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Southern Ocean carbon sink enhanced by sea-ice feedbacks at the Antarctic Cold Reversal

Citation

Fogwill, CJ and Turney, CSM and Menviel, L and Baker, A and Weber, ME and Ellis, B and Thomas, ZA and Golledge, NR and Etheridge, D and Rubino, M and Thornton, DP and van Ommen, TD and Moy, AD and Curran, MAJ and Davies, S and Bird, MI and Munksgaard, NC and Rootes, CM and Millman, H and Vohra, J and Rivera, A and Macintosh, A and Pike, J and Hall, IR and Bagshaw, EA and Rainsley, E and Bronk-Ramsey, C and Montenari, M and Cage, AG and Harris, MRP and Jones, R and Power, A and Love, J and Young, J and Weyrich, LS and Cooper, A, Southern Ocean carbon sink enhanced by sea-ice feedbacks at the Antarctic Cold Reversal, Nature Geoscience, 13 pp. 489-497. ISSN 1752-0894 (2020) [Refereed Article]

Copyright Statement

Copyright 2020 The Authors, under exclusive licence to Springer Nature Limited

DOI: doi:10.1038/s41561-020-0587-0

Abstract

The Southern Ocean occupies 14% of the Earth’s surface and plays a fundamental role in the global carbon cycle and climate. It provides a direct connection to the deep ocean carbon reservoir through biogeochemical processes that include surface primary productivity, remineralization at depth and the upwelling of carbon-rich water masses. However, the role of these different processes in modulating past and future air–sea carbon flux remains poorly understood. A key period in this regard is the Antarctic Cold Reversal (ACR, 14.6–12.7 kyr bp), when mid- to high-latitude Southern Hemisphere cooling coincided with a sustained plateau in the global deglacial increase in atmospheric CO2. Here we reconstruct high-latitude Southern Ocean surface productivity from marine-derived aerosols captured in a highly resolved horizontal ice core. Our multiproxy reconstruction reveals a sustained signal of enhanced marine productivity across the ACR. Transient climate modelling indicates this period coincided with maximum seasonal variability in sea-ice extent, implying that sea-ice biological feedbacks enhanced CO2 sequestration and created a substantial regional marine carbon sink, which contributed to the plateau in CO2 during the ACR. Our results highlight the role Antarctic sea ice plays in controlling global CO2, and demonstrate the need to incorporate such feedbacks into climate–carbon models.

Item Details

Item Type:Refereed Article
Keywords:Southern Ocean, ice core, carbon sink, Antarctic Cold Reversal
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Palaeoclimatology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:van Ommen, TD (Dr Tas van Ommen)
UTAS Author:Moy, AD (Dr Andrew Moy)
UTAS Author:Curran, MAJ (Dr Mark Curran)
ID Code:139595
Year Published:2020
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2020-06-23
Last Modified:2021-02-03
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