Algal development of the Cunovo Reservoir on the River Danube

Considering the structures in connection with the hydropower plant at Gabcikovo in Slovakia the change of ecosystem in the reservoir have been expected, Therefore the monitoring of the about mentioned area was started from 1994. Beside the chemical determinands the algal dynamics of the River Danube and the reservoir at Cunovo were investigated. The paper is focused on summarised results of the species diversity, abundance, biomass and the seasonal dynamics of the planktonic algae during 1994-1997. The upper part of the reservoir is very similar to the station in Bratislava. The lower part shows a slightly increased level of the algal abundance and biomass as was expected. Species composition of the reservoir is virtually identical with that of the Danube river in Bratislava. 329 taxa of planktonic algae have been observed during a four year period. Based on the species diversity, the diatoms dominance persisted during the whole monitored period, however their density decreased during summer when other taxa, first of all green algae, became more common.