Qualitative and quantitative studies on phytoplankton and chlorophyll content in the pelagic water of Lake Żarnowieckie in 1974

Abstract

Species composition of phytoplankton, its biomass, share of nannoplankton, and concentration of chlorophyll and pheophytin in phytoplankton and nannoplankton were assessed basing on the materials collected from two pelagic stations of Lakę Żarnowieckie during the period 30 March - 6 December 1974. Average and maximal values of phytoplankton biomass (4-5 and 10-11 mg/1 respectively), as well as the concentration of chlorophyll (1.7 -10.0 μg/l together with pheophytin) point to slightly advanced eutrophication of the lake. Share of nannoplankton in total phytoplankton biomass was very low (as a rule below 3%) with an increase to 15% only in spring. Relatively slight taxonomic differentiation of phytoplankton (164 taxons), its qualitative composition with the predominance of Cyanophyceae in summer, and of Bacillariophyceae in spring and autumn, as also seasonal succession of algae, point to eutrophic character of the lake.