Volga River Basin Research Articles

Modelling fields of hydrological cycle characteristics in the Nizhnekamskoye Reservoir watershed of the Volga River basin under climate change

The assessment of trends in averaged over the watershed area hydroclimatic characteristics and changes in the fields of the hydrological cycle components in the XXI century in large river basin of the Nizhnekamskoye reservoir was carried out on the basis of a model approach combining regional space distributed hydrological model and GCMs. It is shown that a slight decrease by 8% is expected in the area-averaged specific runoff by the end of the century according to the RCP8.5 scenario. However, in various parts of the watershed both a slight increase by 3-6% and a significant decrease in the mean annual runoff by 22% can occur, depending on physiographic conditions. Moreover, climatic changes can increase contrasts in the ecological status of the territory: warm regions in the steppe zone become even hotter and more arid, and the moisture availability of wetter territories in the center and east of the basin increases even more.

Зообентос и зоопланктон малых рек бассейна реки Кобры (национальный парк «Койгородский»)

The studies were carried out on two small rivers – tributaries of the Kobra River (the Volga River basin), located on the territory of Koygorodsky National Park. The structure, quantitative development of zoobenthos and fauna of benthic invertebrates were studied. Hydrobiological sampling was carried out in June – July 2021. Standard methods were used for sampling. 87 species and taxa of a higher rank of invertebrates were found in the benthic fauna. The most diverse were caddisflies (21), mayflies (21), stoneflies (13) and oligochaetes (12 species). Quantitative development of the zoobenthos of the Kobra River basin is comparable to the average for the rivers of the Vyatka River basin as a whole and was 19 thous. ind./m2 and 74.6 g/m2 in the Suran River, and 14.1 thous. ind./m2 and 19.2 g/m2 in the Mytets River. The chironomids played a leading role in benthic invertebrate communities, and accounted for an average of 26.3–33.4% of the total zoobenthos abundance. Mayfly larvae and leeches dominated in the Suran River by biomass, as well as molluscs and caddisflies – in the Mytets River. The maximum quantitative characteristics were noted on the reaches of both rivers. The development of benthos was much poorer on the riffles. Three rare species from the orders of mayflies, stoneflies and dragonflies were identified. Zooplankton in the small tributaries of the Kobra River was studied using standard methods: in the Suran River on the early June and in the Mytets River – on the end of the July 2021. Plankton fauna was represented by 28 taxa, rotifers and copepods prevailed. Plankton species diversity, abundance and biomass were lower in the Suran River (the beginning of the vegetation season), which indicated the processes of zooplankton formation. The above indicators were higher in the middle of the summer season in the Mytets River, and indicated the stability of plankton communities. The presented data significantly expand the understanding of the biodiversity of aquatic ecosystems in the southern taiga zone.

Forecast modeling of the resource potential of forests in the volga river basin for the regulation of carbon cycle and mitigation of global warming

Forecast modeling of the resource potential of forests in the volga river basin for the regulation of carbon cycle and mitigation of global warming

ДИНАМИКА ЗАГРЯЗНЕНИЯ ПОВЕРХНОСТНЫХ ВОД РЕКИ ВОЛГИ ФЕНОЛОМ

Phenols are priority pollutants of the natural environment and enter water sources through wastewater treatment plants of industrial enterprises. They pose a certain threat to the human body, since many of them are highly toxic and belong to the first class of danger. Organochlorine derivatives of phenol exhibit particularly high toxicity; under conditions of water disinfection with chlorine-containing preparations, they can form polychlorinated dibenzo-n-dioxins, which are classified as super-ecotoxicants and have a negative effect on the genetic code of the human body. As a result of the studies, the surface waters of the Volga river basin of the Kuibyshev reservoir in the water area of the city of Kazan were analyzed for the content of phenol and its derivatives using gas-liquid chromatography. When analyzing phenols in the aquatic environment, it was established that the maximum permissible concentrations norms for ortho-, meta-, para- chlorophenols, which are characterized by high toxicity to the human body and wildlife, were exceeded. The dynamics of seasonal changes in the concentration of phenol and its derivatives in the surface waters of the Volga river has been established, which are associated with the intensification of redox processes in the summer, occurring under the influence of temperature factors involving dissolved oxygen.

Responses of zebra and quagga mussels to copper and tribytiltin exposure: Bioconcentration, metabolic and cardiac biomarkers

One of the top ecological priorities is to find sensitive indicators for pollution monitoring. This study focuses on the bioconcentration and responses (condition index, survival, oxygen consumption, heart rates, and oxidative stress and neurotoxic effect biomarkers) of mussels from the Volga River basin, Dreissena polymorpha and Dreissena bugensis, to long-term exposure to toxic chemicals such as tributyltin (TBT, 25 and 100 ng/L) and copper (Cu, 100 and 1000 μg/L). We found that TBT was present in the tissues of zebra and quagga mussels in comparable amounts, whereas the bioconcentration factor of Cu varied depending on its concentration in water. Differences in responses between the two species were revealed. When exposed to high Cu concentrations or a Cu-TBT mixture, quagga mussels had a lower survival rate and a longer heart rate recovery time than zebra mussels. TBT treatment caused neurotoxicity (decreased acetylcholinesterase activity) and oxidative stress (increased levels of thiobarbituric acid reactive substances) in both species. TBT and Cu levels in mussel tissues correlated positively with the condition index, but correlated with the level of acetylcholinesterase in the mussel gills. The principal component analysis revealed three main components: the first consists of linear combinations of 14 variables reflecting TBT water pollution, TBT and Cu levels in mussel tissues, and biochemical indicators; the second includes Cu water concentration, cardiac tolerance, and mussel size; and the third combines weight, metabolic rate, and heart rates. Quagga mussels are less tolerable to contaminants than zebra mussels, so they may be used as a sensitive indicator.

The genus Alchemilla (Rosaceae) in the Republic of Mordovia flora

In the flora of the republic, 41 Alchemilla species have been registered. Of the previously noted species, the presence of A. devestiens, A. glaucescens, and A. heptagona in the region is not confirmed by herbarium collections. The species A. atrifolia, previously listed for the republic but included in the most recent synopses only as a synonym of A. lindbergiana, is considered by us as a separate species. Previous works of co-authors have supplemented the Alchemilla list of the Mordovia flora with such species as Alchemilla argutiserrata, A. barbulata, A. cheirochlora, A. homoeophylla, A. kemlensis, A. longipes, A. mininzonii, A. psiloneura, A. pustynensis, A. schmakovii, A. sibirica, A. tichomirovii, A. vorotnikovii, and A. zimoenkensis. Here, two species are recorded for the first time for the republic – A. hians and A. prasina. The presence of A. litwinowii in Mordovia, which was previously noted exclusively on the basis of collections attributed subsequently to the newly described species A. tichomirovii, has also been confirmed. An original key, comprising all species of the genus registered in the middle part of the Volga River basin, has been compiled.

Ecological Monitoring of Pollution of Surface Waters of the Volga River Basin with Phenol and its Derivatives

The results of gas chromatographic control of the content of phenol and its derivatives in the surface waters of the Volga River basin are presented. The assessment of the water quality of the studied reservoir by categories of pollution at different times of the year was carried out. The results of environmental monitoring of the surface waters of the Volga River basin, taking into account the transformation of phenols into more toxic compounds, are discussed.

Species Composition of the Volgograd Reservoir Basin Rivers (the Yeruslan River)

The river network of the vast territory of the Lower Volga basin in the semidesert area of the Russian Plain belongs to the least studied tributaries of the River. Among the rivers of the left bank in this natural and climatic zone, the Yeruslan River is the most important one, which largely determines the ecological characteristics of the area. The article presents the data of long-term (2015–2017) studies of macrozoobenthos of the Yeruslan River (a tributary of the Volgograd Reservoir) are presented. For the first time the detailed composition of fauna including 148 species and taxa of higher systematic rank is given. The basis of the taxonomic composition of the river is formed by a complex of eurybiont species. The limnophilic taxa Limnodrilus hoffmeisteri, Polypedilum nubeculosum, Cladotanytarsus mancus and Paratanytarsus sp. have the highest frequency. These taxa are widely distributed in plain rivers of the Upper, Middle and Lower Volga basin. The vast majority of species recorded in the Yeruslan River are typically freshwater forms. In the observed water salinity gradient (0,235–1,42 g/l), the highest species richness of macrozoobenthos was observed in the range of 0,5–0,8 g/l. Under highly saline conditions (>1,2 g/l) there are mayflies Caenis robusta and Cloeon gr. dipterum, caddisflies Oecetis furva, dragonflies Ischnura elegans, mollusks Viviparus viviparus, ceratopogonids Sphaeromias pictus, oligochaetes Limnodrilus hoffmeisteri, Stylaria lacustris, Tubifex tubifex, chironomids Cladotanytarsus mancus, Cryptochironomus gr. defectus, Dicrotendipes nervosus, Glyptotendipes barbipes, Glyptotendipes glaucus, Polypedilum nubeculosum, Parachironomus varus, Paratanytarsus sp, Psectrocladius sordidellus, Tanytarsus pallidicornis, Tanytarsus sp. etc. These species should be classified as euryhaline taxa. The flat character of the Yeruslan River, characterized by low gradients of the river bed and low flow velocity, determines the development of limnophilic, lake-pond fauna of macrozoobenthos. Along with typical freshwater taxa, euryhaline groups of hydrobionts inhabiting areas where saline soils are drained by river waters are widespread. The contribution of rheophilic species to macrozoobenthos composition is negligible, which distinguishes bottom communities of the Yeruslan River from plain rivers of forest and forest-steppe natural-climatic zones of the Volga River basin.

Исследование многолетней изменчивости элементов водного баланса речного бассейна в современном климате

The assessment of changes in the elements of the water balance of the Volga River basin in the formation zone near Volgograd for the entire period of the twentieth century and at the beginning of the first half of the XXI century is considered. The conducted retrospective conjugate analysis of the EWB of the Volga River basin is based on the use of sufficiently long hydro meteorological arrays of initial observation data covering the period 1891/1892‑2020/2021. Two time series of annual and seasonal values of atmospheric precipitation, river runoff, total evaporation of land, changes in basin moisture reserves and changes in surface air temperature of the cold and warm periods and the year as a whole are organized. It was established that until 1935, in the long-term course of the runoff of the Volga River basin, natural factors were of decisive importance, i.e. the nature of the humidification of the territory, the regime of total evaporation from its surface and the change in moisture reserves in the soil-soils. Since 1935, the water content of the river has changed. Human economic activity began to have a significant impact on the Volga, especially the operating modes of the Volga-Kama cascade of waterworks. However, anthropogenic influences do not affect the formation of lateral tributaries, which are controlled by 11 reservoirs of the Volga-Kama cascade. Therefore, for a retrospective conjugate analysis of the EWB of the Volga River basin, two conditionally natural time series of different durations were used

Alien Algae Species Invasions in Humic Rivers within Weakly Human Impact Basin.

Increasing anthropogenic influence and climate change are leading to significant transformations in living conditions for indigenous representatives of aquatic communities. The problem of alien species invasions is actively discussed in the example of large rivers and water reservoirs, but medium and small rivers with weak anthropogenic influence have been insufficiently studied in this aspect. With the help of analysis of literary data and the results of our own long-term observations of phytoplankton using morphological and molecular genetic methods in some left-bank Volga tributaries, we identified six invasive species of different taxonomic groups of algae, with a predominance of diatoms. The relevance of using both traditional and modern approaches to identifying invasive algae species is revealed. Such invasive species as Thalassiosira incerta, T. faurii, Skeletonema subsalsum, Unruhdinium kevei, and Gonyostomum semen were part of planktonic communities; the benthic species Plagiotropis lepidoptera var. proboscidea sometimes reached a significant level of development (up 6 to 44% from total biomass) in plankton. It was demonstrated that some algae species have firmly taken the position of dominants and subdominants in planktonic algae communities. The expansion of alien representatives of microphytobenthos was noted in the Volga River basin for the first time. For Gonyostomum semen, its European origin was revealed, for plankton and benthic diatom-Ponto-Caspian. Our study showed that the processes of invasion and subsequent development of alien species take place in habitats with weak anthropogenic influence, which is likely determined by the hydrological, hydrochemical, and climatic changes in river basins and the high adaptive capabilities of invasive species.

Новые данные по радиоуглеродной хронологии неолитических комплексов Виловатовской стоянки

Introduction. The article presents some latest absolute dates for Neolithic pottery from the Vilovatoye site, the latter being characterized by a most impressive pottery collection from the Middle and Late Neolithic across the forest-steppe Volga River basin. Goals. The work shall introduce a series of radiocarbon dates for Neolithic patterns of the Vilovatoye site. To facilitate this, the paper shall describe the vessels that yielded such radiocarbon dates, analyze and interpret the absolute values, compare the latter to those of the Middle Volga culture. Materials and methods. In 2018–2019, shards from a total of fourteen Neolithic vessels excavated in the site of Vilovatoye were selected. Four of them were decorated with pricks of different shapes, one bore pricks combined with blackened lines, and nine vessels had comb stamps. Radiocarbon dating by liquid scintillation was conducted at the Radiocarbon Laboratory of Herzen University. Results. The pricked vessels of the Vilovatoye site dated from the third quarter of the 6th millennium BC to the second quarter of the 5th millennium BC. These results tend to well correlate with dates yielded by pricked pottery of the Middle Volga culture. The shards of the vessel decorated with pricks and blackened lines were dated to the first half of 5th millennium BC. The absolute dates for the comb-imprinted pottery cluster within a vast interval — from the last quarter of the 6th millennium BC to the third quarter of the 5th millennium BC. So, the latter dates also well correlate with available radiocarbon values for comb-ornamented pottery of both the Vilovatoye site and the Middle Volga culture. Conclusions. The newly obtained radiocarbon values shall significantly add to the set of dates for the Middle Volga culture. Those are evidence that the traditions of pricked and comb-stamped pottery somewhat co-existed — on the Vilovatoye site in particular, and within the Middle Volga culture at large.

Integral Assessment of Water Quality in the Volga River Basin According to Monitoring Data in the 21st Century

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.

Water Consumption and Water Discharge in the Volga River Basin and Their Impact on Water Quality

Water Consumption and Water Discharge in the Volga River Basin and Their Impact on Water Quality

Spatiotemporal Evaluation of the Flood Potential Index and Its Driving Factors across the Volga River Basin Based on Combined Satellite Gravity Observations

Floods have always threatened the survival and development of human beings. To reduce the adverse effects of floods, it is very important to understand the influencing factors of floods and their formation mechanisms. In our study, we integrated the Gravity Recovery and Climate Experiment and its Follow-On and Swarm solutions to estimate an uninterrupted 19-year flood potential index (FPI) time series, discussed the spatiotemporal distribution characteristics of the FPI and monitored major floods in the Volga River basin (VRB) from 2003 to 2021. Finally, we analyzed the relationship between the FPI and hydrometeorological factors to comprehend the flood formation mechanism. The results show that data fusion has reduced the uncertainty of terrestrial water storage change (TWSC), and the TWSC from the combined satellite gravity observations has a good consistency with that from the Global Land Data Assimilation System model (correlation coefficient = 0.92). During the study period, two major floods (June 2005 and May 2018) occurred in the VRB. The FPI has a significant seasonal change characteristic, and shows a high flood risk in spring and a low one in autumn. With regards to spatial distribution, the flood risk is increasing in the north (increasing rate = 0.1) and decreasing in the south (decreasing rate = 0.39). Snow water equivalent (SWE, correlation coefficient = 0.75) has a stronger correlation with the FPI than precipitation (PPT, correlation coefficient = 0.46), which is attributed to the recharge of SWE on water resources greater than that of PPT. The rising surface temperature (ST) speeds up snow melt, resulting in excessive groundwater and soil moisture, and the flood risk greatly increases at this time. The process lasts about three months. Therefore, except for PPT, ST is also a climatic factor leading to the floods in the VRB. Our study provides a reference for flood research in high-latitude regions.

Influence of contemporary warming on landscape-zonal systems of the East-European sub-continent: Predictive empirical-statistical modeling

Presented in the given article regional geo-ecological prognoses are based on the construction of discrete empirical-statistical models of zonal and regional ecosystems. The analysis was carried out on the examples of the flat territories of the Volga River basin, as well as the northern macro-slope of the Main Caucasian ridge. Regional landscape-ecological calculations and mapping were carried out according to the global climatic models GISS-1988 and E GISS-2007 belong­ing to the family of models of general atmospheric circulation. The strategy of geo-ecological prognosis was as follows: first to identify the selected ecosystem objects (either zonal type of plant formations and regional kinds of landscape) to certain values of contemporary climatic conditions and then to estimate the most probable transformation of the revealed ecological niches of the given objects according to the expected climatic changes for the given prognostic date. The geo-ecological analysis has been performed using mainly two types of empirical models: (a) informational, describing the geo-component interrelations, serving as a basis for the regional bank of their ecological niches that characterizes their parametric space; (b) “fuzzy” set-theoretical models, describing the polysystem units of landscape-zonal organization by operations with the ecological niches as descriptive vectors. Predictions of ecosystem transformations include two stages of analysis: (1) evaluation of the probabilities of changes in the functional states of ecosystems and (2) calculations of the rates of ecosystem transformations. Quantitative predictive analysis is carried out by means of operations with the hydro-thermal niches of zonal-regional ecosystems. The ecological estimates of forthcoming global warming refer first of all to the functional but not structural-morphological prediction. The most probable directions and degree of conversion of the ecosystem are estimated by the maximum values of transformation. The algorithms of predictive calculations are described in detail for both stages of analysis. The results of the zonal-regional prognostic analysis are presented in both graphic-analytical models and small-scale maps.

Pleistocene Glacial Refugia in the Don River Basin: Witness from the Endangered Depressed River Mussel

The depressed river mussel Pseudanodonta complanata (Rossmässler, 1835) is an endangered freshwater bivalve with sparse distribution across Europe. Despite its high conservation priority, available data on the current population genetics and biogeography of P. complanata are very limited. In this paper, we studied the genetic diversity and differentiation of P. complanata based on newly sequenced COI and ND1 gene fragments, and on available sequences from the NCBI GenBank. We discovered a localized and highly divergent lineage in the Don River basin and a widespread but low diversified lineage distributed from the Volga River basin to the Oise River in France. A star-like haplotype network, results of mismatch analysis, and significant negative values of neutrality tests reveal that the pan-European lineage went through a bottleneck event. The discovery of the separate lineage in the Don River basin is and additional evidence of the existence of Pleistocene glacial refugia in the south of the Russian Plain. Moreover, this finding confirms the significance of the Azov Sea drainage as a freshwater biodiversity hotspot of great conservation importance.

Биоаккумуляция тяжёлых металлов и других токсичных элементов в мышцах рыб бассейна р. Волги

The purpose of this work was to study the accumulation of heavy and toxic elements in the muscles of the main commercial fish of the Volga River basin. Sampling was carried out throughout the Volga River, in areas that are characterized by varying degrees of industrial development. In the course of the work, tissue samples of the main species of commercial fish were selected (about 300 samples in total). The analysis of the selected material was carried out by a set of methods: induction coupled plasma mass spectrometry, flamу atomic absorption spectroscopy and cold steam atomic absorption. Based on this analysis, the levels of accumulation of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr, Cd, Sb, I, Hg, Pb in the muscles of the main species of commercial fish were determined. Graphs of the distribution of the concentration of elements in the muscles of perch depending on the area of fishing are given: the maximum concentration of the sum of toxic elements in the muscles of perch is characteristic of the Rybinsk reservoir and the area of the village of TsaganAman, and the minimum – for the upper Volga and delta. The dependence of accumulation of As, Cd, Hg, Se, I and Br in the muscles of perch on the mass of fish has been assessed. It was found that the concentration of Hg and Se in the muscles of the perch is directly proportional to the weight of the fish.

Trematodes of Small Mammals (Erinaceomorpha, Soricomorpha, Rodentia and Chiroptera) in the Middle Volga Region (Russia)

In this study, we present our dataset containing up-to-date information about occurrences of trematodes in small mammals in the Middle Volga region (European Russia). The dataset summarizes micromammals’ trematode occurrences obtained by long-term field helminthological studies of soricomorphs, erinaceomorphs, bats and rodents during a period of more than 20 years (1999–2022). Our studies of trematodes in micromammals were conducted using the method of complete helminthological necropsy. The dataset includes 7470 records of trematode occurrences in micromammals with 4483 digenean records in Samara Oblast, 2986 records in Republic of Mordovia and one trematode record in Ulyanovsk Oblast. Our dataset presents the data on 43 trematode species from 21 genera and 9 families found in the region studied. The data on trematodes from 28 species of micromammals belonging to 14 genera are presented. In total, the number of collected trematode specimens in our dataset is 153,050. Each occurrence record contains the trematode species name, basis of record, locality of finding, host species, site in host, date and authors of the record and species identification. All occurrence records are georeferenced. The dataset is based on the research of the staff of the Institute of Ecology of the Volga River basin of RAS and the Joint Directorate of the Mordovia Nature Reserve and National Park “Smolny”. The distribution and diversity of trematodes of small mammals in the Middle Volga region has not been completely studied, and further investigation may reveal both new occurrences of trematodes and new host records.

ALIEN VIMBA BREAM VIMBA VIMBA (CYPRINIDAE) IN THE URAL RIVER BASIN

This paper provides information on the presence of the vimba bream ( Vimba vimba ) in the middle reaches of the Ural River. One of the distinguishing features of this species from the native Caspian vimba ( V. persa ) is a greater number of scales in the lateral line. In the late 1980s, the vimba bream was introduced from the Don River basin into the Volga River basin. Having successfully adapted in the Volgograd reservoir, the species subsequently settled in the unregulated section of the Lower Volga, in the northern and, apparently, middle parts of the Caspian Sea, and also formed a stable residential population in the Ural River basin.

Communities of trematodes in Ponto-Azov gravel snail Lithoglyphus naticoides (C. Pfeiffer, 1828) Gastropoda: Hydrobiidae) and their potential impact on the development of marginal host populations in the Volga River basin

Communities of trematodes in Ponto-Azov gravel snail Lithoglyphus naticoides (C. Pfeiffer, 1828) Gastropoda: Hydrobiidae) and their potential impact on the development of marginal host populations in the Volga River basin