Specific features of Lake Ladoga ecosystem under the effect of anthropogenic eutrophication

Abstract

The evolution of Lake Ladoga ecosystem under the effect of a long period of critical anthropogenic phosphorus load is analyzed. It is shown that relatioships between organic matter accumulation and mineralization with considerable predominance of destruction over autochthonous production have formed in the lake by the moment when the input of P of anthropogenic origin dropped to the estimated admissible level. Studying the transformation of aquatic organic matter of tributaries in the water of Lake Ladoga suggest that a considerable portion of it, primarily, the conservative humic fraction, is now involved in turnover and serves as an additional source of C and P both for producer and destructor organisms. The processes taking place in Lake Ladoga suggest the allochthonous variant of ecosystem evolution.