Presentation Biogeochemistry Gustafsson and Gschwend, 1997. Masiello, Druffel and Currie, 2002....
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Transcript of Presentation Biogeochemistry Gustafsson and Gschwend, 1997. Masiello, Druffel and Currie, 2002....
Presentation Biogeochemistry
Gustafsson and Gschwend, 1997.
Masiello, Druffel and Currie, 2002.
Middelburg, Nieuwenhuize and Van Breugel, 1999.
Mitra, Bianchi, McKee and Sutula, 2002.
Schmidt and Noack, 2000.
Black carbon
Highly condensed carbonaceous residue from
incomplete combustion processes
Soot, charcoal, char and elemental carbon
Unit and Structure BC
Schmidt and Noack, 2000
Identification techniques
• Optical
• Thermal
• Chemical
• Spectroscopic
• Molecular marker
Compare 2 techniques
• Thermal oxidation/HCl method for soot
• Thermal oxidation/HNO3 method for charcoal
Relation 2 techniques
Middelburg, Nieuwenhuize and Van Breugel, 1999
Relation with oc, sc and charcoal
Middelburg, Nieuwenhuize and Van Breugel, 1999
Unidentified fraction OC
Middelburg, Nieuwenhuize and Van Breugel, 1999
Identification techniques
• Optical
• ThermalThermal
• Chemical
• Spectroscopic
• Molecular marker
Masiello, Druffel and Currie, 2002
Masiello, Druffel and Currie, 2002
Degradation
• Assumed to be inert because:– Identified in sediments of 65 Ma– Down-core trend in size distribution– It reacts very slow towards chemical oxidation
• Chemical and microbial mechanisms unknown
Biogeochemical processes
• BC is sink in global carbon cycle
• Affect the Earth’s radiative heat balance
• Catalytic effects on chemical reactions
• Tracer for Earth’s fire history
• Paleo-atmospheric oxygen concentrations
Geological time tableCenozoic Era Quarternary Period Holocene Epoch
Pleistocene Epoch
Tertiary Period Pliocene Epoch
Miocene Epoch
Oligocene Epoch
Eocene Epoch
Paleocene Epoch
Mesozoic Era Cretaceous Period
Jurassic Period
Triassic Period
Paleozoic Era Permian Period
Carboniferous Period
Devonian Period
Silurian Period
Ordovician Period
Cambrium Period
Global Biogeochemical Cycle of BC
Schmidt and Noack, 2000
Flux calculation for the continental shelf
• Sedimentation rates
• Observed surface BC inventories
• BC concentrations
• Area of the shelf region
Determination sedimentation rates
Gustafsson and Gschwend, 1998
Comparison fluxes BC
Gustafsson and Gschwend, 1998
Global Biogeochemical Cycle of BC
Schmidt and Noack, 2000
Mississippi River BC input
• Thermal oxidation followed by acidification
• Discharge in 1999 was 4,8*10-4 Pg
• 5% of total BC in oceanic and coastal sediments
• Santa Clara River 5,4*10-5 Pg
Conclusion
• Analyses of BC remains with uncertainties
• Degradation
• Effect of BC on the global carbon cycle has to be quantified