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Isotope offsets in marine diatom δ18O over the last 200 ka

Swann, George E.A.; Leng, Melanie J.; Sloane, Hilary J.; Maslin, Mark A.

Authors

George E.A. Swann george.swann@nottingham.ac.uk

Melanie J. Leng

Hilary J. Sloane

Mark A. Maslin



Abstract

Previous work has suggested that a species effect may be present in diatom oxygen isotope ratios (δ18Odiatom). While predominantly attributed to be a size related species effect, currently the precise mechanism remains unknown. Here, two size fractions of diatoms (38-75 μm and >100 μm) covering the last 200 ka are analysed for δ18O from ODP Site 882 in the North West Pacific Ocean. Synchronous variations of up to 13‰ occur in both size fractions. However, large isotope offsets (mean = 2.02‰) exist between the two fractions with no relationship between their magnitude and the overlying palaeoenvironmental conditions. In contrast to earlier work from the same site, no one size fraction is constantly higher or lower in δ18O relative to the other. As such, the dominant mechanism is most likely separate to the size effect previously detected. In addition, no relationship exists between the magnitude of the offsets and the species composition of the two size fractions. The presence of these isotope offsets imposes significant constraints upon the future use of δ18Odiatom in palaeoceanographic reconstructions and reiterates the need to extract and analyse only species and size specific diatom samples.

Journal Article Type Article
Publication Date Jan 1, 2008
Journal Journal of Quaternary Science
Print ISSN 0267-8179
Electronic ISSN 0267-8179
Publisher Wiley
Peer Reviewed Not Peer Reviewed
Volume 23
Issue 4
APA6 Citation Swann, G. E., Leng, M. J., Sloane, H. J., & Maslin, M. A. (2008). Isotope offsets in marine diatom δ18O over the last 200 ka. Journal of Quaternary Science, 23(4), doi:10.1002/jqs.1185
DOI https://doi.org/10.1002/jqs.1185
Publisher URL http://dx.doi.org/10.1002/jqs.1185
Copyright Statement Copyright information regarding this work can be found at the following address: http://eprints.nottingh.../end_user_agreement.pdf
Additional Information The definitive version is available at www3.interscience.wiley.com

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://eprints.nottingham.ac.uk/end_user_agreement.pdf





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