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dc.contributor.authorRaberg, J.H.
dc.contributor.authorHarning, D.J.
dc.contributor.authorCrump, S.E.
dc.contributor.authorDe Wet, G.
dc.contributor.authorBlumm, A.
dc.contributor.authorKopf, S.
dc.contributor.authorGeirsdóttir, Á.
dc.contributor.authorMiller, G.H.
dc.contributor.authorSepúlveda, J.
dc.date.accessioned2021-07-20T00:11:25Z
dc.date.available2021-07-20T00:11:25Z
dc.date.issued2021
dc.identifier.citationRaberg, J. H., Harning, D. J., Crump, S. E., De Wet, G., Blumm, A., Kopf, S., Geirsdóttir, Á., Miller, G. H., & Sepúlveda, J. (2021). Revised fractional abundances and warm-season temperatures substantially improve brGDGT calibrations in lake sediments. Biogeosciences, 18(12), 3579–3603.
dc.identifier.issn1726-4170
dc.identifier.doi10.5194/bg-18-3579-2021
dc.identifier.urihttp://hdl.handle.net/10150/660835
dc.description.abstractDistributions of branched glycerol dialkyl glycerol tetraethers (brGDGTs) are frequently employed for reconstructing terrestrial paleotemperatures from lake sediment archives. Although brGDGTs are globally ubiquitous, the microbial producers of these membrane lipids remain unknown, precluding a full understanding of the ways in which environmental parameters control their production and distribution. Here, we advance this understanding in three ways. First, we present 43 new high-latitude lake sites characterized by low mean annual air temperatures (MATs) and high seasonality, filling an important gap in the global dataset. Second, we introduce a new approach for analyzing brGDGT data in which compound fractional abundances (FAs) are calculated within structural groups based on methylation number, methylation position, and cyclization number. Finally, we perform linear and nonlinear regressions of the resulting FAs against a suite of environmental parameters in a compiled global lake sediment dataset (ng Combining double low lineg 182). We find that our approach deconvolves temperature, conductivity, and pH trends in brGDGTs without increasing calibration errors from the standard approach. We also find that it reveals novel patterns in brGDGT distributions and provides a methodology for investigating the biological underpinnings of their structural diversity. Warm-season temperature indices outperformed MAT in our regressions, with the mean temperature of months above freezing yielding the highest-performing model (adjusted R2g Combining double low lineg 0.91, RMSEg Combining double low lineg 1.97g g C, ng Combining double low lineg 182). The natural logarithm of conductivity had the second-strongest relationship to brGDGT distributions (adjusted R2g Combining double low lineg 0.83, RMSEg Combining double low lineg 0.66, ng Combining double low lineg 143), notably outperforming pH in our dataset (adjusted R2g Combining double low lineg 0.73, RMSEg Combining double low lineg 0.57, ng Combining double low lineg 154) and providing a potential new proxy for paleohydrology applications. We recommend these calibrations for use in lake sediments globally, including at high latitudes, and detail the advantages and disadvantages of each. © 2021 EDP Sciences. All rights reserved.
dc.language.isoen
dc.publisherCopernicus GmbH
dc.rightsCopyright © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.titleRevised fractional abundances and warm-season temperatures substantially improve brGDGT calibrations in lake sediments
dc.typeArticle
dc.typetext
dc.contributor.departmentDepartment of Geosciences, University of Arizona
dc.identifier.journalBiogeosciences
dc.description.noteOpen access journal
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.
dc.eprint.versionFinal published version
dc.source.journaltitleBiogeosciences
refterms.dateFOA2021-07-20T00:11:25Z


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Copyright © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.
Except where otherwise noted, this item's license is described as Copyright © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License.