ABSTRACT OPP 9615942 NADELHOFFER MARINE BIOLOGICAL LABORATORY This project is designed to characterize climatic and environmental controls on carbon inputs to tundra soils from belowground sources and on carbon balances in tundra soils. Specific objectives of this project include 1) quantifying root production and root-derived carbon fixation in wet sedge tundra, 2) assessing how global change influences both rates of carbon inputs from belowground sources to soils and the fate of these carbon inputs in arctic ecosystems, and 3) characterizing the fluxes of root-derived carbon across the soil-water-atmosphere interface under current and projected climatic conditions. The carbon-labeled experiments proposed here will permit measurements of plant carbon allocation to belowground production, fine root turnover, rates of carbon transfer from plants to soil and atmospheric pools, and rates of soil carbon turnover over timescales of days to years. Without such research on belowground carbon dynamics, it will be difficult to develop realistic predictions of arctic ecosystem responses to climate and environmental change.
