Distribution of Heterotrophic Flagellates at the Littoral of Estuary of Chernaya River (Kandalaksha Bay, White Sea)

摘要

Species composition, distribution, and the character of structural changes in the heterotrophic flagellate community were studied along environmental gradients in the Chernaya River estuary. There were 99 species and forms of heterotrophic flagellates, subdivided into three groups: prevalently marine species and euryhaline species preferring biotopes either of higher or decreased salinity. The heterotrophic flagellate community of the estuary was continuously divided into two distinct variants: (1) cenosis of halophilic species, prevalently of sea forms and euryhaline species preferring biotopes of increased salinity; (2) cenosis of halophobic species with prevalence of euryhaline forms gravitating to fresh biotopes. The arbitrary and indistinct boundary between the variants of the community ran at a salinity of 9-10per thousand. The response of estuarine communities of heterotrophic flagellates and infusorians to variation of abiotic factors was similar and differed from response of communities of microphyte-, meiozoo- and macrozoobenthos; this implied similarity of the response mechanism to environmental factors in organisms of one level of organization.