Peculiarities of the species composition and seasonal dynamics of ciliofauna in summer-autumn period in freshwater reservoirs of the lower current of the Taranay river (southern part of Sakhalin island)

Abstract

Background. Despite the wide distribution of many types of ciliates, ciliate communities in each regionare formed with their own characteristics, depending on the specific environmental conditions. Study of the freshwater ciliofauna of Sakhalin island before our research has not been conducted. For the first time, on the example of three small reservoirs and two watercourses, the features of the ciliate community of freshwater objects in the autumn in the southern part of Sakhalin island were investigated. The purpose of the work is to study seasonal changes in the species compositions of ciliate communities in small water bodies and in the flat part of watercourses in the southern part of the Sakhalin island. Materials and methods. The material was collected in 2020 by randomized sampling in small water bodies of the old type and in watercourses located in the lower reaches of the Taranay river (southern part of Sakhalin Island). Samples were taken into plastic non-specialized wide-mouth samplers with a volume of 500 ml by scooping up water together with a small layer of soil and dead macrophytes, as well as 100 ml by spilling 20 liters of water from the reservoir through the Apshtein plankton net. Results. During this periodin reservoirs and watercourses located in the lower reaches of the Taranay river we found 75 species of ciliatus, of which 5 species (Spathidium porculus, Tokophrya infusionum, Tokophrya lemnarum, Chilodontopsis depressa, Glaucoma macrostoma) were identified for the first time in freshwater bodies of the Russian Far East. Of the species discovered in autumn, only 53 were found in this area in the summer. 115 species of ciliates in the study area in total were found. The expected similarity of the species composition of the ciliofauna of water bodies in one study area was not confirmed; only 5 species were common to all objects. Almost all water bodies of the study area in autumn were α-mesosaprobic (polluted) water bodies. Conclusions. Seasonal fluctuations of environmental factors significantly affect changes in the ciliofauna in the studied water bodies, of the 115 species, only 53 were found in the area in summer and autumn. Even in one study areaciliate communities with their own specific features in each of the water bodiesare formed.

Keywords

• ciliofauna
• southern part of sakhalin island
• freshwater objects
• seasonal dynamics
• comparative analysis