HETEROTROPHIC FLAGELLATES OF THE UZH RIVER, THEIR SEASONAL DYNAMICS, TAXONOMIC AND TROPHIC STRUCTURES

The article presents the results of the study of taxonomic and trophic structure, as well as features of seasonal dynamics of heterotrophic flagellates of the Uzh River (Korosten). In the investigated reservoir, 21 species of heterotrophic flagellates were identified, among which 7 species belong to the Excavata supergroup, 9 to the SAR (systematic group including Stramenopiles, Alveolata and Rhizaria) and 5 species of uncertain systematic position. According to the nutrition strategy, 76% of the species found are actively searching for food and 24% are catching or intercepting a food particle with flagella, absorbing it directly on the cell surface; the main trophic group are bacteriodetritophages-collectors, they amount 62%, at 14% are bacteriodetritophages-filterers and euryphages; and 10% (2 species) are predators – Allantion tachyploon and Phyllomitus apiculatus. Peaks of heterotrophic flagellates were recorded in June – 9 species and in October – 7 species, at the highest number in June – 5410 copies/ml and in April – 5062 copies/ml. The lowest species wealth was observed in January – 2 species, at the lowest number in January – 116 copies/ml and in December – 174 copies/ml. It has been established that eudominant species were absent in June and August due to the dominance of other flagellates. Most often, in January, February, May, July and December, this was Bodo designis. Goniomonas truncata and Spumella vivipara are slightly inferior. A. saltans, Rhynchomonas nasuta and Paraphysomonas vestita were eudominants in only one month. Almost the same trend persists among dominant species, most often B. designis and G. truncate. The predominant subdominants are represented by S. major, Heteromita minima and Protaspis gemmifera, moreover S. major, P. geminifera, P. apiculatus, A. tachyploon, Anthophysa vegetans and Protaspis simplex occur only in this flagellate group.