As a result of the research conducted on the territory and in the area of influence of the facility “Construction of the second, third, and fourth launch complexes of the Volga River bridge in Volgograd,” it was found that 7 species of rare insects live within the boundaries of the permanent and temporary allotment zone: Lucanus cervus L. (deer beetle), Calosoma sycophanta L. (red-smelling jelly), Anax imperator Leach. (the emperor's watchman), Protaetia speciosissima Scopoli (smooth bronze), Catocala fraxini L. (blue ribbon of the Order), Catocala sponsa L. (crimson ribbon of the Order), and Driopa Mnemosyne L. (mnemosyne). Information about the areas of the territory where the considered rare insect species had not previously been recorded is systematized, information about confirmed and identified habitats is obtained, and ecological and biological features of the development and distribution of rare arthropod species within the specially protected natural territory of federal significance – the Volga-Akhtuba Floodplain Nature Park – are revealed. A program of industrial environmental control over the nature of changes in all components of the ecosystem during the construction and operation of a linear feature has been developed, and a set of appropriate measures and technical solutions has been proposed.

An effect of modes of flow discharge of the Nizhny Novgorod hydroelectric complex on the water level in the Volga River according to the data of the Gorodets hydraulic station is analyzed in the paper. The dependences of the water level on both the stationary H(Qstac) and the average H(Qsr) values of the daily flow rate are obtained. The results of the study showed that daily variations of the water level in the vicinity of the hydroelectric complex for the period from May 18 to May 25, 2022 correspond to changes in the stationary discharge flow Qstac. And the dynamics of the daily discharge of Qdin does not affect the water level in the flow range studied. At the same time, taking into account the daily dynamic consumption of Qdin within the average daily volume of Qsr leads to an overestimation of its calculated values. The previous study [1] showed that the source of this deviation is an effect of the hydrodynamics of the discharge stream being determined by the morphology of the bottom in the energy section of the lower reaches of the Nizhny Novgorod hydroelectric complex. Field measurements of the spatial parameters of the wave field revealed the presence of two orthogonally oriented streams in the water area [2]. Each of them serves as a generator of a wave system consisting of several harmonics. And their spatial superposition in the daytime forms a wavy surface profile with a pronounced decrease of the water level towards the locks gateway under an action of the discharge stream with the increased dynamic volume of Qdin.

The Volga is the largest river in Europe and its headwaters comprise reference or least disturbed conditions. In the headwaters of the Volga (445 km) upstream of Tver, 27 diatom samples (18 from the Volga and nine from selected tributaries) were collected in shallow water along the banks from different habitats, wherefrom 270 taxa (244 pennate and 26 centric) were identified. Most benthic taxa were found within Naviculaceae (40 taxa), Fragilariaceae (29 taxa), Bacillariaceae (27 taxa), Achnanthaceae (23 taxa), Gomphonemataceae (19 taxa), Cymbellaceae (17 taxa), and 16 taxa belong to the Amphora-complex. Species richness in the Volga and its tributaries was comparable; the mean value was 46 in the Volga and 50 in the tributaries. Regarding the saprobic index, the source region (reach R1) was characterized by a large proportion of xeno- and oligo-saprobic species, with the proportion of oligo-beta and beta-meso-saprobic species increasing along the continuum. This study provides a first comprehensive checklist of benthic diatoms for the Volga headwaters and analyzes longitudinal changes as well as the interplay between abiotic parameters and the diatom community in the headwaters of the Volga.

Abstract In this article, we present the first results from radiocarbon dating of the Kirakle-Tobe settlement located in the central part of the Volga River Delta, southern Russia. Archaeological artifacts and 14 C measurements on charcoal indicate three stages of settlement development on the Kirakle-Tobe knoll. The oldest 14 C age corresponds to the Late Sarmatian period—early 4th century CE. The abundance of archaeological artifacts associated with the 6th–8th centuries CE indicates a long period of occupation. The youngest 14 C age presumably corresponds to the Khazarian period (9th century CE). These results suggest dynamic human activity in the central part of the Volga River Delta during the Great Migration Period. These initial results can be used to verify the impact of fluctuations in the Caspian Sea level on the Volga River Delta during the Great Migration Period.

DNA barcoding is an effective method for species identification, but its practical application, as implemented in the Barcode of Life Data System (BOLD), faces numerous challenges. In our work, we conducted an empirical test of this approach using butterflies of the Volga River region in eastern Europe as a model system. We demonstrate that DNA barcoding is a powerful tool for identifying species clusters of the local fauna studied. However, assigning the identified clusters to scientific species names using BOLD was problematic for more than half of the species analyzed. The reasons for these problems are numerous errors in (1) species and even (2) generic identifications of DNA barcodes in the BOLD database (30% and 26% of all problematic cases, respectively), (3) similarity of DNA barcodes in different species (22%), (4) unresolved taxonomic problems associated with the species names that BOLD suggests as identifications (18%), (5) anomalous barcodes (2%), and (6) incompleteness of the BOLD database (2%). Solving problems 1, 2 and 5 requires improving the DNA barcode curation system and minimization of the identification errors in the BOLD database. Problems 3 and 6 can be partly solved by accumulating DNA barcodes, especially barcodes of local faunas, since populations of different species with identical DNA barcodes often have non-overlapping areas. Problem 4 is the most difficult and requires further intensive taxonomic research to solve it.

This article analyzes the Russian Federation's strategic weaponization of environmental policy in the Caspian Sea region as a sophisticated, non-kinetic instrument within its general hybrid warfare strategy. Avoiding the general assumption of environmental degradation as a byproduct of war, this analysis assumes that Russia is taking conscious measures in applying natural resources and environmental disasters as an heterogenous policy to accomplish political and economic objectives. By dominating the Caspian's principal water source, the Volga River, Moscow acquires the ability to inflict disproportionate, cumulative harm on the economies and legitimacy of governments of littoral states—specifically Kazakhstan, Azerbaijan, Turkmenistan, and Iran—without crossing the threshold of formal armed conflict. This piece outlines the mechanisms of this weaponization of the environment in physical and economic arguing that it is a central and expanding frontier of international competition, a key challenge to traditional understandings of national security.

The article considers the features of the spatial and biotypic distribution of specially protected objects of flora and fauna on the territory and in the zone of influence of the object “Construction of the second, third and fourth launch complexes of the bridge crossing over the Volga River in Volgograd”. A comprehensive (cadastral and landscape) description of the survey sites of the linear feature, where rare species of animals, plants and fungi were previously recorded and not recorded, is presented, and the number of rare species locations is indicated. As a result of the research conducted on the territory of the bridge crossing, 5 species of rare animals, plants and fungi were registered within the boundaries of the permanent and temporary allotment area, 44 meeting/growing sites were identified within the boundaries of the permanent and temporary allotment areas of special protection facilities listed in the Red Books of the Russian Federation and the Volgograd Region, within the boundaries of the zone of influence of the linear object. 154 locations/meeting places of 10 rare species of plants, fungi and animals.

This article describes the results of a study on DDT content in the watercourses of the Volga River delta. Based on the data from the long-term state environmental monitoring in 1985–2022, DDT concentrations in the water of the investigated region were determined, as well as the main sources and levels of DDT pollution. The associated environmental risks were assessed. All data were processed using standard statistical methods. For each period, a range of DDT concentrations was established, with significant spatial and temporal variations. It was demonstrated that, on average, DDT concentrations in recent decades have remained in compliance with general environmental quality standards. The areas with the highest levels of DDT pollution were identified. The transit runoff was found to be the primary source of DDT pollution. The environmental risk analysis revealed that the impact of DDT pollution in the Volga River delta is of no concern, but systematic monitoring is needed to manage it effectively.

The article presents the indicators of biological diversity and productivity of zooplankton communities and zoo-benthos of the Kizan River in the area of the object of accumulated environmental impact of the Sokolovsky oil pits (the Volga River delta, Astrakhan Region, the vicinity of the village of Kizan). It was revealed that the dominant groups of organisms in the study area are Calanoida, Cyclopoida. Each of the studied stations is distinguished by dominant species – Calanus helgolandicus at station 1, Cyclops sp. at station 2, Daphnia ambigua and Polyphemus pediculus at station 3 were predominant in number. The positive impact of coastal reclamation on the biomass and composition of zooplankton is shown. The number of zooplankton at the station where restoration work was previously carried out was maximum – 32.5 thousand specimens/m3. The biomass in this area also exceeded the values at other stations by more than two times and amounted to 3.8 g/m3. The study of the species composition of zooplankton allowed us to estimate the degree of saprobity of the studied section of the Kizan River. The saprobity analysis revealed zones of moderate (β-mesosaprobic) and strong (α-mesosaprobic) pollution with organic substances. Eight species of organisms were registered in the macrozoo-benthos; crustaceans were the dominant group of the benthocenosis near the shore. A significant share in the sample was also occupied by the larvae of dipterous insects Chironomus plumosus and Cricotopus sylvestris. Mollusks Viviparus viviparus and Lymnaea stagnalis were found as single specimens. At a distance of several meters from the coastline, an increase in the number of zoobenthic organisms in the sample up to 60 specimens/m2 was noted. The dominant species remain amphipods, making up 33.3% of the total number of individuals and represented by two species (Gammarus minutus and Dikerogammarus villosus). A significant number of dipteran larvae (Culex pipiens and Cricotopus sylvestris) were found, making up 31.7% of the total number of organisms.

Plankton Primary Production in Volga River Reservoirs: Current Status and Trends in Long-Term Changes

The record of a mandibular tooth plate of the chimaeroid fish Ischyodus sp. from the Lower Cretaceous deposits of the north of the Saratov Volga River Right Bank is described. The presumed age of the find is the Lower Aptian. This is the first recorded occurrence of chimaeroid remains in the Lower Cretaceous (pre-Albian) deposits of the Middle and Lower Volga regions, and the fourth record in deposits of this age in Eastern Europe. The composition of the global Early Cretaceous (pre-Albian) chimaeroid assemblage, including 3-4 genera of “edaphodontids” and 1-2 genera of rhinochimaerids, and the possible migration path of Ischyodus thurmanni to the southern hemisphere (Australia) in the Early Cretaceous are discussed.

The distribution and ecological preferences of the rare water flea Ovalonakarelica (Stenroos, 1897) (Crustacea, Branchiopoda, Cladocera) were analysed for the first time for European Russia. The species was found in different types of waterbodies, such as floodplain lakes of the Kerzhensky State Nature Biosphere Reserve, Nizhny Novgorod City and mouths of rivers inflowing into reservoirs. Ovalonakarelica inhabits waters with wide ranges of pH, salinity, oxygen content and trophicity. Development of semi-submerged macrophytes (Stratiotes, Hydrocharis, Salvinia) is the main factor influencing occurrence of the species and its abundance.

This manuscript continues a series of papers devoted to the study of bio-optical characteristics of the Volga River waters in the context of development of regional bio-optical models. A particularly weak point in this effort is the limited knowledge of dissolved organic matter (DOM): its component composition, spectral absorption characteristics, and the lack of satellite-based assessment algorithms. Using excitation–emission matrix fluorescence spectroscopy, we examined the fluorescent fraction of DOM of surface water layer of the Volga River and its tributaries in the area from the Gorky Reservoir to the Volgograd Reservoir, a stretch spanning over 1500 km, in the period from May to September 2022–2024. Four fluorescent components were validated in parallel factor analysis. The ratio of fluorescent components was mostly stable, while their fluorescence intensities varied a lot. For example, the fluorescence intensity of the DOM of the Gorky Reservoir and the Kama River differed by more than 2.5-fold. The highest FDOM fluorescence was found in the Gorky Reservoir. Downstream, it decreased due to the inflow of the Oka and Kama rivers. The influence of small rivers such as Kerzhenets, Sundovik, Sura, and Vetluga was insignificant. It is demonstrated that neither conventional remote sensing techniques (LiDAR) plus in situ measurements of DOM with a probe nor DOM absorption at 440 nm allows probing all the fluorescent components, so their efficiency is determined by the correlation of fluorophore group content.

Recently, when studying river basins, the QGIS system has been widely used to obtain various hydrological factors from a Digital Elevation Model (DEM). This study is aimed at determining the fractal dimension of vector layers of river basins obtained using QGIS.Aim. For a number of hydrological networks, investigate the relationship between the values of the fractal dimensions calculated for the corresponding QGIS layers and used for calculation by the software, as well as the dependence of the fractal dimension on the initial conditions set for the software (the latter only for "shp" files): also determine possible correlations between the resulting dependencies.For 9 hydrological objects (the Aya, Belaya, Sars, Sura, Ufa and Yuryuzan rivers and the mouths of the rivers Volga, Lena and Selenga), the fractal dimension was calculated using the “box-counting” method. Calculations were carried out using free software: Minkowski Dimension Calculator for QGIS, Fractalyse, ImageJ, Frac Lac for ImageJ, Gwyddon, Fractal and FDE.The data reveal that, firstly, the calculation result depends on the initial conditions set for the computer programme, and secondly, there are correlations between the fractal dimensions calculated under both different initial measurement conditions and using different software.Our results suggest the possibility of using all the software under consideration to determine fractal dimension from images of hydrological objects, obtained using QGIS. Moreover, the recommendations proposed in the conclusion will allow more effective use of the special opportunities of each of the programmes for further research.

В конце XIX в. П. Л. Мартынов доказал, что г. Синбирск (совр. г. Ульяновск) был основан в 1648 г. окольничим Б. М. Хитрово. Попытки уточнить эту дату предпринимались неоднократно. Наибольшее значение имел 1998 г., когда В. А. Гуркин ввел в оборот документ, из которого следовало, что в июле 1648 г. строительство Синбирска еще не завершилось. Это было самое раннее и, вместе с тем, единственное упоминание Синбирска под 1648 г., годом его основания. Первое же известие об уже отстроенном городе находится в статейном списке русского гонца в Иран Г. В. Булгакова: 19 сентября 1648 г. шедшее по р. Волге посольство остановилось на ночлег в «новом городе Синбирском». В этом же году о городе и его первом воеводе И. Б. Камынине сообщается повторно, в другом документе, под 12 октября. В отличие от вполне конкретных дат первых упоминаний города (на стадии строительства и по завершении работ), точное время его основания по-прежнему неясно. Гипотеза Ю. Н. Мельникова о закладке Синбирска 21 мая, в день Св. Троицы, не подкреплена серьезными аргументами. Предположение В. А. Гуркина о прибытии окольничего Хитрово на Среднюю Волгу и начале строительства Синбирска к середине марта хотя и возможно, но маловероятно. Новейшая публикация наказа об основании Синбирска, подготовленная В. А. Гуркиным, доказывает, что подготовка к строительным работам на месте будущего города велась до приезда Б. М. Хитрово, а значит, сам процесс закладки Синбирска не был единовременным, но происходил в несколько этапов, растянувшихся с марта — апреля по конец апреля — май 1648 г. В приложении публикуется отрывок из росписи сбора полоняничных денег 1648/49–1649/50 гг., являющийся, по сути, первым кратким «статистическим описанием» г. Синбирска и его уезда. At the end of 19th century Pavel L. Martynov proved that the fortress town of Sinbirsk was founded in 1648 by okol’nichii Bogdan Khitrovo. There were repeated attempts to clarify this date. The greatest significance was in 1998, when Vladimir A. Gurkin introduced a document from which it followed that in July 1648 the construction of Sinbirsk had not yet been completed. This was the earliest and, at the same time, the only mention of Sinbirsk under 1648, the year of its foundation. The first information about the already built city is in the report (stateinyi spisok) of the Russian messenger to Iran, Grigory Bulgakov: on 19 September 1648 the embassy travelling along the Volga River stopped for a night in “the new town of Sinbirsk”. In the same year, the town and its first voivode Ivan Kamynin are reported again, in another document dated 12 October. Unlike the quite specific dates of the first mentions of the town, the exact time of its foundation is still unclear. Yuri N. Melnikov’s hypothesis about the foundation of Sinbirsk on 21 May, the day of the Holy Trinity, is not supported by serious arguments. Vladimir A. Gurkin’s assumption about the arrival of okol’nichii Khitrovo to the Middle Volga and the beginning of the construction of Sinbirsk by the middle of March, although possible, is unlikely. The new publication of the order on the foundation of Sinbirsk, prepared by Vladimir A. Gurkin, proves that the preparation for construction work on the site of the future city was carried out before the arrival of Bogdan Khitrovo, which means that the process of laying Sinbirsk was not a one-time event, but took place in several stages, stretching from March — April to the end of April — May 1648. The Appendix publishes an extract from the list of tax collection for the redemption of captives in 1648/49–1649/50, which is the first brief “statistical description” of the town of Sinbirsk and its district.

ABSTRACT Unusually large masses of green filamentous algae were recently discovered in the Volga River, European Russia. Macroscopically, their thick, slightly curled, bright-green filaments are distinct from the commonly occurring Cladophora glomerata. Microscopic examination showed that the filaments were entirely unbranched and composed of relatively large cells containing up to 170 nuclei, features characteristic of Chaetomorpha. However, molecular phylogenetic analyses based on nuclear rDNA sequences placed these algae within the genus Rhizoclonium, leading to its description as a new species, Rhizoclonium volgense sp. nov. Unlike many other Rhizoclonium species, R. volgense lacks lateral rhizoids, is completely unbranched, and becomes unattached in later growth stages. It was consistently found to form free-floating mats, although the presence of primary rhizoids in sporelings indicates an initially attached phase. Molecular analyses indicate a close relationship with taxa from saline environments. Currently, the new species appears to be restricted to the regulated reservoirs of the upper Volga River, where fluctuating hydrological conditions may influence its distribution. Its absence from earlier studies suggests either historical oversight or a recent introduction.

The article is devoted to the study of key aspects of the development of navigation and merchant trade on the Irtysh River in the second half of the XIX century, with a focus on the cities of the Irtysh region — Omsk, Pavlodar, Semipalatinsk and Ust-Kamenogorsk. On the basis of archival documents, statistical reports and primary sources stored in the Central State Archive of the Republic of Kazakhstan, the features of formation of river transport infrastructure and its influence on the economy and social structure of the region are consid-ered. Special attention was paid to the introduction of the system of fees for transportation across the Irtysh in Pavlodar in 1864 as one of the first examples of local tax regulation of trade. It is shown that the fees contrib-uted not only to the replenishment of the city budget, but also to the active development of infrastructure: construction of wharves, warehouses, and organization of river logistics. Shipping provided regular transpor-tation of grain, coal, industrial goods, which stimulated economic growth and the formation of new trade routes. The growth of transportation volumes was accompanied by an increase in the number of merchants, workers and artisans, which affected the social structure of cities. The development of water transport was accompanied by adaptation to seasonal limitations of navigation and integration with the railway network. In contrast to the Volga and Don rivers, where river transport gradually yielded to railroads, it retained its key role on the Irtysh until the beginning of the XX century. It contributed to their transformation into major trade and transportation hubs, stimulated economic growth, formation of urban identity and development of inter-national trade. It is concluded that the Irtysh navigation was strategically important for the economy, migra-tion and social transformation of the cities of the Irtysh region. Thus, this study makes a significant contribu-tion to understanding the role of water transport in the history of the Priirtysh region and demonstrates how local initiatives (introduction of fees, development of wharves) could influence macroeconomic processes in the imperial and international context.

Introduction. In the flat part of the Volgograd region, two forms of oak have been identified – early and late-blooming, the preservation of which in low-wooded regions is the main task of forestry. The relief of the research region rises towards the south-eastern part, dividing into forms in which oak plantations were studied. Materials and methods. The results of field and laboratory observations of the growth, condition, and projection of the crown of oaks in floodplain, beam, and plain terrain areas were used, using statistical processing of the data obtained. Results and discussion. It is established that the relief forms of the Volgograd region include the Volga upland, the Don plain, the Lowland of the Volga-Akhtuba floodplain, the Ergeninsky upland with a variety of natural conditions. It was revealed that oak plantations grow best on loamy soils of the southern slopes and on the northern limit of their range (the floodplain of the Volga River) with its non saline soils and favorable microclimate. In lowland conditions, young oak undergrowth dies by 8–10 years, while in floodplain conditions it is preserved up to 16–18 years. Due to the later start of the growing season in the floodplain, damage to self-seeding oak is reduced. At higher elevations, the climate is less continental compared to lowlands and plains, so the frost resistance of oak is higher here and less affected by recurrent spring frosts. Competition with other tree species is determined by the type of terrain. Anthropogenic activity in floodplain and beam landscapes leads to a decrease in the number of oak populations and the disappearance of rare specimens. Conclusion. Oak plantations in lowland terrain are less drought-resistant, and a decrease in frost resistance of individual plants has also been noted. Gully slopes create a microclimate, provide snow accumulation and additional soil moisture, however, they can slow down the growth and development of young oak plantations due to competition for light, nutrients and moisture. The best oak growth is observed on the southern and western slopes. The early-spreading form of oak in such conditions is characterized by better resistance to adverse environmental factors. In floodplain areas, oaks receive additional nutrition from silt and a fertile soil layer during flooding, however, conditions of constant flooding can lead to the death of individual trees. Individual specimens are characterized by the highest degree of drought resistance and lower transpiration intensity. Suggestions for practical applications and directions for future research. The results of the work can be used to develop a strategy for preserving the biodiversity of oak forests, optimizing forestry and improving the efficiency of using natural resources.

The article discusses the possibilities of solving environmental problems of pollution of the main waterway of the European part of Russia, which necessitated the search for effective financing mechanisms for environmental projects aimed at reducing anthropogenic impact on the ecosystem of the river, where the use of sustainable environmental banking products will reduce the severity of financing projects aimed at reducing pollution of the Volga River. The article analyzes legislative and regulatory acts, as well as the positive and negative practice of financing projects within the framework of the Federal project "Improving the Volga River". Recommendations on attracting green bank loans as an alternative to government support are proposed. The author has studied and proposed options for currently available green banking products. The article discusses the author's recommendations on options for attracting green bank loans to solve this problem, including the risk of penalties for enterprises, the amount of which can lead to fines of up to 5% of the company's revenue. Green bonds and other investment instruments can be used to finance the construction or renovation of wastewater treatment plants, including the issuance of green bonds by regional governments. Special attention is paid to the role of government support, the interaction of the banking sector and industrial enterprises, reducing the impact of ESG risks, as well as the prospects for the development of ESG banking in Russia.

Remote sensing methods are widely used to monitor ongoing climate change, and the area of sea ice in the Arctic and Antarctic is used as one of the criteria. The duration of ice cover on inland waters can be used to assess processes within continents. The small size of internal waters does not allow the use of traditional methods that have proven themselves well in marine conditions. This study considers the possibility of using dual-frequency precipitation radar data to detect ice formation and destruction on small inland waters. Due to the features of backscatter at small incidence angles (< 18∘), inland waters with sizes smaller than the radar resolution (5 km) are “visible” in radar images. Using the Volga River as an example, it is shown that water-ice and ice-water transitions can be detected when analyzing radar images, and thus, possible to estimate the duration of ice cover on inland waters.