Providing rapid and targeted responses to how climatic extremities influence on communities is crucial not just from ecological, but even more from economic perspectives. Till now, however, only a limited number of studies and scientific papers dealt with such an important topic how these extremities regulate and change the composition of one of the most significant primary producers, benthic algae in watercourses. Benthic diatoms play a huge role not only as primary producers in the ecosystem but also as an environmental filter.