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Refined estimation of marine and terrigenous contributions to sedimentary organic carbon
Author(s) -
Jasper John P.,
Hayes J. M.
Publication year - 1993
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 - 10.1029/93gb00599
Subject(s) - terrigenous sediment , isotopes of carbon , total organic carbon , carbon cycle , geology , oceanography , deep sea , interglacial , environmental science , glacial period , environmental chemistry , sedimentary rock , paleontology , chemistry , ecology , ecosystem , biology
Molecular carbon isotopic ( 13 C/ 12 C) ratios of a selected marine organic biomarker compound (a C 37 alkadienone) from the Pigmy Basin (Deep Sea Drilling Program Hole 619) in the northern Gulf of Mexico varied by 5.3‰ in sychrony with the last ∼100 ka glacial‐interglacial cycle. This carbon isotopic (δ 13 C) variation is likely due to the effect of climatically linked variations in concentrations of CO 2 (aq) on photosynthetic fractionation of carbon isotopes by phytoplankton. Measurement of the δ 13 C of the alkadienone (δ 37:2 ) to reconstruct the carbon isotopic composition of total marine organic carbon permits improved estimates of the time‐varying δ 13 C of preserved marine organic carbon end members. With the time series record of marine end members, the concentrations and net accumulation rates of terrigenous C org and marine C org are calculated and their paleoceanographic significance is considered. Although this method may be improved by consideration of additional biomarkers representative of diverse marine and terrigenous inputs, it is the first application of molecular isotopic analysis to quantifying marine and terrigenous C org concentrations. Further application of such techniques will be become valuable in reconstructing regional and global budgets of marine and terrigenous C org accumulation.