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Variations of marine plankton δ 13 C with latitude, temperature, and dissolved CO 2 in the world ocean
Author(s) -
Goericke Ralf,
Fry Brian
Publication year - 1994
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/93gb03272
Subject(s) - phytoplankton , dissolved organic carbon , latitude , fractionation , oceanography , atmosphere (unit) , carbon cycle , isotopes of carbon , plankton , environmental science , total organic carbon , atmospheric sciences , chemistry , environmental chemistry , geology , nutrient , meteorology , ecology , biology , physics , organic chemistry , geodesy , ecosystem
Variations of the 13 C content of marine participate organic carbon (δ 13 C POC ) in the modern ocean were studied using literature data to test the assumptions underlying the calculation of atmospheric pCO 2 through geological time from the δ 13 C of sedimentary organic matter. These assumptions are that (1) concentrations of CO 2 in the atmosphere and the surface ocean are at equilibrium at all times and latitudes and that (2) carbon isotopic fractionation of phytoplankton (ϵ p ) covaries primarily with concentrations of dissolved molecular CO 2 ([CO 2 ] aq ). Previous studies and compilations have shown that the first assumption does not strictly hold, although [CO 2 ] aq may be predicted with a reasonable degree of accuracy from sea surface temperature for specific regions of the world ocean. The second assumption is shown to be questionable due to the weak covariation of ϵ p and [CO 2 ] aq in the modern ocean. The large residual variance for regressions of ϵp against [CO 2 ] aq suggests that factors other than [CO 2 ] aq strongly affect carbon isotopic fractionation in phytoplankton. It is concluded that the relationship between ϵp and [CO 2 ] aq cannot be easily calibrated using δ 13 C POC data from the modern ocean.