Does sedimentary organic delta 13C record variations in quaternary ocean [CO2(aq)]?
Ocean surface water [CO2(aq)] variations based on glacial/interglacial changes in sediment delta 13Corg are shown to compare favorably with reconstructions based on ice core [CO2].  In particular, an approximate 80 microatmospheres increase in atmospheric pCO2 during the last glacial-interglacial transition is calculated to correspond to a 3-4 micromolar increase in ocean surface water [CO2(aq)] at atmospheric equilibrium.  A widespread marine delta 13Corg decrease of 1-2% accompanied this event and was not preceded by an equivalent isotopic change in surface water total dissolved inorganic carbon.  These observations support the hypothesis that [CO2(aq)] influences photosynthetic isotope fractionation between marine inorganic and organic carbon pools, and therefore that plankton/sediment delta 13Corg may serve as a proxy for surface water [CO2(aq)].
Rau
G H
GH
Institute of Marine Sciences, University of California, Santa Cruz, USA.
Froelich
P N
PN
Takahashi
T
T
Des Marais
D J
DJ
D000818:Animals; D001272:Atmosphere; D002244:Carbon / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis*; D002247:Carbon Isotopes; D019015:Geologic Sediments / Q000737:chemistry*; D007053:Ice / Q000032:analysis; D009791:Oceanography; D009792:Oceans and Seas; D010163:Paleontology; D010933:Plankton; D012623:Seawater / Q000737:chemistry*
D002247:Carbon Isotopes; D007053:Ice; D002245:Carbon Dioxide; D002244:Carbon