The Species Diversity Assessment of Azygia Looss, 1899 (Digenea: Azygiidae) from the Volga, Ob, and Artyomovka Rivers Basins (Russia), with Description of A. sibirica n. sp.

The Volga River has been the main Russian river for several centuries. The river, originating on the Valdai Hills, crosses several natural and climatic zones on its way to the Caspian Sea: from the southern taiga to the dry steppes of the Caspian Lowland. According to the latest data, 45% of industrial enterprises and 50% of agricultural production in Russia are concentrated in the river basin. The anthropogenic load on the river with its tributaries and their basins significantly exceeds the load on other large Russian rivers. The largest contaminated wastewater volumes fall on the share of Moscow, Samara, Nizhny Novgorod, Yaroslavl, Saratov, Ufa, Volgograd, Balakhna, Tolyatti, Ulyanovsk, Cherepovets, Naberezhnye Chelny and other large cities. All these negative processes occur against the background of ongoing climate change. The article analyzes the Roshydromet hydrochemical monitoring data of river waters in the Volga River basin for the 2000–2021 period by water bodies and federal subjects. Regardless of the year water content, almost 70% of hydrochemical monitoring stations in the Volga River basin correspond to the third quality class (“polluted”). An integral assessment of the water quality in the Volga River basin shows that the situation has not changed significantly since the end of the last century. To improve the ecological condition of the Volga River basin, it is necessary to implement a set of measures for the protection and reproduction of water resources in catchment areas, rationalize water use systems, and reduce the volume of freshwater intake. Reducing water consumption is a necessary condition for reducing the wastewater volume discharged and, consequently, the number of pollutants contained in it. One of the problems is that almost all types of water use harm the surface waters’ natural quality, including the Volga River basin.

Microplastics (MPs) in aquatic environments can be associated with various substances, including persistent organic pollutants, which add to the problem of plastic ecotoxicity. The abundance of 1-5 mm microplastics and concentrations of particle-adsorbed organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in sandy sediments from three beaches in recreational areas along the upper Ob River in Western Siberia were assessed. MP pollution levels in the Ob River beach sands ranged from 24 ± 20.7 to 104 ± 46.2 items m-2 or, in terms of mass concentration, from 0.26 ± 0.21 to 1.22 ± 0.39 mg m-2. The average abundance of MP particles reached 0.67 ± 0.58 items kg-1 or 8.22 ± 6.13 μg kg-1 in the studied sediments. MP concentrations were significantly higher in number (p < 0.05) and mass (p < 0.01) at the riverbank site downstream of the Novosibirsk wastewater treatment plant (WWTP) outfall compared to these at the upstream and more distant beaches. Most MPs (70-100%) were represented by irregularly shaped fragments. The polymer composition of MPs varied between sites, with a general predominance of polyethylene (PE). The study revealed associations of MPs with PCBs and OCPs not previously detected in the riverbed and beach sediments, suggesting that these substances are circulating in the Ob River basin. Although MP concentrations were higher downstream of the WWTP, the maximum levels of particle-associated OCPs were observed in the beach sands of the site farthest from the urban agglomeration. The pesticides γ-HCH, 4,4-DDT, and 4,4-DDE were detected on MPs at relatively low concentrations. PCBs were more abundant in the studied samples, including 118 dioxin-like congener. The results obtained indicate that the Ob River is susceptible to plastic and persistent organic pollutant (POP) contamination and serve as a starting point for further studies and practical solutions to the problem.

An analysis of observation data was conducted on the chemical composition of river and groundwater in the Ob River basin, covering more than 23 thousand samples taken from the network of governmental monitoring of surface and groundwater, the materials of scientific research, and engineering surveys. A model was developed for computing the total content of major ions along a stem of the Ob River. As a result, quantitative estimates of the total ion runoff and its underground component were obtained. Conclusions were drawn relating to: (1) uneven distribution of the ion flow over the Ob basin; (2) the predominant removal of dissolved solids from mountain regions and adjacent forest steppe and southern taiga areas and their accumulation in the middle taiga subzone with the maximum thickness of sedimentary cover of Mesozoic–Cenozoic deposits; (3) the influence of the main tributaries on the total dissolved solids (TDS) in the Ob River, limited to only a few kilometers downstream of their mouths (the rivers of Irtysh, Chumysh, and Severnaya Sosva as exceptions); (4) the maximum impact of groundwater on river water TDS in the forest steppe and southern taiga areas of the upper and middle Ob basin and minimum impact in the flat part of the lower reaches of the Ob in forest–tundra and tundra.

In the Tomsk region, the main fishing is concentrated on the Ob River and its large tributaries. At the same time, the region is rich in lakes — there are about 113 thousand of them with a total area of more than 4.5 thousand km². Of these, about 84 thousand reservoirs with a total area of about 2.9 thousand km² are lakes outside rivers floodplain — these are non-flood lakes. Mostly they are located in the taiga. They differ from each other in many parameters, including area, depth, ground, overgrowth of aquatic vegetation, and hydrochemical characteristics. Existing information about the fish of these lakes dates back to the mid-twentieth century and, against the backdrop of ongoing changes in the ichthyofauna of the region, seems outdated. During our research, we recorded 11 species of fish in non-flood lakes: northern pike Esox lucius, freshwater bream Abramis brama, common dace Leuciscus leuciscus, lake minnow Rhynchocypris percnurus, roach Rutilus rutilus, prussian carp Carassius gibelio, crucian carp C. carassius, tench Tinca tinca, ruffe Gymnocephalus cernua, european perch Perca fluviatilis, and chinese sleeper Perccottus glenii. Thus, over the past 60 years, changes have occurred in the ichthyofauna of non-flood lakes of the Tomsk region: there are alien fish species (naturalized in the Ob river basin) appeared — freshwater bream and chinese sleeper. Probably, in the near future we should also expect registrations of the belica Leucaspius delineatus and the Nikolsky loach Misgurnus nikolskyi, currently found in the Ob floodplain of the region. In addition, we did not observe ide Leuciscus idus in non-flood lakes; roach and common dace, which were relatively widespread in taiga lakes in the mid-20th century, were rarely encountered. Perhaps the decrease occurrence of these species is associated with climate change — the trend of increasing average temperatures which can cause a deterioration in the gas regime of water bodies.

The discharge of major cations and dissolved organic carbon (Corg) with water of the Ob River and its tributaries along the natural zones within the Ob River basin was calculated, and the contribution of the underground component to the volumes of total discharge of the Ob River basin was estimated. It was demonstrated that the total chemical composition of river water and the geochemical discharge in the Ob River basin were consistent with the zoned hydroclimatic conditions controlling the character and duration of interaction in the water–rock system. It was established that the average ionic discharge of the Ob River increased from 6–7 × 106 t/year near Barnaul to 46–47 × 106 t/year near Salekhard; the discharge of dissolved Corg increased from 0.1 × 106 to 3.8 × 106 t/year. Multiple enrichment of underground waters of the Ob River in dissolved organic matter from the upper to the lower reaches was revealed.

Opisthorchis felineus is a food-borne trematode which causes opisthorchiosis and affects mainly the liver and bile ducts of the liver with a possible risk of bile duct carcinogenesis resulting in cholangiocarcinoma. In Russia, O. felineus is mainly endemic in Western Siberia (Ob and Irtysh river basins) and occurs throughout the Volga, Kama, Don, and Dnepr river basins. The prevalence, intensity, and clinical significance of human infections and the incidence of cholangiocarcinoma vary geographically in endemic regions. Currently, there is substantial evidence on genetic variation of O. felineus, but information on the population genetic structure is so far very scarce. Because microsatellite DNA of this parasite is not available, we for the first time isolated sufficient microsatellite loci to examine the genetic diversity and population structure of O. felineus, using multiple nuclear loci approach. A total of ten highly polymorphic microsatellite loci from a constructed enriched genomic DNA library were characterized, using 29 samples representing huge O. felineus metapopulation extended in latitude over 5000km from Middle Europe to Western Siberia. At least three populations can be discerned as result of analysis of the microsatellite loci genetic diversity. Based on the results for the first time, a hypothesis was put forward about the formation of a modern habitat of O. felineus.

In 1992, we discovered populations of the nonindigenous quagga mussel Dreissena rostriformis bugensis in the middle reaches of the Volga River. The same species was found in samples collected between 1994 and 1997 in the Volga delta and in shallow areas of the Northern Caspian Sea. D. r. bugensis always co-occurred with its more widespread congener, the zebra mussel D. polymorpha (Pallas 1771). The quagga mussel's contribution to total Dreissena abundance increased over time in the middle Volga reservoirs and Volga River delta. D. r. bugensis was common in the Volga portion of Rybinsk Reservoir during 1997 and, by 2000, it was in Uglich, Rybinsk and Gorky Reservoirs on the Upper Volga River. D. r. bugensis was neither found in Ivankov Reservoir, nor in terminal sections of the Volga-Baltic corridor including the eastern Gulf of Finland. Presently, all but the northern-most regions of the Volga River have been colonized by D. r. bugensis. We hypothesize that its introduction into the Volga River and Caspian basin occurred no later than the late 1980s via commercial shipping that utilized the Volga-Don waterway to navigate between the source Black-Azov Sea region and recipient areas on the Volga River. Larval drift likely contributed to establishment of populations at downstream sites, while human-mediated vectors may be responsible for introductions to upstream locations on the Volga River. We anticipate continued northward dispersal in conjunction with shipping activities.

The aim of this paper is to provide comprehensive analysis of channel changes (horizontal and vertical movements of channel boundaries due to water flow and sediment transport interactions) in rivers across Russia. Evidences from channel transformations indicate that largest Russian rivers (Volga, Oka, Amur) are sensitive to mostly human impacts (reservoir construction, in-channel quarries, land disturbance and bank fortification). Channel changes in the Severnaya Dvina, Lena, Pechora and Ob Rivers over the past 100 years have been driven mainly by natural factors at the river scale, whereas some reaches were influenced by human interventions (including single reservoirs). Reservoir construction is probably the most extended influence on morphodynamics of the largest rivers of Russia, but the influence of other controls resulting in channel boundary movement and channel pattern changes could also be detected.

To date, the largest Russian rivers discharging to the Arctic Ocean remain a “blank spot” on the world map of data on the distribution of microplastics in freshwater systems. This study characterizes the abundance and morphology of microplastics in surface water of the Ob River and its large tributary, the Tom River, in western Siberia. The average number of particles for the two rivers ranged from 44.2 to 51.2 items per m3 or from 79.4 to 87.5 μg per m3 in the Tom River and in the Ob River, respectively. Of the recovered microplastics, 93.5% were less than 1 mm in their largest dimension, the largest group (45.5% of total counts) consisted of particles with sizes range 0.30–1.00 mm. Generally, microfragments of irregular shape were the most abundant among the Ob and Tom samples (47.4%) and exceeded microfibers (22.1%), microfilms (20.8%), and microspheres (9.74%) by average counts. Results from this study provide a baseline for understanding the scale of the transport of microplastics by the Ob River system into the Arctic Ocean and add to currently available data on microplastics abundance and diversity in freshwater systems of differing global geographic locations.

Regional patterns in recent trends in sediment yields of Eurasian and Siberian rivers

In this paper, the author analyzed the film The Road from the River Ob’ directed by Zinaida Longortova from the Yamal, who won the grand prize in the competition of regional cinema at the Cheboksar International Film Festival in 2019, the film Lord-Bird directed by Eduard Novikov from the Sakha Republic, who won the grand prize at the Moscow International Film Festival in 2018, film the Baigal directed by Ildar Yakaparov from the Republic of Tatarstan, and the First Republic directed by Bulat Yusupov from the Republic of Bashkorstan and tried to uncover some of the distinctive features of Russian regional cinema.<BR> What the film Lord-Bird wanted to say was the relationship between nature and civilization. This work shows the life of a minority ethnic group living as a Russian citizen while maintaining their own identity. In the Russian minority, Orthodox and folk beliefs do not exclude each other, but coexist.<BR> The film Vigal goes back and forth 30 years ago and now in time. In the film, two worlds, the real world and the mythical world, intersect. The large fish called Vigal lives in the Volga River. In other words, this film seeks to secure the regionality and identity of Tatarstan with the existence of the Tatarstan myth called Vigal and the geographical background of the Volga River, and acquire universality under the theme of parents and children and art.<BR> The First Republic can be seen as a kind of tribute to the Republic of Bashkorstan and as a tribute to those who devoted themselves to the birth of the Republic.<BR> The film The Road from the River Ob’ is a feature film in the Yamal region, a minority region in Russia that is rarely produced. The screening itself deserves a record as an example of expanding the horizons of Russian regional cinema in Russian cinema history.<BR> The characteristic of Russian regional cinema is to express the cultural and historical identity of the region. And Russia

The possibility of use of the previously developed calculation technique of the North Rivers flow hydraulic records for the Ob River, the largest river in Russia by basin area, flowing under severe conditions in West Siberia was examined. The calculation technique is based on the model of heat and moisture exchange of the geological substrate with the Earth’s atmosphere, the Soil-Water–Atmosphere–Plants (SWAP) model, in conjunction with information support based on global databases of geological-substrate parameters and information obtained from observational data collected by weather stations within the Ob River basin. Uncertainty of the Ob River flow was assessed. Additionally, the ability of the SWAP model to reproduce multiyear dynamics from average values of snow reserves in the Ob-Irtysh basin was examined.

Summary Two alternative hypotheses about aquarium vs fish-farm vectors of non-native distribution of the fish rotan, Perccottus glenii (Odontobutidae), within the Volga River Basin were assessed using a parasitological approach. Three separate locations were studied where rotan populations were assumed to have different introduction histories: (i) vicinities of Tarakanovo pond, Moscow province (aquarium release in 1950), (ii) Ilev fish farm, Nizhniy Novgorod province (unintentional transportation together with stocking of commercial fish in 1970), (iii) the lower Volga River, Saratov province (unknown origin; first record in 1983). The odontobutidspecific tapeworm Nippotaenia mogurndae was the most informative species because it has a complex life cycle and therefore does not persist in aquarium conditions. Absence of this tapeworm in the rotan populations in the first locality and presence in the second location are in agreement with the available information about appropriate vectors of introduction. Populations of rotan in the lower Volga (third locality) where N. mogurndae occurs could originate from individuals unintentionally transported to fish farms together with commercial fish species or have mixed origins. Thus, the presented parasitological data are in agreement with information concerning introduction vectors of P. glenii and confirm that the specific parasite N. mogurndae is a valuable biological tag for analysing vectors and pathways of geographical dispersal of rotan, P. glenii.

On the basis of the materials obtained from the studies carried out from 2000 to 2015, we present the data on distribution of the Yellow Wagtail forms in the north of Western Siberia, i.e. within the overlapping boundaries of the ranges of a complex set of several polytypical forms – Motacilla flava sensu lato. Four forms have been identified here: two forms from the group of Western Yellow Wagtails (M. f. thunbergi and M. f. beema &amp; flava) and two forms from the group of Eastern Yellow Wagtails (M. t. plexa and M. t. tschutschensis). Western “black-headed” form M. f. thunbergi is spread in the area of the northern taiga, forest tundra and south shrub tundra within the Ob River basin, while eastern “black-headed” form M. t. plexa is found in the shrubby tundra and further to the east from the Ob River in forest tundra and northern taiga. Western “light headed” wagtails M. f. beema &amp; flava spread as far as 65º05'N along the floodplain of the Ob River. Eastern “light-headed” wagtail M. t. tschutschensis penetrates the Taz peninsula and, through the anthropogenic sites, the north-east coast of the Yamal Peninsula, i.e. the Sabetta area as far as 71º14'N. The entire range of the Yellow Wagtail is characterized by the interchange of zones inhabited by “black-headed” (without the expressed eyebrows on males) and “light-headed” (with notable eyebrows on males or white-headed) forms from the north to the south.

Data on new findings of the Nikolsky loach Misgurnus nikolskyi in the south of Western Siberia are presented. The maximum distance from the place of the first detection is about 200 km downstream of the Ob River. It has been suggested that the main method of dispersal of the Misgurnus nikolskyi in this region is deliberate introduction. It has been shown that the mtDNA haplotypes of the cyt b locus of the Misgurnus nikolskyi from the Ob River basin are identical to those described from the Lower Amur River basin.