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In the world, there is a general increase in sea surface temperatures with higher values reaching in enclosed seas. Türkiye is surrounded by these enclosed seas, and sea surface temperatures have been measured since the 1940s. Since most of the stations contained missing data, only 23 stations were used in the study. First of all, the distribution of sea surface temperatures was determined, and then annual and monthly trends were revealed using Mann-Kendall series correlation analysis and Sen slope value. As a result of the study, it was seen that the annual average sea surface temperatures in Fethiye, Ordu, Finike, Çanakkale, Kuşadası, Sinop, Konak and Sarıyer stations have a significant increase trend. Monthly trends show different patterns depending on the seas, with increases in the Mediterranean during the beginning of summer, in the Aegean and Marmara seas during the winter, and in the Black Sea coast during the summer. The analysis shows that the rate of increase in the Mediterranean is 0.67°C/decade and 2°C/decade in the Aegean and Marmara seas and the Black Sea coast. In the Black Sea, the increase in the average maximum sea surface temperature in June at Giresun station is 4°C/decade. [ABSTRACT FROM AUTHOR]

Mangalia area harbors in the western Black Sea a distinctive marine environment thriving under specific hydrochemical conditions, largely influenced by a significant number of sulphurous springs occurring in shallow marine waters. These springs led to the designation of the area as part of the Natura 2000 Marine Protected Area (MPA) network at European level (Underwater Sulphurous Springs from Mangalia - ROSAC0094), as unique hydro-geomorphological features in the region. In 2021 and 2023, two research cruises led by GeoEcoMar investigated underwater sulphurous springs primarily located offshore of Mangalia (Constant, a County, Romania). The study area, located between 17-29 meters water depth and 1.8-3 km offshore, encompasses two marine protected areas: the Underwater Sulphurous Springs from Mangalia (ROSAC0094) and Cape Aurora (ROSCI0281). The research combined geophysical and geochemical techniques and sediment sampling. Considering the susceptibility of these natural systems to human activities such as fishing and dredging, as well as the impact of ecological and climate changes, this paper offers significant insights contributing to the development of effective conservation and management strategies for these environments. The surveys were conducted for benthic habitats mapping, with the objective of improving our understanding of these ecosystems' distribution, composition and dynamics. As these sulphurous waters are rich inmethane, a powerful greenhouse gas, our results also contribute to the inventory of greenhouse gas sources. The results presented in this paper provide valuable new insights into this specific environment, contributing to the understanding of its complex functioning and evolution. [ABSTRACT FROM AUTHOR]

The article presents the species diversity, abundance, and distribution features of ichthyoplankton and fodder zooplankton in the northern Black Sea in summer 2021. The intensification of cyclonic activity over the Black Sea in June–July slowed the formation of summer-type thermal stratification in the studied water area. At the beginning of July, only 13 species of eggs and fish larvae were observed in ichthyoplankton of the Crimean Peninsula, and their average abundance was 29 and 2 ind./m2, respectively. At the beginning of August, summer-type vertical thermal stratification off the coast of the Caucasus had already formed. The number of ichthyoplankton species increased to 20. Activation of atmospheric processes in June–July intensified the intraseasonal wind "pumping" of the upper layer of the sea. The Black Sea Rim Current transformed into a pronounced jet over the continental slope, oriented alongshore, partially extending to the shelf. This did not affect the spawning activity of mass fish species. The average abundance of eggs in the shelf and deep-water zone was about 160 ind./m2, and the average abundance of larvae on the shelf was almost five times higher, 452 ind./m2. [ABSTRACT FROM AUTHOR]

Upwelling is due to the combined effect of the coastal divergence process and Ekman pumping. The author aims to investigate two new upwelling indices for the Black Sea, derived from climate reanalysis models and the following in situ data: (a) the Coastal Upwelling Transport Index (CUTI) that estimates the rate of vertical volume transport and (b) the Biologically Effective Upwelling Transport Index (BEUTI) that estimates the nitrate flux into the surface mixed layer. Average monthly wind by the European Centre for Medium-Range Weather Forecasts (ECMWF) and Copernicus Marine Services for the Black Sea basin is used to calculate the CUTI and BEUTI Indexes for over 26 years (1993–2019) to analyse the sites along the North-Western Black Sea where changes in divergence phenomena occur. From 2000 to 2018, 31 divergence processes were observed based on daily in situ data from the coastal monitoring stations, with significant predominance in late spring and early summer. Nitrate supply by coastal upwelling has been estimated by combining sea surface temperature and salinity for the in situ data for the North-Western Black Sea shallow waters, and BEUTI indices were determined. Comparing 18 years of data results, the calculated indices and the observed upwelling events showed significant correlations. [ABSTRACT FROM AUTHOR]

Studies of the energy metabolism in a bivalve mollusk, the ark clam Anadara kagoshimensis (Tokunaga, 1906), were carried out for the first time under experimental conditions simulating dynamic variations in the seawater characteristics at the stages of development and end of upwelling event in the Black Sea. It was shown that the level of energy metabolism of A. kagoshimensis, while being in the zone of upwelling formation, decreased, on average, by 5% per degree of temperature decrease. During the upwelling relaxation phase (14 → 26°C), the restoration of the respiration intensity parameters of the clam was slower than expected, with a temperature coefficient of Q10 = 1.31. The acidification of the seawater by 1.0 (up to рН 7.2), combined with a temperature decrease (26 → 20°C), aggravated the negative effect by 25–45%. It has been found that the clam A. kagoshimensis reduces energy expenditure by approximately 60% under upwelling conditions (cold stress and acidification). The consequences of the negative effect of a sharp temperature variation lead to a delay in the metabolism recovery to normal values. [ABSTRACT FROM AUTHOR]

Garfish Belone belone (Linnaeus, 1761) are distributed over a wide area covering all the East Atlantic coasts including the North and Baltic Seas and the entire Mediterranean basin. Researchers have presented different opinions regarding the presence of subspecies and endemic species of garfish due to certain morphological variations found in Mediterranean populations up to the current day. The purpose of this study is to clarify the taxonomic status of Belone euxini Günther, 1866, described as the Black Sea endemic by Günther (1866) and Belone acus Risso, 1827, described as the Mediterranean gar fish population by Risso (1827) with an integrative perspective. B. belone specimens were sampled from 12 localities in the North-Eastern Mediterranean. The congeneric Belone svetovidovi Collette & Parin, 1970, specimens were sampled at different locations in the Eastern Aegean Sea and included molecular analyses in order to determine the interspecific distance between Belone species. Detailed morphological description and genetics are provided for B. belone populations. Based on the results, it can be supported that the differences observed between B. belone populations are within the limits of intraspecific variation thus indicating that there are no distinct populations at the species level in the Mediterranean basin. [ABSTRACT FROM AUTHOR]

This article delves into the historical and cartographic significance of the Manganari Atlas, a monumental work that marked a pivotal moment in the maritime cartography of the Black Sea during the nineteenth century. Originating from the Russian Empire's strategic desire to enhance navigation and assert its presence in the Black Sea, the atlas represents not only a technical achievement in mapping but also a cultural and political artifact of its time. Through a meticulous analysis of the atlas, this study highlights the challenges encountered in its creation, the technical innovations employed, and the political motivations driving its development. The atlas is examined not merely as a collection of maps but as a synthesis of the cultural, linguistic, and geopolitical landscape of the era, reflecting the Russian Empire's aspirations. The panoramic images by Kukharevsky are particularly noted for their potential to aid in coastal geomorphological studies and the reconstruction of various geographical landscapes. The article also addresses the necessity of understanding the technical aspects of cartography for accurate analysis and comparison of historical maps. [ABSTRACT FROM AUTHOR]

The presence of biota in the Black Sea is mostly determined by seawater temperature and salinity. The consensus of many scientists doing research on global warming is that in 2100, the average air temperature will be increase than today's values. With climate changing, precipitation rates will change due to the Black Sea water temperature and the changing atmospheric regime, causing an unbalanced entry of nutrients into the sea, and as a result, excessive plankton proliferation may occur. This may mean that the habitats of the species in the Black Sea are further limited. The increases in sea levels may not be serious, but there is no doubt that there will be some increases. These increases will affect the coastal ecosystem, especially the rich living life in the region where the waves hit the shore, which we call the wave zone, will be adversely affected. These predictions should be followed up with regular scientific monitoring studies and it should be investigated how biota from invertebrates to fish are affected by the changes. This review explored and discussed the long-term changes and causes of biota communities on the southern coast of the Black Sea. [ABSTRACT FROM AUTHOR]

Sea surface temperature (SST) has an important local and remote influence on global climate through the distribution and transport of heat and moisture. As a result of climate forcing, significant changes occur in the SSTs, which result in many natural disasters such as supercharged storms, higher wind speeds, heavier precipitation and flooding. This study investigates the spatiotemporal changes and underlying atmospheric mechanisms of the Black Sea (BLS) surface temperature. For this purpose, National Oceanicand Atmospheric Administration (NOAA) high‐resolution SST data (0.25°), which were verified with buoy observations, were used for the period 1982–2021. To investigate the circulation impacts, the relationship between North Atlantic Oscillation and East Atlantic/West Russia (EA/WR) phases and SSTs of the western BLS (WBLS) and eastern BLS (EBLS) was analysed. According to the results, SST values increased from 1.64°C (in winter) to 2.52°C (in summer) during the 40‐year period. Significant SST increases are shown in the EBLS during the summer and fall months. Statistically significant negative correlations (p < 0.05) were found between EA/WR and winter (r = −0.57) and summer (r = −0.56) SSTs in the EBLS. During winter, surface high located in the eastern Anatolia causes southerly winds, which blows from the terrestrial areas to the EBLS and result in above‐normal SST values. During summer (under negative EA/WR phases), the Azores high‐pressure centre extends to the Balkan Peninsula and WBLS and as a consequence, a significant amount of moisture associated with high sea surface temperature (>27°C, above‐normal 2.0°C) develops low‐level moisture convergence. Proper synoptic conditions, strong instability conditions between the surface and upper levels, and orographic forcing enable the occurrence of convective cloud cells. The movement of these cells to the northeastern part of Turkiye by strong northwesterly winds causes extreme precipitation and associated flash‐flood events in a limited area where land–sea interaction occurs (i.e., Artvin, Rize and Hopa provinces of Turkiye). [ABSTRACT FROM AUTHOR]

This study aims to develop a methodology for identifying predominant pressures on the marine ecosystem, emphasizing the significance of examining these pressures and the necessity for management scenarios. The research focuses on how the Black Sea ecosystemresponds to the combined effects of human pressures, climate change, and policies. An in-depth analysis was conducted on environmental pressures affecting the Romanian Black Sea, highlighting dominant pressures such as physical habitat loss, hydrocarbon introduction, and non-indigenous species invasion. The research employs a novel methodological approach to assess the implications of these pressures under different Shared Socioeconomic Pathways (SSPs): SSP1 "Taking the Green Road", SSP2 "Middle of the Road", and SSP5 "Taking the Highway". The findings reveal a complex interplay between economic development and environmental conservation, with each pathway presenting distinct outcomes for marine ecosystems. Recent developments, including beach rehabilitation, maritime transport, and oil and gas exploitation, have overshadowed traditional pressures such as nutrient introduction and fishing. The study identifies the increasing vulnerability of critical habitats to anthropogenic pressures, with the rehabilitation of these ecosystems remaining challenging even under reduced pressures. The results underscore the need for adaptive management strategies to enhance the Black Sea ecosystem's sustainability and resilience. The study's insights are important for developing management strategies that address ongoing environmental challenges. This research provides knowledge for policymakers and stakeholders involved in marine management and conservation efforts in the Black Sea region, emphasizing the importance of adaptive strategies to mitigate the adverse effects of human activities and climate change on marine ecosystems. [ABSTRACT FROM AUTHOR]

The incidental capture (bycatch) of seabirds is a global conservation issue and a top threat to European species that demands urgent conservation and management action. Here, we present the first European review of seabird bycatch data, considering all fishing gears and data collection methods available in the region. We calculate seabird bycatch numbers per species, family, country and European marine region and assess the reliability of the data available. The cumulative bycatch estimate extracted from this review suggests that about 195,000 seabirds (ranging from around 130,000 to 380,000) are bycaught in European waters annually. The most affected seabird species is the Common Guillemot Uria aalge with over 31,000 birds killed per year. The marine region with the highest bycatch estimate is the Northeast Atlantic (over 115,000 seabirds year−1). Gillnet fisheries are responsible for the highest bycatch levels, with over 95,000 seabirds year−1, followed by longline fisheries. The families most affected by bycatch are Anatidae and Alcidae. These numbers are likely an underestimation since we were unable to find bycatch estimates, or to extrapolate estimates from available bycatch data for 12 (out of 34) European coastal states. Our assessment also identified significant data gaps in key areas such as Gran Sol (in the north‐east Atlantic), the central and Eastern Mediterranean and the Black Sea. Combining systematic data collection with immediate implementation of mitigation measures will be crucial to fill in knowledge gaps, reduce current mortality levels and meet international conservation commitments such as those of the European Union and the Convention on Migratory Species. [ABSTRACT FROM AUTHOR]

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This study assessed the chemical composition of wild and culture-adapted golden grey mullet (Chelon auratus) and flathead grey mullet (Mugil cephalus). Wild samples were collected seasonally from Trabzon shores and compared to those adapted to aquaculture conditions for one year. Both species had high levels of glutamate, aspartate, alanine, leucine, and isoleucine. Mugil cephalus was a high protein source for adults, with a digestible indispensable amino acid score (DIAAS) score above 100 in both wild and culture forms. However, a DIAAS score exceeding 100 was only detected in wild Chelon auratus in the winter and spring. Both species had high levels of EPA and DHA, with Mugil cephalus having the highest lipid quality. Despite seasonal variations, cultured fish maintained a good nutritional profile similar to wild fish, especially in the autumn and summer.

In this study, exhaust emissions originating from purse seine fishing vessels were calculated. A bottom-up method based on ship activities was used for emission calculations. Necessary information for the calculations was obtained from the BAGIS (Fishing Vessels Monitoring System) system. Eighteen purse seiners in the Black Sea region with a length of 20 m or more engaged in fishing activities in the 2017-2018 fishing season were used as samples. These vessels were categorized into three different groups according to their length. The emissions produced by each length group were calculated separately under different conditions for vessels identified as 'port', 'operation', and 'navigation'. The total emissions in the Black Sea region and Türkiye were estimated. This study provides emission estimates using operational conditions and real data from Turkish-flagged purse seiners engaged in fishing in the Black Sea. In this respect, this research presents novelty and addresses an important gap in the existing literature. The annual emission amount of purse seine fishing vessels in the Black Sea is 260,000 tons, while the annual emission amount from purse seine vessels throughout Türkiye has been calculated as 440,000 tons. As a result, the effectiveness of the Emission Control Area (ECA)/Sulphur ECA region implementation in reducing emissions from maritime activities has been demonstrated. In addition, this study constitutes a source for the exhaust emission inventory of purse seiners in the Black Sea region.

For the first time, the stocks of bottom vegetation at the natural monuments of Sevastopol city were assessed on the basis of hydrobiological studies (2020–2021). The largest total macrophyte stock and their dominant species (Ericaria crinita and Gongolaria barbata) are typical for the water area of the natural monument “Nearshore Aquatic Complex (NAC) at Cape Lucullus”, the lowest, for “NAC at Cape Sarych”. Maximum biomass stock of Phyllophora crispa algae was recorded in the waters of the natural monument “NAC at Tauric Chersonese”. The results obtained may be recommended for optimizing the environmental regime of the natural monuments.

As a continuation of our previous research, wild and farmed mussels from the town of Sozopol, located on the Southern Bulgarian Black Sea coast, were collected to assess and compare the survival rates (stress on stress response, SoS) as a biomarker for the multi-stressor environment. This time we aimed to investigate further if there could be any seasonal differences. Overall, the mussels collected in April had a longer survival time than those collected at the end of January 2024. However, the survival time of wild and farmed mussels had a shorter survival rate in the air than in other studies. The answer to the question “Why is that?” persists.

A study was conducted on the changes in sea surface temperature (SST) on the southwestern shelf of the Crimea between 2000 and 2020. The equations of trends in the change of SST were found. It is shown that the following three periods can be distinguished according to the nature of changes in the average annual sea temperature: 2000 - 2007, 2008-2013 and 2014 - 2020. The influence of changes in the average annual SST on the development of pelagic fish of the cold-water complex was considered (using the example of the Black Sea sprat). Changes in the main parameters of the populations and their relationship with the change in the average annual SST were determined. It was found that the increase in sea temperature negatively affected the development of the sprat population, and the average age of the population decreased by 1.3 times. In general, the population was rejuvenated, and the average size and weight of individuals decreased.

Under climatic and anthropogenic factors, the Black Sea ecosystem is being transformed and replenished with new species of fish and Decapoda. Therefore, regular monitoring studies become relevant which allow identifying the effect of these processes on biocenoses of the Crimean Peninsula coastal waters. The aim of this work was to investigate taxonomic, structural, and quantitative characteristics of decapods and ichthyofauna of the Black Sea in the area of the Cape Martyan nature reserve. To make the results more complete, both adult individuals and planktonic and larval stages were sampled and analyzed. Fish and decapods were sampled with fixed nets, bottom traps, and hand nets. Ichthyoplankton and Decapoda larvae were sampled with an ichthyoplankton cone-shaped net IKS-80. For decapods, a high level of species diversity was revealed: those were represented by 17 species from 14 families. Two species, Alpheus dentipes Guérin, 1832 and Lysmata seticaudata (Risso, 1816), were recorded in the study area for the first time. The taxonomic composition of ichthyofauna was formed by about 30 species, mostly benthic and demersal fish. The structure of fish communities was quite stable; there was a trend towards an increase in diversity, a decrease in the prevalence of certain species, and an overall improvement in their state. A rise in abundance of some Atlantic–Mediterranean species, such as Serranus scriba (Linnaeus, 1758) and Chromis chromis (Linnaeus, 1758), can serve as an indicator of variations in hydrological and hydrochemical parameters of the environment related to general climate and ecological changes. The values of the quantitative parameters of fish eggs and larvae, (76.3 ± 11.4) and (18.8 ± 4.6) ind.·m−2, respectively, were sufficiently high for the Black Sea coastal waters. However, the proportion of living, normally developing fish eggs in the water area was low, 28.6% of the total. The data obtained can be used for comparative analysis during long-term monitoring in the Black Sea water area.

Abstract Background Recent studies have reported the identity and functions of key anaerobes involved in the degradation of organic matter (OM) in deep (> 1000 m) sulfidic marine habitats. However, due to the lack of available isolates, detailed investigation of their physiology has been precluded. In this study, we cultivated and characterized the ecophysiology of a wide range of novel anaerobes potentially involved in OM degradation in deep (2000 m depth) sulfidic waters of the Black Sea. Results We have successfully cultivated a diverse group of novel anaerobes belonging to various phyla, including Fusobacteriota (strain S5), Bacillota (strains A1T and A2), Spirochaetota (strains M1T, M2, and S2), Bacteroidota (strains B1T, B2, S6, L6, SYP, and M2P), Cloacimonadota (Cloa-SY6), Planctomycetota (Plnct-SY6), Mycoplasmatota (Izemo-BS), Chloroflexota (Chflx-SY6), and Desulfobacterota (strains S3T and S3-i). These microorganisms were able to grow at an elevated hydrostatic pressure of up to 50 MPa. Moreover, this study revealed that different anaerobes were specialized in degrading specific types of OM. Strains affiliated with the phyla Fusobacteriota, Bacillota, Planctomycetota, and Mycoplasmatota were found to be specialized in the degradation of cellulose, cellobiose, chitin, and DNA, respectively, while strains affiliated with Spirochaetota, Bacteroidota, Cloacimonadota, and Chloroflexota preferred to ferment less complex forms of OM. We also identified members of the phylum Desulfobacterota as terminal oxidizers, potentially involved in the consumption of hydrogen produced during fermentation. These results were supported by the identification of genes in the (meta)genomes of the cultivated microbial taxa which encode proteins of specific metabolic pathways. Additionally, we analyzed the composition of membrane lipids of selected taxa, which could be critical for their survival in the harsh environment of the deep sulfidic waters and could potentially be used as biosignatures for these strains in the sulfidic waters of the Black Sea. Conclusions This is the first report that demonstrates the cultivation and ecophysiology of such a diverse group of microorganisms from any sulfidic marine habitat. Collectively, this study provides a step forward in our understanding of the microbes thriving in the extreme conditions of the deep sulfidic waters of the Black Sea. Video Abstract

The article analyzes the current global risks faced by the maritime industry and explores potential solutions to minimize their negative impact on supply chains. It highlights the damaging effects of regional armed conflicts and the challenges associated with different stakeholders working together to ensure connectivity in combat zones at sea. The article also examines the impact of climate change on maritime transport, using the Suez and Panama Canals as examples. In both instances, the instability factors cause significant changes to shipping routes, volumes, and types of cargo transported by sea. These effects can also be observed beyond the region affected by the destabilizing factors or the corresponding types of cargo.

Members of the genus Ortholinea are among the worldwide distributed myxozoan parasites that mainly infect marine fish. In this study, a new myxosporean species, Ortholinea hamsiensis n. sp., was isolated from the urinary bladder of European anchovy Engraulis engrasicolus collected from the Sinop coasts of the Black Sea. The prevalence and density values of infection were 1.4% and 1–5 individuals in the field of view (1 + ), respectively. Mature myxospores are subspherical with slight tapering down to the less pronounced tip in the frontal view and subspherical in the sutural view. Myxospores measured 9.1 ± 0.25 (8.8–9.9) μm in length, 9.2 ± 0.11 (8.9–9.4) μm in thickness, and 8.4 ± 0.33 (8.2-9.1) μm in width. Two polar capsules equal in size measured 3.1 ± 0.11 (3.0–3.3) μm in length and 2.7 ± 0.11 (2.6–2.9) μm in width. The polar tubule had 3–4 coils. Along with morphological peculiarities, the results of the 18S rDNA also revealed it to be a new species for science compared to the other species of the genus. In this study, another myxosporean species O. gobiusi was also detected in round goby Neogobius melanostomus with a prevalence of infection value of 4.8% and a density of 1–5 individuals in the field of view (1 + ). The present study also provided the first data of 18S rDNA of O. gobiusi from N. melanostomus and type species of the genus O. divergens from Gobius niger and the phylogenetic relationships of these species with other Ortholinea species have been revealed.

This study analyzed the past wave climate of the Black Sea region for the period from 1988 to 2021. The wave field has been simulated using the state-of-the-art, third-generation wave model WAVEWATCH III forced by the ECMWF reanalysis ERA5 winds, with the model resolution being the highest ever applied to the region in a basin-scale climate study. The surface currents provided by the Copernicus Marine Service have been included in the wave model to evaluate wave--current interactions. The wave model results have been validated with respect to satellite and buoy observations, showing that the simulation accurately reproduces the past evolution of the wave field, exceeding 0.9 correlation with respect to satellite data. The inclusion of wave--current interaction has been positively evaluated. Four statistics (significant wave height 5th and 95th percentiles, mean, and maxima) have been used to describe the wave field at seasonal timescale, showing a clear distinction between the Western (rougher sea conditions) and Eastern (calmer sea conditions) sub-basins. Furthermore, the intra-annual wave climate variability has been investigated using a Principal Component Analysis (PCA) and the Mann--Kendall test on significant wave height (SWH). This study represents the first time the PCA is applied to the region, identifying two main modes that highlight distinct features and seasonal trends in the Western and Eastern subbasins. Throughout most seasons, the SWH trend is positive for the Eastern basin and negative for the Western basin. The PCA shows a regime shift with increasing eastward waves and decreasing north and north-eastward waves. Finally, SWH correlation (r) with four Teleconnection indexes (East Atlantic Pattern, Scandinavian Pattern, North Atlantic Oscillation, and East Atlantic/West Russia Pattern) revealed that the strongest r is observed with the Eastern--Atlantic--Western Russia teleconnection, with a peculiar spatial pattern of correlation, and is positive for the northwestern and negative for the southeastern sub-basin. [ABSTRACT FROM AUTHOR]

Eutrophication, driven by excessive nutrient enrichment from sources like agricultural runoff, industrial discharge, and urbanisation, has severely impacted the Black Sea since the 1980s. This study aimed to assess eutrophication dynamics in the Romanian Exclusive Economic Zone from 2020 to 2022 using the Black Sea Eutrophication Assessment Tool (BEAST), an integrated approach to the causes and effects of eutrophication. Data were collected from 68 stations during five oceanographic expeditions, analysing 617 water samples for nutrients, chlorophyll a, zooplankton species Noctiluca scintillans, and dissolved oxygen. Additionally, 179 zoobenthic and 251 phytobenthic community samples were collected. The results indicate that coastal waters exhibit higher nutrient levels and algal blooms compared to offshore waters, necessitating significant reductions in nutrient concentrations to achieve good environmental status. In transitional waters, within the Danube Delta Biosphere Reserve, a 55% reduction in inorganic phosphorus and a 43% reduction in inorganic nitrogen concentrations are required, while coastal waters need reductions of 38% and 37%, respectively. The study highlights the need for improved wastewater treatment, stricter agricultural runoff controls, and continuous monitoring. Effective ecosystem-based management strategies, integrated coastal zone management, and international cooperation are essential to mitigate eutrophication and promote the long-term health of the Black Sea ecosystem. [ABSTRACT FROM AUTHOR]

During World War I, fierce clashes took place between the Ottomans and Russia on the Caucasus Front. The Ottoman state, whose army in the region was not fully prepared for the war, was heavily wounded in the Sarıkamış Operation and then could not adequately defend against Russian attacks. Consequently, the conflicts in the east ended in defeat for the Ottomans. Especially after the Russians took control of Erzurum in 1916, they intensified their military operations directly to the west, south and east coast of the Black Sea. Having taken Erzurum, the Russian Caucasus Army command devised a plan to capture Trabzon, a strategically located city that played a key role in equipping the Ottoman III Army in the east. In fact, if the Russian army captured Trabzon, it would be able to supply its troops in the east with arms, ammunition and food more quickly. In this sense, Trabzon was very important for the Russians. Consequently, after the occupation of Erzurum, the Russian armies moved towards Bayburt and Gümüshhane via Aşkale on the one hand, and towards Trabzon with both navy and land forces in the eastern Black Sea region on the other. In late March 1916, attacks on Trabzon intensified, culminating in the occupation of the city on April 18, 1916. In this study, the process of the occupation of Trabzon is written in the context of Russian sources. The main difference of this study from the previous ones is that it was prepared by analyzing the information provided in the Russian archival documents and press of the period, as well as in Russian-language sources in general. Therefore, the archival records of the correspondence of Russian commanders with their headquarters during the occupation of Trabzon and the day-to-day news of newspapers and magazines about the war constituted the basis of the originality of the article. [ABSTRACT FROM AUTHOR]

Coasts are settlement areas that attract human for many years. Türkiye, geographically located on Mediterranean Basin and Asian Continent passage with unique climate regime, has a great coastal zone. The mid-latitude geographic setting makes possible to experience coastal recreation and tourism activities for almost all year along. Among all activities sun, sea and sand tourism can be placed on the first stage. Recent changes in local climate of the Black Sea such as rising mean atmospheric temperatures and increasing number of sunny days have triggered touristic beach activities in the region. In the literature, there are different techniques for grading and classifying coastal beaches. In this study, as an integral part of coastal landscape formation Land Use/Land Cover (LULC) structure is linked to landscape value and regarded as cover changes that determines landscape pattern of the area under investigation. The research rationale of this study is based on an assumption of Southern Black Sea coastal blue flag beaches are under severe anthropogenic pressure. For this purpose, 15 blue flag beaches which are located on the Black Sea coast of Türkiye were selected based on their morphological dimensions. To determine landscape changes and potential human induced effects on selected beaches for the last 35–40 years period, georeferenced, atmospherically corrected Landsat 5 TM and Landsat 8 OLI-TIRS satellite images were used. Furthermore, carrying capacities for all researched beaches were calculated and documented in order to find the actual human usage frequencies during the high season. According to results of the study, it is clearly observed that all beach areas are under anthropogenic pressure. The most important evidence of this situation is the proportional increases in the IS (Impervious Surface) cover class in the classified images between 1984 and 1985 and 2021 in all 15 beaches. Moreover, these increases have reached up to 5–6 times for some beaches. As inferred, from the field surveys, beach carrying capacities were also exceeded for the most of the beaches under investigation. This means the blue flag beaches of Southern Black Sea are not only affected by construction and urbanization but also under intense pressure of overuse during the high seasons. It is revealed that these areas should be carefully managed with state-of-the-art techniques that prioritize adaptive planning that takes into account all stakeholders participation. Moreover, the activities, authorization and attitudes of municipalities regarding the coastal zones must be limited and inspected by a higher organization. [ABSTRACT FROM AUTHOR]

The field data on the abundance, biomass, age structure, and lipid reserves of the copepod Сalanus euxinus population in deep pelagial and Crimean shelf regions of the Black Sea in November 2017 were analyzed. The abundance and biomass of this species in deep areas (10.2 ± 0.5 × 103 ind./m2 and 7.3 ± 0.5 g/m2, respectively) were similar to the average annual values for seasons with moderate development of planktivorous jellyfish populations. The average abundance and biomass of the copepods were similar to analogous 2016 values when the jellyfish abundance was twice as low. However, in 2017, the denser aggregations of C. euxinus (12.8 ± 1.0 × 103 ind./m2 and 9.8 ± 0.5 g/m2) were found in the central parts of cyclonic circulations, while in 2016, they were recorded more frequently at the peripheries of cyclonic gyres. A structure of the C. euxinus population also changed. In November 2017, the percentage of copepodites I–IV, females and males, increased, whereas the proportion of copepodites V reduced. These changes likely resulted from a later sampling period in 2017, when the C. euxinus population was ready for active reproduction. Sufficient amounts of lipids in copepodites V, decreased oil sac volumes in females, and increased abundance of males in anticyclonic regions are indicative of more favorable trophic conditions for this part of the C. euxinus population and its higher maturity. [ABSTRACT FROM AUTHOR]

Based on contact data, the dynamics of the abundance (N) and biomass (B) of phytoplankton in 2013–2014 and the concentration of chlorophyll a (Cсhl) in 2000–2003 and 2008–2021 were analyzed using fast Fourier transform (FFT) under conditions of changing water temperature (T) in the vicinity of Sevastopol in the Black Sea. Estimates of the contribution made by the variability of the annual and semiannual harmonics of N, B, Cchl, T to the seasonal cycle amounted to more than 56% for all parameters. A significant relationship between B and Cchl (r < –0.83) at two stations indicates the aging of microalgae. The dominance of different groups of microalgae in the phytoplankton biomass has been detected. A typical period of 2–4 years is distinguished in the interannual variability of Cchl and T in different seasons. [ABSTRACT FROM AUTHOR]

Climate change poses a significant challenge for life on Earth. Different climate modes have been shown to come along with changes of the magnesium/calcium (Mg/Ca) ratio of seawater, and such changes are believed to control the primary mineral phase of marine authigenic carbonates. However, factors controlling marine carbonate phases other than seawater Mg/Ca ratios exist. Fibrous cements forming at methane seeps in the Black Sea provide new insight into the factors governing elemental and mineral phase compositions of fibrous carbonates. In this study, the distribution of aragonite and fibrous Mg calcite cements from three seep sites in the Black Sea is described as a function of water depth. The Mg/Ca ratio of seawater, as well as the ratio in shallow pore water, is close to four at the examined sites. Fibrous Mg calcite post‐dated aragonite cement in seep carbonates from shallow water depth of 120 to 190 m, whereas Mg calcite is the only cement at a greater depth of ca 2000 m. The primary formation of fibrous Mg calcite is confirmed by its zonation under cathodoluminescence, crystal morphologies agreeing with competitive growth, uniformly distributed MgCO3 contents and precipitation in equilibrium with local conditions calculated from δ18O values. The MgCO3 contents (4.5 to 12.2 mol%) are negatively correlated with δ13C values, indicating that the incorporation of Mg into the calcite crystal structure was favoured by high concentrations of sulphide generated by sulphate‐driven anaerobic oxidation of methane. Unlike open oceanic basins, stratification in the Black Sea leads to euxinic conditions in the deeper water column, favouring fibrous Mg calcite formation. This observation is consistent with sulphide catalysis as a critical agent for the formation of low‐Mg calcite to very high‐Mg calcite at high Mg/Ca ratios and is possibly relevant to carbonate cements forming during times of oceanic euxinia. [ABSTRACT FROM AUTHOR]

In this study, the spatial and temporal changes in the landings of whiting (Merlangius merlangus), red mullet (Mullus barbatus) and turbot (Scophthalmus maximus) caught in the Black Sea were discussed using the open access data set of officially recorded landing statistics published by Turkish Statistical Institute (TUIK). The landings of whiting in Turkish seas increased steadily from 1981 to 1988, reaching the highest amount in the 56-year period in 1988. In order years, fluctuation was observed in the production. The catch quantity of red mullet, which continued to increase until 1989, has been decreasing since then and reached its lowest catch amount since 1971 in the year 2022. Turbot, which had the highest catch in 1983, has a catch amount of less than 1000 tons since the early 2000s. In the period between 1967 and 2022, when comparing the production amounts of the Eastern and Western Black Sea, it was found that the majority of the red mullet and turbot catch was obtained from the Eastern Black Sea. Although the catch amount of whiting was high in the Eastern Black Sea until 2017, it has been determined that the Western Black Sea has had more catch since 2017. [ABSTRACT FROM AUTHOR]

Türkiye's extensive coastline and geopolitics position necessitates the importance of Ro-Ro transportation with neighbouring countries. Türkiye's rapidly growing Ro-Ro transportation significantly contributes to imports and exports, which is of great importance to the national economy. Samsun Port is one of the most active ports in Türkiye's Ro-Ro transportation sector, operating in the Black Sea region. This study examined Ro-Ro transportation at Samsun Port, and future cargo forecasting was conducted. For this purpose, artificial neural networks and time series analysis methods were combined. Input variables used in the study included the number of Ro-Ro ships arriving at the port between 2009 and 2021, population figures, a specialized CPI indicator (fresh fruits and vegetables), and export values. The output variable was the amount of cargo carried by Ro- Ro ships. According to the results obtained, it was observed that Samsun Port would have sufficient capacity for Ro-Ro transportation in the next 27 months in terms of wharf, port area, and operational space. [ABSTRACT FROM AUTHOR]