Interaction between Phytoplankton and Epiphytic Algae in the Kaniv Water Reservoir (Ukraine)

The paper considers the patterns of interaction between algae relating to different ecological groups (phytoplankton and epiphytic algae) in the upper section of the Kaniv Water Reservoir (Ukraine). Phytoplankton and epiphytic algae have been shown to form the dynamic system, wherein phytoplankton makes an impact upon the epiphytic algal community structure, and, on the contrary, epiphytic algae in certain periods of the year can influence the phytoplankton structure. Several species were simultaneously present in both communities, and this was caused by: their habitat versatility, algae sedimentation from plankton to higher aquatic plant surface and transition of typically epiphytic species to plankton owing to hydrodynamic processes. The “phase opposition” was observed between phytoplankton and epiphytic algae: the maximal biomass of phytoplankton was recorded in summer, while that of epiphytic algae – in autumn. Such “phase opposition” is explained by different temperature optimums of dominant species and divisions in these communities, and also by shading of epiphytic algae by phytoplankton in case of intensive growth of the latter.