title: Does sedimentary organic delta 13C record variations in quaternary ocean [CO2(aq)]?
abstract: 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)].
authors.affiliation: Institute of Marine Sciences, University of California, Santa Cruz, USA.
authors.forename: G H
authors.initials: GH
authors.lastname: Rau
authors.forename: P N
authors.initials: PN
authors.lastname: Froelich
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: D J
authors.initials: DJ
authors.lastname: Des Marais
mesh_terms: 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*
chemical_list: D002247:Carbon Isotopes; D007053:Ice; D002245:Carbon Dioxide; D002244:Carbon