Black Sea Coast Research Articles

First Evidence-Based Record of Common Pandora Pagellus erythrinus on the Turkish Coast of the Black Sea

This paper documents the first evidence-based record of the common pandora (Pagellus erythrinus) from the Turkish coast of the Black Sea, with specimens sampled during 2024. The samples were collected from four locations along the Black Sea coast, from Şile in the west to Perşembe in the east, at depths of 10–17 m in rocky habitats. The study suggests that the common pandora likely entered the Black Sea via the Bosphorus, a natural biological corridor linking the Sea of Marmara and the Black Sea. The recent warming of Black Sea waters and the ongoing process of Mediterraneanization, which facilitates the northward spread of species, are additional contributing factors. Biometric analysis of the specimens revealed total lengths ranging from 20.7 cm to 26.4 cm and body weights between 101.7 g and 248.5 g, confirming that all individuals were mature adults. With their reproductive maturity and high fecundity, the species is well-positioned for successful establishment and expansion in the Black Sea. Proactive monitoring and conservation strategies are recommended to assess the ecological and socio-economic implications of this species, including its potential as a commercially valuable fishery resource in the Black Sea.

Assessment of Heavy Metal Contamination of Seawater and Sediments Along the Romanian Black Sea Coast: Spatial Distribution and Environmental Implications

This study assesses the spatial distribution and contamination levels of some heavy metals (HMs), i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb), in seawater and surface sediments along the Romanian Black Sea coast (RBSC). Sampling was conducted at 40 stations across 12 transects during May–June 2021, and the measured levels of HM concentrations were compared with Environmental Quality Standards (EQS), i.e., maximum allowable concentration (MAC) values, for seawater and effects range-low (ERL) thresholds for sediments. HM concentrations were measured using high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). In seawater, the levels of Cd, Cu, and Pb concentrations exceeded the MAC values at three stations located in areas influenced by the Danube River or anthropogenic activities. In sediments, exceedances of ERL thresholds were found for Ni at 11 stations, for Cu at three stations, and for Pb at one station. HM contamination of sediment samples collected from these stations can be caused by both natural and anthropogenic sources, e.g., the Danube River, rock/soil weathering and erosion, agricultural runoff, port and construction activities, maritime and road transport, coastal tourism, petrochemical industry, wastewater discharges, offshore oil and gas extraction. Principal Component Analysis (PCA) provided valuable information about the relationships between relevant variables, including water depth and HM concentrations in seawater and sediments, and potential sources of contamination. The results highlight the influence of fluvial inputs and localized human activities on HM contamination. While the overall chemical status of Romanian Black Sea waters and sediments remains favorable, targeted management strategies are needed to address localized pollution hotspots and mitigate potential ecological risks. These findings provide valuable insights for environmental monitoring and sustainable coastal management.

Psycho-emotional state of mentally retarded children before and after going on holiday: a pilot study findings

INTRODUCTION. The specific climatic and geographical conditions of the northern region can negatively affect the psycho-emotional state of children and adolescents with disabilities. One of the most common diseases among children with disabilities is mental retardation (MR). Addressing the issues of comprehensive rehabilitation of children with disabilities living in the Far North, increasing the availability of health resort treatment, promoting socialization and adaptation, and improving the quality of their lives is a priority. AIM. To study the effectiveness of summer recreation in the resort area of the Black Sea coast on the psycho-emotional state of mentally retarded children permanently residing in the northern region. MATERIALS AND METHODS. The study included children with disabilities in public educational institutions with instruction under adapted programs in Magadan (n = 37 children, mean age 13.89 ± 2.66 years). The majority of the subjects (94.6 %) were diagnosed with mild (F70) and moderate (F71) mental retardation. The study was conducted using the House-Tree-Person test and included three stages: stage 1 took place 2 months before the wellness holiday; stages 2 and 3 were conducted 2 weeks and 2 months after the wellness holiday, respectively. RESULTS AND DISCUSSION. The study found a reliable improvement in the indicators of the psycho-emotional state of the subjects 2 weeks after departure for summer holidays in the parameters: mood decline (p = 0.039); anxiety (p = 0.0001); unmet needs for social and emotional contacts (p = 0.037); fears (p = 0.0001). Two months after the summer holidays, the improved level of the psycho-emotional state indicators persisted, the analysis showed a reliable decrease in the values for the following parameters: mood decline (p = 0.001); anxiety (p = 0.0001); unmet needs for social and emotional contacts (p = 0.015); fears (p = 0.006). CONCLUSION. The analysis of the findings obtained in the study demonstrated positive trends in the psycho-emotional state of children with mental retardation living in Magadan region before and after their departure for a summer wellness holiday in the resort area of the Black Sea coast. Notable improvements were observed in the parameters of anxiety, communicative activity, and the levels of manifestation of fears and depressive symptoms.

First Report of Microplastic Ingestion and Bioaccumulation in Commercially Valuable European Anchovies (Engraulis encrasicolus, Linnaeus, 1758) from the Romanian Black Sea Coast

First Report of Microplastic Ingestion and Bioaccumulation in Commercially Valuable European Anchovies (Engraulis encrasicolus, Linnaeus, 1758) from the Romanian Black Sea Coast

Multiple factor analysis using water quality index scores and parameters as an approach for evaluating the environmental status of polluted lakes along the Black Sea coast of Bulgaria

Multiple factor analysis using water quality index scores and parameters as an approach for evaluating the environmental status of polluted lakes along the Black Sea coast of Bulgaria

Ecological stoichiometry of macroalgae from Sinop Peninsula coast of Black Sea, Türkiye: characterization of C:N:P.

This comprehensive ecological investigation systematically analyzed the temporal and spatial variations in carbon (C), nitrogen (N), and phosphorus (P) concentrations across diverse macroalgal assemblages inhabiting the upper infralittoral zone of the Sinop peninsula. The study encompassed seasonal sampling conducted at five distinct stations between October 2019 and July 2020, targeting nine prevalent macroalgal species representing three major taxonomic groups: Chlorophyta, Rhodophyta, and Phaeophyceae. Statistical analyses revealed statistically significant (p < 0.05) variations in mean elemental concentrations across seasonal, regional, and species-specific dimensions. The elemental concentration ranges demonstrated substantial diversity, with carbon concentrations spanning from 14.73% in Corallina officinalis to 43.04% in Pterocladiella capillacea. Nitrogen concentrations exhibited remarkable variability, ranging from 0.50% in C. officinalis to 5.14% in Ceramium spp., while phosphorus concentrations varied from 0.02% in Ceramium spp. to 0.32% in Ulva rigida. The elemental ratio analyses uncovered intricate inter-specific variations, with carbon/phosphorus ratios ranging from 157 in C. officinalis to 4255 in Laurencia obtusa, nitrogen/phosphorus ratios varying from 9 to 304, and carbon/nitrogen ratios spanning from 9 to 51. Taxonomic group-level analyses revealed nuanced nutritional characteristics, with nitrogen concentrations showing slight variations across green (1.98%), brown (1.76%), and red (2.20%) algae, and phosphorus concentrations exhibiting similar patterns across these taxonomic groups. The macroalgal community presented a mean C:N:P atomic ratio of 1187:57:1, with a median ratio of 859:41:1. These stoichiometric signatures predominantly indicate phosphorus limitation across the studied macroalgal assemblages along the Sinop coastal region, with C. officinalis emerging as a notable exception.

Current state of natural and artificial radiation in the Eastern Black Sea Coast of Türkiye (Trabzon–Rize–Artvin) 38 years after Chernobyl

Abstract The aim of this study was to evaluate the artificial and natural radiation dose levels in the coastal areas of Trabzon–Rize–Artvin provinces 38 years after the Chernobyl nuclear accident. Radioactive 232Th, 238U, 40K and 137Cs concentrations were determined in 49 soil samples by HPGe gamma spectrometry. Average concentrations were 12 Bqkg−1 for 238U, 15 Bqkg−1 for 232Th, 162 Bqkg−1 for 40K and 37 Bqkg−1 for 137Cs. Annual effective dose equivalents and excess lifetime cancer risk values are below the world average. This study also presents the average 137Cs value measured in the same area from 1990–2004–2024.

DNA metabarcoding study of the diet and feeding preferences of the Grey Plover (Pluvialis squatarola) during migration on the SW Black Sea coast, Bulgaria

We studied the diet composition and feeding preferences of the Grey Plover (Pluvialis squatarola) at its migration stopover at Pomorie Lake on the South-Western Black Sea coast, Bulgaria, through DNA metabarcoding of faeces. Faecal samples were collected in autumn 2020 and spring 2021, preserved in 95% ethanol, and stored at -20ºC until DNA extraction and metabarcoding. Two molecular markers were initially targeted - ITS2 for plant identification, and CO1 for animal identification; however, the subsequent analyses focused on the dominant animal prey identified by CO1. Concurrently, coastal habitats where the birds were observed to feed, such as the surf zone and the sandy supralittoral shore, were also sampled to determine prey availability. The Grey Plover had a broad diet spectrum, with 332 prey taxa in total identified by metabarcoding, belonging to 7 phyla, 14 classes, 24 orders, 78 families and 119 genera. The birds consumed both terrestrial and marine taxa, suggesting that multiple coastal habitats are used for foraging. Terrestrial arthropods, particularly insects, predominated in the diet, while mytilid bivalves were the most represented marine taxon. The results suggest that at the studied migration stopover site at the SW Black Sea, the Grey Plover was a generalist feeder, which agrees with previous studies from different areas. Most birds fed on insects (Diptera, Lepidoptera, Hymenoptera); a few individuals also specialised on marine molluscs, arachnids and polychaetes. The most abundant potential prey in the environ­ment were not the most frequently consumed, possibly because the sampling methods were not suitable for the full spectrum of available prey (particularly the flying insects). We found limited seasonal variation in Grey Plover diet composition and preferences, with the proportions of some prey taxa differing slightly between seasons, probably due to seasonal variations in their abundance and activity in coastal habitats. Our results contribute to the knowledge of Grey Plover diet, prey choice and habitat use in a little-studied region on the Black Sea-Mediterranean Flyway. The new information could contribute towards designing effective conservation measures to preserve habitat quality at stopover sites for this wader and others with similar ecology, ensuring migration success at a time when migratory bird populations are increasingly threatened by habitat loss and degradation. The results are presented and analysed in detail in Vassileva et al. (2024). The full CO1 dataset is available in BOLD (https://doi.org/10.5883/DS-PLUVS).

Coastal motion at tide gauge stations along the Black Sea coast from in-situ and space-based observations

Coastal motion at tide gauge stations along the Black Sea coast from in-situ and space-based observations

Riverine microplastic discharge along the southern Black Sea coast of Türkiye

Abstract Rivers are critical pathways of microplastic (MP) pollution to marine environments, yet their contributions to the Black Sea remain understudied. This study evaluates the abundance and characteristics (polymer composition, shape, size, and color) of MPs discharged from 29 rivers flowing into the southern Black Sea. Using a plankton net with a 200 μm mesh size, samples were collected from river mouths, revealing an average MP abundance of 9.63±1.27 MP/m³, ranging from 1.03 to 29.8 MP/m³. Eastern Black Sea rivers exhibited significantly higher MP levels (11.0±1.57 MP/m³) compared to western rivers (5.15±1.25 MP/m³). Annual MP discharge to the Black Sea was estimated at 1.49×10¹¹ particles. Polyethylene terephthalate (PET, 59.3±2.66%), polyethylene (PE, 20.8±2.04%), and polypropylene (PP, 14.1±2.36%) were the most common polymers, with PET and PE being significantly dominant. MP sizes ranged predominantly between 200–1.000 μm, and fibers constituted the majority of shapes (64.1%), followed by fragments (28.3%). White (36.8±1.93%) and transparent (30.9±2.39%) MPs were the most prevalent colors. While no significant differences in MP characteristics were detected between basins (NMDS and ANOSIM), this study emphasizes rivers as major pathways for MP pollution in the Black Sea. These findings underscore the urgent need for targeted mitigation strategies to safeguard marine ecosystems and biodiversity.

Investigation of Marine Litter Pollution on the Coast According to Different Usage Purposes and Urbanization.

Three beaches on the Eastern Black Sea coast of Türkiye, with different usage purposes and urbanization, were evaluated regarding marine litter densities and categories in four seasons. 3573 marine litter items were collected, classified, and recorded. In an area of 3,000 m2, the highest amount of litter was counted in summer with a total of 1473 pieces of litter (Average: 0.491 ± 0.131 items/m2), and the lowest was counted in the spring months with 577 pieces of litter (Average: 0.192 ± 0.026 items/m2). Plastics (79 ± 0.9%) were the most predominant, and litter items mainly consisted of metal (7.2 ± 0.5%) and paper/cardboard (5.6 ± 0.6%.). Beach litter was also associated with fishing activities and tourism. It was observed that litter relatively increased during the fishing season in the region where fishing activities were intense. SIMPER analysis revealed that Çamburnu, located near a fishing port, exhibited a significantly different litter composition, with fishing gear being the most dominant category.

Exploring secondary contamination in river and spring waters: A novel phenomenon arising from seawater intrusion into deep coastal aquifers.

Exploring secondary contamination in river and spring waters: A novel phenomenon arising from seawater intrusion into deep coastal aquifers.

Ecdysteroids in Native Trees and Callus Cultures of the Genus Vitex L. of the Flora of Russia and Vietnam.

Vitex L. is a large genus of tropical and subtropical trees used in medicine of many nations. Some species are used in gynecology due to flavonoids, iridoids, and diterpenes. Other species were shown to contain ecdysteroids and are used as tonic remedies. This study aimed to investigate content and patterns of distribution of ecdysteroids in native trees and their accumulation in in vitro cell cultures as potential biotechnological agents of Vitex species growing in remote flora of Russia and Vietnam. Targeted UPLC-MS/MS was used for the quantitation of the ecdysteroids in samples of plants and callus cultures of Vitex species. Determination of nucleotide sequences was carried out on ABI PRISM 3730xl sequencer. Phylogenetic tree was constructed using Mega v.7.0. Samples of Vitex agnus-castus L. from Russian Black Sea coast of the Caucasus, as well as samples of nine species of Vitex from Vietnam were collected for ecdysteroids quantification. Relationships between the content of ecdysteroids and the systematic position of the Vitex species were shown. Higher levels of ecdysteroids were revealed in different plant parts of Vitex canescens Kurz, Vitex pinnata L., Vitex quinata (Lour.) F.N.Williams, and Vitex tripinnata (Lour.) Merr. It has been established that species rich in ecdysteroids, as well as those containing trace amount of ecdysteroids (V. agnus-castus L., Vitex negundo L., and Vitex rotundifolia L.f.) are grouped in certain clades isolated from each other on the molecular phylogenetic tree of the genus. The most promising raw materials are the young leaves of V. tripinnata (8562 μg/g of dry biomass), as well as the bark of V. canescens (16,520 μg/g) and V. quinata (19,130 μg/g). The bark of V. canescens could be a good source of turkesterone (11α-oxyecdysteroid) that has pronounced pharmacological effects. Its content reaches up to 1400 μg/g in the bark. Discovering ability of callus cultures for synthesis of ecdysteroids allows us to outline experimental ways to increase the level of ecdysteroid biosynthesis in biotechnological systems as alternative source of ecdysteroids.

A Long-Term Perspective of Seasonal Shifts in Nutrient Dynamics and Eutrophication in the Romanian Black Sea Coast

This study investigates the long-term seasonal shifts in nutrient dynamics and eutrophication processes in the Romanian Black Sea coastal waters using multi-decadal data (1960/1976/1980–2023). The findings highlight significant seasonal and interannual changes, revealing a progressive rise in seawater temperature, declining oxygen concentrations, and notable shifts in nutrient stoichiometry, particularly an increasing nitrogen–phosphorus (N:P) ratio. These changes are closely associated with increased occurrences of harmful algal blooms (Noctiluca scintillans), emphasizing the complex relationship between warming, nutrient and dissolved oxygen cycles, and biological activity. Seasonal patterns show that prolonged warmer periods, especially during autumn, exacerbate oxygen depletion and nutrient imbalances, with implications for marine life and food webs. The study underscores the importance of targeted nitrogen reduction strategies, including optimized fertilizer use, improved wastewater treatment, and the establishment of buffer zones to minimize land-based nutrient inputs. Regional cooperation and integrated coastal management aligned with the Marine Strategy Framework Directive are essential for mitigating eutrophication. The results provide critical insights into the impacts of climate change on the Black Sea ecosystems. This research contributes to global efforts under SDG 13 (Climate Action), SDG 14 (Life Below Water), and SDG 3 (Good Health and Well-being), addressing the key challenges to marine biodiversity, water quality, and ecosystem sustainability.

Cladoceran species and their population abundance across the Black Sea from west to east during summer 2020

ABSTRACT The study aimed to trace the influence of several abiotic factors on the distribution of the cladoceran group from the southern Black Sea. Samples were collected from 21 stations located on the Turkish Black Sea coast from west to east in the summer season of 2020. After determining the species composition, and abundance, the results were subjected to statistical analysis. A total of four Cladocera species (Penilia avirostris, Pseudevadne tergestina, Evadne spinifera, Pleopis polyphemoides) were identified. The abundance was relatively higher in the stations located on the south-eastern Black Sea coast. Cladocera composition quantitatively showed a significant separation above and below the thermocline according to nonmetric multidimensional scaling (NMDS). Similarity Percentage Analysis (SIMPER) determined 70.51% dissimilarity by composition above and below the thermocline, where P. avirostris contributed 87.62% of the dissimilarity. The cladoceran community responded differently to the analysed environmental factors, showing both positive and negative correlations. A positive correlation was observed between cladocerans and temperature, nitrate + nitrite-N (NO3 + NO2-N) and chlorophyll-a, while a negative correlation was observed between cladocerans and salinity, nutrients (silicon, Si) and oxygen (O2).

When “More” Is “Too Much”—A Study on Tourists’ Perception Regarding Beach Restoration in Mamaia on the Romanian Black Sea Coast

When “More” Is “Too Much”—A Study on Tourists’ Perception Regarding Beach Restoration in Mamaia on the Romanian Black Sea Coast

Fusion of In-Situ and Modelled Marine Data for Enhanced Coastal Dynamics Prediction Along the Western Black Sea Coast

This study explores the use of Temporal Fusion Transformers (TFTs), an AI/ML technique, to enhance the prediction of coastal dynamics along the Western Black Sea coast. We integrate in-situ observations from five meteo-oceanographic stations with modelled geospatial marine data from the Copernicus Marine Service. TFTs are employed to refine predictions of shallow water dynamics by considering atmospheric influences, with a particular focus on wave-wind correlations in coastal regions. Atmospheric pressure and temperature are treated as latitude-dependent constants, with specific investigations into extreme events like freezing and solar radiation-induced turbulence. Explainable AI (XAI) is exploited to ensure transparent model interpretations and identify key influential input variables. Data attribution strategies address missing data concerns, while ensemble modelling enhances overall prediction robustness. The models demonstrate a significant improvement in prediction accuracy compared to traditional methods. This research provides a deeper understanding of atmosphere-marine interactions and demonstrates the efficacy of Artificial intelligence (AI)/Machine Learning (ML) in bridging observational and modelled data gaps for informed coastal zone management decisions, essential for maritime safety and coastal management along the Western Black Sea coast.

Mapping the Distribution and Population Status of Alosa immaculata and Alosa tanaica (Teleostei, Clupeidae) in the Bulgarian Black Sea Area

(1) Background: To date, data concerning the population of Alosa immaculata and Alosa tanaica from the marine waters of Bulgaria are rather scarce. In the range of a project for mapping the Bulgarian marine protected sites from the network NATURA 2000, we provide an intense investigation of the biology and distribution of both Alosa species. (2) Methods: A trawling survey was carried out within 102 predefined sampling plots of 10 × 10 km grid cells (93 cells on the continental shelf, up to 100 m depth, and 9 offshore cells). In some coastal regions, sampling was conducted with gill nets of different mesh sizes (28 mm to 36 mm). Analysis of the suitability of the occupied habitat of both species was carried out using the MAXENT v 3.4.0 software application. The status of the populations was studied based on the parameters abundance (ind./km−2), biomass (kg/km−2), size, sex structure, maturity, and food spectrum. (3) Results: Out of 102 transects studied, A. immaculata was found in 12 transects and A. tanaica in 13. A total of 408 fish specimens were captured, out of which 313 were A. immaculata and 95 were A. tanaica. Both species were distributed along Bulgaria’s entire Black Sea coast, with a numerical prevalence of the catches in the southern part. The population size of A. immaculata for the number of individuals on a biographical level in the Marine Black Sea Biographic Region (MBLS) was a minimum of 100,255 individuals and a maximum of 526,408 individuals (the average was 313,286). The population size for A. tanaica was a minimum of 28,183 individuals and a maximum of 449,549 individuals (an average of 238,866). The current population density of A. immaculata in the MBLS was 25.98 ind./km−2, and for A. tanaica, it was 19.00 ind./km−2. The current biomass of the population of A. immaculata in the MBLS was 3.44 kg/km−2, and the population of A. tanaica was 0.53 kg/km−2. The sex ratio for A. immaculata was 1 male:2.6 females, and for A. tanaica, 1 male:3.8 females. Both shad species were feeding with less intensity or not feeding during the winter. The diversity in the food spectrum of A. tanaica was more limited compared to that of A. immaculata. (4) Conclusions: Key parameters for the Bulgarian Black Sea Exclusive Economic Zone indicate current stability in the resources of A. immaculata and A. tanaica and more favorable conditions for the populations in the Natura 2000 sites compared to that outside the Natura 2000. The results of this study should be used to develop management plans for marine protected areas, and future monitoring projects should follow the sampling protocol.

Coastal Inlet Analysis by Image Color Intensity Variations: Implications for the Barrier Coast of Ukraine

Inlets through coastal barriers in functionally non-tidal settings have been relatively understudied. Yet, they have morphosedimentary elements and morphodynamic behaviors that are similar to their tidal counterparts, especially microtidal (often wave-dominated) inlets. Increasingly, remote sensing technologies (aerial and satellite imagery, small unmanned aerial vehicles, etc.) are employed as sources of high-definition spatial databases. Such approaches are important in areas with limited access, especially in regions of military conflict, such as along parts of the northern Black Sea coast, Ukraine. For rapid spatial analysis of remotely sensed or archival datasets, image color intensity (ICI) patterns are obtained using grayscale (GS) spectra and a wide range of filter options. Areal and profile-style GS patterns based on relative ICI values are extracted from available imagery, so that in a full 256-value GS spectrum the deepest parts of a channel (inlet throat) will have the lowest (darkest) values (GS &lt; 50). Landward (flood-tidal/bayside) and seaward (ebb-tidal/seaside) deltas will exhibit lighter colors (GS &gt; 100). Exposed siliciclastic/carbonate sand-dominated barriers and shoals will yield the lightest values (GS &gt; 200), with dark vegetation requiring GS inversion. Hypsometric information, as well as key metrics (perimeter and area) can be easily computed using instant tracing tools, without the need for labor-intensive contour outlining. This study is the first example of assessing cross-shore and longitudinal channel morphology of microtidal (USA) and non-tidal (Ukraine) inlets. The approach is also extended to a temporal analysis of inlet closure and a recent re-activation by an intense storm.

Assessing the Black Sea Mesozooplankton Community Following the Nova Kakhovka Dam Breach

In June 2023, following the breach of the Nova Kakhovka Dam during the Ukraine-Russia war, a comprehensive study was conducted along the Romanian Black Sea coast to assess water quality and mesozooplankton communities. Surface water analyses revealed significant gradients in nutrient levels and salinity, particularly from north to south, influenced by the influx of freshwater and nutrients from riverine sources and the dam breach. Flooding was found to significantly impact nutrient dynamics and species distributions, with increased concentrations of SiO4 and NO3 in flooded stations. A strong relationship was observed between environmental factors and biological assemblages, with silicates identified as a key driver. Biodiversity patterns varied across regions, with the Shannon–Wiener Index indicating lower zooplankton diversity in transitional waters, reflecting environmental stress. Statistical methods, including correlation analysis, multidimensional scaling, t-tests, and canonical analysis, were employed to investigate the links between mesozooplankton communities and environmental variables. These findings underscore disruptions in trophic dynamics and ecosystem balance, emphasizing the need for integrated environmental management strategies to mitigate further degradation and foster the ecological recovery of the Black Sea.