HR: 12:05h
AN: PP42B-08 [Abstracts]
TI: The High Latitude Glacial Ocean as Viewed Through the Sea of Okhotsk Window
AU: * Hays, J D
EM: jimhays@ldeo.columbial.edu
AF: Lamont Doherty Earth Obs.
of Columbia University, P O Box 100, Palisades, NY 10964, United States
AB:
The physical and biological properties of the Sea of Okhotsk's upper kilometer are probably more similar to
comparable depths of the high latitude glacial ocean than to any other modern sea other than the Arctic. Evidence
for this stems from the fact that in Holocene sediments of other modern seas the accumulation rates of shallow-
living far exceed those of deep-living radiolarians. In Sea of Okhotsk Holocene, and high latitude glacial
sediments of the North Pacific, Bering Sea and Antarctic, the accumulation rates of deep- may equal or surpass
shallow-living radiolarians, producing sea floor assemblages with greater than 20 percent of the deep-living { \it
C. davisiana}. Glacial sediments with such high { \it C. davisiana} percentages are ubiquitous in these seas as
well as the Atlantic at latitudes above 45 degrees. In the Sea of Okhotsk these unusual accumulation rates result
from low radiolarian concentrations in cold (-1 to 0 C) near-surface water between 20 and 200m, and higher
concentrations, including { \it C. davisiana}, in warmer (1 to 2 C) subsurface water between 200 and 1000m
(Nimmergut and Abelmann, 2002). This is evidence that water column properties similar to the modern Sea of
Okhotsk and the Arctic were widespread in high latitudes of the glacial ocean.
Cold winter air and the nonlinear behavior, at near freezing temperatures, of both heterotrophic metabolism and
seawater's coefficient of thermal expansion, produce these unusual physical and biological properties in the Sea
of Okhotsk today as they probably did in latitudes above 45 degrees in the glacial Atlantic, Pacific and Antarctic
Oceans. Such water column properties promote the spread of sea ice, reduce winter heat flux from ocean to
atmosphere and provide for the efficient transfer of carbon from the atmosphere to the deep-ocean. Strengthening
or weakening these water column properties, in response to changing winter air temperatures, probably
amplified glacial interglacial climate change.
DE: 4926 Glacial
DE: 4944 Micropaleontology (0459, 3030)
DE: 4999 General or miscellaneous
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting