AbstractWe studied water chemistry and phytobenthos in streams of the Bohemian Forest (Šumava, Böhmerwald) in order to determine the influence of sewage originating from recreational usage on the diversity and structure of periphytic assemblages. Sites both above and below the outflow of sewage from touristically exploited villages and small recreational centres were compared. All together, we identified 113 species of algae and cyanobacteria in the samples, including very rare species such as Clastidium setigerum (Cyanobacteria). In some streams, waste discharge increased the concentration of nutrients to a marked degree. Species richness of phytobenthos was correlated neither to nutrient concentration nor to algal growth potential. However, an increase in chlorophyll-a, and a shift in the structure of phytobenthos assemblages were observed at sites below the source of pollution. At the most polluted sites Chlorophyta (e.g., Pseudodendoclonium basiliense, Chlorosarcina sp.) dominated, and Bacillariophyceae species sensitive to pollution were replaced by tolerant ones (Cymbella minuta, C. caespitosa, Diploneis oblongella and Nitzschia spp.).
Water Quality of Soil Leachate under Acid Rain and Its Effect on Algal Growth Potential.
