摘要：Variations in hydrolytic activity of six extracellular enzymes were measured in subsurface waters in eutrophic Lake Chełmżyńskie. The ranking of potential activity rates of the assayed enzymes was: lipase > aminopeptidase > phosphatase > α-D-glucosidase > chitinase > β-D-glucosidase. The selected extracellular enzymatic activities were all characterized by a distinct seasonal variability and depended on the location of the research site. In spring and in autumn, the waters of Lake Chełmżyńskie were more eutrophic than in summer. Significant differences in enzyme activity between different parts of the studied lake were demonstrated. In autumn, stations near the town of Chełmża (I–II) were more eutrophic than the stations far from the town; this was supported by the activity of aminopeptidase being higher in the urban area of the lake than in the zone away from town. On the other hand, in spring the activity of aminopeptidase near town (stations II–IV) was lower than far from town (stations VI, VII, X and XI). The enzyme chitinase exhibited higher activity far from town both in summer and autumn.
