Sea Coastal Area Research Articles

Wind Variation near the Black Sea Coastal Areas Reflected by the ERA5 Dataset

In the context of the European Green Deal implementation, it is expected that there will be an increase in number of the wind farms located near the coastal areas in order to support this initiative. The Black Sea represents an important source of wind energy, and as a consequence, in the present work the regional wind resources (onshore and offshore) are evaluated by considering a total of 20 years of ERA5 wind data covering the 20-year time interval from January 2002 to December 2021. From a general perspective, it is clear that the offshore areas (100 km from the shoreline) are defined by much higher wind speed values than in the onshore, reaching an average of 8.75 m/s for the points located on the western sector. During the winter, these values can go up to 8.75 m/s, with the mention that the northern sectors from Ukraine and Russia may easily exceed 8 m/s. In terms of the wind turbines’ selection, for the offshore areas defined by consistent wind resources, generators will be considered that are defined by a rated wind speed of 11 m/s. Finally, we can mention that a theoretical offshore wind turbine of 20 MW can reach a capacity factor located between 20.9 and 48.3%, while a maximum annual electricity production of 84.6 GWh may be obtained from the sites located near the Romanian and Ukrainian sectors, respectively.

Ostracods reveal the palaeoenvironmental changes in Laizhou Bay, Bohai Sea (eastern China) since the Late Pleistocene

Laizhou Bay is located in the Bohai Sea, eastern China. Since the Late Pleistocene, Laizhou Bay has gone through frequent transgressive and regressive activities and both marine and non-marine sediments have been deposited. In order to further understand the palaeoenvironmental changes since the Late Pleistocene, a core (DK06) was drilled on the coastal plain of Laizhou Bay. From this core, we obtained abundant well-preserved ostracod specimens. After environmental analysis and cluster analysis of these ostracods, four biofacies have been recognised: Biofacies I (shallow marine facies), Biofacies II (estuarine facies), Biofacies III (brackish water facies), Biofacies IV (freshwater facies). The studied ostracod assemblages suggest that the palaeoenvironment of Laizhou Bay went through four transgressions including three well-known marine transgressions during MIS 1, MIS 3 and probably MIS 5 and three regressions since the late Pleistocene, indicating substantial impact of glacial-interglacial sea level changes on the Bohai Sea coastal areas and their biota.

Evaluation of halophilic microalgae isolated from Rabigh Red Sea coastal area for biodiesel production: Screening and biochemical studies

In the present study, different water samples from Red Sea coastal area at Rabigh city, Saudi Arabia were studied for their dominant algal species. Microalgal isolation was carried out based on dilution method and morphologically examined using F/2 as a growth medium. Dry weight and main biochemical composition (protein, carbohydrates, lipids) of all species were performed at the end of the growth, and biodiesel characteristics were estimated. Nannochloropsis sp., Dunaliella sp., Tetraselmis sp., Prorocentrum sp., Chlorella sp., Nitzschia sp., Coscinodiscus sp., and Navicula sp. were the most dominant species in the collected water samples and were used for further evaluation. Nannochloropsis sp. surpassed all other isolates in concern of biomass production with the maximum recorded dry weight of 0.89 g L−1, followed by Dunaliella sp. (0.69 g L−1). The highest crude protein content was observed in Nitzschia sp. (38.21%) and Dunaliella sp. (18.01%), while Nannochloropsis sp. showed 13.38%, with the lowest recorded lipid content in Coscinodiscus sp. (10.09%). Based on the growth, lipid content, and biodiesel characteristics, the present study suggested Dunaliella sp. and Nitzschia sp. as promising candidates for further large-scale biodiesel production.

Environmental DNA reveals fine‐scale habitat associations for sedentary and resident marine species across a coastal mosaic of soft‐ and hard‐bottom habitats

AbstractAccurate knowledge on spatiotemporal distributions of marine species and their association with surrounding habitats is crucial to inform adaptive management actions responding to coastal degradation across the globe. Here, we investigate the potential use of environmental DNA (eDNA) to detect species–habitat associations in a patchy coastal area of the Baltic Sea. We directly compare species‐specific qPCR analysis of eDNA with baited remote underwater video systems (BRUVS), two non‐invasive methods widely used to monitor marine habitats. Four focal species (cod Gadus morhua, flounder Platichthys flesus, plaice Pleuronectes platessa, and goldsinny wrasse Ctenolabrus rupestris) were selected based on contrasting habitat associations (reef‐ vs. sand‐associated species), as well as differential levels of mobility and residency, to investigate whether these factors affected the detection of species–habitat associations from eDNA. To this end, a species‐specific qPCR assay for goldsinny wrasse is developed and made available herein. In addition, potential correlations between eDNA signals and abundance counts (MaxN) from videos were assessed. Results from Bayesian multilevel models revealed strong evidence for a sand association for sedentary flounder (98% posterior probability) and a reef association for highly resident wrasse (99% posterior probability) using eDNA, in agreement with BRUVS. However, contrary to BRUVS, eDNA sampling did not detect habitat associations for cod or plaice. We found a positive correlation between eDNA detection and MaxN for wrasse (posterior probability 95%), but not for the remaining species and explanatory power of all relationships was generally limited. Our results indicate that eDNA sampling can detect species–habitat associations on a fine spatial scale, yet this ability likely depends on the mobility and residency of the target organism, with associations for sedentary or resident species most likely to be detected. Combined sampling with conventional non‐invasive methods is advised to improve detection of habitat associations for mobile and transient species, or for species with low eDNA concentrations.

Trace metal accumulation in tissues of wedge clams from sandy habitats of the Bulgarian Black Sea coast

The aim of the present study was to carry out an initial screening of trace metals bioaccumulation in soft tissues of the wedge clam (Donax trunculus Linnaeus, 1758) from different localities of the Bulgarian Black Sea coastal area and to evaluate the bioindicator potential of this species. Wedge clams were collected in June and September 2020 from sublittoral sandy habitats at different localities of the Bulgarian Black Sea coast. Soft tissues of individual clams were digested with nitric acid followed by ICP-OES analytical determination. The content of trace metals in the wedge clams differed significantly amongst localities. Higher metal content was present in wedge clams from Sveti Vlas, Shkorpilovtsi, Slanchev Bryag, Ahtopol and Kranevo. The highest values of lead (Pb) (2.51 mg/kg) and cadmium (Cd) (0.32 mg/kg) were found in samples from Sveti Vlas and the highest concentration of copper (Cu) (34.12 mg/kg), iron (Fe) (269.52 mg/kg) and nickel (Ni) (0.32 mg/kg) were detected in wedge clams from Shkorpilovtzi. Maximum content of chromium (Cr) (0.58 mg/kg) was present in samples from Slanchev Bryag, together with high values of Fe. The highest concentration of zinc (Zn) (18.04 mg/kg) together with high values of Cr and Fe were measured in wedge clams from Irakli. In conclusion, the wedge clams from the localities known to have higher coastal inflows and touristic pressures, i.e. Varna, Shkorpilovtzi, Sveti Vlas, Slanchev Bryag and Ahtopol accumulated significantly higher metal elements in their tissues. Only few significant seasonal differences in the concentration of metal elements in wedge clams were present and the observed seasonal variations were probably connected to the hydrological parameters of the ecosystems. The wedge clam D. trunculus is a suitable bioindicator for assessment and monitoring of metal pollution in the Bulgarian Black Sea environment.

Seasonal changes in the pro/antioxidant status of mussels Mytilus galloprovincialis (Lamarck, 1819) from Bulgarian Black Sea coastal habitats

The pro/antioxidant status of marine macrozoobentic organisms is being increasingly applied in environmental monitoring and conservation programs. The oxidative stress level in marine bivalves can provide valuable information not only on the health of the organisms and their populations, but also on the current state of habitats and ecosystems. The aim of the present study was to make the first comprehensive investigation of the seasonal changes in the antioxidant activity in different organs (gills, digestive gland and foot) of M. galloprovincialis from representative Bulgarian Black Sea coastal habitats. The lipid peroxidation and glutathione levels, as well as activities of the antioxidant enzymes catalase, superoxide dismutase, glutathion peroxidase, glutathion reductase, glucose-6-phosphate dehydrogenase and glutathione-S-transferase of the organs were measured spectrophotometrically. Our hypothesis was that enhanced environmental pressure during the summer season, induced by multiple factors (biogenic, abiogenic and anthropogenic) led to weakening of the antioxidant protection in mussels at the beginning of autumn. The reaction of the mussel organism to the multiple stress factors was specific for the target organ and the type of the biomarker. Significant differences were present in the activity of the antioxidant system in mussels from the northern and southern coastal locations. The seasonal changes in the pro/antioxidant status of mussels were primarily due to specific seasonal changes in factors concerning the marine environment at the concrete locality. Further research is obviously needed to confirm the present results and provide a more complete data of seasonal and spatial changes in the antioxidant defense system of mussels from the Bulgarian Black Sea coastal area and their implementation in biomonitoring programs.

THE SEDIMENTOLOGY OF HYDROCARBON RESERVOIR ROCKS IN INDONESIA, A CASE STUDY FROM THE NORTH SUMATRA BASIN

The North Sumatra backarc basin has been an important hydrocarbon province for more than 100 yrs. High grade light oils and condensates have been produced from sandstone reservoirs in the deltaic Keutapang Formation and the shallow marine sandstones of the Baong Formation. The basin has a high geothermal gradient, which is in the order of 40-50 C/km (compared to 30/km in the North Sea or Gulf Coast areas) and is a result of its position close to the subducting margin of the Indian Ocean Plate.

Seasonal Distributions of Methane in a Populous Urban Coastal Sea Area

Methane (CH4) is an important greenhouse gas, and its concentrations in aquatic areas are heavily influenced by anthropogenic activities, especially human-induced eutrophication, polluted river discharge and wastewater treatment plant (WWTP) effluents. Although coastal areas and estuaries contribute large amounts of global oceanic CH4 emissions, the relative contributions of different sources have not been well determined. The Tamsui River located in northern Taiwan is an urban river flowing through populated cities and thus likely carries large amounts of contaminants, such as nutrients and organic matter to the estuary. In this study, we characterized the spatial distribution and seasonal variations in CH4 in the Tamsui River estuary adjacent marine areas. The sea-to-air CH4 fluxes were also estimated to quantify the strength of the study area as an atmospheric CH4 source. Our results showed that CH4 concentrations in coastal sea areas were influenced by WWTP effluents, sediment and freshwater inputs. Thus, river discharge and nutrient levels as well as strong vertical mixing and disturbances might increase CH4 concentrations and emissions. The seasonal surface CH4 concentrations and sea-to-air CH4 fluxes were 13.7 ± 18.7 nM and 41.7 ± 68.0 μmol m-2 d-1 in autumn; 29.3 ± 19.8 nM and 61.3 ± 44.6 μmol m-2 d-1 in spring; 21.8 ± 13.9 nM and 37.0 ± 26.2 μmol m-2 d-1 in summer; and 27.0 ± 21.4 nM and 85.9 ± 75.4 μmol m-2 d-1 in winter.

Multi-technique geodetic detection of onshore and offshore subsidence along the Upper Adriatic Sea coasts

• InSAR-GNSS-Levelling data cross-validation procedure. • Unprecedented 20-years window estimation of onshore deformation along the Upper Adriatic Sea coastal areas. • Cross-validated deformation detected at an offshore platform for hydrocarbon extraction activity. We assess about 20 years of onshore and offshore subsidence along a sector of the Upper Adriatic Sea (Italy) coastal areas affected by natural soil compaction and intense anthropogenic activities such as aquifers exploitation and hydrocarbons extraction. Our approach is based on the synergistic use of independent remote sensing and in-situ geodetic data to detect and spatially characterise the deformation pattern by cross-validating the different available measurements. We collect extensive datasets from i) SAR images provided by Envisat, Cosmo-SkyMed and Sentinel-1 missions, ii) GNSS measurements from continuous stations managed by public institutions, local authorities and private companies and iii) Leveling surveys. The cross-validation analysis shows good agreement among all the independent datasets, thus providing a reliable assessment of the ongoing deformation. We detect an onshore and offshore subsidence peak of about −1/-1.5 cm/yr in the proximity of the coastline, close to Lido di Dante and Fiumi Uniti villages, and at the present offshore platform. The outcomes highlight how the integration of different remote sensing and in situ geodetic techniques is successful to retrieve deformation history in time and space in complex areas, where different natural and anthropogenic sources concur to the overall deformation pattern. Moreover, such approach provides a robust support to modelling studies for hazard assessment in both inland and shoreline areas.

Analysis of hyperspectral and multispectral reflectance spectra in the Black Sea coastal area near the Danube delta: comparison of PRISMA and Sentinel-2 observations

Abstract In this study we investigate the possibility to distinguish between different water types in the Danube delta and the Black Sea coastal zone based on the reflectance spectra. For this we use hyperspectral satellite images from PRISMA (PRecursore IperSpettrale della Missione Applicativa) and multispectral images from Sentinel-2 MSI (MultiSpectral Instrument) in July 2020. The visual inspection of the available acquisitions differentiates between four aquatic types: lagoons; river and stream plumes mixing with marine waters; turbid and optically complex coastal waters; and optically clean waters away from the shore. For each of the four types we determine the characteristic averaged reflectance spectra from PRISMA and Sentinel-2 for the spectral range from 400 nm to 2500 nm. It is found that Sentinel-2 spectra are very similar for the 4 water types, in contrast to the PRISMA spectra which give substantial additional information. Further we analyse the gradual modification of the characteristic hyper- and multispectral spectra from the shoreline to the open sea (∼25 km distance) in 15 locations passing through areas of varying turbidity. We demonstrate that the intensity of surface reflectance from the hyperspectral instrument decreases gradually with distance from shoreline, clearly showing the transition zone between riverine and marine water. The multispectral reflectance spectra for the same study areas did not present such consistent behaviour. The presented results demonstrate the benefits of hyperspectral over multispectral images for turbid aquatic regions in the Black Sea coastal zone. They show that with little requirements regarding pre-processing and computational resources hyperspectral data can contribute greatly to classification of water types, in respect of their turbidity.

Species composition and density of fish eggs and larvae in the coastal waters of the South-Central Vietnam

Based on species composition and density data of fish egg and larvae in South Central coastal sea areas of Vietnam Sea waters were collected at Cù Lao Cham - Thu Bon river, Ly Son - Tra Bong river - Sa Ky river and Nha Trang - Nha Phu lagoon. Thirty-one fish eggs and larvae families were identified (about 18% of total fish eggs and 100% of wholte larvae). Cu Lao Cham - Thu Bon river has the richest species composition as 18 families, following to that is Ly Son - Tra Bong - Sa Ky and lower is Nha Trang - Nha Phu identified 15 and 10 families, respectively. The highest frequency was found in families such as Mullidae, Engraulidae and Synodontidae with 2 to 3 species (groups). The above families account for about 60% of the total number of fish eggs and larvae collected. The average fish eggs and larvae abundance about 3,630 eggs/1,000 m3 of water and 122 larvae/1,000 m3 of water. The highest eggs density is Nha Trang - Nha Phu, and the highest larvae density is Cu Lao Cham - Thu Bon river. Ly Son - Tra Bong - Sa Ky areas have eggs density lower than other areas, especially for larvae density with 22 larvae/1,000 m3 of water.

Mapping coastal fishing grounds and assessing the effectiveness of fishery regulation measures with AIS data: A case study of the sea area around the Bohai Strait, China

AIS data provide a good data source for revealing the distribution of marine fishing activities, assessing marine ecological pressure, and formulating and improving fishery regulation measures. In this study, a method of rapidly mapping fishing grounds was proposed, which combined Kernel Density Estimation (KDE) with Hot Spot Analysis (HSA). Then, taking the coastal sea area around the Bohai Strait in China as an example, the fishing ground in the coastal sea area was mapped based on Automatic Identification System (AIS) data, and the effectiveness of fishing regulation measures was analysed. The results showed that the fishing activities in the sea area around the Bohai Strait had obvious monthly and quarterly changes and spatial heterogeneity. Fishery regulation measures such as a summer fishing moratorium, stock enhancement, marine functional zoning, and coastal zones close to motorized bottom trawling have had certain restrictive effects on fishing activities. China has made significant efforts in the restoration of coastal fishery resources and the regulation of fishing activities to promote the sustainable development of fisheries and improve the marine ecological environment.

Контроль течений на поверхности прибрежных морских акваторий дистанционными методами

Object and purpose of research. The compare analysis carried out on the vorticies structure optical satellite pictures observation of the sea surface and the velocities field obtained by the ground HF Doppler radar. The purpose of this research is estimation of the possibility on fast monitoring feasibility assessment for the changes in littoral waters dynamics through joint application of satellite surveillance, radar probing of sea currents, wind data and numerical simulation of water circulation in the area under investigation. Materials and methods. The Sea surface observation data obtained by the satellites Sentinel 1 and 2 and by the coastal Doppler HF radar Sea Sonde in the South-east Black Sea area are analyzing. The additional data on the satellite observation of this area and on the wind condition is used from LANCE processing system [9, 10] and reanalysis NCEP/NCAR [11, 12]. The comparative analysis is carried out on the large vertical structures (LVS) establishing in the research coastal area. The numerical modeling of the water mass circulation in this area is carried out by the software package COHERENS (Belgian Institute of Natural Science) to investigate the role of the wind conditions at LVS appearance in the research area. Main results. The LVS in the vicinity of Sea coast line could be generated, as satellites observations demonstrated, by the vortices arrived along the coast line from the east-south direction in accordance with the Black Sea general circulation flow. Such vortices could be induced by the bottom roughness, rivers discharges and another local sources. Another LVS source could be connected with the wind impact in some affordable direction as demonstrated by the numerical modeling of the coastal water circulation. The continuous currents measurements at the Sea surface by Doppler HF coastal Radar supply the valuable data for further details on the space –time variation of LVS parameters and operational forecast of the hydrology regime in the aquatic areas. The operative numerical modelling of the wind impact to the surface currents structures formation provides the efficient estimation of the local large vorticity structure appearance in the research area. Conclusion. Satellite radar and optical observation provide the large scale control on the Sea surface dynamics conditions, but that is limited by relatively long interval between satellite tracks over the region of interest and do not acquire optical data at the cloud cover. The additional data could be operative obtain from the open internet resource in satellite optical, radar and meteorological data (LANCE, NCEP/NCAR), to get the more details development of the Sea surface dynamics. Sub-satellite Sea currents measurements by HF Doppler radar are useful for the reliable interpretation of satellite pictures and for the proper forecast of the aquatic area dynamics. Operative numerical modelling of the Sea coastal water circulation in accordance with variable meteo data combining with dynamic processes remote measurements could be efficient for the forecast of the environment parameters variation due the water mass transfer. In general the presented results demonstrates the combined application possibilities of the satellite observations, coastal Doppler radar measurements, internet data and operative numerical modelling for operational oceanographic and ecological monitoring of Sea coastal areas with heavy pollution load.

제주 남해 해역에서의 저서어족 생물의 조사연구

The primary goal of this study is to survey a fisheries resources in south coastal sea area of Jeju island. The method of trawl survey conduct to fishing survey through bottom trawl net. The surveys are carried out 4 days on 14-15th Aug. 2020 and 8-9th Aug. 2021 by the training ship “Sae Dong Baek” of Chonnam National University. The total fish species caught by bottom trawl net during 4 times survey for 4 days were 34 species and the total weight was 81.585Kg. In the caughted species the first superior species was Solenocera melantho, 84(16%), the next Zenopsis nebulosa, 79(15%), the third Trachurus japonicus 73(14%). In individual numbers the most fish body length size caught by bottom trawl net was between 201mm and 250mm and the least fish body length size was between 10mm and 50mm. The fish weight size caught by bottom trawl net was 101~200g(38%), 31~40g(12%), 201~300g(10%), respectively. And the size range caught by bottom trawl was between 10g and 1,000g. The catch is showing a decreasing trend every year. In order to efficiently protect and manage our fishing grounds we need continuous research and this study is expected to be provided as basic data for this.

Occurrence of microfibres in wild specimens of adult sea urchin Paracentrotus lividus (Lamarck, 1816) from a coastal area of the central Mediterranean Sea

This study investigates the occurrence of anthropogenic fibres inside wild Paracentrotus lividus at a Mediterranean coastal area in 2020. From each sea urchin, the coelomic fluid was directly analysed while digestive tracts and gonads were removed, pre-treated with trypsin (0.3%) and digested with H2O2 (10%) before analysis. A total of 260 fibres and 1 fragment were found in 100 specimens, with an average of 2.6 items/individual. Fibres were more abundant in the digestive system, less in gonads and in the coelomic fluid, respectively. Fourier transform infrared (FTIR) analysis of representative fibres identified 67% natural (cotton-based) and 33% synthetic polymers (polyester) suggesting their origin from textiles, possibly released from laundry sewages. Overall, these results encourage further in-depth investigations on fibres accumulation and potential transfer through the trophic chain up to humans.

Coastal Shipping Radar Monitoring System with Satellites as Transmitters of Opportunity

Introduction. With the development of technology and science, passive radar systems operating on the basis of third-party transmitters of illumination signal sources are increasingly attracting research interest. The use of satellite systems as transmitters of opportunity for a radar station makes it possible to monitor coastal sea areas, where the ground sources of illumination signals are absent. Satellite systems can cover any point on the Earth's surface. Passive radar systems can be used to determine the location of ships and monitor navigation. They are also promising as part of vessel traffic control systems.Aim. To develop a model of a passive radar system that uses satellite systems as third-party sources of illumination signals and to conduct an experimental study of a system for monitoring ships in coastal waters.Materials and methods. The AA2-KKС antennas of satellite signals and radio recording tools based on the universal USRP B210 board were used. Signal processing was performed using a program developed in the MATLAB environment.Results. An algorithm for processing satellite signals of the GPS global navigation system in a passive radar system is proposed. An experimental model of the receiving station for such a radar monitoring system was created on the basis of a data input device for a universal USRP board of the B210 series. Experimental results for the receiving station using the satellite signal GPS L1 C/A-code for coastal monitoring were obtained.Conclusion. The developed experimental model of a passive radar receiving station using third-party transmitters of GPS satellitebased illumination signals on the L1 frequency range of the C/A-code type can be used for detecting ships and monitoring coastal navigation. Future research will consider a multiposition modification of such a monitoring system for improving its detection quality and increasing its target positioning accuracy.

An Appraisal of CFOSAT Wave Spectrometer Products in the South China Sea

AbstractThe China‐France ocean satellite (CFOSAT) has obtained synchronized observations of sea winds and sea waves for the first time in the world, providing accurate data support for the study of swells. In this paper, the accuracy of key parameters and the wave spectrum of CFOSAT surface waves investigation and monitoring (SWIM) L2 data are analyzed and evaluated using a spatial‐temporal matching criterion. The accuracies of the significant wave height (SWH), spectrum peak period (Tp) and dominant azimuth (Azi) are 0.76 m, 2.89 s and −24.02°, respectively, in the coastal area of the South China Sea (SCS) and 0.30 m, 0.97 s and 13.02° in the offshore area of the SCS. Calculated based on CFOSAT SWIM data, the annual average SWH of mixed waves in the SCS is 1.47 m, and 80% of them are between 0.5 and 3 m. There are high value areas in the central, northeastern and southwestern parts of the SCS. The average annual SWH of swells is 0.93 m, and 99% of swells are less than 2 m. A high swell SWH also exists in the central part of the SCS.

Techno-economic modeling to produce biodiesel from marine microalgae in sub-Saharan countries: An exploratory study in Guinea-Bissau

Commercial production and academic research on microalgae for biodiesel are in their infancy. This research explores the case of a sub-Saharan country that has limited resources (land) to produce biodiesel from first-generation feedstock (oilseed or animal fat) but has abundant availability of coastal sea areas and solar irradiation to produce microalgae (feedstock for third-generation biofuels). This article deals with the technoeconomic analysis of biodiesel production from microalgae in Guinea-Bissau. The Aspen Plus® V12 simulator was used to model the flowsheet of chemical conversion processes from microalgae oil to biodiesel production and to widen the technoeconomic assessment. Simulations revealed that for a production of 5.47 m³ d-1 of biodiesel (incorporating 3% of biodiesel into the conventional diesel), the estimated cost is 0.9 US$ kg-1 and the cultivated area is 1.5 × 102 ha. This cost is promisingly competitive with the diesel in the service station in Guinea-Bissau. Sensitivity analyses of predictive scenarios allowed us to identify significant gains in the scale of production. The widening of the scope of the feasibility simulations, including chemical processes, technological alternatives, mass and energy balance, environmental impacts, and productive and economic parameters, is a relevant contribution to the advancement of the techno-economic analysis of microalgae bioenergy production on a commercial scale. Although Guinea-Bissau has a small biodiesel demand, the scenarios are encouraging and may be explored as a bottom line to support the policy and investment decision-making processes to design a biodiesel from microalgae program in Guinea-Bissau and other coastal sub-Saharan countries.

Metagenomic and Recombination Analyses of Antimicrobial Resistance Genes from Recreational Waters of Black Sea Coastal Areas and Other Marine Environments Unveil Extensive Evidence for Their both Intrageneric and Intergeneric Transmission across Genetically Very Diverse Microbial Communities.

Microbial communities of marine coastal recreation waters have become large reservoirs of AMR genes (ARGs), contributing to the emergence and transmission of various zoonotic, foodborne and other infections that exhibit resistance to various antibiotics. Thus, it is highly imperative to determine ARGs assemblages as well as mechanisms and trajectories of their transmission across these microbial communities for our better understanding of the evolutionary trends of AMR (AMR). In this study, using metagenomics approaches, we screened for ARGs in recreation waters of the Black Sea coastal areas of the Batumi City (Georgia). Also, a large array of the recombination detection algorithms of the SplitsTree, RDP4, and GARD was applied to elucidate genetic recombination of ARGs and trajectories of their transmission across various marine microbial communities. The metagenomics analyses of sea water samples, obtained from across the above marine sites, could identify putative ARGs encoding for multidrug resistance efflux transporters mainly from the Major Facilitator and Resistance Nodulation Division superfamilies. The data, generated by SplitsTree (fit ≥95.619; bootstrap values ≥ 95; Phi p≤0.0494), RDP4 (p≤0.0490), and GARD, provided strong statistical evidence not only for intrageneric recombination of these ARGs, but also for their intergeneric recombination across fairly large and diverse microbial communities of marine environment. These bacteria included both human pathogenic and nonpathogenic species, exhibiting collectively the genera of Vibrio, Aeromonas, Synechococcus, Citromicrobium, Rhodobacteraceae, Pseudoalteromonas, Altererythrobacter, Erythrobacter, Altererythrobacter, Marivivens, Xuhuaishuia, and Loktanella. The above nonpathogenic bacteria are strongly suggested to contribute to ARGs transmission in marine ecosystems.

Investigation of spatial and seasonal variation of water quality along the mid-Black Sea coast (from Sinop to Ordu) of Turkey, by multivariate statistical techniques

The Black Sea is a closed basin surrounded by six countries and is the last spill point for the rivers from different watersheds. Due to these discharges from surrounding countries, the Black Sea is exposed to high and moderate pollution levels. Therefore, monitoring water quality changes in the mid-Black Sea coastal area is necessary to develop pollution control strategies. This study aims to examine the temporal and spatial changes of seawater quality along the mid-Black Sea coast of Samsun, Turkey. The samples were collected from 13 monitoring stations from the three distances in four seasons in 2013. The samples were analyzed for 22 parameters: nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), phenol, methylene blue active substances (MBAS), total carbon (TC), total inorganic carbon (TIC), total organic carbon (TOC), iron (Fe), aluminum (Al), manganese (Mn), chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), pH, temperature (T), dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS) and salinity. Multivariate statistical techniques (Principal component analysis (PCA), factor analysis (FA), and cluster analysis (CA)) were applied to analyze seawater quality variations. Factor analysis of seawater chemical variables was found to be eight factors in total. These eight factors account for 79.13%, 82.27%, 78.60%, and 78.69% of the total variances in winter, spring, summer, and fall, respectively. Cluster analysis classified the monitoring sites into two groups based on similarities of seawater characteristics.