CARBON DIOXIDE AND METHANE FLUXES FROM THE OMBROTROPHIC PARTS OF A SUBARCTIC MIRE

Abstract

A field study is presented of carbon dioxide and methane fluxes to the atmosphere in relation to temperature and moisture for the ombrotrophic parts of the subarctic mire at Stordalen (Swedish IBP Tundra Biome study site). Measurements were made on six occasions over a season of 145 days, and a regression model explaining 69% of variation was obtained for carbon dioxide versus temperature and moisture. Using a mean moisture value for the season and temperature as a driving force in the regression model, a flux of 33.1 g C m2 yr-1 was calculated. This value included respiration by mosses in darkness, roots, soil fauna and microorganisms, which were estimated to account for 20, 10, 3 and 67% respectively. The temperature response showed the usual pattern: QlQ-values were found to increase with decreasing temperature. The Q10-values also increased with moisture content in the peat. The methane flux was found not to be correlated with temperature, but moisture could explain 30% of the variation. However, a methane flux of 0.6 g C m~2 yr-1 was estimated, which is 1.8% of the total carbon flux.