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Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals

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posted on 2023-05-16, 22:49 authored by Charrassin, JB, Mark HindellMark Hindell, Stephen Rintoul, Roquet, F, Sokolov, S, Biuw, M, Costa, D, Boehme, L, Lovell, P, Richard ColemanRichard Coleman, Timmermann, R, Meijers, AJ, Meredith, M, Park, YH, Bailleul, F, Goebel, M, Tremblay, Y, Bost, CA, McMahon, CR, Field, IC, Fedak, MA, Guinet, C
Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals (Mirounga leonina) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice zone, allowing the major fronts to be mapped south of 60°S and sea-ice formation rates to be inferred from changes in upper ocean salinity. Sea-ice production rates peaked in early winter (April–May) during the rapid northward expansion of the pack ice and declined by a factor of 2 to 3 between May and August, in agreement with a threedimensional coupled ocean–sea-ice model. By measuring the highlatitude ocean during winter, elephant seals fill a ‘‘blind spot’’ in our sampling coverage, enabling the establishment of a truly global ocean-observing system.

History

Publication title

Proceedings of the National Academy of Sciences of the United States of America

Volume

105

Issue

33

Pagination

11634-11639

ISSN

0027-8424

Department/School

School of Natural Sciences

Publisher

National Academy of Sciences

Place of publication

Washington, USA and online

Rights statement

© 2008 by The National Academy of Sciences of the USA. Freely available online through the PNAS open access option.

Repository Status

  • Open

Socio-economic Objectives

Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)

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