Sea-ice response to climate change in the Bering Sea during the Mid-Pleistocene Transition

Worne, Savannah; Stroynowski, Zuzia; Kender, Sev; Swann, George

Abstract

Sea-ice is believed to be an important control on climatic changes through the Mid-Pleistocene Transition (MPT; 0.6-1.2 Ma). However, the low resolution/short timescale of existing reconstructions prevents a full evaluation of these dynamics. Here, diatom assemblages from the Bering Sea are used to investigate sea-ice evolution on millennial timescales. We find that sea-ice was primarily controlled by ice-sheet/sea level fluctuations that modulated warm water flow into the Bering Sea. Facilitated by an amplified Walker circulation, sea-ice expansion began at ~1.05 Ma with a step-increase during the 900 kyr event. Maximal pack ice was simultaneous with glacial maxima, suggesting sea-ice was responding to, rather than modulating ice-sheet dynamics, as proposed by the sea-ice switch hypothesis. Significant pack ice, coupled with Bering Strait closure at 0.9 Ma, indicates that brine rejection played an integral role in the glacial expansion/deglacial collapse of intermediate waters during the MPT, regulating subarctic ocean-atmospheric exchanges of CO2.

Citation

Worne, S., Stroynowski, Z., Kender, S., & Swann, G. (2021). Sea-ice response to climate change in the Bering Sea during the Mid-Pleistocene Transition. Quaternary Science Reviews, 259, Article 106918. https://doi.org/10.1016/j.quascirev.2021.106918

• Journal Article Type: Article
• Acceptance Date: Mar 25, 2021
• Online Publication Date: Apr 7, 2021
• Publication Date: May 1, 2021
• Deposit Date: Apr 6, 2021
• Publicly Available Date: Apr 8, 2022
• Journal: Quaternary Science Reviews
• Print ISSN: 0277-3791
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 259
• Article Number: 106918
• DOI: https://doi.org/10.1016/j.quascirev.2021.106918
• Keywords: Archaeology; Archaeology; Global and Planetary Change; Geology; Ecology, Evolution, Behavior and Systematics
• Public URL: https://nottingham-repository.worktribe.com/output/5434078
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S0277379121001256