Acknowledgement
1
ACKNOWLEDGEMENT First and foremost, I would like to thank God for without him truly none of this would have been possible. Thanks to Mr. E. Froburg, NERU collaborators, and NSF for making this research experience possible. To Ms. Kaitlyn Steele, I most graciously appreciate the selflessness actions and contributions to the overall success of the NERU 2012. Figures 1- 4 provided by Maria Paula (MP) Mugnani..Figures 5 & 6 provided by Dr. Ruth K. Varner . This research was supported through the Northern Ecosystems Research for Undergraduates (NERU) program (NSF REU site EAR#1063037). RESEARCH FIELD SITE Stordalen Mire near Abisko, Sweden (68°21' N, 19°03' E) (Figure 1, shown below) Primarily composed of three different ecosystems: I. Elevated, dry palsa underlain by permafrost) (Figure 2) II.Intermediate moisture site dominated by Sphagnum spp. (Figure 3) III.Completely thawed wet site dominated by Eriophorum spp. (Figure 4) RESEARCH OBJECTIVES Examine the dynamics of CO 2 Net ecosystem exchange (NEE) Respiration Gross Primary Production (GPP) Examine CH 4 exchange Flux measurements Measure δ 13 C-CH 4 of emitted CH 4 INTRODUCTION Northern peatlands currently store ~30% of the world’s soil carbon and are the largest single natural source of atmospheric methane (CH 4 ) Since 2000, the Swedish sub-Arctic mean annual temperature has crossed the significant 0 C threshold 1 As the climate warms, possible positive feedbacks driven by changes in peatland carbon dioxide (CO 2 ) and CH 4 cycling could have major impacts on the atmospheric concentrations of both greenhouse gases 2 cryospheric and ecological processes 1 Methane has 62 times the global warming potential (GWP) of CO 2 at 20 year timescales 3 In wetland systems, CH 4 emissions are highly variable (both spatially and temporally) 4,5 In terrestrial freshwater systems, CH 4 is formed by two main pathways: I. CH 3 COOH → CH 4 + CO 2 II.2CH 2 O + 2H 2 O → 2CO 2 + 4H 2 CO 2 + 4H 2 → CH 4 + 2H 2 O III.2CH 2 O → CH 4 + CO 2 Equation II: Reduction of CO 2 with Hydrogen; dominates Sphagnum sites 7 RESULTS Automatic Chamber Measurements of Methane and Carbon Dioxide Fluxes and Isotopologues of CH 4 in a sub-Arctic Mire Ryan D. Lawrence 1* , Carmody K. McCalley 2 , Patrick M. Crill 3 , Ruth K. Varner 4 , Scott R. Saleska 2 1 Department of Chemistry, Geology, and Physics, Elizabeth City State University, Elizabeth City, NC 27909, USA. (*[email protected]) 2 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85719, USA. 3 Department of Geological Sciences, University of Stockholm, Svante Arrhenius Va ̈g 8 C, SE-10691 Stockholm, Sweden. 4 Climate Change Research Center, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, NH 03824, USA. CONCLUSION As the landscape transitions from a dry palsa, underlain by permafrost, to a predominately wet site dominated by Eriophorum spp. I. Sequestration of CO 2 II.Increasing amount of CH 4 to the atmosphere The average carbon isotope composition of emitted CH 4 was -68 ‰ at the Sphagnum site compared to -62 ‰ at the Eriophorum site I. Depicts relative shift from CO 2 -reductive towards acetate fermentation 6 Isotopic signature of derive CH 4 appears to not be affected by light conditions METHODOLOGY Individual automated chamber measurements were conducted using two 5 minute interval lid closures, under two different light conditions: I. Ambient light [transparent chamber] (Figure 5*) II.Darkened [shrouded chamber] (Figure 6) δ 13 C-CH 4 was determined using a Quantum Cascade Laser Spectrometer (QCL) Methane isotopic composition derived from Keeling regressions of isotope and concentration data from automated chamber flux measurement Measurement Type Light Condition Ambient Dark NEE ✓ Respiration ✓ ✓ CH 4 Exchange ✓ ✓ δ 13 C-CH 4 ✓ ✓ Table III. Automated Chamber Measurements FUTURE WORK More measurements should be conducted, especially during the 21:00 – 03:00 time period larger data sets will begin to offset the the high variability of CH 4 emissions provide more information about potential impact of light on δ 13 C-CH 4 Collect active layer depth 8 , water table depth 4,9 , chamber plant species composition by percent cover 8,6 , and pH 8 if suitable for site Aforementioned variables shown to affect CH 4 exchange and CO 2 dynamics Further analyze data using a statistical package, such as SPSS or SAS Example : paired t-test of average day vs. night δ 13 C-CH 4 to determine if isotopic composition of derived CH 4 source is affected by light REFERENCES [1] Callaghan, T. V., F. Bergholm, T. R. Christensen, C. Jonasson, U. Kokfelt, and M. Johansson (2010), A new climate era in the sub-Arctic: Accelerating climate changes and multiple impacts, Geophys. Res. Lett., 37, L14705, doi:10.1029/2009GL042064. [2] Nykänen, H., J. E. P. Heikkinen, L. Pirinen, K. Tiilikainen, and P. J. Martikainen (2003), Annual CO 2 exchange and CH 4 fluxes on a subarctic palsa mire during climatically different years, Global Biogeochem. Cycles, 17(1), 1018, doi:10.1029/2002GB001861. [3] Houghton, J. T., Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Winden, and X. Dai (2001), Climate Change 2001: The Scientific Basis. Contri- bution of Working Group 1 to the Third Assessment Report, Cambridge Univ. Press, New York. [4] Bubier, J., T. Moore, K. Savage, and P. Crill (2005), A comparison of methane flux in a boreal landscape between a dry and a wet year, Global Biogeochem. Cycles, 19, GB1023, doi:10.1029/2004GB002351. [5] Joabsson, A., and T. R. Christensen (2001), Methane emissions from wet- lands and their relationship with vascular plants: An Arctic example, Global Change Biol., 7(8), 919–932 [6] Bäckstrand, K., Crill, P. M., Jackowicz-Korczyñski, M., Mastepanov, M., Christensen, T. R., and Bastviken, D. (2009), Annual carbon gas budget for a subarctic peatland, northern Sweden, Biogeosciences Discuss., 6, 5705- 5740, doi:10.5194/bgd-6-5705-2009. [6] Whiticar M.J. (1999), Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane. Chem Geol 161: 291-314. [7] Lansdown J. M., Quay E D. and King S. L. (1992), CH 4 production via CO 2 reduction in a temperate bog: A source of 13 C depleted CH 4 . GeochimCosmochimActa 56: 3493-3503. [8] Bubier, J. L., T. R. Moore, L. Bellisario, N. T. Comer, and P. M. Crill (1995), Ecological controls on methane emissions from a Northern peatland complex in the zone of discontinuous permafrost, Manitoba, Canada, Global Biogeochem. Cycles, 9(4), 455–470. [9] Updegraff, K. (2001), Response of CO 2 and CH 4 emissions from peatlands to warming and water table manipulation, Ecol. Appl., 11(2), 311–326. Equation I: Acetate Fermentation; dominates freshwater systems 6 / Eriophorum sites 7 Equation III: Overall reaction encompassing both pathways of CH 4 production Time # of Sampling Days 09:00 – 15:00 7 12:00 – 18:00 2 21:00 – 03:00 4 Chamber # Ecosystem 1, 3, 5 palsa 2, 4, 6 Sphagnum 7, 8, 9 Eriophorum Table II. Sample Time Period Table I. Automated Chamber Ecosystem * In addition, entire automated chamber system was calibrated every 90 minutes. * One complete cycle (Chamber 1-9) is three hours. Fig. 2) Fig. 5 Ambient light chamber *chamber lid open in photo Fig. 6 Darkened chamber Fig. 3) Fig. 4) palsa Sphagnum Eriophorum -290 -245 -200 -155 -110 -65 -20 25 70 -25.93 -44.83 -150.77 51 33.23 69.23 -77.39 -78.41 -219.38 Carbon Dioxide Dynamics by Site NEE Respirat ion mg C m-2h-1 Ambient Light Dark -73 -72 -71 -70 -69 -68 -67 -66 -65 -64 -68.61 -67.65 -67.18 -67.95 -72.33 -66.98 Sphagnum Site δ13C-CH4 All Measurements Day (0900- 1500) Night (2100- 0300) δ13C-CH4 (‰) Ambient Light Dark -63.5 -63 -62.5 -62 -61.5 -61 -60.5 -60 -59.5 -61.49 -62.26 -60.87 -62.48 -63.27 -61.63 Eriophorum Site δ13C-CH4 All Measurments Day (0900- 1500) Night (2100- 0300) δ13C-CH4 (‰) 0 2 4 6 8 0.02 1.17 5.51 0.00 1.56 6.33 Average CH4 Exchange by Site Ambient Flux Dark Flux mg CH4 m-2 h-1 Figure 7) GPP was calculated using the equation GPP = NEE – respiration. From permafrost to Eriophorum, more plants result in overall uptake of CO 2 . Figure 8) Methane flux measurements were made under ambient light and shrouded conditions. Differences in CH 4 emission occur; however, high variability and small sample size may reason that result in observed change. Figure 9 & 10) The averages of all δ 13 C-CH 4 within each cover type are similar; however, measurements conducted during the hours of 09:00 – 15:00 vs. 21:00 – 03:00 may potentially be significantly different. Yet, CH 4 high variability may heavily influence results of small sample size (n = 24).
description
Automatic Chamber M easurements of Methane and Carbon Dioxide Fluxes and I sotopologues of CH 4 in a sub-Arctic M ire Ryan D. Lawrence 1* , Carmody K. McCalley 2 , Patrick M. Crill 3 , Ruth K. Varner 4 , Scott R. Saleska 2 - PowerPoint PPT Presentation
Transcript of Acknowledgement
ACKNOWLEDGEMENT
First and foremost, I would like to thank God for without him truly none of this would have been possible.
Thanks to Mr. E. Froburg, NERU collaborators, and NSF for making this research experience possible. To Ms. Kaitlyn Steele, I most graciously appreciate the selflessness actions and contributions to the overall success of the NERU 2012. Figures 1- 4 provided by Maria Paula (MP) Mugnani..Figures 5 & 6 provided by Dr. Ruth K. Varner.
This research was supported through the Northern Ecosystems Research for Undergraduates (NERU) program (NSF REU site EAR#1063037).
RESEARCH FIELD SITE Stordalen Mire near Abisko, Sweden
(68°21' N, 19°03' E) (Figure 1, shown below)
Primarily composed of three different ecosystems:
I. Elevated, dry palsa underlain by permafrost) (Figure 2)
II. Intermediate moisture site dominated by Sphagnum spp. (Figure 3)
III. Completely thawed wet site dominated by Eriophorum spp. (Figure 4)
RESEARCH OBJECTIVES
Examine the dynamics of CO2
Net ecosystem exchange (NEE)
Respiration Gross Primary
Production (GPP)
Examine CH4 exchangeFlux measurements
Measure δ13C-CH4 of emitted CH4
INTRODUCTION Northern peatlands currently store ~30% of the world’s soil carbon and are the largest
single natural source of atmospheric methane (CH4)
Since 2000, the Swedish sub-Arctic mean annual temperature has crossed the significant 0 C threshold1
As the climate warms, possible positive feedbacks driven by changes in peatland carbon dioxide (CO2) and CH4 cycling could have major impacts on
the atmospheric concentrations of both greenhouse gases2
cryospheric and ecological processes1
Methane has 62 times the global warming potential (GWP) of CO2 at 20 year timescales3
In wetland systems, CH4 emissions are highly variable (both spatially and temporally)4,5
In terrestrial freshwater systems, CH4 is formed by two main pathways:
I. CH3COOH → CH4 + CO2
II. 2CH2O + 2H2O → 2CO2 + 4H2
CO2 + 4H2 → CH4+ 2H2O
III. 2CH2O → CH4 + CO2
Equation II: Reduction of CO2 with Hydrogen; dominates Sphagnum sites 7
RESULTS
Automatic Chamber Measurements of Methane and Carbon Dioxide Fluxes and Isotopologues of CH4 in a sub-Arctic Mire
Ryan D. Lawrence1*, Carmody K. McCalley2, Patrick M. Crill3, Ruth K. Varner4, Scott R. Saleska2
1Department of Chemistry, Geology, and Physics, Elizabeth City State University, Elizabeth City, NC 27909, USA. (*[email protected]) 2Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85719, USA.
3Department of Geological Sciences, University of Stockholm, Svante Arrhenius Va ̈g 8 C, SE-10691 Stockholm, Sweden. 4 Climate Change Research Center, Institute for the Study of Earth, Oceans and Space, Morse Hall, University of New Hampshire, Durham, NH 03824, USA.
CONCLUSION As the landscape transitions from a dry palsa, underlain by permafrost, to a
predominately wet site dominated by Eriophorum spp.I. Sequestration of CO2
II. Increasing amount of CH4 to the atmosphere
The average carbon isotope composition of emitted CH4 was -68 ‰ at the Sphagnum site compared to -62 ‰ at the Eriophorum site
I. Depicts relative shift from CO2-reductive towards acetate fermentation 6
Isotopic signature of derive CH4 appears to not be affected by light conditions
METHODOLOGY Individual automated chamber measurements were conducted using two 5 minute interval lid
closures, under two different light conditions:I. Ambient light [transparent chamber] (Figure 5*)II. Darkened [shrouded chamber] (Figure 6)
δ13C-CH4 was determined using a Quantum Cascade Laser Spectrometer (QCL) Methane isotopic composition derived from Keeling regressions of isotope and
concentration data from automated chamber flux measurement
Measurement Type Light Condition Ambient Dark
NEE ✓ Respiration ✓ ✓ CH4 Exchange ✓ ✓ δ13C-CH4 ✓ ✓
Table III. Automated Chamber Measurements
FUTURE WORK More measurements should be conducted, especially during the 21:00 – 03:00 time
period larger data sets will begin to offset the the high variability of CH4 emissions provide more information about potential impact of light on δ13C-CH4
Collect active layer depth8, water table depth4,9, chamber plant species composition by
percent cover8,6, and pH8 if suitable for site Aforementioned variables shown to affect CH4 exchange and CO2 dynamics
Further analyze data using a statistical package, such as SPSS or SAS
Example : paired t-test of average day vs. night δ13C-CH4 to determine if isotopic composition of derived CH4 source is affected by light
REFERENCES[1] Callaghan, T. V., F. Bergholm, T. R. Christensen, C. Jonasson, U. Kokfelt, and M. Johansson (2010), A new climate era in the sub-Arctic: Accelerating climate
changes and multiple impacts, Geophys. Res. Lett., 37, L14705, doi:10.1029/2009GL042064.[2] Nykänen, H., J. E. P. Heikkinen, L. Pirinen, K. Tiilikainen, and P. J. Martikainen (2003), Annual CO2 exchange and CH4 fluxes on a subarctic palsa mire during
climatically different years, Global Biogeochem. Cycles, 17(1), 1018, doi:10.1029/2002GB001861.[3] Houghton, J. T., Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Winden, and X. Dai (2001), Climate Change 2001: The Scientific Basis. Contri- bution of Working
Group 1 to the Third Assessment Report, Cambridge Univ. Press, New York. [4] Bubier, J., T. Moore, K. Savage, and P. Crill (2005), A comparison of methane flux in a boreal landscape between a dry and a wet year, Global Biogeochem. Cycles,
19, GB1023, doi:10.1029/2004GB002351.[5] Joabsson, A., and T. R. Christensen (2001), Methane emissions from wet- lands and their relationship with vascular plants: An Arctic example, Global Change Biol.,
7(8), 919–932[6] Bäckstrand, K., Crill, P. M., Jackowicz-Korczyñski, M., Mastepanov, M., Christensen, T. R., and Bastviken, D. (2009), Annual carbon gas budget for a subarctic
peatland, northern Sweden, Biogeosciences Discuss., 6, 5705-5740, doi:10.5194/bgd-6-5705-2009.[6] Whiticar M.J. (1999), Carbon and hydrogen isotope systematics of bacterial formation and oxidation of methane. Chem Geol 161: 291-314.[7] Lansdown J. M., Quay E D. and King S. L. (1992), CH4 production via CO2 reduction in a temperate bog: A source of 13C depleted CH4. GeochimCosmochimActa
56: 3493-3503.[8] Bubier, J. L., T. R. Moore, L. Bellisario, N. T. Comer, and P. M. Crill (1995), Ecological controls on methane emissions from a Northern peatland complex in the
zone of discontinuous permafrost, Manitoba, Canada, Global Biogeochem. Cycles, 9(4), 455–470.[9] Updegraff, K. (2001), Response of CO2 and CH4 emissions from peatlands to warming and water table manipulation, Ecol. Appl., 11(2), 311–326.
Equation I: Acetate Fermentation;dominates freshwater systems 6 / Eriophorum sites 7
Equation III: Overall reaction encompassing both pathways of CH4 production
Time # of Sampling Days 09:00 – 15:00 7 12:00 – 18:00 2 21:00 – 03:00 4
Chamber # Ecosystem 1, 3, 5 palsa 2, 4, 6 Sphagnum 7, 8, 9 Eriophorum
Table II. Sample Time Period
Table I. Automated Chamber Ecosystem
* In addition, entire automated chamber system was calibrated every 90 minutes.
* One complete cycle (Chamber 1-9) is three hours.
Fig. 2)
Fig. 5 Ambient light chamber*chamber lid open in photo
Fig. 6 Darkened chamber
Fig. 3) Fig. 4)
palsa Sphagnum Eriophorum
-290
-245
-200
-155
-110
-65
-20
25
70
-25.93-44.83
-150.77
5133.23
69.23
-77.39 -78.41
-219.38
Carbon Dioxide Dynamics by Site
NEERespirationGPP
mg
C m
-2h-
1
Ambient Light Dark
-73
-72
-71
-70
-69
-68
-67
-66
-65
-64
-68.61
-67.65-67.18 -67.95
-72.33
-66.98
Sphagnum Site δ13C-CH4
All MeasurementsDay (0900-1500)Night (2100-0300)δ1
3C-C
H4
(‰) Ambient Light Dark
-63.5
-63
-62.5
-62
-61.5
-61
-60.5
-60
-59.5
-61.49
-62.26
-60.87
-62.48
-63.27
-61.63
Eriophorum Site δ13C-CH4
All MeasurmentsDay (0900-1500)Night (2100-0300)δ1
3C-C
H4
(‰)
palsa Sphagnum Eriophorum
012345678
0.02
1.17
5.51
0.00
1.56
6.33
Average CH4 Exchange by Site
Ambient FluxDark Flux
mg
CH
4 m
-2 h
-1
Figure 7) GPP was calculated using the equation GPP = NEE – respiration. From permafrost to Eriophorum, more plants result in overall uptake of CO2.
Figure 8) Methane flux measurements were made under ambient light and shrouded conditions. Differences in CH4 emission occur; however, high variability and small sample size may reason that result in observed change.
Figure 9 & 10) The averages of all δ13C-CH4 within each cover type are similar; however, measurements conducted during the hours of 09:00 – 15:00 vs. 21:00 – 03:00 may potentially be significantly different. Yet, CH4 high variability may heavily influence results of small sample size (n = 24).
