Composition of ciliate fauna and its seasonal changes in fluvial drift

Ciliate composition and its seasonal changes in seston depending on the discharge regime were analyzed in the lower rhithral area of the river Sava. Higher values for ciliate density, dry biomass, index of species diversity and concentration of particulate organic matter (POM) were associated with discharge peaks. Using the power model: y = ax^b ± c a significant positive correlation was found between POM and ciliate dry biomass (as dependent variables) and discharge (as independent variable). The ciliate drift constitutes 0.78% of the total annual POM transport. Depending on the discharge regime, the composition of ciliate drift reflects the temporal and structural changes in periphytic community.