Productivity and dissolved oxygen controls on the Southern Ocean deep‐sea benthos during the Antarctic Cold Reversal

Joseph A. Stewart*, Tao Li, Peter T. Spooner, Andrea Burke, Tianyu Chen, Jenny Roberts, James W. B. Rae, Victoria Peck, Sev Kender, Qian Liu, Laura F. Robinson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)
6 Downloads (Pure)

Abstract

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 re-expansion 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 multi-faunal 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 (i) a northward migration of food supply (primary production) into the Subantarctic Zone and (ii) poorly oxygenated seawater at depth during this Antarctic cooling interval.
Original languageEnglish
Article numbere2021PA004288
Number of pages17
JournalPaleoceanography and Paleoclimatology
Volume36
Issue number10
DOIs
Publication statusPublished - 19 Oct 2021

Keywords

  • Coral
  • Foraminifera
  • Drake Passage
  • Deglacial

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