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Interpretation and application of carbon isotope ratios in freshwater diatom silica

Webb, Megan; Barker, Philip A.; Wynn, Peter M.; Heiri, Oliver; van Hardenbroek, Maarten; Pick, Frances; Russell, James M.; Stott, Andy W.; Leng, Melanie J.

Authors

Megan Webb

Philip A. Barker

Peter M. Wynn

Oliver Heiri

Maarten van Hardenbroek

Frances Pick

James M. Russell

Andy W. Stott



Abstract

Carbon incorporated into diatom frustule walls is protected from degradation enabling analysis for carbon isotope composition (δ13Cdiatom). This presents potential for tracing carbon cycles via a single photosynthetic host with well-constrained ecophysiology. Improved understanding of environmental processes controlling carbon delivery and assimilation is essential to interpret changes in freshwater δ13Cdiatom. Here relationships between water chemistry and δ13Cdiatom from contemporary regional data sets are investigated. Modern diatom and water samples were collected from river catchments within England and lake sediments from across Europe. The data suggest dissolved, biogenically produced carbon supplied proportionately to catchment productivity was critical in the rivers and soft water lakes. However, dissolved carbon from calcareous geology overwhelmed the carbon signature in hard water catchments. Both results demonstrate carbon source characteristics were the most important control on δ13Cdiatom, with a greater impact than productivity. Application of these principles was made to a sediment record from Lake Tanganyika. δ13Cdiatom co-varied with δ13Cbulk through the last glacial and Holocene. This suggests carbon supply was again dominant and exceeded authigenic demand. This first systematic evaluation of contemporary δ13Cdiatom controls demonstrates that diatoms have the potential to supply a record of carbon cycling through lake catchments from sediment records over millennial timescales.

Citation

Webb, M., Barker, P. A., Wynn, P. M., Heiri, O., van Hardenbroek, M., Pick, F., …Leng, M. J. (2016). Interpretation and application of carbon isotope ratios in freshwater diatom silica. Journal of Quaternary Science, 31(4), https://doi.org/10.1002/jqs.2837

Journal Article Type Article
Acceptance Date Dec 22, 2015
Online Publication Date Jun 17, 2016
Publication Date May 1, 2016
Deposit Date Jun 30, 2016
Publicly Available Date Jun 30, 2016
Journal Journal of Quaternary Science
Print ISSN 0267-8179
Electronic ISSN 1099-1417
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 31
Issue 4
DOI https://doi.org/10.1002/jqs.2837
Keywords carbon cycling; diatom frustule carbon; Lake Tanganyika; palaeoclimate; stable carbon isotopes
Public URL http://eprints.nottingham.ac.uk/id/eprint/34521
Publisher URL http://onlinelibrary.wiley.com/doi/10.1002/jqs.2837/abstract
Copyright Statement Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0

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Copyright Statement
Copyright information regarding this work can be found at the following address: http://creativecommons.org/licenses/by/4.0





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