My research focuses on the biogeochemical cycling of dissolved organic matter (DOM) in temperate and boreal ecosystems. DOM gives natural waters a characteristic “tea stained” colour and provides important nutrients including carbon, nitrogen and phosphorous for the basic ecological functioning of lake ecosystems. DOM controls the light regime of lakes, plays an important role in contaminant transport and is an important energy source for bacteria, which lie at the base of the food web. The biogeochemical cycling of DOM through inland waters has been widely recognized for its contribution to the global carbon cycle. My research focuses primarily on ecological questions related to the biogeochemical cycling of DOM in freshwaters and soils, and secondly in relation to applied questions aimed at improving drinking water quality.