Phytoplankton communities of St. Petersburg lake-river systems

The results of seasonal studies of the phytoplankton associations in three lake-river systems of Saint Petersburg territory subjected to different anthropogenic impacts are represented. Comparison with the data of the previous observations is carried out. Seasonal dynamics and long-term succession influenced by eutrophication have been traced. Is shown a change in the prevailing complexes and an increase in the quantity of algae, including of blue-green, during increase of biogenic load.