HOLOCENE CARBON ACCUMULATION AND HIGH-RESOLUTION DECOMPOSITION PROXY RECORDS FROM PEATLANDS OF WESTERN SIBERIA, RUSSIA

Peatland initiation and carbon (C) accumulation began throughout the Western Siberian Lowland (WSL) between 9 - 11k cal yr BP. Long-term apparent rates of C accumulation (LARCA) based on peat basal dates, depths, and densities from 75 cores averages 17.7 ±± S.E.), but varies from 4.6 - 104.9 g C m^-2 yr^-1, and shows little relationship with latitude or peatland type. To investigate C accumulation over the Holocene, size-fraction records sampled at 2-cm resolution were developed for five cores that span the peatland distribution of the WSL. Core chronologies based on multiple radiocarbon dates per core show diferent LARCA patterns between cores. The fine organic debris fraction of the peat (material <100m m), mainly the product of incomplete plant litter decomposition, typically fluctuated between 5 - 50% of total peat mass. Periods of low debris generally correspond to periods of high LARCA. Millennium-scale departures from an overall trend of increasing fine debris with depth were evident. Paleoecological core analyses to determine autogenic and local disturbance effects on C accumulation are ongoing, but some temporal synchrony in fine-fraction records suggests at least partial regional climatic control over decomposition-mediated carbon accumulation.