Sea-ice response to climate change in the Bering Sea during the Mid-Pleistocene Transition. (1st May 2021)

• Record Type: Journal Article
• Authors: Worne, Savannah; Stroynowski, Zuzia; Kender, Sev; Swann, George E.A.
• Is Part Of: Quaternary science reviews. Volume 259(2021)
• Publication Date: 2021-05-01
• Subjects: Sea-ice -- Bering Sea -- Mid-Pleistocene Transition -- Diatoms -- IODP Site U1343; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2021.106918
• Languages: English
• ISSNs: 0277-3791

Abstract

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 . Highlights: Sea-ice expansion began at ∼1.05 Ma, facilitated by amplified Walker Circulation. Significant pack ice increase occurs at 0.9 Ma, congruent with ice-sheet expansion. Sea-ice growth supports glacial Bering Sea intermediate water expansion after 0.9 Ma. Coincident sea-ice and glacial maxima suggests sea-ice responds to global climate.