Abstract:
Samples of epiphyton collected in 2016-2018 from the Dnieper River reservoirs were studied using scanning electron microscopy and revealed 15 new species for Ukrainian taxa of diatoms. A total of 133 species (138 intraspecific taxa) of Bacillariophyta in the phytoepiphyton of Kyiv, Kaniv, Kremenchuk, Kamianske, Zaporizhzhia, Kahovka reservoirs and in the Lower Dnieper were identified. They belong to 43 genera, 22 families, 13 orders, and 3 classes. Among them, 15 taxa are new records for Ukraine: 14 species and one variety from the genera Achnanthidium Kutzing, Amphora Ehrenberg, Cymbella Agardh, Encyonema Kutzing, Gomphonema Ehrenberg, Halamphora (P.T. Cleve) Levkov, Navicula Bory, and Nitzschia Hassall. Here we give their brief descriptions illustrated by original microphotographs, synonyms, ecological features, and sampling localities are presented as well. Most of the newly cited Ukraine epiphytic pennate diatoms found on higher aquatic plants are common freshwater taxa. They also include two freshwater-brackish species (Halamphora thermalis (Hustedt) Levkov and Navicula vekhovii Lange-Bertalot et Genkal). Navicula cf. vaneei Lange-Bertalot may occur in the moderately to high mineralized water; Halamphora cf. subholsatica (Krammer) Levkov inhabits mesohaline water bodies. Seven taxa from the genera Amphora, Aneumastus D.G Mann & Stickle, Cymbella, Gomphonema, Nitzschia, and Ulnaria Compere were identified to the genus. The largest number of new and interesting records of pennane Bacillariophyta were found in Kremenchuk and Kaniv reservoirs, and in the Lower Dnieper. New for Ukraine diatom species belong to the class Bacillariophyceae. The algae, identified only to the genus, belong to the classes Bacillariophyceae and Fragilariophyceae. It has been suggested that the centric small-cell planktonic forms of diatoms respond more quickly to increased salinity of the Dnieper water than the pennate forms occurring in epiphyton. This reaction is because the phytoepiphyton is a more inert algocenosis compared to phytoplankton.
