Spatial variability of carbon emissions within a drained lake basin and its surrounding tundra, Illisarvik, Northwest Territories

This study investigates the spatial and temporal variations of carbon emissions and their controls at a 38-year-old drained lake basin located on Richards Island, NT. Greenhouse gas fluxes were collected from plots with different vegetation throughout the basin and in surrounding tundra during the growing season. Wet sedge sites were significant sources of methane (7 to 355 nmol m-2 s-1) while most other sites were sinks. Carbon dioxide fluxes varied from 0.5 to 13 mol m-2 s-1 with highest fluxes outside the basin. Air temperature was positively correlated with carbon dioxide emissions at the majority of sites while soil moisture and vegetation type was the main control on methane fluxes. Bulk age of the respired carbon dioxide was mostly modern, reflecting rapid cycling of recently sequestered carbon. Overall, the carbon emissions were similar to other tundra sites elsewhere.