Antarctic Circumpolar Current (ACC) analysis of sediment core PS97/085-3 from POLARSTERN cruise PS97 (ANT-XXXI/3) in the Drake Passage

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...

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Bibliographic Details
Main Authors: Wu, Shuzhuang, Lembke-Jene, Lester, Lamy, Frank, Arz, Helge Wolfgang, Nowaczyk, Norbert R, Xiao, Wenshen, Zhang, Xu, Hass, H Christian, Titschack, Jürgen, Zheng, Xufeng, Liu, Jiabo, Dumm, Levin, Diekmann, Bernhard, Nürnberg, Dirk, Tiedemann, Ralf, Kuhn, Gerhard
Format: Other/Unknown Material
Language:English
Published: PANGAEA 2020
Subjects:
Antarctic Circumpolar Current
AWI_Envi
Drake Passage
Grain Size
Polar Terrestrial Environmental Systems @ AWI
Antarc*
Antarctic
Sea ice
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.923843
https://doi.org/10.1594/PANGAEA.923843
Description
Summary: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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