High-resolution paleoceanography of the Gulf of Alaska, subarctic Northeast Pacific Ocean, since the last glacial maximum: Insights into a dynamic atmosphere-ocean-ecosystem linkage at decadal to millennial timescales
University of Alaska Fairbanks
Environmental conditions in the Subarctic Northeast Pacific Ocean are an important component of North American climate patterns, as well as a potential driver of Northern Hemisphere climate variability. The North Pacific Ocean is also the terminus of modern global thermohaline circulation, suggesting that paleoceanographic records from this region have the potential to preserve evidence of both climate forcing and response on regional and global scales. A suite of high-resolution marine sediment cores collected from the Gulf of Alaska margin in 2004 provide new paleoceanographic records at decadal and centennial timescales from fjord and continental slope environments. Key findings include: (i) decadal oscillations in marine productivity correlate with previously identified terrestrial records, indicative of forcing by the Aleutian Low pressure cell; (ii) the standard binary model of the modern Pacific Decadal Oscillation (PDO) as the major pattern of ocean-atmosphere variability is insufficient to describe the full range of Holocene paleoenvironmental fluctuations observed in Gulf of Alaska records of marine productivity, freshwater discharge, and bottom-water anoxia; (iii) the North Pacific ecosystem is a sensitive recorder of abrupt climate events observed in global records; and (iv) the fjords of Southeast Alaska contain a detailed record of volcanic activity and fallout events useful for developing composite chronological models of sedimentation that correlate with other regionally important stratigraphic records. Collectively, the results presented here will potentially redefine current theoretical models of atmosphere-ocean-ecosystem variability in the North Pacific Ocean, as well as contribute to a growing body of high-resolution paleoenvironmental time-series datasets from the high latitudes.
Minerals Data and Information Rescue in Alaska (MDIRA)