Due to the increasing load of humic substances, the water colour of numerous lakes is rising

. Human activities in the catchment (peat mining, forestry) can have a strong effect on this brownification process. Brownification again strongly affects temperature stratification, light and oxygen circumstances and predator prey interactions in lakes. We have carried out numerous field studies and experimental studies on this subject area. The studies have shown, for instance, that brownification has differential effects on the prey capture rate and prey choice of different fish species and even on the different genders of the same fish species. Presently a large and long-lasting (2018-2027) project (funded by R. Erik and Bror Serlachius Foundation) studies the effects of increasing loading of humic substances on lake food webs and seeks for new measures for monitoring the effects of such loading. Financial support for the brownification studies has been granted also by the University of Helsinki and the Academy of Finland.