Orbital- and millennial-scale Antarctic Circumpolar Current variability in Drake Passage over the past 140,000 years

• Published in: Nature Communications
• Main Authors: Wu, Shuzhuang, Lembke-Jene, Lester, Lamy, Frank, Arz, Helge W., Nowaczyk, Norbert, Xiao, Wenshen, Zhang, Xu, Hass, H. Christian, Titschack, Jürgen, Zheng, Xufeng, Liu, Jiabo, Dumm, Levin, Diekmann, Bernhard, Nürnberg, Dirk, Tiedemann, Ralf, Kuhn, Gerhard
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Research 2021
• Subjects: Antarctic; Drake Passage; Pacific; The Antarctic; Antarc*; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/52997/; https://oceanrep.geomar.de/id/eprint/52997/1/s41467-021-24264-9.pdf; https://oceanrep.geomar.de/id/eprint/52997/2/41467_2021_24264_MOESM1_ESM.pdf; https://oceanrep.geomar.de/id/eprint/52997/13/s41467-021-24264-9.pdf; https://doi.org/10.1038/s41467-021-24264-9

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.