The relationship between. delta. sup 13 C of organic matter and (CO sub 2 (aq)) in ocean surface water: Data from a JGOFS site in the northeast Atlantic Ocean and a model

Journal Article · Sun Mar 01 00:00:00 EST 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90073-R· OSTI ID:7067059

Rau, G H ^[1]; Takahashi, T ^[2]; Des Marais, D J ^[3]; Repeta, D J ^[4]; Martin, J H ^[5]

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1. Univ. of California, Santa Cruz, CA (United States) NASA-Ames Research Center, Moffett Field, CA (United States)
2. Columbia Univ., Palisades, NY (United States)
3. NASA-Ames Research Center, Moffett Field, CA (United States)
4. Woods Hole Oceanographic Inst., MA (United States)
5. Moss Landing Marine Lab., CA (United States)

The {delta}{sup 13}C of suspended particulate organic matter (SPOM) in surface waters increased from {minus}22.9 to {minus}18.1{per thousand} during April 25-May 31, 1989 at the JGOFS North Atlantic Bloom Experiment Site (NABE Site; 47{degree}N, 20{degree}W). During the same period, nearly parallel increases in sinking POM {delta}{sup 13}C were also found, although these values were usually lower than those of the corresponding SPOM. Consistent with the hypothesis that plankton {delta}{sup 13}C and (CO{sub 2}(aq)) are inversely related, the increases in both sinking and suspended POM {delta}{sup 13}C were highly negatively correlated with mixed-layer (CO{sub 2}(aq)) that generally decreased from 13.2-10.1 {mu}moles/kg during the five weeks. The change in SPOM {delta}{sup 13}C per change in (CO{sub 2}(aq)), however, appears to be somewhat greater than that expected from previous, though less direct, ocean and laboratory evidence. By adapting a model of plant {delta}{sup 13}C by Farquhar et al. (1982), it is shown that under a constant phytoplankton demand for CO{sub 2} an inverse, nonlinear SPOM {delta}{sup 13}C response to ambient (CO{sub 2}(aq)) is expected. Such trends are unlike the negative linear relationships indicated by data from the NABE Site and or from Southern Hemisphere waters. Such differences between predicted and observed SPOM {delta}{sup 13}C vs. (CO{sub 2}(aq)) trends and among observed relationships can be reconciled, however, if biological CO{sub 2} demand is allowed to vary. This has significant implications for the use of the {delta}{sup 13}C of plankton (or their organic subfractions or sedimentary remains) as a proxy for past or present ocean CO{sub 2} concentrations and biological productivity.

• OSTI ID: 7067059
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 56:3; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
ORGANIC MATTER
ISOTOPE RATIO
ATLANTIC OCEAN
CARBON 13
CORRELATIONS
EXPERIMENTAL DATA
GEOLOGIC HISTORY
MATHEMATICAL MODELS
PARTICULATES
PLANKTON
VARIATIONS
WATER CHEMISTRY
AQUATIC ORGANISMS
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
CHEMISTRY
DATA
EVEN-ODD NUCLEI
INFORMATION
ISOTOPES
LIGHT NUCLEI
MATTER
NUCLEI
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PARTICLES
SEAS
STABLE ISOTOPES
SURFACE WATERS
540310* - Environment
Aquatic- Basic Studies- (1990-)