Structural investigations of periphytic protozoan communities in three layers of the Danube River

Abstract

During two periods of investigations, 122 species of periphytic protozoans were found, of which 45 species occurred in both years. At the beginning of colonization in 1979 sessile Peritricha species dominated the community and in 1980 two Suctoria species (Acineta tuberosa, Tokophrya lemnarum) were dominant. During the first eight days of colonization of substrata, species that consume bacteria and microalgae were dominant; on the 16th day carnivores and omnivores also occurred. No species were characteristics within individual depth strata of the Danube River. The community reached its maximum development on the 8th day at the sessile, and on the 16th day at the mobile portions of the community. The rate of colonization was far less on the surface substrata than on substrata at lower depths.