Biological quality of lakes
Assessment made on 01 May 2004
ClassificationWater (Primary theme)
Coasts and seas
- WEC 005
Policy issue: Is good surface water ecological status being achieved?
Many European lakes are heavily impacted by eutrophication, indicated by a high proportion of cyanobacteria in the phytoplankton communities. The situation is worst in densely populated countries.
Cyanobacteria are dominant in the phytoplankton community in many lakes, most conspicuously in Denmark where, until recently, many lakes have been polluted with phosphorus from sewage and industrial discharges. Norwegian lakes are less impacted by pollution, and the concentration of phytoplankton, in particular cyanobacteria, is lower. The French Lac Leman and Greek Lake Trihonida are dominated by taxa of phytoplankton other than cyanobacteria, contrary to the French reservoir Cheze / Jean Descottes with complete dominance by cyanobacteria during July and August. These 3 lakes cannot be considered representative for regions or countries.
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