Sensitivity of Holocene East Antarctic productivity to subdecadal variability set by sea ice

Type Article
Date 2021-10
Language English
Author(s) Johnson Katelyn M.ORCID1, 2, McKay Robert M.2, Etourneau Johan3, 4, 5, Jiménez-Espejo Francisco J.ORCID3, 6, Albot Anya2, Riesselman Christina R.ORCID7, 8, Bertler Nancy A. N.ORCID1, 2, Horgan Huw J.2, Crosta XavierORCID5, Bendle JamesORCID9, Ashley Kate E.9, Yamane MasakoORCID10, Yokoyama YusukeORCID11, Pekar Stephen F.12, Escutia CarlotaORCID3, Dunbar Robert B.13
Affiliation(s) 1 : GNS Science, Lower Hutt, New Zealand
2 : Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
3 : Andaluz Institute of Earth Sciences, CSIC-University of Granada, Granada, Spain
4 : EPHE, PSL University, Paris, France
5 : UMR 5805 EPOC CNRS, University of Bordeaux, Bordeaux, France
6 : Biogeochemistry Center, JAMSTEC, Yokosuka, Japan
7 : Department of Geology, University of Otago, Dunedin, New Zealand
8 : Department of Marine Science, University of Otago, Dunedin, New Zealand
9 : School of Geography, Earth, and Environmental Sciences, University of Birmingham, Birmingham, UK
10 : Institute for Space–Earth Environmental Research (ISEE), Nagoya University, Nagoya, Japan
11 : Analytical Center for Environmental Study, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
12 : School of Earth and Environmental Sciences, City University of New York - Queens College, New York, NY, USA
13 : School of Earth, Energy, and Environmental Sciences, Stanford University, Stanford, CA, USA
Source Nature Geoscience (1752-0894) (Springer Science and Business Media LLC), 2021-10 , Vol. 14 , N. 10 , P. 762-768
DOI 10.1038/s41561-021-00816-y
WOS© Times Cited 1

ntarctic sea-ice extent, primary productivity and ocean circulation represent interconnected systems that form important components of the global carbon cycle. Subdecadal to centennial-scale variability can influence the characteristics and interactions of these systems, but observational records are too short to evaluate the impacts of this variability over longer timescales. Here, we use a 170-m-long sediment core collected from Integrated Ocean Drilling Program Site U1357B, offshore Adélie Land, East Antarctica to disentangle the impacts of sea ice and subdecadal climate variability on phytoplankton bloom frequency over the last ~11,400 years. We apply X-ray computed tomography, Ice Proxy for the Southern Ocean with 25 carbon atoms, diatom, physical property and geochemical analyses to the core, which contains an annually resolved, continuously laminated archive of phytoplankton bloom events. Bloom events occurred annually to biennially through most of the Holocene, but became less frequent (~2–7 years) at ~4.5 ka when coastal sea ice intensified. We propose that coastal sea-ice intensification subdued annual sea-ice break-out, causing an increased sensitivity of sea-ice dynamics to subdecadal climate modes, leading to a subdecadal frequency of bloom events. Our data suggest that projected loss of coastal sea ice will impact the influence of subdecadal variability on Antarctic margin primary productivity, altering food webs and carbon-cycling processes at seasonal timescales.

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Johnson Katelyn M., McKay Robert M., Etourneau Johan, Jiménez-Espejo Francisco J., Albot Anya, Riesselman Christina R., Bertler Nancy A. N., Horgan Huw J., Crosta Xavier, Bendle James, Ashley Kate E., Yamane Masako, Yokoyama Yusuke, Pekar Stephen F., Escutia Carlota, Dunbar Robert B. (2021). Sensitivity of Holocene East Antarctic productivity to subdecadal variability set by sea ice. Nature Geoscience, 14(10), 762-768. Publisher's official version : , Open Access version :