Review article

The article discusses a special role of phosphorus in eutrophication of surface water. Due to the features of its natural cycle, phosphorus is one of the most inaccessible biogenic elements, therefore, eutrophication is primarily connected with the amount of available phosphorus. The authors present the method for estimating the phosphorus fluxes from bottom depositions into the water on the example of the conditions in the Neva Bay and the eastern part of the Gulf of Finland in the Baltic Sea.