My research focus on impacts of climate change on the biogeochemistry and ecology of high latitude aquatic ecosystems. The studies integrate abiotic (chemical and physical) and biotic factors and processes with special emphasis on distinguishing between direct (mainly temperature) and indirect (via changes in catchment export of matter) climate impacts and between short and long-term effects. Part of the research study the magnitude and control of greenhouse gas (carbon dioxide, methane) exchange and carbon burial in aquatic systems, and its quantitative importance in comparison with other carbon fluxes in the landscape. Another part of the research study the control of productivity and resources use in food webs, from the base of the food web (bacteria and algae), via intermediate consumers (zoobenthos, zooplankton) to top consumers (fish). The research includes mainly boreal-arctic lakes and streams/rivers and is based on comparative studies along climate and permafrost gradients and experimental studies where different environmental stressors are manipulated.