9700830 Schlesinger This project, centered around the Free-Air Carbon dioxide Enrichment (FACE) experiment in the Duke Forest of central North Carolina, is designed to elucidate changes in soil carbon dynamics in response to an ecosystem-level atmospheric CO2 enrichment. In reaching this objective, the research proposed here is intended to address questions surrounding process-level understanding of soil function and its link with the atmosphere and groundwater. Fluxes of carbon into and out of the soil system, as well as transfers and storage within the soil profile, will be examined. Importantly, the study will capitalize on the use of stable carbon isotope (C-13) tracers that will be introduced into the atmosphere of the FACE plot with the CO2 enrichment. This isotope tracer will allow the examination of the rate of carbon incorporation into soil organic matter, the effect of soil acidity on weathering rates, and the potential of a long-term atmospheric carbon sink in soils and groundwater. This research is of particular interest and importance to global change scientists and policy-makers interested in the "missing sink", soil scientists examining carbon dynamics, and geochemists interested in the extent of biotic control over chemical weathering.
