Search Results (40)

The aim of the present work is to assess the wind and hydrogen production capacity of the Black Sea basin from a spatial point of view, by using reanalysis data that covers a 10-year interval (2015–2024). Based on the ERA5 data it was possible to highlight the general distribution of the wind resources at 100 m height, with more consistent resources being noticed in the region of the Azov Sea or in the north-western sector of the Black Sea, where average values of 8.3 m/s are expected. Taking into account that at this moment in the Black Sea area there are no operational offshore wind farms, several generators ranging from 3 to 15 MW were considered for assessment. In this case, from a single turbine, we can expect values in the range of 11.04 GWh (3 MW system) and 89 GWh (15 MW system), respectively. As a next step, the electricity generated from each wind turbine was used to highlight the hydrogen production of several electrolysers systems (or PEMs). The equivalent number of PEMs was identified, and in some cases it was noticed that some devices will not reach their full capacity, while for smaller PEMs a single 10 MW wind turbine could support the operation of almost four modules. Regarding hydrogen output, a maximum of 1560 tons/year can be expected from the PEMs connected to a 15 MW wind turbine. Full article

The abundance of the Russian sturgeon population in the Sea of Azov declined many times in the XX–XXI centuries. This paper presents long-term annual and spatial occurrence datasets to create statistical and machine learning models to better understand the distribution patterns as well as biological and ecological features. The annual dataset provides annually averaged results of environmental and biotic population estimates obtained by in situ observations for 1925–2024. The spatial occurrence dataset contains raw survey observations with a bottom trawl over the period of 2000–2024. Preliminary diagnostics of the annual dataset reveal no evidence of non-stationarity or significant outliers that cannot be explained by biological parameters. The published dataset allows any researcher to perform statistical and machine learning-based analysis in order to compare and describe the population abundance or spatial occurrence of Russian sturgeon in the Sea of Azov. Full article

The coastal zone of the Sea of Azov is a dynamic environment influenced by various natural and anthropogenic factors, including wind, wave action, beach material removal, and cultivation on cliff edges. The coastal zone of freezing seas is also influenced by ice cover during winter. This study investigates the dynamics of the Sea of Azov’s coastal zone during winter (2014–2023), focusing on the impacts of waves and ice, to identify the most vulnerable coastal areas. We analyzed high-resolution satellite imagery and employed mathematical modeling to obtain data on ice pile-up, fast ice formation, wind patterns, and storm wave dynamics within the shallow coastal zone. Long-term wind data revealed an increase in maximum wind speeds in December and January, while February and March showed a decrease or no significant trend across most coastal observation stations. Storm waves (significant wave height) during the cold season can reach heights of 3.26 m, contributing to coastal erosion and instability. While the overall ice cover in the Sea of Azov is decreasing, with fast ice rarely exceeding 0.85% of the total sea area, ice pile-up still occurs almost annually, with the eastern part of Taganrog Bay exhibiting the highest probability of these events. Our analysis identified the primary impacts affecting the shallow coastal zone of the Sea of Azov between 2014 and 2023. A map was generated to illustrate these impacts, revealing that nearly the entire coastline is subject to varying degrees of wave and ice impact. Exceptions include the eastern coast, which experiences minimal fast ice and ice pile-up, with average or lower dynamic loads, and the southern coast, where wind–wave action is the dominant factor. Full article

This article is devoted to the analysis of the simulated meteorological and hydrodynamic characteristics of the Sea of Azov using the WRF (Weather Research and Forecasting) model and INMOM (Institute of Numerical Mathematics Ocean Model). The goal is to investigate the sea’s response to atmospheric forcing using two different horizontal resolutions. A comparison of the atmospheric simulation results with available meteorological in situ data from the land-based hydrometeorological stations (HMSs) did not reveal any significant differences between the simulations with different atmospheric forcing resolutions. A spatiotemporal analysis of the WRF model and INMOM results showed the most prominent differences along the entire coastal zone, especially in Taganrog Bay, along the spits in the north part of the sea, and in the Kerch Strait. Here, the wind speed obtained at a high spatial resolution (3.3 km) was ~10–15% higher than that obtained at a coarse resolution (10 km), and the surface and bottom currents were up to ~40% and ~15% higher. In marine coastal zones, the greatest differences were noted in a band of ~5 km, and differences in the rest of the Sea of Azov were negligible. An analysis of the bottom current speed revealed the presence of a counter-current flowing into Taganrog Bay. This shows the necessity of using three-dimensional marine circulation models to study the Sea of Azov’s dynamics. Full article

The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mC_d) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River. Full article

The aim of the article is to assess the level of aliphatic hydrocarbon (AHC) contamination in bottom sediments of the Azov–Black Sea coast of the Crimea, as well as to identify potential sources of its formation. Bottom sediment samples obtained from 19 stations during the research cruise of the R/V “Professor Vodyanitsky” (June 2020) were used as the material for this investigation. Sampling stations were located along the coast of the Crimean Peninsula and the Caucasus coastlines (the Black and Azov Seas). N-hexane extracts of sediments were studied by gas chromatography to determine the AHC amount and composition. It was established that AHC concentrations in the study area varied from 1.30 to 127.8 mg/100 g. Generally, bottom sediments of the Black and Azov Seas were characterized by low AHC contents, while increased AHC contents were found in the outer harbor of Sevastopol and Yalta regions. To identify potential hydrocarbon sources, various hydrocarbon markers were used. In most of the study areas, n-alkane composition was determined by similar sources of inputs and organic compound transformation. At the same time, oil pollution linked with use of fuel was recorded almost everywhere. Full article

This article is about the diversity of diatoms in the benthos of the upper sublittoral near Kazantip Cape, located on the shore of the Sea of Azov in the northeastern part of Crimea. The study was conducted in 2022 and 2023 at a depth of 0.1 to 1 m at temperatures from 3.7 °C to 29 °C and salinity from 13.6 to 15.6 psu on the following 11 species of macroalgae: Phaeophyta of Ericaria crinita, Gongolaria barbata, and Cladosiphon mediterraneus; Chlorophyta—Bryopsis hypnoides, Cladophora liniformis, Ulva intestinalis, and Ulva linza; and Rhodophyta—Callithamnion corymbosum, Ceramium arborescens, Polysiphonia denudata, and Pyropia leucosticta. A total of 97 taxa of Bacillariophyta belonging to 3 classes, 21 orders, 30 families, and 45 genera were found. The highest number of diatom species was found on U. linza (61 species), P. denudata (45), E. crinita (40), the lowest number was recorded on thalli P. leucosticta (9). On macroalgae were found of 80% benthic diatoms, 50% marine species, 36% brackish-marine, 9% freshwater, 5% brackish, and 36% cosmopolites. The maximum abundance of the diatom community was 243.4 × 10³ cells/cm² (P. denudata in September at 23.9 °C and 15.0 psu) with dominance by the diatom of Licmophora abbreviata, and the minimum was 3.8 × 10³ cells/cm² (P. leucosticta in January at 3.7 °C and 15.0 psu). The presence in the epiphyton of diatoms—indicators of moderate organic water pollution (32 species), which developed in masse in late summer—indicate a constant inflow of organic matter into the coastal waters of the Kazantip Cape. The bioindicator and statistical studies indicate the effectiveness of the conservation regime, especially at stations within the IUCN reserve, despite relatively high saprobity rates at stations exposed to recreational pressure and poorly treated domestic wastewater. Full article

The Sea of Azov, an inland shelf sea bounding Ukraine and Russia, experiences the effects of ongoing and legacy pollution. One of the main contaminants of concern is the heavy metal mercury (Hg), which is emitted from the regional coal industry, former Hg refineries, and the historic use of mercury-containing pesticides. The aquatic biome acts both as a major sink and source in this cycle, thus meriting an examination of its environmental fate. This study collated existing Hg data for the SoA and the adjacent region to estimate current Hg influxes and cycling in the ecosystem. The mercury-specific model “Hg Environmental Ratios Multimedia Ecosystem Sources” (HERMES), originally developed for Canadian freshwater lakes, was used to estimate anthropogenic emissions to the sea and regional atmospheric Hg concentrations. The computed water and sediment concentrations (6.8 ng/L and 55.7 ng/g dw, respectively) approximate the reported literature values. The ongoing military conflict will increase environmental pollution in the region, thus further intensifying the existing (legacy) anthropogenic pressures. The results of this study provide a first insight into the environmental Hg cycle of the Sea of Azov ecosystem and underline the need for further emission control and remediation efforts to safeguard environmental quality. Full article

Studying the distribution of morphologically cryptic animal species is always a very difficult task. Because most marsh frog species (the Pelophylax ridibundus complex) are cryptic, we used molecular markers to identify them. Three marsh frog species (P. ridibundus, P. kurtmuelleri and P. cf. bedriagae) inhabit the northern part of Western Palearctic. We created a database of localities and built models of their modern distribution. These models showed that the most suitable habitats are on the north of the Mediterranean region for P. cf. bedriagae, temperate Europe for P. ridibundus, and the Balkan coastal areas for P. kurtmuelleri. The projection of the modern ecological niches under the late-Quaternary climatic conditions showed that the range of P. kurtmuelleri remained largely unchanged during the period, whereas the ranges of P. cf. bedriagae and especially P. ridibundus changed greatly over time. During the Last Glacial Maximum, the presumed range of P. cf. bedriagae covered a relatively large area in the north of the Mediterranean region and the south of European Russia. Glacial refugia of P. ridibundus were apparently located in the northern Balkans, the northern coast of the Black and Azov seas, and possibly in Western Europe. The northward long-distance post-glacial dispersal of P. ridibundus occurred from refugia in the northeastern Balkans and the Black-Azov seas region. Since the Late Pleistocene, suitable habitats for P. cf. bedriagae in southern Russia began to decline, but local habitats for P. ridibundus become more suitable. Therefore, a mosaic of populations consisting of these both species and their hybrids has now been found here. Full article

Large amounts of macroalgae and grass are dumped on the shores of the Sea of Azov in different seasons. Aquatic plant biomass management could contribute to sustainable development. By mixing them with co-substrates in an anaerobic bioreactor, not only can biogas be extracted, but suitable fertilizers can also be obtained. This study discusses the possibility of using methanogenesis waste from Azov Sea algae and sea grass as a fertilizer for agriculture. The main criterion is the presence of carbon (C) and nitrogen (N) in the waste products of methanogenesis. The influence of climatic and seasonal factors in the Azov region on the quality and quantity of storm emissions, on the productivity of methanogenesis, and changes in the ratio of carbon (C) and nitrogen (N) during methanogenesis and in the fermented substrate has been established. The influence of the ratio of the components of the mixture in various proportions, before methanogenesis, on the productivity of methanogenesis and the change in the ratio of carbon (C) and nitrogen (N) during the process of methanogenesis, and in the fermented substrate were studied. The biomass of the Sea of Azov, cattle manure and wastewater waste in various proportions, were used as components of the mixture. Recommendations are given for the selection of mixture components for methanogenesis, with predicted indicators of the ratio of carbon (C) and nitrogen (N) in the fermented substrate. Full article

The decline of fossil fuels, the increase in greenhouse gases, and the global demand for energy are driving the search for alternative energy sources. Anaerobic digestion is a promising technology because it can convert organic biomass into biogas. As the climate warms, there is an increase in the biomass of plant origin in water bodies, and ecosystems are unable to clean themselves. The novelty of the work is that it determines the energetic values of macroalgae growing in the Sea of Azov and freshwater bodies using theoretical and experimental methods. This work aims to show that macroalgae and aquatic plants can be an excellent raw material for biogas production. By mixing them with co-substrates such as cattle manure, higher biogas and methane yields can be obtained. When Cladophora glomerata and Enteromorpha intestinalis macroalgae are mixed with cattle manure, the biogas yield is up to 458.8 mL/gVS and 397.9 mL/gVS, respectively. Methane concentration remained high and reached 62.4–64.1%. The obtained research results show the high energy value of biogas and the energy potential of biomass. Macroalgae increased the energy potential of biogas to 22.9 MJ/m³, and the energy potential of biomass reached 2.40 MJ/Kg. Due to its high energy value, biogas produced from the considered substrates can be an excellent alternative to fossil fuels. Integrating aquatic macroalgae into anaerobic digestion is a promising approach for a waste-free marine and freshwater system. Full article

Despite the full attention of malacologists to the study of Corbicula clams, stimulated mainly due to their high invasive potential and unique breeding system, studies based on an integrative taxonomic approach to identify various invasive lineages of this genus in European Russia are still limited. Our fieldwork was conducted in the Don, Volga, and Caspian Sea basins. In total, four distinct morphotypes belonging to the European forms R, Rlc, S, and “Int” of Corbicula clams were distinguished. According to our molecular genetic data, two Corbicula lineages, relevant to the nominal species Corbicula fluminea and C. fluminalis, can be defined. We observed a discrepancy between mtDNA haplotypes and morphological features for all individuals that were sampled from the Don and Kura Rivers. Identified mismatch may be due to the androgenetic reproduction of Corbicula that leads to cytonuclear inconsistencies. The 28S rRNA polymorphism in C. fluminea and C. fluminalis from studied localities was recorded. This occurrence is perhaps due to hybridization events between forms R, S, and Rlc. The biogeographic origins of Corbicula invasive lineages are discussed. Corbicula fluminalis (FW17, form S) has been detected for first time in the native range, namely in Azerbaijan, Tajikistan, Turkey, and Myanmar. We assume that the invasion of C. fluminalis into reservoirs and watercourses of the Caspian Sea basin (Republic of Dagestan and Stavropol Krai of Russia) was from Western Asia and Transcaucasia, and the introduction of C. fluminea to the Don and Volga River basins was from unspecified European countries. Full article

This overview presents the different water masses present in the various primary and secondary marine regions of the Mediterranean Sea and Black Sea, providing information on their main physical characteristics (i.e., temperature, salinity, density), the water depths at which they have been observed and the processes involved in their formation. There is a characteristic difference in the overall hydrology of the Mediterranean Sea compared to the Black Sea, in terms of the number and characteristics of water masses and their formation processes, although they form a single (integrated) marine system. This difference is explained by the limited communication between the two seas through the Sea of Marmara and its straits (the Dardanelles and Bosporus) and by the fact that the Mediterranean Sea is a condensation basin while the Black Sea is a dilution basin; therefore, the deficit of water in the former is compensated by the inflow of Atlantic waters, while the surplus in the latter outflows to the Aegean Sea. In total, 21 different water masses have been identified in the Mediterranean Sea (excluding the Straits of Gibraltar and the Sea of Marmara) compared to the 5 water masses identified in the Black Sea (excluding the Sea of Azov). This large number of water masses is attributed to coastal morphology (i.e., presence of straits) and submarine relief (i.e., deep basin separated by shallow sills) and different formation processes. Full article

During the second half of August 2022, a dust intrusion event occurred when dust that originated in the dry regions of the Kalmyk steppe (located in Russia, northeast of the Black Sea, north of Georgia, and northwest of the Caspian Sea) and the Precaspian plain was transported over the eastern region of Romania. The arid soil found in these areas can be attributed to an extended period of intense drought, with notable instances occurring in 2002, 2003, 2015, and 2018. This situation was further intensified by heatwaves experienced in May and June of 2022. The dust event was captured in MODIS images. In addition, smoke trains originating from fires in the north of the Azov were detected, but these did not reach Romania. Optical parameters from AERONET were used to confirm the dust event. To determine the trajectory of the particles, the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used in this paper. The ensemble median model was used to highlight the presence and concentration of dust in the eastern part of Romania. Aerosols were detected between 0 and 4 km, according to radar and ceilometer data from the REXDAN cloud remote sensing facility in Galați, Romania. This dust intrusion event was the result of the dominant easterly circulation caused by the extension of the East European High to the northeast of the continent, which transported the dust towards the eastern part of Romania for more than 2 days. Moreover, the torrential rains between 22 and 24 August did not clear the atmosphere of dust, since the intense easterly circulation kept carrying the dust into the Moldavian area. Full article

This paper considers the features of determining the total tin content in waters with different salinity. Direct ICP-spectrometric analysis of sea waters with a salinity of more than 6‰ significantly reduced the analytical signal of tin by 70% (ICP-MS) and 30% (ICP-OES). The matrix effect of macrocomponents was eliminated by generating hydrides using 0.50 M sodium borohydride and 0.10 M hydrochloric acid. The effect of transition metals on the formation of tin hydrides was eliminated by applying L-cysteine at a concentration of 0.75 g/L. The total analyte concentrations, considering the content of organotin compounds, were determined after microwave digestion of sample with oxidizing mixtures based on nitric acid. The generation of hydrides with the ICP-spectrometric determination of tin leveled the influence of the sea water matrix and reduced its detection limit from 0.50 up to 0.05 µg/L for all digestion schemes. The developed analysis scheme made it possible to determine the total content of inorganic and organic forms of tin in sea waters. The total content of tin was determined in the waters of the Azov and Black seas at the levels of 0.17 and 0.24 µg/L, respectively. Full article