY1. The research concludes that MS1, MS2 and MS are effective NMR parameters for evaluating the effectiveness of the reservoir.



In the present work, a novel method has been proposed, which can be used for generating carbon nanotubes (CNTs) using coal as the raw material and potassium hydroxide as the catalyst precursor. The results of Fourier Transform Infrared (FTIR) spectroscopy indicated that the groups of –CH3,–CH2 contained in the coal gradually disappeared during the potassium catalyzed pyrolysis. Raman analysis showed that the graphitization degree of catalytic pyrolysis products of raw coal was high, and the ratio of the intensities of G and D peaks (IG/ID) was 3.0. The results of Scanning Electron Microscope (SEM) showed that there were many CNTs in the product. The Transmission Electron Microscopy (TEM) showed that these CNTs had different shapes (linear or curved) and have good graphite crystal structure with a wall number of 18–65 layers and a diameter of 20–155 nm. The potassium catalyst has the dual function of catalyzing the formation of CNTs and etching large molecular structure to generate carbon source. The formation process of CNTs is as follows: coal takes pyrolysis to produce small carbon-containing molecules such as CH4, and the small carbon-

containing molecules formed CNTs through catalytic cracking under the action of catalyst. A “stepwise growth” model of CNTs was established.

Zhang, X., Xia, Y., Zhang, Y., Chen, Y., Zhang, G., Gao, W., 2018. Volcanic reservoir characteristics and hydrocarbon genesis of Jiamuhe formation in Jinlong 2 wellblock, Junggar Basin. Petroleum Science and Technology 36, 1516-1523.

https://doi.org/10.1080/10916466.2018.1471486

Due to deeper buried, multi-stage tectonic influences, rapid changing, and unclear originate of oil and gas in Jinlong 2 wellblock, we analyzed the volcanic reservoir characteristics and the genesis of hydrocarbon by cores, thin slices, loggings, physical properties, oil testing data, and carbon isotopes. Results demonstrated that the major lithology were pyroclastic rocks and lavas, the reservoir was generally poor and strongly homogeneous, the main reservoir space were primary pores, and the favorable reservoir mainly developed in the pyroclastic rocks of the third phase. Furthermore, the results of carbon isotopes indicated that the crude oil and dissolved gas originated from Fengcheng formation, while the condensate gas derived from Jiamuhe formation.

Zhang, X.L., Ha, B.B., Wang, S.J., Chen, Z.J., Ge, J.Y., Long, H., He, W., Da, W., Nian, X.M., Yi, M.J., Zhou, X.Y., Zhang, P.Q., Jin, Y.S., Bar-Yosef, O., Olsen, J.W., Gao, X., 2018. The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago. Science 362, 1049-1051.


Abstract: The Tibetan Plateau is the highest and one of the most demanding environments ever inhabited by humans. We investigated the timing and mechanisms of its initial colonization at the Nwya Devu site, located nearly 4600 meters above sea level. This site, dating from 40,000 to 30,000 years ago, is the highest Paleolithic archaeological site yet identified globally. Nwya Devu has yielded an abundant blade tool assemblage, indicating hitherto-unknown capacities for the survival of modern humans who camped in this environment. This site deepens the history of the peopling of the “roof of the world” and the antiquity of human high-altitude occupations more generally.

Editor's Summary: Paleolithic occupation of Tibet. Human colonization of the high-altitude Tibetan Plateau has generally been thought to have been confined to the past few thousand years of the Holocene. Zhang et al. report an investigation of the Nwya Devu archaeological site in central Tibet, 4600 meters above sea level, with Paleolithic occupation dates of ∼40 thousand to 30 thousand years ago (see the Perspective by Zhang and Dennell). The site has yielded a range of stone tools, indicating the adaptive ability of early modern humans to the harsh environment of the “roof of the world.” The findings also suggest that people from Tibet and Siberia may have interacted at this time.

Zhang, Y.-Y., He, Z.-L., Jiang, S., Lu, S.-F., Xiao, D.-S., Chen, G.-H., Zhao, J.-H., 2018. Controls on the organic carbon content of the lower Cambrian black shale in the southeastern margin of Upper Yangtze. Petroleum Science 15, 709-721.

https://doi.org/10.1007/s12182-018-0262-x

Control of various factors, including mineral components, primary productivity and redox level, on the total organic carbon (TOC) in the lower Cambrian black shale from southeastern margin of Upper Yangtze (Taozichong, Longbizui and Yanbei areas) is discussed in detail in this article. Mineral

components in the study strata are dominated by quartz and clay minerals. Quartz in the Niutitang Formation is mainly of biogenic origin, and the content is in positive correlation with TOC, while the content of clay minerals is negatively correlated with TOC. Primary productivity, represented by the content of Mobio (biogenic molybdenum), Babio (biogenic barium) and phosphorus, is positively correlated with TOC. The main alkanes in studied samples are nC18–nC25, and odd–even priority values are closed to 1 (0.73–1.13), which suggest the organic matter source was marine plankton. Element content ratios of U/Th and Ni/Co and compound ratio Pr/Ph indicate dysoxic–anoxic bottom water, with weak positive relative with TOC. In total, three main points can be drawn to explain the relationship between data and the factors affecting organic accumulation: (1) quartz-rich and clay-mineral-poor deep shelf–slope–basin environment was favorable for living organisms; (2) high productivity provided the material foundation for organic generation; (3) the redox conditions impact slightly on the content of organic matter under high productivity and dysoxic–anoxic condition.

Zhang, Z., Wu, Y., Zhang, X.-H., 2018. Cultivation of microbes from the deep-sea environments. Deep Sea Research Part II: Topical Studies in Oceanography 155, 34-43.


The deep-sea environment has rich microbial resources, and these resources have been an important subject in the efforts to culture microflora. Special devices that maintain in situ pressures have been developed and applied in culturing piezophilic and hyperpiezophilic microbes. However, culturable microorganisms comprise the minority of deep-sea microbes (archaea and bacteria), which reflects the disadvantages of traditional cultivation methods, the ignorance of microbial habitats, and the fastidiousness of microbial growth requirements. This mini-review introduces the diversity of microbes in the deep sea and discusses the deep-sea species that have been identified in the past two years. In addition, this review summarizes almost all of the recognized piezophilic microbes and describes the isolation methods that have been employed. Additionally, we recommend that some of the methods that have been developed to obtain microbes from surface water, freshwater, sediments, soils and organisms should be modified to enable the isolation of the deep-sea microbes. It is anticipated that this mini-review will provide novel insights into exploration of “uncultured” deep-sea microbial resources.

Zhao, G., Li, J., Gu, C., Li, L., Sun, Y., Dai, C., 2018. Dispersed particle gel-strengthened polymer/surfactant as a novel combination flooding system for enhanced oil recovery. Energy & Fuels 32, 11317-11327.


A novel dispersed particle gel-strengthened polymer–surfactant (DPS) combination flooding system was proposed and demonstrated for enhanced oil recovery in high water cut mature oilfields. As compared to a conventional polymer–surfactant (PS) combination flooding system, DPS systems have a higher viscosity and a more stable network structure. The polymer is mainly a source of the viscosity, while the surfactant plays a key role in reducing the interfacial tension (IFT). The added dispersed particle gel (DPG) has a synergistic viscosity increase effect, whereas for the DPG particles, the salinity and aging time have a slight effect on the IFT reduction capacity of the DPS system. On the basis of sand-pack flowing experiments, the DPS system has a better mobility control capacity than the PS system in the combination flooding stage and the following water flooding stage. Parallel sand-pack flowing experiments indicate that injection of a DPS system can effectively improve the profile control. The added DPG particles could intersperse in the three-dimensional network structure, which increases the stability of the DPS system in solution and porous media.

Through the improved synergistic effect of the swept volume capacity and high displacement efficiency, the oil recovery capacity of the DPS system is significantly enhanced. The DPS system may be an alternative for enhanced oil recovery in other similar high water cut mature oilfields.

Zhao, G., Wang, Y., Huang, B., Dong, Y., Li, S., Zhang, G., Yu, S., 2018. Geological reconstructions of the East Asian blocks: From the breakup of Rodinia to the assembly of Pangea. Earth-Science Reviews 186, 262-286.


Pangea is the youngest supercontinent in Earth's history and its main body formed by assembly of Gondwana and Laurasia about 300–250 Ma ago. As supported by voluminous evidence from reliable geological, paleomagnetic and paleontological data, configurations of major continental blocks in Pangea have been widely accepted. However, controversy has long surrounded the reconstructions of East Asian blocks in Pangea. To determine whether or not the East Asian blocks were assembled to join Pangea before its breakup, we carried out geological and paleomagnetic investigations on East Asian blocks and associated orogenic belts, supported by a NSFC Major Program entitle “Reconstructions of East Asian blocks in Pangea”. Our results indicate that the breakup of Rodinia around 750 Ma ago led to the opening of the Proto-Tethys and Paleo-Asian oceans in East Asia, with the former separating the South China, North China, Alex Qaidam and Tarim blocks from other East Asian blocks at the margins of Australia and India, whereas the Paleo-Asian Ocean existed between the East Asian blocks and Siberia-Eastern Europe. The Proto-Tethys Ocean closed in the early Paleozoic (500–420 Ma), leading to the collision of South China, North China, Alex, Qaidam and Tarim with other East Asian blocks at the northern margin of Gondwana. The subduction of the Paleo-Asian Ocean formed the Central Asian Orogenic Belt, the largest accretionary orogen in Earth's history, and its closure was diachronous, with its western, central and eastern segments closing at 310–280 Ma, 280–265 Ma and 260–245 Ma, respectively, leading the Tarim, Alex and North China blocks to join Eastern Europe-Siberia as part of Pangea. During the early Devonian (420–380 ma), the East Paleo-Tethys Ocean opened with two branches, of which the north branch is called the Mianlue Ocean that separated the Tarim-Qaidam-Central Qilian-Alex and North China blocks in the north from North Qiangtang-Indochina-South China in the south, and the south branch is the stricto sensu East Paleo-Tethys Ocean that separated North Qiangtang-Indochina-South China from the Sibumasu and South Qiangtang-Lhasa blocks at the northern margin of Gondwana. In the Triassic, the East Paleo-Tethys Ocean (stricto sensu) closed along the Longmu Co – Shuanghu – Changning – Menglian – Inthanon belt, leading to the collision of North Qiangtang-Indochina-South China with Sibumasu and South Qiangtang-Lhasa, forming a single southern continent, which then collided with the Tarim-Qaidam-Central Qilian-Alex and North China blocks to form a coherent East Asian continent that had become part of Pangea by 220 Ma, when the Mianlue Ocean closed, leading to the formation of the E-W-trending Central China Orogenic System.



It has been revealed that the formation of most giant tight oil and gas fields is inconsistent with both the typical basin-centered/continuous hydrocarbon accumulation (CHA) model and the discontinuous hydrocarbon accumulation (DHA) model. We argued that hydrocarbon accumulations in tight reservoirs are dominated by an intermediate form between these two models, termed quasi-

continuous hydrocarbon accumulation (QHA). This accumulation model is akin to the CHA in that both are extensively distributed with no distinct boundaries. However, oil and gas in the CHA occur within source rocks, accumulate mainly at or nearby where they are generated, have undergone no significant migration, and their occurrence is not controlled by traps. The QHA, however, occurs in tight reservoirs in the vicinity of source rocks. The accumulation of oil and gas occurs in multiple closely related lenticular or blanket-like reservoirs that are laterally adjacent and vertically stacked. Neither noticeable inversion of oil/gas and water nor complete bottom water or edge water is present. The charging of hydrocarbons is pervasive and the migration is mainly driven by overpressures, while the effects of buoyancy are limited. Hydrocarbon accumulation is not controlled by anticlinal traps but mainly governed by non-anticlinal traps. In fact, the CHA and DHA represent two end-member types of hydrocarbon accumulation and the QHA is a transitional mechanism by which most giant tight oil and gas fields are formed.

Zhao, J., Li, J., Xu, Z., 2018. Advances in the origin of overpressures in sedimentary basins. Petroleum Research 3, 1-24.


Much progress in the studies on overpressuring mechanisms has been made during the past one to two decades. (1) The causes of overpressure are divided into five categories, namely, disequilibrium compaction, fluid expansion, diagenesis, tectonic compression and pressure transfer. The fluid expansion involves hydrocarbon generation, oil cracking to gas and hydrothermal expansion. The diagenesis includes smectite-to-illite transformation. (2) Six methods for identifying overpressure origin are proposed, including log curves combination analysis, Bowers method (loading-unloading diagram), velocity-density crossplotting, correlation of porosities, pressure calculation and correlation, and comprehensive analyses. (3) With more and more application of empirical methods in the study of overpressure formation, almost all of the overpressure cases that are traditionally thought to be caused by disequilibrium compaction are denied totally or partly. Instead, the hydrocarbon generation is demonstrated to be the most significant mechanism for overpressure formation; the clay diagenesis (especially the smectite-illite transformation) as well as tectonic compression and pressure transfer are also important for overpressure formation. In addition, the overpressure formation in many basins is thought to be influenced by the combination of two or more overpressuring mechanisms. (4) Causes of overpressuring differ in lithology; for mudstones, the overpressure formation in source rocks is usually different from that of non-source rocks, the former of which is frequently related to hydrocarbon generation and sometimes also affected by diagenesis, while the later of which is commonly related to disequilibrium compaction, diagenesis and pressure transfer; for permeable rocks such as sandstones, overpressure is mainly caused by pressure transfer. (5) Because organic matter has an obvious influence on logging parameters such as density and acoustic velocity, an appropriate correction on the content of organic matter is needed when these logging data are used to analyze overpressure formation in organic-rich mudstones. It has been revealed that the cause of overpressuring based on the corrected log data can be quite different from that without correction.



Low-salinity water flooding of formation water in rock cores is, potentially, a promising technique for enhanced oil recovery (EOR), but details of the underlying mechanisms remain unclear. The salinity

effect on the interface between water and oil was investigated here using the molecular dynamics (MD) simulation method. n-Decane was selected as a representative oil component, and SPC/E water and all-atom optimized potentials for liquid simulations (OPLS-AA) force fields were used to describe the water/oil/ionic interactions for saltwater and n-decane molecules. Equilibrium MD simulations were first conducted to study the n-decane/vapor and saltwater/vapor interface systems at six different NaCl concentrations (0, 0.05, 0.10, 0.20, 0.50, and 1.00 M). The water/oil interface was then investigated by calculating bulk density distribution, radial distribution function, interface thickness, and water/oil interfacial tension (IFT). Sufficiently long MD simulations of water/n-decane/vapor were performed, followed by an analysis of the effect of salinity on the water/oil/vapor interface. The IFT values for the water/vacuum interface, n-decane/vacuum interface, and water/n-decane interface were obtained from the pressure tensor distribution after system equilibration, with values of 71.4, 20.5, and 65.3 mN/m, respectively, which agree well with experimental and numerical results reported in the literature. An optimal salinity of ∼0.20 M was identified corresponding to a maximum interfacial thickness between water and the oil phase, which results in a minimum water/oil IFT value and a maximum value for the oil/water contact angle, a condition beneficial for EOR.



Low salinity flooding has been proposed as a promising method for enhanced oil recovery, but the underlying mechanism remains unclear especially for carbonate reservoirs. This work investigates the effect of water salinity in altering the wettability of nano-slit pores for three types of calcite surfaces (i.e., a neutral nonpolar {101-4} surface, and the polar {0 0 0 1} surface with positively and negatively charged surfaces) using classical, equilibrium molecular dynamic (EMD) simulations. In addition, non-equilibrium MD simulations (NEMD) reveal the influence of wettability on the oil transport properties in a nano-pore at different salt concentrations of sodium chloride (NaCl) (0.20 M, 0.50 M, and 1.00 M). Results show that increasing water salinity has little effect on the wettability of a nano-pore comprised of neutral calcite surfaces. For a calcite nano-slit pore comprised of charged surfaces, however, the dipole-ion interaction alters the surface wettability creating a more hydrophilic surface due to the hydration effect of ions at elevated salt concentrations. While a partially decane-wet neutral nonpolar calcite surface greatly inhibits the movement of an oil droplet in the pore, greater oil mobility is achieved for dipolar nano-pores, especially at elevated salt concentrations.



The Kelasu Thrust Belt is a key area for oil and gas exploration within the Tarim Basin of China, an area containing abundant oil and gas resources but where the processes that controlled hydrocarbon accumulation remain unclear. This study reconstructs the accumulation history of hydrocarbons within the Kelasu Thrust Belt by studying multiple sets of fluid inclusions from the Cretaceous reservoirs using laser Raman, infrared spectroscopy, fluorescence spectroscopy, total scanning fluorescence, and PTV simulation analyses. The resulting data yield the following results. (1) Three types of Cretaceous hydrocarbon-bearing fluid inclusions are present, and they record three periods of hydrocarbon accumulation. Period I involved low-maturity medium oil as recorded by the presence of yellow–green fluorescent oil inclusions, with this accumulation occurring between the Neogene

Jidike and Kangcun stages (20–5 Ma). Period II involved high-maturity light oils (or condensates) that are recorded by the presence of blue–white fluorescent oil inclusions, with this accumulation occurring during the early Kuche stage (5–2.5 Ma). Period III involved the significant accumulation of gas, as recorded by non-fluorescent gas inclusions, during and after the late Kuche stage (2.5–0 Ma). (2) Inclusion PVT simulations indicate that the pressures during the trapping of oil inclusions within the west Kelasu reservoirs increase with increasing capture temperature, suggesting that west Kelasu Cretaceous oil reservoirs formed over a short period of time. In contrast, the trapping pressures of oil inclusions within the east Kelasu area are invariant with increasing trapping temperature, indicating that the formation of east Kelasu Cretaceous oil reservoirs was a relatively slow and gradual process. This most likely relates to the fact that the east Kelasu reservoirs are close to the hydrocarbon generation centre in an area with sufficient hydrocarbon supply, with hydrocarbon accumulation processes involving all of the stages of hydrocarbon generation recorded by the source rocks in this area. In comparison, the west Kelasu reservoirs are far from the hydrocarbon generation centre and as such record only one phase of oil filling. (3) Significant tectonism associated with the uplift of the South Tianshan Mountain during the late Kuche stage caused widespread changes to Cretaceous paleo-oil reservoirs in this area. This led to some Cretaceous paleo-oils being transported to shallower traps to form secondary oil reservoirs, whereas others were transported to the surface and were lost, with residual paleo-oils were also changed to condensate gas as a result of gas washing after the addition of large amounts of late-stage gas.

Zhao, S., He, J., 2019. Reductive dechlorination of high concentrations of chloroethenes by a Dehalococcoides mccartyi strain 11G. FEMS Microbiology Ecology 95, fiy209-fiy209.


Chloroethenes are common groundwater and soil contaminants due to extensive historic utilization and inappropriate discharge. The tendency for chloroethenes to become sequestered as dense non-aqueous phase liquids (DNAPL)—a point source to groundwater contamination and causing high concentrations of chloroethenes in proximal aquifers poses a great challenge for remediation of chloroethene contaminated sites. In this study, we report isolation and characterization of a Dehalococcoides mccartyi strain 11G which couples growth with reductive dechlorination of trichloroethenes (TCE), dichloroethene (DCE) isomers and vinyl chloride (VC) to ethene at a growth yield ranging from 2.47 ± 0.23 × 108 to 5.64 ± 0.43 × 108 cells/µmoles Cl− released and co-metabolically dechlorinates tetrachloroethene (PCE) in the presence of TCE. Compared with previous D. mccartyi strains showing dechlorination of TCE at up to 2.0 mM, strain 11G is distinguished by its capacity to dechlorinate chloroethenes at initial concentrations of DCE isomers as high as 4 mM and TCE as high as 3.5 mM to ethene. Bioaugmentation of a contaminated microcosm with strain 11G resulted in complete detoxification of a mixture of 5 mM chloroethenes (2.5 mM of each TCE and cis-DCE) after 40 days. Strain 11G is a promising candidate for in situ bioremediation of high-concentration-chloroethene contaminated sites.

Zhao, Y., Bai, Y., Guo, Q., Li, Z., Qi, M., Ma, X., Wang, H., Kong, D., Wang, A., Liang, B., 2019. Bioremediation of contaminated urban river sediment with methanol stimulation: Metabolic processes accompanied with microbial community changes. Science of The Total Environment 653, 649-657.


The intense pollution of urban river sediments with rapid urbanization has attracted considerable attention. Complex contaminated sediments urgently need to be remediated to conserve the ecological functions of impacted rivers. This study investigated the effect of using methanol as a co-substrate on

the stimulation of the indigenous microbial consortium to enhance the bioremediation of petroleum hydrocarbons (PHs) and polycyclic aromatic hydrocarbons (PAHs) in an urban river sediment. After 65 days of treatment, the PAHs degradation efficiencies in the sediment adding methanol were 4.87%–40.3% higher than the control. The removal rate constant of C31 was 0.0749 d−1 with 100 mM of supplied methanol, while the corresponding rate was 0.0399 d−1 in the control. Four-ring PAHs were effectively removed at a degradation efficiency of 65%–69.8%, increased by 43.3% compared with the control. Sulfate reduction and methanogenesis activity were detected, and methane-producing archaea (such as Methanomethylovorans, with a relative abundance of 25.87%–58.53%) and the sulfate-reducing bacteria (SRB, such as Desulfobulbus and Desulfobacca) were enriched. In addition, the chemolithoautotrophic sulfur-oxidizing bacteria (SOB, such as Sulfuricurvum, with a relative abundance of 34%–39.2%) were predominant after the depletion of total organic carbon (TOC), and markedly positively correlated with the PHs and PAHs degradation efficiencies (P < 0.01). The SRB and SOB populations participated in the sulfur cycle, which was associated with PHs and PAHs degradation. Other potential functional bacteria (such as Dechloromonas) were also obviously enriched and significantly positively correlated with the TOC concentration after methanol injection (P < 0.001). This study provides a new insight into the succession of the indigenous microbial community with methanol as a co-substrate for the enhanced bioremediation of complexly contaminated urban river sediments.

Zhao, Y., Cai, J.-G., Lei, T.-Z., Yang, Y., 2018. A geochemical investigation of the free and carbonate-bound organic matter in the clay-sized fraction of argillaceous source rocks and its significance for biogenic interpretation. Petroleum Science 15, 681-694.

https://doi.org/10.1007/s12182-018-0257-7

The molecular composition and biomarker distribution of various occurrences of organic matter in argillaceous source rocks developed in fresh and saline lacustrine environments were revealed by successive treatments of solvent extraction followed by acid hydrolysis using gas chromatography–mass spectrometry. The free fraction obtained by solvent extraction provided abundant geochemical information concerning the sedimentary environment, thermal maturity and biogenic origin, and obvious differences existed between fresh and saline lacustrine source rock samples. Our research results indicate that the carbonate-mineral-bound (CM-bound) fraction released by successive acid hydrolysis could also serve as a significant biogenic indicator, as the bicyclic sesquiterpenoids, indicative of Botryococcus braunii origin, were specifically detected in quite high abundance in the acid-soluble fraction. In addition, the light end hydrocarbons were much better preserved in the acid-soluble fraction, and elemental sulfur was only detected in the CM-bound fraction, suggesting a relatively confined environment for the CM-bound fraction, which thus could preserve additional geochemical information compared to that of the free fraction. The CM-bound fraction also exhibited discernable differences between fresh and saline lacustrine samples. Therefore, it can be concluded that comprehensive analysis of free and CM-bound fractions in the argillaceous source rocks can provide a more authentic and objective interpretation of geologic conditions.

Zheng, J., RoyChowdhury, T., Yang, Z., Gu, B., Wullschleger, S.D., Graham, D.E., 2018. Impacts of temperature and soil characteristics on methane production and oxidation in Arctic tundra. Biogeosciences 15, 6621-6635.


Rapid warming of Arctic ecosystems accelerates microbial decomposition of soil organic matter and leads to increased production of carbon dioxide (CO2) and methane (CH4). CH4 oxidation potentially

mitigates CH4 emissions from permafrost regions, but it is still highly uncertain whether soils in high-latitude ecosystems will function as a net source or sink for CH4 in response to rising temperature and associated hydrological changes. We investigated CH4 production and oxidation potential in permafrost-affected soils from degraded ice-wedge polygons on the Barrow Environmental Observatory, Utqiaġvik (Barrow), Alaska, USA. Frozen soil cores from flat and high-centered polygons were sectioned into organic, transitional, and permafrost layers, and incubated at −2, +4 and +8°C to determine potential CH4 production and oxidation rates. Significant CH4 production was only observed from the suboxic transition layer and permafrost of flat-centered polygon soil. These two soil sections also exhibited highest CH4 oxidation potentials. Organic soils from relatively dry surface layers had the lowest CH4 oxidation potential compared to saturated transition layer and permafrost, contradicting our original assumptions. Low methanogenesis rates are due to low overall microbial activities measured as total anaerobic respiration and the competing iron-reduction process. Our results suggest that CH4 oxidation could offset CH4 production and limit surface CH4 emissions, in response to elevated temperature, and thus must be considered in model predictions of net CH4 fluxes in Arctic polygonal tundra. Future changes in temperature and soil saturation conditions are likely to divert electron flow to alternative electron acceptors and significantly alter CH4 production, which should also be considered in CH4 models.



The Upper Triassic Xujiahe Formation is a key target layer for development of tight sandstone gas reservoirs in the Sichuan Basin. Most of the previous work focused on the main reservoirs such as T3x2 and T3x4 with lack of research attention on T3x5, an equally important source-reservoir unit. Here we examine the organic matter and source rock distribution in the T3x5 using rock pyrolysis, asphalt extraction, and gas chromatography. The thickness of T3x5 source rocks reduces from west and northwest Sichuan Basin to east and southeast Sichuan Basin. The main sedimentary facies are salt lakes and deltas, of which the organic matter originated from aquatic organisms and a small amount of terrestrial matter. The abundance of total organic carbon (TOC) in T3x5 is relatively high, at values of 0.07%–7.2%. According to the vitrinite reflectance (Ro), pyrolysis, and gas chromatography measurement results, the T3x5 source rocks are at the stage of mature to over-mature, and their hydrocarbon expulsion threshold and hydrocarbon expulsion peak correspond to Ro of 1.05% and 1.23%, respectively. Furthermore, a hydrocarbon generation center and a hydrocarbon expulsion center are formed horizontally, with the maximum hydrocarbon generation intensity of 50 × 108 m3/km2 and the maximum hydrocarbon expulsion intensity of 48 × 108 m3/km2. The natural gas resource is 3.19–5.36 × 1012 m3, indicating great exploration potential.

Zheng, X., Zhang, B., Sanei, H., Bao, H., Meng, Z., Wang, C., Li, K., 2019. Pore structure characteristics and its effect on shale gas adsorption and desorption behavior. Marine and Petroleum Geology 100, 165-178.


As the largest producing shale gas field in China and had just announced its great annual production of 10 billion cubic meters capacity, the Wufeng-Longmaxi (O3w-S1l) formation in Fuling shale gasfield, Sichuan Basin had obtained great attention both in China and globally. Twelve samples from

three different wells were collected to explore the pore types and the corresponding pore developing status, pore structure characteristics, sorption capacity and their relationship, for fundamental shale gas reservoir evaluation. The TOC (total organic carbon) content ranges from 0.21% to 6.79%, while quartz and clay mineral content made up 46.92% and 34.12% of the mineral composition. Intergranular pore, intragranular pore, fracture and different OM pore types (in biotic debris organic matter, within porous solid bitumen and in organo-mineral compound) were identified. Porosity obtained by different methods showed great difference because of detecting limitation, therefore it is necessary to combine multiple porosity detecting methods to explore the reservoir porosity more accurately. He porosity is not effective in detecting unaccessible discrete micropore in organic matter while NMR could reflect the nanopore although it is influenced by pore surface wettability. The preserved inorganic pores are affected by diagenesis, with intergranular pore volume and OM pores, without sufficient mineral framework, reduced by compaction and dissolved pores developed in unstable mineral, like carbonate. Clay mineral and other accessory mineral also influence OM pore development, as energy dispersive X-ray spectroscopy (EDS) result illustrated that solid bitumen mixing with mineral during hydrocarbon charging tend to be more porous. Surface area obtained from MIP, N2-GA and CO2 experiment all showed positive correlation with the content of TOC, quartz and pyrite, which also are the main contributors of reservoir sorption capacity, total gas content and desorption rate.

Zhi, S., Elsworth, D., Wang, J., Gan, Q., Liu, S., 2018. Hydraulic fracturing for improved nutrient delivery in microbially-enhanced coalbed-methane (MECBM) production. Journal of Natural Gas Science and Engineering 60, 294-311.


Microbially enhanced coalbed methane (MECBM) recovery is a novel method to increase gas production by injecting nutrients, either with/without microorganisms, in depleted CBM wells. However, to be effective, methanogens require that the nutrient must be delivered efficiently by aqueous solution to a maximally large reservoir volume for microbial colonization. This study seeks to improve understanding of solute transport and microbial gas generation in naturally fractured reservoirs that are both pristine and hydraulically fractured. We complete a field-scale numerical simulation using an equivalent multi-continuum method to define the effectiveness of nutrient delivery. The complex pre-existing fracture pattern in the coalbed is represented by an overprinted discrete fracture network (DFN) to capture the natural heterogeneity and anisotropy of fracture permeability. A simplified PKN model is adopted to simulate hydraulic fracture propagation based on linear elastic fracture mechanics (LEFM). The hydraulically stimulated case is compared to the untreated control case, both without and with a network of natural fractures. Saturated cleat area, cumulative injection volume and prediction of methane yields are systematically modeled and analyzed for all three cases. We show that hydraulically stimulated fracture pathways, especially when connecting with a natural fracture network, optimally deliver nutrient remotely from the injection well, thereby increasing nutrient delivery and improving methane production and potential recovery. However, large magnitudes of proppant embedment and related permeability loss in the hydraulic fractures may reduce MECBM recovery. In the optimal production scenario, the methane production rate may reach 31 ft3/ton, an approximately 5-fold increase over that from the pristine unstimulated case.

Zhou, M., Luo, T., Huff, W.D., Yang, Z., Zhou, G., Gan, T., Yang, H., Zhang, D., 2018. Timing the termination of the Doushantuo negative carbon isotope excursion: evidence from U-Pb ages from the Dengying and Liuchapo formations, South China. Science Bulletin 63, 1431-1438.


The Doushantuo negative carbon isotope excursion (DOUNCE) is the largest known marine inorganic carbon isotope anomaly. The origin of this pronounced negative excursion is still an enigmatic issue that attracts geologists. Time constraints on the excursion are the critical information that would provide insight into its genesis. In previous decades, the timing of its termination has been constrained by the widely cited zircon U-Pb age of 550.5 ± 0.8 Ma for the tuff at the top of the Miaohe Member at the Jiuqunao section in the Yangtze Gorges area, South China. However, results of recent studies indicate that the reliability of this time constraint needs to be re-evaluated. Here, a geochronological study was carried out using two K-bentonites from Fanglong in South China. A K-bentonite in the lower Dengying Formation yielded a U-Pb age of 557 ± 3 Ma, while a K-bentonite in the basal Liuchapo Formation yielded an age of 550 ± 3 Ma. Based on regional correlations between the Ediacaran successions in South China, the age (557 ± 3 Ma) for the K-bentonite in the lower Dengying Formation may serve as a second critical timing constraint for the ending of the DOUNCE. Combined with available estimates of the DOUNCE duration, our new data indicate that the DOUNCE has a maximum onset age ∼570 Ma.

Zhou, W., Wang, J., Zhao, Y., Yu, L., Fang, Y., Jin, H., Zhou, H., Zhang, P., Liu, Y., Zhang, X., Liang, X., 2018. Discovery of β2- adrenoceptor agonists in Curcuma zedoaria Rosc using label-free cell phenotypic assay combined with two-dimensional liquid chromatography. Journal of Chromatography A 1577, 59-65.


Traditional Chinese Medicines (TCMs) have been widely used in clinical practice, and provided a rich source for discovering new drug leads. However, efficient identification of active molecules responsible for the therapeutic effects of complex TCMs is still highly challenging. Here, we combined label-free cell phenotypic assay with two dimensional liquid chromatography (2DLC) to identify potential β2-adrenoceptor (β2-AR) agonists related to anti-asthmatic effect of Curcuma zedoaria Rosc (C.zedoaria), a commonly used TCM. The ethyl acetate extract of C.zedoaria was first fractionated into 26 fractions. Label-free cell phenotypic profiling was then used to locate the active sites. Orthogonal second-dimensional (D2) separation was performed on two fractions displaying agonistic effect at the β2-AR, combined with screening of the D2 fractions to track the activity. Finally, this approach led to the isolation of three known diarylheptanoids, among which diarylheptanoid b exhibited the most potent agonistic activity with an EC50 value of 5.93 μM. This result was further demonstrated through the chemical synthesis of diarylheptanoid b. It is the first time to discover that diarylheptanoids could activate the β2-AR, which may be responsible for the anti-asthmatic effect of C.zedoaria observed traditionally and in clinical application. This study also demonstrates the potential of this integrated strategy for identifying active ingredients and determining the basis of therapeutic materials in complex TCMs.



Due to deep burial of Precambrian in Tarim Basin, no breakthrough in the hydrocarbon exploration has been achieved from these strata, and development of high-quality source rocks is also uncertain. More than 30 exploratory wells have been drilled in the southwest Tarim Basin and the pediment

region of Kunlun Mountains with a total area of more than 100 × 103 km2. Though some marine oil/gas fields such as Hetianhe, Bashituopu, Yubei and Luosi 2 have been discovered, the Cambrian or Ordovician source rocks have not been drilled, and hydrocarbon source still remain controversial. Recently, a set of thick black shales and mudstones has been found in the southwest Tarim Basin. The total thickness of mudstones is more than 140 m, and the total organic carbon mainly ranges from 0.6% to 1.9% with an average of 1.0%. Tmax is from 490 °C to 520 °C, equivalent to Ro from 1.99% to 2.99%. Pyrites are very rich in mudstone. According to stratigraphic contact relationship and isotopic chronology, this mudstone may have the age of more than 517 Ma, and is tentatively named as the “Western Kunlun black rock series”. Through the plate tectonic analysis, this set of thick black mudstones is possibly distributed widely in the southwest Tarim Basin, and its formation may be controlled by the aulacogen. This set of black mudstones may be an important source rocks in the southwest Tarim Basin, which suggest that the Precambrian-Cambrian strata in Tarim Basin has geological conditions for hydrocarbon accumulations. This discovery of the black thick mudstones in the southwest Tarim Basin will promote hydrocarbon exploration in the deep and ultra-deep strata of the Tarim Basin.

Zhu, G., Zhang, Z., Zhou, X., Yan, L., Sun, C., Zhao, B., 2018. Preservation of ultradeep liquid oil and its exploration limit. Energy & Fuels 32, 11165-11176.


Crude oil in reservoirs may crack to gas with increasing buried depth and temperature, resulting in natural gas as the major exploration target in deep strata. Exploration of ultradeep targets in the Tarim Basin, Northwest China, unexpectedly discovered huge accumulations of liquid oil in Ordovician carbonate reservoirs with burial depths of >7000 m. Applying comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry, this paper analyzes the chemical compounds of crude oil in these ultradeep layers and has found that these oils are slightly cracked with low conversion of oil to gas, as evidenced by limited diamondoid compound analogues and low concentrations. Gold tube pyrolysis simulation and kinetic calculation suggest that the cracking temperatures of oil are in the range of 210–220 °C. The temperature implies that the deepest liquid oil surviving limit is inferred as 9000 m in this basin with the increase of the temperature. The major controlling factors on preserving abundant liquid oil in ultradeep layers of the Tarim Basin include the insufficient compensation effect of a low geothermal gradient and fast deep burial during a later period. It has potential to find oil in ultradeep (>7000 m) layers.

Zhu, X., Mao, S., Sun, Y., Jia, G., Wu, N., Wu, D., Guan, H., Yan, W., 2018. Organic molecular evidence of seafloor hydrocarbon seepage in sedimentary intervals down a core in the northern South China Sea. Journal of Asian Earth Sciences 168, 155-162.


The hydrocarbons in sedimentary organic matter (OM) at Site 4B in the Pearl River Mouth Basin (PRMB), northern South China Sea (SCS) were analyzed. The odd/even predominance (OEP) of long chain n-alkanes (>n-C24) with CPI (carbon preference index) values from 1.62 to 3.80 and n-C29/n-C31 being the two most abundant in most of the samples are strongly indicative of a terrestrial higher plant source, and the even/odd predominance (EOP) distribution of mid-chain n-alkanes (n-C16–22) suggests a marine bacterial input, probably chemical autotrophic bacteria. However, the biomarker distributions at the 65–70 cm, 80–85 cm and 85–90 cm intervals show a similar to those of crude oils, which were characterized by a dominance of an unresolved complex mixture (UCM) in the n-C20+ region, low CPI values (<1.5) of long chain n-alkanes, low values of ββ/(αβ + ββ + βα)-C30 hopane

(<0.15), and high values (>9) of total tricyclic terpanes/αβ-C30 hopane. These features are typical characteristics of mature OM that has experienced catagenesis and metagenesis, suggesting that outside hydrocarbons migrated into these three intervals. In terms of petroleum systems developed in the PRMB, hydrocarbon seepage from deep source rocks via a diaper structure and fault system is proposed to be responsible for the occurrence of this mature OM.



In this study, a novel approach to characterize and identify acidic oil compounds utilizing the fragmentational behavior of their corresponding precursor ions is presented. Precursor ions of seven analyzed pyrolysis oils that were generated from pyrolysis educts of different origins and degrees of coalification were produced by electrospray ionization in the negative ion mode (ESI(−)). Following a fragmentation of all ions in the ion cloud by collision-induced dissociation (CID), the precursor and product ions were subsequently detected by ultrahigh resolving Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The ESI(−)-CID data sets were evaluated by applying either a targeted classification or untargeted clustering approach. In the case of the targeted classification, 10% of the ionized precursor ions of the analyzed pyrolysis liquid samples could be classified into one of 11 compound classes utilizing theoretical fragmentation pathways of these classes. In contrast, theoretical fragmentation pathways were not necessary for the untargeted clustering approach, making it the more transmittable method. Results from both approaches were verified by analyzing standard compounds of known structure. The analysis and data evaluation methods presented in this work can be used to characterize complex organic mixtures, such as pyrolysis oils, and their compounds in-depth on a structural level.

Zuo, P., Qu, S., Shen, W., 2019. Asphaltenes: Separations, structural analysis and applications. Journal of Energy Chemistry 34, 186-207.


Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical properties of asphaltene due to its structural similarity, composition complexity and source dependences. Many techniques, like Mass spectrometry, Chromatography, Nuclear magnetic resonance spectroscopy, Infrared spectroscopy, Roman spectroscopy, Fluorescence spectroscopy, X-ray diffraction analysis and Small-angle scattering techniques and so on, have revealed some valuable descriptions of asphaltenes chemical compositions and fundamental structures. Moreover, advanced Mass spectrometry, Atomic force microscopy and Scanning tunneling microscopy could provide more clear and essential molecular compounds and structures in asphaltenes. In addition, several asphaltenes models have succeeded to illustrate aggregation properties asphaltene. In this work, the progress on asphaltene separation, characterization and application was summarized, and the similarities and differences between coal-derived asphaltenes and petroleum asphaltenes were compared. Furthermore, the reactivity of asphaltenes has been discussed in the aspect of hydroprocessing, pyrolysis and gasification. Asphaltene was excellent carbon precursor for functional carbon material due to its high aromaticity and carbon yield; several porous carbon nanosheets from asphaltenes that would be prospective electrode materials after being graphitized were shown. Pitch-based carbon fiber derived from coal-derived asphaltenes displayed a tensile strength of 1.0 GPa and

elastic modulus of 350 MPa, respectively. These powerful advances will provide asphaltenes promising developments.



Ancient methane-seep carbonates are geological archives of environmental conditions and record past microbial activity. To better understand the information stored in this archive, a comparison was made of phase-specific major, trace, and rare earth element (REE) patterns, mineralogies, and textures of two early diagenetic carbonate phases in five ancient methane-seep deposits including Oligocene limestones from the Satsop and Canyon rivers (Washington State), the Cretaceous Tepee Buttes (Colorado), and the Carboniferous Ganigobis limestones (Namibia). (1) Cryptocrystalline, yellow aragonite and (2) banded and botryoidal aggregates of clear, fibrous aragonite typify many Phanerozoic seep limestones, and are common features of authigenic seep carbonates forming close to the sediment-water interface today. Light REE enrichment in yellow aragonite is observed together with high organic matter contents, indicated by intense autofluorescence of yellow aragonite, and occurs in combination with low Mg/Sr ratios. Conversely, heavy REE enrichment is observed in neomorphic yellow calcite spar typified by high Mg/Sr ratios, indicating progressive diagenetic alteration during early diagenesis in marine pore waters affected by a succession of biogeochemical reactions. These observations suggest that REE contents and patterns of early diagenetic carbonate phases are a function of the quality of preservation. Transformation of primary aragonite to calcite resulting from changing pore water compositions during later-stage early diagenesis is apparently capable to significantly modify elemental composition. The new results reveal that rare earth elements do not necessarily behave conservatively if early diagenesis is controlled to a large extent by evolving pore water compositions in environments strongly affected by biogeochemical processes. For such settings a careful assessment of diagenetic alteration is consequently required before calcite resulting from aragonite transformation can be used for reliable paleoenvironment reconstruction.

eaogorg.files.wordpress.com€¦ · Web viewGEOCHEMISTRY ARTICLES – November 2018. Analytical...

Documents

Transcript of eaogorg.files.wordpress.com€¦ · Web viewGEOCHEMISTRY ARTICLES – November 2018. Analytical...