Collaborative Research: Centennial-to-Millennial-Scale Climatic Fluctuations in Northeast Siberia during the Last Glacial Cycle

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Studies of Earth's history show that climate is capable of changing rapidly (within a few years or decades) and dramatically (from glacial to interglacial conditions). The response of the Earth's ecosystems to such global-scale changes can be spatially complex. Paleoclimatic fluctuations are evident during the last glacial cycle (~12,000 and 110,000 years ago) when temperatures were generally cooler than present and were interrupted by 24 warm events during which temperature ranged from 15-20 degrees C. Understanding the mechanisms and timing of such environmental change is particularly important for the Arctic, a region particularly sensitive to climate variability. Historically, data from the Greenland ice sheet has been the foundation for paleoclimatic reconstruction for the region. Still lacking, however, is an understanding of how northern ecosystems have responded to changes in climate.This research will address this knowledge gap by providing the first continuous, high-resolution, multi-proxy record of paleovegetational and paleoclimatic change from the Arctic for the period ~22,000 to 50,000 years ago. A sediment core from Elikchan Lake in northeast Siberia will be recovered and analyzed for pollen and diatom remains as well as sediment geochemistry with sufficient temporal control to be compared to climate trends found in ice cores. These new data will be used to define the number, magnitude, and timing of climatic fluctuations to assess the similarities and differences in the climate histories between the eastern (North Atlantic) and western (northeast Siberia) Arctic. Specifically, the research will: 1) evaluate computer simulations of past temperature in northern Asia as related to climatic and oceanic changes in the North Atlantic region; 2) explore the role of Siberia in transmitting climatic fluctuations originating in the North Atlantic to the North Pacific; and 3) examine the range of ecosystem responses to various climatic conditions and the potential importance of biofeedback to the climate system (e.g., whether changes in the distribution of boreal forests, a major methane source, can affect levels of methane in the atmosphere).