Factors triggering the occurence and excessive development of Mougeotia spp. in large lakes

During the last decades the filamentous green alga, Mougeotia spp. has been giving important contributions to the phytoplankton of some large peri-alpine lakes (Lake Geneva, Lake Garda, Lake Maggiore) and also in subtropical Lake Kinneret. Excessive Mougeotia blooms have been observed in these lakes but with different frequencies and intensities. While Lake Maggiore and Lake Kinneret were affected only a few years, Lake Geneva and Lake Garda displayed regular blooms. Besides the ecological consequences, these blooms cause practical problems in professional fishing. Mougeotia spp. has many features making it a good competitor; low sinking velocity, resistance to grazing, effective phosphorus uptake. In this study we focus on bottom-up environmental factors related to human activities, lake restoration processes or to global climate change that may trigger changes favouring development of Mougeotia spp.