Assessment of the running water quality by comparing ciliate and macroinvertebrate community structure

Comparative analysis of both ciliated protozoa and macroinvertebrates present in six stations along the Mincio river (northern Italy) has been carried out. Samples were collected monthly during one year. The purpose was to compare the response of these communities in indicating the quality of the water along the water course characterized by strong variations in both organic load and hydrodynamic and geomorphological characteristics. Some differences in the judgements on the biological quality at the six sampling stations were observed between the two methods. Ciliates showed higher sensitivity to changes in the organic load, while macroinvertebrates showed higher sensitivity to changes in the hydro-morphologic structure along the fluvial system; this emphasizes the use of both communities in evaluating the biological quality in rivers.