Role of the Bering Sea on the glacial strength of North Pacific Intermediate Water in the North Pacific
Abstract
Various kinds of geochemical and micropaleontological data were obtained from an 18-m long piston core (PC23A) collected from the northern slope area (60°09.52'N, 179°27.82'W, 1002 m deep) in the Bering Sea. The age of the upper part of core was determined by planktonic foraminifera AMS 14C dates and the presence of L. nipponica sakaii and absence of A. setosa constrained the age of lowermost of core to be younger than 70 kyr. Our paleoceanographic data demonstrate that the glacial period in the Bering Sea was clearly characterized by low production in the surface water and oxic bottom-water condition, maintaining relatively fast ventilation. In contrast, during the deglacial period, the Bering Sea shows high surface-water production and anoxic bottom-water condition, featuring the slow ventilation. Our results confirm that the Bering Sea played an important source region for North Pacific Intermediate Water (NPIW) during the glacial period. In addition, during stadials in the Bering Sea, strong intermediate water formation with weak Alaskan Current corresponds to strong cold California Current in the California margin of NE Pacific, resulting in the oxic bottom-water condition because of the full influence of NPIW when southward North Pacific Current in the warm NW Pacific was strong due to weakened subarctic gyre system. In contrast, during interstadials in the Bering Sea, weak intermediate water formation with strong Alaskan Current was associated with strong warm counter California Current in the NE Pacific margin due to weak cold California Current, resulting in anoxic or dysoxic bottom condition because of little influence of NPIW, when nouthward Subarctic Current in the cold NW Pacific was strong due to strengthened subarctic gyre system.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP43B1518K
- Keywords:
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- 4825 Geochemistry;
- 4900 PALEOCEANOGRAPHY (0473;
- 3344);
- 4901 Abrupt/rapid climate change (1605)