Productivity and Dissolved Oxygen Controls on the Southern Ocean Deep‐Sea Benthos During the Antarctic Cold Reversal

• Published in: Paleoceanography and Paleoclimatology
• Main Authors: Stewart, JA, Li, T, Spooner, PT, Burke, A, Chen, T, Roberts, J, Rae, JWB, Peck, V, Kender, S, Liu, Q, Robinson, LF
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) / Wiley 2021
• Subjects: Antarc*; Antarctic; Drake Passage; Sea ice; Southern Ocean
• Online Access: http://hdl.handle.net/10871/127568; https://doi.org/10.1029/2021pa004288

This is the final version. Available on open access from Wiley via the DOI in this record Data Availability Statement: Data sets for this research are available at https://pangaea.de/ https://doi.pangaea.de/10.1594/PANGAEA.924088, https://doi.pangaea.de/10.1594/PANGAEA.924091, and https://doi.pangaea.de/10.1594/PANGAEA.924097 The Antarctic Cold Reversal (ACR; 14.7 to 13 thousand years ago; ka) phase of the last deglaciation saw a pause in the rise of atmospheric CO2 and Antarctic temperature, that contrasted with warming in the North. A reexpansion of sea ice and a northward shift in the position of the westerly winds in the Southern Ocean are well-documented, but the response of deep-sea biota and the primary drivers of habitat viability remain unclear. Here, we present a new perspective on ecological changes in the deglacial Southern Ocean, including multifaunal benthic assemblage (foraminifera and cold-water corals) and coral geochemical data (Ba/Ca and δ11B) from the Drake Passage. Our records show that, during the ACR, peak abundances of thick-walled benthic foraminifera Uvigerina bifurcata and corals are observed at shallow depths in the sub-Antarctic (∼300 m), while coral populations at greater depths and further south diminished. Our ecological and geochemical data indicate that habitat shifts were dictated by (a) a northward migration of food supply (primary production) into the sub-Antarctic Zone and (b) poorly oxygenated seawater at depth during this Antarctic cooling interval. European Research Council (ERC)