Soil-atmosphere carbon dioxide, methane, and nitrous oxide fluxes across time and space in a forested watershed.

摘要

Forest soils are sources and sinks of greenhouse gases (GHGs) across time and space, potentially offsetting the forest carbon (C) sink due to biomass C accumulation. Ground-based measurements of GHG (CO2,CH 4, N2O) flux at sites representing the hydrogeomorphic attributes found in northern temperate forests were related to overall indicators of watershed conditions across each season and throughout several 24 hour periods in a forested watershed in the Adirondack Mountains of New York, U.S. Diurnal GHG fluxes did not exhibit any clear patterns. Large CO2 fluxes are associated with 90% of the watershed soils, mainly the hillslopes, and CO2 fluxes exhibited significant positive correlations with soil temperature. Wetlands were hot spots for CH4 emissions during the summer/autumn seasons, whereas the rest of the landscape was often a CH 4 sink. N2O fluxes were low in magnitude, but soils acted as both sinks and sources of N2O across the watershed.