Late Pleistocene stratigraphy and palaeoceanographic implications in northern Bering Sea slope sediments: evidence from the radiolarian species Cycladophora davisiana

A high-resolution abundance curve of the radiolarian species, Cycladophora davisiana, was obtained from a Late Pleistocene sediment core, PC-23A, which was obtained from the northern slope of the Bering Sea. The abundance pattern of this species was high during the glacial period and low during the Holocene. This general stratigraphic pattern was correlated with a previously reported pattern for the subarctic Pacific Ocean. However, planktonic foraminifera-based accelerator mass spectrometry C-14 dating revealed that a significant peak in the C davisiana curve during the glacial period correlates to 15.5 ka, which is younger than that previously estimated as being the Last Glacial Maximum. The higher abundance of this species implies that there was well-ventilated water with a large amount of organic matter in the intermediate-water layer. An unusually high propagation of C. davisiana during the earliest Holocene period, Bolling-Allerod (B-A) and Dansgaad-Oescheger interstadial event # 12, was most likely related to a significant increase in the amount of organic matter released into the intermediate-water depths by a brine pump system via ventilation. In addition, centennial-scale variations in the abundance of C. davisiana during the B-A period suggest that the intermediate-water ventilation was sensitively affected by brine rejection during sea ice formation as well as large-scale atmospheric circulations Such as the Arctic Oscillation. Copyright (C) 2009 John Wiley & Sons, Ltd.