engleski

Structure and development of periphytic ciliate community in a Danube floodplain lake

Periphyton is a complex community of autotrophic and heterotrophic organisms, detritus and mineral particles present on various substrata in aquatic environments. Studies on this type of communities are fundamental since they play an important ecological role inside the aquatic ecosystems. Ciliates, a remarkably successful group of microorganisms existing in almost all freshwater ecosystems, are important constituents of periphytic communities as one of the main consumers of bacteria, algae, other protozoans and detritus, thus participating in biomass transfer to higher trophic levels. Considering the lack of information on ciliated protozoans in a temperate floodplain periphyton, we studied the colonization and succession dynamics of these microorganisms on artificial substrata (glass slides) exposed in the Lake Sakadaš (Danubian floodplain) during 2010 in two experimental series, from spring until winter and from summer until winter. Floods, different in their extent and duration, strongly influenced the lake conditions during the study period, consequently affecting the composition and growth dynamics of the ciliate community. Colonization and succession of ciliates in periphyton occured throughout several phases, different in the structural and functional composition of ciliates and influenced by diverse environmental factors. The results showed that the periphyton formation and ciliate colonization are more rapid during the summer period than in spring, and ciliate community becomes stable earlier under the summer conditions. Ciliates reached rather high abundance and diversity in periphyton formed on artificial substrata in a floodplain lake, with sessile peritrich species as dominant. The trophic structure of periphytic ciliates was characterized by the bacterivorous and bacterivorous-algivorous filter-feeding species, important for carbon and energy transfer from planktonic to periphytic food web. This research contributed to a better knowing of taxonomic and functional diversity of periphytic ciliates and clarified their ecological role in riverine floodplain ecosystems.

Ciliophora, growth dynamics, artificial substrata, functional groups, hydrology

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