Inland Water Biology

During the study of waterlogged tundra soils of the Pleistocene Park Nature Reserve using light and scanning electron microscopy, 133 species of Bacillariophyta from 36 genera, 25 families, 14 orders and 3 classes were identified. Of these, 13 species are new to the flora of the Kolyma River basin, 10 are new to the flora of Russia, and 7 taxa are identified only to the genus. The most taxonomically rich genera are Gomphonema (25 species), Eunotia (16), Pinnularia (10), Encyonema (8), Cymbella (7), and Nitzschia (7). The species composition of the studied samples was more similar to that of aquatic ecosystems of the Kolyma River basin and nearby lakes (95 common taxa), which is apparently due to periodic flooding of the studied soils.

The data on the Rotifera fauna in the Sura basin lower course are summarized. The biology and occurrence of the rare and new for the Middle Volga Region and Russia rotifers of Families Lecanidae, Brachionidae, Colurellidae, Mytilinidae, Proalidae, Euchlanidae, Filiniidae and Notommatidae, found on the territory of State Nature Reserve “Prisursky” and its buffer zone, are described. The most of the species are rare on the total area. There are species, more common ore usually occurring in the South or North latitudes. The Cephalodella apocolea record is, probably, the first one on the territory of Russia.

The pelagic zooplankton of Lake Teletskoye and its vertical distribution at stations of various depths have been studied. The taxonomic composition includes 20 species: Rotifera (13), Copepoda (4) and Cladocera (3). The abundance in the column of water was significantly higher at shallower stations and varied from 93.2 to 19.7 thous. ind./m³ in different years of observation, while at the deepest station it did not exceed 1 thous. ind./m³. On species composition and density of zooplankton, the lake belongs to oligotrophic. The maximum density at stations with thermal stratification of the water column was recorded in the upper five-meter water layer (13-33 thous. ind./m³) with a gradual decrease to the deep layers by three orders of magnitude and probably partially consisting of dead animals from the overlying water layers.

The results of studies of the seasonal dynamics of macrozoobenthos, meiobenthos and planktonic communities throughout the polyhaline Chernavka River flowing through the territory of the Nature Park Eltonskiy are presented. Zoobenthos communities in all research seasons are characterized by consistently high abundance, biomass and production, the main contribution to which is made by ostracods Cyprideis torosa, and by halophilic polycyclic chironomids Cricotopus salinophilus and by biting midges Palpomyia schmidti. The average values of the production of macrozoobenthos during the research period of the Chernavka River (1.295 g C dry wt m² × day) were higher than the average daily production of this group of aquatic organisms in the coastal lagoons of the northern part of the Adriatic Sea, and the production of meiobenthos (0.13 mg C dry wt m² × day) was an order of magnitude or more higher than that known for freshwater lakes of all trophic types and close to the values characteristic of the tidal zone some seas and estuaries. The large amounts of zoobenthos production are due to the high water temperature from April to October and the high production of the primary trophic link. An increase in production indicators from the middle to the lower reaches of the river has been established, which determines a stable food base for native and migratory waterfowl.

The fauna, spatial distribution and ecological peculiarities of annelides in reservoirs and watercourses of the Upper Volga basin at Vladimir and Ryazan regions are investigated. The literature and own data from 1927 to 2023 are summarized. An assessment of annelides habitats has shown that predominate widespread species of Holarctic and cosmopolitans. According to the prevailing type of nutrition, these worms are mainly detritus and phytophagous, less often predatory. Ecological groups are mainly represented by benthos, less often by periphyton and amphibionts. The following species of oligochaetes are most common: Aeolosoma hemprichi Ehrenberg, 1828, Limnodrilus hoffmeisteri Claparede, 1862, Limnodrilus udekemianus Claparede, 1862, Tubifex tubifex (O.F. Müller, 1773), Tubifex newaensis (Michaelsen, 1902), Lumbriculus variegatus (O.F. Müller, 1773). The revealed species diversity of oligochaetes is significantly less than for the Volga River basin.

This study presents a new data on taxonomic and genetic diversity of freshwater mollusks of Bering Island. Twelve species of freshwater mollusks belonging to four genera and two families were identified. Detected mollusks are widespread in Holarctic and Palearctic. An analysis of 16S rRNA sequences of bivalve mollusks of genus Euglesa from Bering Island showed their similarity with the populations from the reservoirs of Eurasia and North America. Apparently, the settlement of freshwater bivalves of genus Euglesa to Bering Island originated from Eastern Europe or Siberia, or both of the proposed routes existed. The distribution of the Sphaerium nitidum probably occurred both across the Atlantic and through Beringia. An analysis of the sequences of the mtDNA COI gene fragment in gastropods indicates that the Galba pacifica species occurred from the Japanese archipelago, and the Radix auricularia from Northeast Asia.

The species composition and structure of the fish population and the taxonomic diversity of the ichthyofauna of lake Bolshoye Murakanskoye have been established for the first time, a description is given, and data on the biology and state of the fish populations living there are presented. The history of the formation of the lake's ichthyofauna is described, including an unsuccessful attempt to acclimatize peled in it. The belonging of fish to freshwater faunistic complexes and ecological groups is considered. Currently, 5 fish species are found in lake B. Murakanskoye, including such valuable ones as whitefish and vendace. It is noted that the reservoir is the only habitat of the common whitefish (Coregonus lavaretus L.) within the boundaries of the specially protected natural area. The living conditions of the lake's fish population are described – its thermal regime, water chemistry, oxygen supply. The history of fishing on the lake is given. B. Murakanskoe and an assessment of fish stocks in the reservoir at present is given. The calculation of the possible catch is made and recommendations on the fishing regime are proposed.

The fauna of the Oka Reserve includes 13 species of fish of alien origin. The most common are three species: the Amur sleeper Perccottus glenii Dybowski, the lake minnow Phoxinus percnurus Berg and the golden carp Carassius auratus (L.). The article presents an analysis of the current state of alien fish species in the reserve: their distribution in water bodies, their relationships with native species and the mutual influence of newcomers. A number of natural factors influencing the success of their introduction into various types of water bodies have been identified, including: the size of the lake, its flood level, the height of the spring flood, temperature conditions and the nature of precipitation, the level of groundwater, the level of the projection of macrophyte coverage of water bodies, etc.

The article presents data on the geographical distribution and ecological features of the hybridogenic species Pelophylax esculentus on the territory of the Mordovian Nature Reserve and Smolny National Park (Republic of Mordovia). According to the data obtained in 2021–2024, a wider distribution of the species was revealed, noted in 8 geographical locations of the Mordovian Reserve and 10 of the Smolny National Park. The factors influencing the spread of the hybridogenic species and the participation of cryptic forms of the parent species in the formation of three variants critical forms of edible frog are discussed.

The grass snake Natrix natrix (Linnaeus, 1758) is a semi-aquatic reptile species, most of which are encountered on the banks of water bodies. Widespread and numerous, N. natrix plays an important role in natural ecosystems, involving in the circulation of many helminth species. In this study, we conducted a comparative analysis of the helminth communities of the grass snakes from the semi-aquatic habitats in the National Park “Smolny” (Republic of Mordovia) and assessed the impact of environmental factors on the helminth fauna of the reptile in the protected area. The material for this study was the collection of parasitic worms from 219 N. natrix individuals in 2018–2021 in 16 localities of the National Park “Smolny”. The helminth communities of N. natrix include 17 species of parasites. Grass snakes from different habitats of the protected area differ in structure, composition of the helminth community and parasite abundance. Only three species out of 17 recorded are found in grass snakes in all 16 studied habitats. The structure and number of dominant and subdominant helminth species varies across the study sites. Reliable differences in the infection of snakes with helminths in different habitats of the National Park “Smolny” were revealed. A comparative analysis of the N. natrix parasite community showed a significant similarity of the reptile's helminth fauna in different habitats, which is due to similar biotic and abiotic conditions of aquatic and semi-aquatic biocenoses of the protected area. The helminth fauna of grass snakes from the vicinities of floodplain water bodies is most represented. A decrease in the species diversity and abundance of helminths is revealed in N. natrix from banks of small rivers and streams, as well as in ponds of populated areas. The formation of the helminth community of the grass snake depends on the diversity and number of vertebrates and invertebrates in the biocenosis, as well as on the abiotic component of the habitat of reptiles – the hydrological conditions of the water bodies.