Zooplankton structure in heated lakes with differing thermal regimes and water retention

Abstract

The aim of the study was to determine the impact water retention time and increased water temperature had on the composition and abundance of zooplankton. Crustacea and Rotifera were examined from lakes Œlesinskie and Lichenskie, which are part of the water cooling system for the Konin and P¹tnow power plants. Lake Œlesinskie is included in the cooling system periodically (from May to September) when the long cooling cycle is in operation, and its waters are heated moderately (< 25C) with a water retention time of about two weeks. The zooplankton biomass in this basin in summer ranges from 1.5 to 4.0 mg dm -3 and was lower than that noted in May (< 25 mg dm -3 ) before the lake was included in the water