Presentation Biogeochemistry Gustafsson and Gschwend, Masiello, Druffel and Currie, Middelburg, Nieuwenhuize and Van Breugel, Mitra, Bianchi, McKee and Sutula, 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

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 table Cenozoic EraQuarternary PeriodHolocene Epoch Pleistocene Epoch Tertiary PeriodPliocene Epoch Miocene Epoch Oligocene Epoch Eocene Epoch Paleocene Epoch Mesozoic EraCretaceous Period Jurassic Period Triassic Period Paleozoic EraPermian 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