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Last Glacial Maximum to Holocene sea surface conditions at Umnak Plateau, Bering Sea, as inferred from diatom, alkenone, and stable isotope records
Paleoceanography (2010)
  • Beth Caissie, University of Massachusetts Amherst
  • Julie Brigham-Grette, University of Massachusetts Amherst
  • Kira T. Lawrence, Lafayette College
  • Timothy D. Herbert, Brown University
  • Mea S. Cook, Williams College
Abstract
The Bering Sea gateway between the Pacific and Arctic oceans impacts global climate when glacialinterglacial
shifts in shore line position and ice coverage change regional albedo. Previous work has shown that
during the last glacial termination and into the Holocene, sea level rises and sea ice coverage diminishes from
perennial to absent. Yet, existing work has not quantified sea ice duration or sea surface temperatures (SST)
during this transition. Here we combine diatom assemblages with the first alkenone record from the Bering Sea
to provide a semiquantitative record of sea ice duration, SST, and productivity change since the Last Glacial
Maximum (LGM). During the LGM, diatom assemblages indicate that sea ice covered the southeastern Bering
Sea perennially. At 15.1 cal ka B.P., the diatom assemblage shifts to one more characteristic of seasonal sea ice
and alkenones occur in the sediments in low concentrations. Deglaciation is characterized by laminated intervals
with highly productive and diverse diatom assemblages and inferred high coccolithophorid production. At 11.3
cal ka B.P. the diatom assemblage shifts from one dominated by sea ice species to one dominated by a warmer
water, North Pacific species. Simultaneously, the SST increases by 3C and the southeastern Bering Sea
becomes ice-free year-round. Productivity and temperature proxies are positively correlated with independently
dated records from elsewhere in the Bering Sea, the Sea of Okhotsk, and the North Pacific, indicating that
productivity and SST changes are coeval across the region.
Disciplines
Publication Date
March, 2010
DOI
10.1029/2008PA001671
Publisher Statement
Copyright 2010 by the American Geophysical Union
Citation Information
Beth Caissie, Julie Brigham-Grette, Kira T. Lawrence, Timothy D. Herbert, et al.. "Last Glacial Maximum to Holocene sea surface conditions at Umnak Plateau, Bering Sea, as inferred from diatom, alkenone, and stable isotope records" Paleoceanography Vol. 25 Iss. 1 (2010)
Available at: http://works.bepress.com/beth-caissie/2/