Free-living ciliates in different coastal zone biotopes at the Azerbaijan sector of the Caspian Sea

Abstract

Samples of plankton, periphyton, benthos and phytocyliocenoses (coastal thickets of aquatic plants with associated ciliates) were collected during 2010–2017 from 7 collection points (from north to south) along the Azerbaijan sector of the Caspian Sea coastal zone. In total, 463 species of free-living ciliates were found. The highest number of ciliate species was noted in the Divichi firth (214) and on the Absheron coast (203). The species composition in Nabran (179 species) and on the coast of Lankaran (107) and Astara (110) was much lower. Minimal species diversity was observed in the Kyzyl-Agach Bay (96) and estuary of the Kura River (72). The similarity of the freeliving ciliate species composition of the seven stationary points along the Azerbaijan sector of the Caspian Sea depends on the similarity of environmental conditions at these collection points, as well as on a certain distance between them. Species diversity in different biotopes of each of the seven stationary collection points showed that, despite the strong differences in the total number of the ciliate species found therein, approximately the same ratio of species diversity in various biotopes is characteristic for all collection points. It was established that in plankton communities there are from 9% to 16% of the total number of ciliate species, in periphyton – from 10% to 25%, in benthos from 30% to 40%, and in phytocyliocenoses communities – from 33% to 44%. The obtained data indicate a general pattern of the distribution of ciliate species richness among different biotopes, even considering the presence of many ciliate species simultaneously in several habitats.