Diversity and distribution of dinoflagellates in water bodies of Ukraine (critical and systematic revision)
Authors:   M.G. Kholodny Institute of Botany NAS of Ukraine, 2 Tereschenkivska Str., Kyiv 01601, Ukraine, Bryantseva Yu.V. 
Published: June 2023

A critical and systematic revision of the superclass Dinoflagellata of the type Miozoa of Ukraine was performed, and the results of the generalization of retrospective and modern data on their zonal and ecological and typological distribution were given. As of 2022, 366 species (393 species and intraspecific) belonging to 3 classes, 14 orders, 45 families and 98 genera are indicated for the territorial waters of Ukraine. Over the past two decades, 108 new species have been discovered. 100 species are new to the Ukrainian sector of the Black Sea, and 8 are found for the first time in continental water bodies of Ukraine, one of which is new to science. Significant changes in the systematic composition of dinoflagellates in this period are due to both new findings and the appearance of new taxonomic combinations, which significantly expanded their generic spectrum. The most diverse orders remained: Peridiniales (118 species), which is a third of all species, Gymnodiniales (80 or 22%), and Gonyaulacales (60 or 16.4%). Among them, the most species-rich genera are Gymnodinium (41), Protoperidinium (41), Tripos (15) and Dinophysis (25) of the order Dinophysiales, the vast majority of which live in the Black Sea. A feature of the zonal distribution of dinoflagellate species on the territory of Ukraine is an increase in diversity in the southeastern direction, from the Ukrainian forest to the Black Sea. More than half of the species (54.4%) and the genera (56.6%) were noted only within one physical-geographic zone or sea. In particular, 174 (47%) species and 41 (41.8%) genera were found only in the seas. Since dinoflagellates are mainly marine algae, the greatest diversity and unique species composition is characteristic of the Black Sea, where almost 77% of all species and genera live. In desalinated Azov there were significantly less of them (21% of species and 25% of genera). In the Steppe zone of Ukraine, which has a wide range of water types, the highest diversity of dinoflagellates was observed among all terrestrial zones: 39.6% of species and 57% of genera known in Ukraine. According to ecological features, the flora of dinoflagellates was dominated by marine and breckish-marine forms (63.5%), were 2.5 times more than freshwater and breckish-reshwater forms (26.5%). A significant share was made up of species with a wide amplitude of adaptation (6.3%). Reservoirs with different degrees of myneralization, which include estuaries and myneralized reservoirs, as well as contact zones of fresh and sea waters (river mouths), had representatives of marine and brackish water complexes that are absent in other types of continental reservoirs. Estuaries ranked second after seas in terms of species richness (36.3% of species and 57% of genera) with a predominance of marine and brackish water species (58.5%). In general, 1.4 times fewer species were found in continental water bodies than in marine water areas. Lakes (22.4%) and ponds (21.6%) were in first place among continental bodies of water (with the exception of estuaries) in terms of species diversity, followed by rivers (16.4%) and swamps (15.8%), in which, of course, predominated freshwater species. There are 34 species that are widespread in Ukraine, 8 – are eurytopeans. T he composition of luminous species remained unchanged (36), and 25 are known as the causative agents of water "blooming", and 27 are toxic. Part of the species (63 or 17%) found mainly in the Black Sea are known from one reference, of which 40 species were identified more than 50 years ago, so their presence in the waters of Ukraine at the present time requires additional research. The taxonomic status of 8 species and one form has not yet been determined, so in the future the systematic composition of dinoflagellates of Ukraine will change thanks to the use of molecular phylogenetic methods.