Changes in structure of the phytoplankton in the Barje Reservoir, Serbia

The paper presents results of investigating phytoplankton of the Barje Reservoir during 1998/99 and in 2001. Changes in the qualitative and quantitative structure of phytoplankton are followed by comparing the obtained results with results of investigations conducted in 1996 (one year after formation of the reservoir). Initially (in 1996) an oligotrophic water body in which Bacillariophyta were dominant, this reservoir during 1998/99 exhibited traits of a mesoeutrophic lake and was characterized by the presence of a large biomass of phytoplankton (Bacillariophyta and Pyrrophyta), Investigations of the phytoplankton community repeated in 2001 showed decline in the abundance of phytoplankton, but further processes of eutrophication too, as reflected in the appearance of Cyanophyta.