Starr, Adrian, Hall, Ian R.  ORCID: https://orcid.org/0000-0001-6960-1419, Barker, Stephen ORCID: https://orcid.org/0000-0001-7870-6431, Nederbragt, Alexandra, Owen, Lindsey and Hemming, Sidney R.
2025.
Shifting Antarctic Circumpolar Current south of Africa over the past 1.9 million years.
Science Advances
11
(1)
, eadp1692.
10.1126/sciadv.adp1692
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Abstract
The Antarctic Circumpolar Current (ACC) dominates the transfer of heat, salt, and tracers around the Southern Ocean (SO), driving the upwelling of carbon-rich deep waters around Antarctica. Paleoclimate reconstructions reveal marked variability in SO circulation; however, few records exist coupling quantitative reconstructions of ACC flow with tracers of SO upwelling spanning multiple Pleistocene glacial cycles. Here, we reconstruct near-bottom flow speed variability in the SO south of Africa, revealing systematic glacial-interglacial variations in the strength and/or proximity of ACC jets. These are superimposed by warmer-than-present “super-interglacials,” whereby extreme slowdown in the midlatitude ACC (41°S) is opposed by faster flow at higher latitudes (>54°S), implying poleward strengthening of the ACC. Coupled with reconstructions of the subsurface-deep stable carbon isotope gradient, we show that the reorganization of ACC coincides with the upwelling of isotopically light deep waters around Antarctica, likely contributing to the interglacial rise in atmospheric carbon dioxide (CO2) levels.
| Item Type: | Article |
|---|---|
| Date Type: | Published Online |
| Status: | Published |
| Schools: | Earth and Environmental Sciences |
| Publisher: | American Association for the Advancement of Science |
| Date of First Compliant Deposit: | 21 November 2024 |
| Date of Acceptance: | 12 November 2024 |
| Last Modified: | 29 Jan 2025 11:02 |
| URI: | https://orca.cardiff.ac.uk/id/eprint/174218 |
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