BIODIVERSITY OF DIATOMS IN THE TEMERNIK RIVER

For the first time, the article provides information about the species diversity of epiphytic diatoms of the Temernik River (on the territory of the October Park, Rostov-on-Don). As a result of the study of three samples (October 2021 and April-May 2022), 50 species of diatoms from 28 genera were identified. The seasonal dynamics of the species diversity of the epiphytic community was heterogeneous: 46 species (from 25 genera) were identified in October, only 7 species from 5 genera in April, and 23 species from 13 genera in May. Significant seasonal differences in genera composition are noted. In autumn, the periphyton community was dominated by species from the genera Nitzschia, Rhoicosphenia, Bacillaria, Navicula. In spring, the genera Gomphonema, Synedra, Tabularia, Navicula dominated the community. Several planktonic species were also observed in the fouling: Chaetoceros muelleri, Entomoneis paludosa, Cyclotella atomus, Cyclotella meneghiniana, Cyclostephanos dubius. In addition to freshwater species typical of rivers, freshwaterbrackish, brackish and brackish-marine species were identified: Navicula salinarum, Pleurosigma elongatum, Pleurosira laevis, Surirella ovalis, Tabularia tabulata, Tryblionella littoralis var. tergestina, T. apiculate, T. hungarica. Hydrochemical analysis showed that the values of total water mineralization in the studied areas of the Temernik River (on average 2.4 g/l) approach the salinity of the waters of the eastern part of the Taganrog Bay (on average 2.75 ‰). Such habitat conditions create dangerous prerequisites for invasion into the freshwater biotope of brackish-water species that are not characteristic of rivers. The article discusses the probability of such invasions using the example of the Pleurosira laevis species (discovered in the Temernik River in October 2021). There is no definite answer about the penetration of P. laevis yet. Considering that the Temernik River is not navigable (even for small vessels and boats) and has not been stocked by fish, the most likely route of invasion is the option of air transport with birds. A large number of birds live in the October Park all year round. Some of these birds (for example gulls, cormorants, etc.) can carry microparticles (including diatoms) from the Don Delta and the Taganrog Bay on their plumage. This fact requires the close attention of researchers.

, diatoms, species diversity, Temernik, , invasions, invaders, transfer of microparticles