Eutrophication of Lake Tasaul, Romania-proposals for rehabilitation.

Abstract

Lake Tasaul on the Black Sea coast is highly eutrophic, but not strongly contaminated (heavy metals, PAHs, and organochlorine pesticides). Cyanophytes dominate phytoplankton by 67-94% and form frequent algal blooms. High primary production (up to 270 mg C(ass)/m(2).h) and algal biomass (maximum chlorophyll a concentration 417 microg/l) may be controlled by light, as Secchi depth is often below 1 m. The main tributary, Casimcea River, provides high quantities of suspended matter and about 3 tons TP/year and 660 tons TN/year. Based on chemical and biological analysis as well as fishery investigations, we provide recommendations for Lake Tasaul rehabilitation.