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Titel |
Variation in stable carbon and oxygen isotopes of individual benthic foraminifera: tracers for quantifying the magnitude of isotopic disequilibrium |
VerfasserIn |
T. Ishimura, U. Tsunogai, S. Hasegawa, F. Nakagawa, T. Oi, H. Kitazato, H. Suga, T. Toyofuku |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1726-4170
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Digitales Dokument |
URL |
Erschienen |
In: Biogeosciences ; 9, no. 11 ; Nr. 9, no. 11 (2012-11-08), S.4353-4367 |
Datensatznummer |
250007380
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Publikation (Nr.) |
copernicus.org/bg-9-4353-2012.pdf |
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Zusammenfassung |
Stable carbon and oxygen isotopic compositions (δ13C and δ18O) of
benthic foraminiferal carbonate shells have been used to reconstruct past
bottom-water environments. However, the details of factors controlling the
isotopic disequilibrium between the shells and the surrounding bottom
seawater (so-called the "vital effect") are still ambiguous. In this
study, we analyzed the isotopic composition of individual benthic
foraminifera of multiple species by using a customized high-precision
analytical system, and found that the magnitude of the isotopic
disequilibrium between benthic foraminiferal shell and the surrounding
bottom seawater (δ13CDIC and δ18Owater) in different
species is correlated with inter-individual isotopic variations. As a
result, we can choose suitable species as bottom-water proxies by using the
inter-individual isotopic variations. In addition, by using the simplified
interpretation of the inter-individual and inter-species isotopic variations
established in this study, we could reconstruct the δ13C values of
dissolved inorganic carbon in bottom water by correcting foraminiferal
isotopic compositions for the isotopic shift resulting from the isotopic
effects (vital effect, microhabitat effect, and many other reported isotopic
effects). Our findings will allow the use of isotope data for benthic
foraminifera as more reliable proxies for reconstructing past bottom-water
conditions and evaluating global carbon cycling. |
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