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dc.contributor.author
Ladd, S. Nemiah
dc.contributor.author
Dubois, Nathalie
dc.contributor.author
Schubert, Carsten J.
dc.date.accessioned
2017-11-17T14:11:27Z
dc.date.available
2017-10-06T02:16:58Z
dc.date.available
2017-11-17T14:11:27Z
dc.date.issued
2017
dc.identifier.other
10.5194/bg-14-3979-2017
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/190627
dc.identifier.doi
10.3929/ethz-b-000190627
dc.description.abstract
The hydrogen isotopic composition (δ2H) of lipid biomarkers has diverse applications in the fields of paleoclimatology, biogeochemistry, and microbial community dynamics. Large changes in hydrogen isotope fractionation have been observed among microbes with differing core metabolisms, while environmental factors including temperature and nutrient availability can affect isotope fractionation by photoautotrophs. Much effort has gone into studying these effects under laboratory conditions with single species cultures. Moving beyond controlled environments and quantifying the natural extent of these changes in freshwater lacustrine settings and identifying their causes is essential for robust application of δ2H values of common short-chain fatty acids as a proxy of net community metabolism and of phytoplankton-specific biomarkers as a paleohydrologic proxy. This work targets the effect of community dynamics, temperature, and productivity on 2H∕1H fractionation in lipid biomarkers through a comparative time series in two central Swiss lakes: eutrophic Lake Greifen and oligotrophic Lake Lucerne. Particulate organic matter was collected from surface waters at six time points throughout the spring and summer of 2015, and δ2H values of short-chain fatty acids, as well as chlorophyll-derived phytol and the diatom biomarker brassicasterol, were measured. We paired these measurements with in situ incubations conducted with NaH13CO3, which were used to calculate the production rates of individual lipids in lake surface water. As algal productivity increased from April to June, net discrimination against 2H in Lake Greifen increased by as much as 148 ‰ for individual fatty acids. During the same time period in Lake Lucerne, net discrimination against 2H increased by as much as 58 ‰ for individual fatty acids. A large portion of this signal is likely due to a greater proportion of heterotrophically derived fatty acids in the winter and early spring, which are displaced by more 2H-depleted fatty acids as phytoplankton productivity increases. Smaller increases in 2H discrimination for phytol and brassicasterol suggest that a portion of the signal is due to changes in net photoautotrophic 2H fractionation, which may be caused by increasing temperatures, a shift from maintenance to high growth, or changes in the community assemblage. The fractionation factors for brassicasterol were significantly different between the two lakes, suggesting that its hydrogen isotope composition may be more sensitive to nutrient regime than is the case for fatty acids or phytol.
en_US
dc.language.iso
en
en_US
dc.publisher
Copernicus
en_US
dc.rights.uri
http://creativecommons.org/licenses/by/3.0/
dc.title
Interplay of community dynamics, temperature, and productivity on the hydrogen isotope signatures of lipid biomarkers
en_US
dc.type
Journal Article
dc.rights.license
Creative Commons Attribution 3.0 Unported
dc.date.published
2017-09-14
ethz.journal.title
Biogeosciences
ethz.journal.volume
14
en_US
ethz.journal.issue
17
en_US
ethz.pages.start
3979
en_US
ethz.pages.end
3994
en_US
ethz.version.deposit
publishedVersion
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Gottingen
en_US
ethz.publication.status
published
en_US
ethz.date.deposited
2017-10-06T02:17:00Z
ethz.source
WOS
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2017-11-17T14:11:32Z
ethz.rosetta.lastUpdated
2019-01-02T10:52:25Z
ethz.rosetta.versionExported
true
ethz.COinS
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