Modelling the effects of climate change on lake eutrophication

The effects of climate change on lake eutrophication were studied using a dynamic simulation model. The climate scenarios of the Finnish Research Programme on Climate Change (SILMU) were applied. As the model, a modified version of the Swedish PROBE was used. The description of water quality and growth of plankton was included in the model in Finland. There were three case study lakes: Lake Villikkalanjärvi in southern Finland and Lakes Kalliojärvi and Längelmävesi in central Finland. The model was successfully calibrated to all three lakes. According to the simulations the effects of climate change on the trophic status of the lakes will not be great. An increase in the spring peak of phytoplankton is expected, but the average biomasses will remain the same as at present. However, on the basis of the modelling results we can conclude that climate change may cause a risk for eutrophication in some lakes.