The effects of copper and zinc on biomass and taxonomic composition of algal periphyton communities from the River Gharasou, Western Iran

Abstract

The effects of copper and zinc on biomass and taxonomic composition of algal periphyton communities from the River Gharasou, Western Iran Indoor artificial streams were used to evaluate the short-term (24 day) influence of copper and zinc, individually and in combination, on the biomass and taxonomic composition of algal periphyton communities. The effects of Cu (50 μg 1-1) and Zn (1 mg 1-1) were assessed using measurements of biomass, ash-free dry mass (AFDM), chlorophyll-a concentration, taxonomic composition and biovolume. In artificial streams with Cu, Zn and Cu+Zn, there were significant (p > 0.05) reductions of chlorophyll-a concentrations, dry mass and AFDM, and also changes in the species diversity and relative abundances of periphyton species. In artificial streams containing both Cu and Zn the taxonomic composition shifted from a Cyanophyceaen dominated community to one consisting mainly of Chlorophyceae, whilst the relative contribution of Bacillariophyceae was not significantly altered.