Orbital- and millennial-scale Antarctic Circumpolar Current variability in Drake Passage over the past 140,000 years
Wu, S.; Lembke-Jene, L.; Lamy, F.; Arz, H.W.; Nowaczyk, N.; Xiao, W.; Zhang, X.; Hass, H.C.; Titschack, J.; Zheng, X.; Liu, J.; Dumm, L.; Diekmann, B.; Nürnberg, D.; Tiedemann, R.; Kuhn, G. (2021). Orbital- and millennial-scale Antarctic Circumpolar Current variability in Drake Passage over the past 140,000 years. Nature Comm. 12(1): 3948. https://dx.doi.org/10.1038/s41467-021-24264-9
In: Nature Communications. Nature Publishing Group: London. ISSN 2041-1723; e-ISSN 2041-1723, more
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| Authors | | Top |
- Wu, S.
- Lembke-Jene, L.
- Lamy, F.
- Arz, H.W.
- Nowaczyk, N.
- Xiao, W.
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- Zhang, X.
- Hass, H.C.
- Titschack, J.
- Zheng, X.
- Liu, J.
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- Dumm, L.
- Diekmann, B.
- Nürnberg, D.
- Tiedemann, R.
- Kuhn, G.
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| Abstract |
The Antarctic Circumpolar Current (ACC) plays a crucial role in global ocean circulation by fostering deep-water upwelling and formation of new water masses. On geological time-scales, ACC variations are poorly constrained beyond the last glacial. Here, we reconstruct changes in ACC strength in the central Drake Passage in vicinity of the modern Polar Front over a complete glacial-interglacial cycle (i.e., the past 140,000 years), based on sediment grain-size and geochemical characteristics. We found significant glacial-interglacial changes of ACC flow speed, with weakened current strength during glacials and a stronger circulation in interglacials. Superimposed on these orbital-scale changes are high-amplitude millennial-scale fluctuations, with ACC strength maxima correlating with diatom-based Antarctic winter sea-ice minima, particularly during full glacial conditions. We infer that the ACC is closely linked to Southern Hemisphere millennial-scale climate oscillations, amplified through Antarctic sea ice extent changes. These strong ACC variations modulated Pacific-Atlantic water exchange via the “cold water route” and potentially affected the Atlantic Meridional Overturning Circulation and marine carbon storage. |
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