Large Lakes Dominate CO₂Evasion From Lakes in an Arctic Catchment

Abstract

Abstract CO 2 evasion from freshwater lakes is an important component of the carbon cycle. However, the relative contribution from different lake sizes may vary, since several parameters underlying CO 2 flux are size dependent. Here we estimated the annual lake CO 2 evasion from a catchment in northern Sweden encompassing about 30,000 differently sized lakes. We show that areal CO 2 fluxes decreased rapidly with lake size, but this was counteracted by the greater overall coverage of larger lakes. As a result, total efflux increased with lake size and the single largest lake in the catchment dominated the CO 2 evasion (53% of all CO 2 evaded). By contrast, the contribution from the smallest ponds (about 27,000) was minor (<6%). Our results emphasize the importance of accounting for both CO 2 flux rates and areal contribution of various sized lakes in assessments of CO 2 evasion at the landscape scale.