Response of Phytoplankton to Copper Treatment with Reference to Species Sensitivity

Responses of different planktonic algae species to copper treatment were tested using semi-continuous culture and compared with studies on copper-induced changes in species composition of phytoplankton samples. Blue-green algae exhibit lower EC₁₀₀-values than diatoms and Scenedesmus. The four tested strains of Microcystis aeruginosa showed different copper sensitivity. Four response types can be distinguished. 1. rapid biomass loss after copper application but subsequent growth recovery. 2. fluctuations of growth but no loss of biomass at sublethal concentrations 3. continuous recovery of growth rates after initially affected growth. 4. growth inhibition (dormancy) and recovery after inoculation into a copper-free medium. Species response to copper application within a phytoplankton sample agrees with pure culture behaviour.