The experience of using the functional classification of phytoplankton to assess the water quality of some left-bank tributaries of the Volga river (basin of the Cheboksary reservoir)

On the example of two flat rivers of the Middle Volga basin, the results of using the approaches adopted in Europe (WDF) and in the Russian Federation to assess water quality and their probable relationship are shown. The use of the functional classification of phytoplankton revealed the predominance of algae in the plankton of the TB, D codons, often when accompanied in the summer by groups, indicators of water eutrophication (P, H1, W2, L0). A higher sensitivity of the community indexes Q and EQR as indicators of environmental status was demonstrated in comparison with the saprobiological analysis and the UKIZV index.