ORCID
- Simon T. Belt: 0000-0002-1570-2924
Abstract
Alkenones are biomarkers produced solely by algae in the order Isochrysidales that have been used to reconstruct sea surface temperature (SST) since the 1980s. However, alkenone-based SST reconstructions in the northern high latitude oceans show significant bias towards warmer temperatures in core-tops, diverge from other SST proxies in down core records, and are often accompanied by anomalously high relative abundance of the C37 tetra-unsaturated methyl alkenone (%C37:4). Elevated %C37:4 is widely interpreted as an indicator of low sea surface salinity from polar water masses, but its biological source has thus far remained elusive. Here we identify a lineage of Isochrysidales that is responsible for elevated C37:4 methyl alkenone in the northern high latitude oceans through next-generation sequencing and lab-culture experiments. This Isochrysidales lineage co-occurs widely with sea ice in marine environments and is distinct from other known marine alkenone-producers, namely Emiliania huxleyi and Gephyrocapsa oceanica. More importantly, the %C37:4 in seawater filtered particulate organic matter and surface sediments is significantly correlated with annual mean sea ice concentrations. In sediment cores from the Svalbard region, the %C37:4 concentration aligns with the Greenland temperature record and other qualitative regional sea ice records spanning the past 14 kyrs, reflecting sea ice concentrations quantitatively. Our findings imply that %C37:4 is a powerful proxy for reconstructing sea ice conditions in the high latitude oceans on thousand- and, potentially, on million-year timescales.
DOI Link
Publication Date
2021-01-04
Publication Title
Nature Communications
Volume
12
Issue
1
ISSN
2041-1723
Acceptance Date
2020-11-12
Deposit Date
2021-05-01
Embargo Period
2021-01-07
Funding
This work was supported by the United States National Science Foundation (NSF) under grant EAR-1762431 and an IBES seed grant to Y.H., IBES Graduate Research, Training & Travel Award to K.J.W., and NSF DEB-1930820 to T.R.K. We would like to thank Dr. Beth Caissie for surface sediment samples from Bering Sea, and Dr. Daniel Sigman, Dr. Cara Manning, Dr. Anissa Merzouk, Dr. Alexandre Forest, Dr. Camille Wilhelmy, Dr. Philippe-Olivier Dumais, Dr. Diana Saltymakova, Dr. Katarzyna Polcwiartek, and Dr. Cindy Grant for surface sediment samples from Amundsen cruise. We would like to thank GEOMAR Helmholtz Centre for Ocean Research, BOSCORF repository, and Lamont-Doherty Core Repository, Columbia University, for other surface sediment samples. We would also like to thank Dr. Robert Spielhagen for sediment samples from core M23258-2.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Wang, K., Huang, Y., Majaneva, M., Belt, S., Liao, S., Novak, J., Kartzinel, T., Herbert, T., Richter, N., & Cabedo-Sanz, P. (2021) 'Group 2i Isochrysidales produce characteristic alkenones reflecting sea ice distribution', Nature Communications, 12(1). Available at: 10.1038/s41467-020-20187-z
