EN
The following phytoplankton characteristics and parameters were studied for different ecological types of river reaches: biomass (PB, mg l-1); abundance (PA, 106 cells l-1); number of taxa per quantitative sample (PT); Nygaard's phytoplankton compound quotient (PCQ); phytoplankton dominants (PD). The quantitative characteristics of phytoplankton (species richness, abundance, biomass and PCQ) revealed an increasing trend from small to large upstream catchment areas, but did not respond to different river bedrock or flow velocity. Additionally, PCQ was the highest for the class of 'good' water quality. The phytoplankton dominants were not suitable for typology in the case of small streams where species composition was heterogeneous, without a well-developed phytoplankton community.