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

Fogwill, C. J., Turney, C. S. M., Menviel, L., Baker, A., Weber, M. E., Ellis, B., Thomas, Z. A., Golledge, N. R., Etheridge, D., Rubino, M., Thornton, D. P., van Ommen, T. D., Moy, A. D., Curran, M. A. J., Davies, S., Bird, M. I., Munksgaard, N. C., Rootes, C. M., Millman, H., Vohra, J., Rivera, A., Mackintosh, A., Pike, J., Hall, I. R., Bagshaw, E. A., Rainsley, E., Bronk-Ramsey, C., Montenari, M., Cage, A. G., Harris, M. R. P., Jones, R., Power, A., Love, J., Young, J., Weyrich, L. S., and Cooper, A. (2020) Southern Ocean carbon sink enhanced by sea-ice feedbacks at the Antarctic Cold Reversal. Nature Geoscience, 13. pp. 489-497.

[img] PDF (Published version) - Published Version
Restricted to Repository staff only

View at Publisher Website: https://doi.org/10.1038/s41561-020-0587-...
 
1
2


Abstract

Increased Southern Ocean productivity driven by sea-ice feedbacks contributed to a slowdown in rising CO(2)levels during the last deglaciation, according to analyses of marine-derived aerosols from an Antarctic ice core.

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 kyrbp), 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 CO(2)sequestration and created a substantial regional marine carbon sink, which contributed to the plateau in CO(2)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 ID: 63768
Item Type: Article (Research - C1)
ISSN: 1752-0908
Copyright Information: © The Author(s), under exclusive licence to Springer Nature Limited 2020
Funders: Australian Research Council (ARC), Royal Society of New Zealand, Keele University, Commonwealth of Australia, European Research Council (ERC), Deutsche Forschungsgemeinschaft (DFG)
Projects and Grants: ARC linkage grant LP120200724, Australian Climate Change Science Project (ACCSP), ERC grant agreement no. 25923, DFG We2039/8-1
Research Data: https://www.ncdc.noaa.gov/paleo/study/29415, https://doi.pangaea.de/10.1594/PANGAEA.819646, https://doi.pangaea.de/10.1594/PANGAEA.789348
Date Deposited: 15 Jul 2020 07:38
FoR Codes: 04 EARTH SCIENCES > 0402 Geochemistry > 040203 Isotope Geochemistry @ 30%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040602 Glaciology @ 40%
04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040605 Palaeoclimatology @ 30%
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960306 Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts) @ 50%
97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 50%
Downloads: Total: 2
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page