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Copyright Copernicus GmbH 2012

Abstract

Stable carbon and oxygen isotopic compositions (δ13 C and δ18 O) 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 (δ13 CDIC and δ18 Owater ) 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 δ13 C 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.

Details

Title
Variation in stable carbon and oxygen isotopes of individual benthic foraminifera: tracers for quantifying the magnitude of isotopic disequilibrium
Author
Ishimura, T.; Tsunogai, U.; Hasegawa, S.; Nakagawa, F.; Oi, T.; Kitazato, H.; Suga, H.; Toyofuku, T.
First page
4353
Publication year
2012
Publication date
2012
Publisher
Copernicus GmbH
ISSN
17264170
e-ISSN
17264189
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1223491994
Copyright
Copyright Copernicus GmbH 2012