Biological quality of lakes

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Assessment made on 01 May 2004

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Jan 12, 2004 - Demonstration indicator: biological quality of lakes

Generic metadata

Classification

Water (Primary theme)

Coasts and seas

DPSIR: State

Identification

Indicator codes

WEC 005

Geographical coverage:

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Contents

Policy issue: Is good surface water ecological status being achieved?

Key messages

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.

Figures

Cyanobacteria percentage of total phytoplankton biomass. Minimum, maximum, upper and lower quartiles by country and lake depth (S=shallow, D=deep)

Key assessment

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.