Gelendzhik Bay Research Articles

Modeling of Hydrodynamic and Lithodynamic Coastal Processes in the Harbour Area

One of the problems in the design of ports is the assessment of coastal sediment movements near structures. The article presents materials for assessing the impact of port facilities on the processes of coastal erosion/accumulations in the area of Gelendzhik Bay (Black Sea). All the main processes of interaction of waves, currents and sediment movement occur in the coastal zone, therefore, the study presents the possibilities of complex application of hydrodynamic and lithodynamic models. In this work, the wind wave models Wave Watch III and SWAN were used. As the initial data, the data of the NCEP/NCAR reanalysis of wind fields in the period from 1989 to 2012 were used. To simulate currents, sediment transport and lithodynamic processes, a model of two-dimensional COASTOX–CUR currents generated by waves and wind, COASTOX-SED sediment transport together with the COASTOX–MORPHO bottom reshaping model was used. In the simulation scenario, a sequence of the 5 strongest storms from the period under consideration was considered. Analysis of washout zones/accumulations have shown that areas of intensive bottom reshaping are associated with the most intense currents. It is shown that the construction of the port facilities will not have a significant impact on the lithodynamic processes in the Gelendjik bay.

СОВРЕМЕННОЕ СОСТОЯНИЕ ДОННЫХ БИОЦЕНОЗОВ ГЕЛЕНДЖИКСКОЙ БУХТЫ ЧЕРНОГО МОРЯ

The state of macrozoobenthos and meiobenthos of the Gelendzhik Bay of the Black Sea was assessed in 2020–2021 based on three bottom grab surveys. Five types of biotopes were identified based on the particle size distribution of the bottom sediments, the redox potential of pore water, the content of organic carbon, and the type and presence of macrophytobenthos. A study of the oxygen content in the water column did not reveal hypoxia. Four types of macrozoobenthos communities were noted in the bay. The main dominants were bivalves and gastropods. In the central part of the bay, the communities were similar to typical Black Sea communities from the venus sand belt. The spatial structure of macrozoobenthos was associated with the type of biotope identified on the basis of abiotic characteristics and benthic vegetation. Macrozoobenthos was represented mainly by mobile burrowing infauna, belonging to the type of food filter feeders with a bivalve shell (bivalves). The meiobenthos of the bay was represented mainly by nematodes, which dominated both coastal areas and deeper waters. The spatial structure of the meiobenthos was determined by the granulometric composition of the bottom sediments, and the dependence on the type of vegetation and the redox potential of pore water was unreliable. In the coastal area, the reducing conditions were found in the surface layer of the bottom sediments, and also the low abundance and biomass of macrozoobenthos. The station with reducing conditions was distinguished by the dominance of larger (up to 5 cm) worm-like segmented polyphages and predators and the absence of juvenile forms of macrozoobenthos. At the station with reducing conditions, the lowest species diversity of meiobenthos was noted, and the nematode-copepod index reached 620:1, which is an order of magnitude higher than at other stations in the bay. A comparison of the current state of communities with historical data (1979, 1990) was made. It is shown that at the present stage the biodiversity of the bay has increased, while the abundance of macrozoobenthos has decreased. There were no stable areas of hypoxia or freezes in the bottom layer of waters.

Dissolved Organic Matter of the Surface Water Layer of Gelendzhik Bay in September 2021 According to Fluorimetry and Lidar Measurements

Dissolved Organic Matter of the Surface Water Layer of Gelendzhik Bay in September 2021 According to Fluorimetry and Lidar Measurements

Mathematical modeling of hydrodynamic processes in shallow waters in the presence of pollutants of various origin, as well as areas covered with plastic waste

The paper covers the modeling of hydrodynamic processes in shallow waters in the presence of pollutants of various types, as well as areas covered with plastic waste, including nano- and microplastics. The simulation performed using new and effective mathematical instruments, including assimilation methods of measurement data, restoration of the state function, diagnostics of quality of the developed models, the research the sensitivity of models to variations in input data, the integration of models with various scales. Interrelated non-stationary, spatially inhomogeneous mathematical models of hydrodynamics and biological kinetics of shallow waters were developed and numerically implemented. They describe non-linear processes of hydrophysics, biogeochemical cycles, transport and transformation of suspensions and sediments with microplastic particles and other pollutants, absorption of it by zooplankton and fish, movement of plastic particles through food, the forecast of their impact on the main hydrobionts of shallow waters of the Azov-Black Sea basin, including the Azov Sea, Taganrog Bay, Gelendzhik Bay. The models take into account the heat and salt transport; the complex, dynamically changing water geometry; friction on the bottom and wind stresses; turbulent and advective heat and mass exchange in three coordinate directions; the Coriolis force; river flows; evaporation, temperature and oxygen regimes. They make it possible to improve the accuracy of hydrophysical processes modeling in shallow waters, to detect vortex structures of currents that can be a natural pollution traps, including microplastic. Based on a supercomputer, a complex of application has been designed and adapted for solving predictive problems of water ecology and water resources management.

Mathematical modeling of the pollutant distribution process in the Gelendzhik Bay

Currently, the pollution problem of coastal sea waters in the resort areas of the Black Sea is becoming increasingly urgent. Thousands of chemicals, industrial and household waste enter the water basins every year, which significantly worsens the state of marine waters. Storm drains are saturated with pollutants at precipitation, washing out various chemical compounds, garbage and transporting them to the sea. In addition, a separate problem is poorly self-cleaning of the Gelendzhik Bay. A complete water change occurs in the period from 1 to 6 days. This paper covers the development, research and numerical implementation of a mathematical model of the pollution transport, including petroleum products, in the Gelendzhik Bay taking into account a number of important hydrodynamic and hydrophysical factors, methods of its numerical implementation, which allow predictive modeling of the pollution spread in shallow water systems in a limited time. A hydrobiological model of a coastal system characterized by significant depth differences has been developed. A three-dimensional mathematical model is designed to research the transformation of the phosphorus, nitrogen and silicon forms in the plankton dynamics problem. It takes into account the convective and diffusive transports, absorption and release of nutrients by phytoplankton, salinity, temperature, oxygen regime, etc. Using a spatial-three-dimensional hydrodynamics model, taking into account the physical properties of water environment of the coastal system, calculation results are used as input data for the development of scenarios for the dynamics of transport processes and the transformation of pollution biogenic elements in the water.

СПУТНИКОВЫЙ РАДИОЛОКАЦИОННЫЙ МОНИТОРИНГ НЕФТЯНЫХ ЗАГРЯЗНЕНИЙ В АКВАТОРИИ АНАПА – ГЕЛЕНДЖИК ЗА ПЕРИОД 2018–2020 гг.

The paper presents the results of satellite monitoring of oil pollution in the northeastern part of the Black Sea in the area between Anapa and Gelendzhik in 2018–2020. The monitoring was carried out using the archives of radar data obtained by SAR-C radars installed on the Sentinel-1A and -1B satellites. The work with the data archives was carried out using the tools of the “See the Sea” (STS) information system developed at the Space Research Institute of the Russian Academy of Sciences. The conducted satellite monitoring revealed the main sources of sea surface pollution with oil products in the study area. The overwhelming pollution (85%) is associated with discharges of water containing oil products from moving vessels. With the help of STS tools, a map of oil pollution detected on radar images was compiled, on the basis of which the main areas of oil pollution were identified. These include the main shipping routes to the Novorossiysk Sea Port, the anchorage of ships and the water areas of the Tsemes (Novorossiysk) Bay and Gelendzhik Bay. Seasonal and interannual variability of oil pollution was determined on the basis of satellite information for the area between Anapa and Gelendzhik. The results of the 2018–2020 monitoring were compared with those obtained during similar monitoring carried out in 2006–2010. It was concluded that there has been no reduction in the amount of detected pollution, which negatively affects the ecological state of the northeastern part of the Black Sea.

КАРТОГРАФИЧЕСКОЕ МОДЕЛИРОВАНИЕ ТЕХНОГЕННОГО ЗАГРЯЗНЕНИЯ ГЕЛЕНДЖИКСКОЙ БУХТЫ

The article describes a case-study in environmental mapping of the Gelendzhik Bay. The role of map representation in the study of causes and effects of marine pollution is indicated. The research object and sources of anthropogenic impact on the environment in the research area are given. Hydro-logical and hydrochemical studies carried out to obtain the initial data are briefly described, the partic-ipators and used methods are listed. The geographic and thematic content of digital environmental maps created on the basis of obtained data is characterized, fragments and legends of maps are pre-sented. The conclusions drawn from created maps on possible reasons of various types of marine pol-lution in the Gelendzhik Bay are presented. Further research prospects are outlined.

Frequency Response Stabilization and Comparative Studies of MET Hydrophone at Marine Seismic Exploration Systems.

Low frequency hydrophone with a frequency range of 1−300 Hz for marine seismic exploration systems has been developed. The operation principle of the hydrophone bases on the molecular electronic transfer that allows high sensitivity and low level self-noise at low frequencies (<10 Hz) to be achieved. The paper presents a stabilization method of the frequency response within the frequency range at a depth up to 30 m. Laboratory and marine tests confirmed the stated characteristics as well as the possibility of using this sensor in bottom marine seismic systems. An experimental sample of the hydrophone successfully passed a comparative marine test at Gelendzhik Bay (Black Sea) with the technical support of Joint-Stock Company (JSC) “Yuzhmorgeologiya”. One of the main results is the possibility of obtaining high-quality information in the field of low frequencies, which was demonstrated in the course of field tests.

Seasonal dynamics of nitrogen-containing substances in the Black Sea coastal zone by example Gelendzhik and Golubaya bay

In the course of studies of hydrochemical monitoring data for the period from 2017 to 2019, we found that the Gelendzhik bay, which belongs to semi-closed water areas, has an increased background of mineral and organic nitrogen forms compared to the background in the Golubaya bay corresponding to the open coast. Increased concentrations of mineral forms of nitrogen in the Gelendzhik bay we detected, probably due to anthropogenic impact.

ИЗУЧЕНИЕ СОДЕРЖАНИЯ АГРЕССИВНЫХ ИОНОВ В АТМОСФЕРЕ И МОРСКОЙ ВОДЕ ГЕЛЕНДЖИКСКОЙ БУХТЫ

The method of capillary electrophoresis was used to measure the content of aggressive ions in 7 geographical points of the Gelendzhik bay in the air atmosphere and sea water during the period from September 1, 2019 to January 31, 2020. The results of measurements of the contents of K+, Na+, Mg2+, Ca2+, , Cl-, F- are compared with meteorological indicators at the time of measurement. It is shown that the total concentration of cations and anions in sea water corresponds to its salinity measured by the standard method. A high correlation between the chemical composition of samples in air and sea water was revealed.

ПРЕДВАРИТЕЛЬНЫЕ РЕЗУЛЬТАТЫ ЭКСПЕРИМЕНТАЛЬНОГО ИССЛЕДОВАНИЯ ДИНАМИКИ ПРИДОННОГО СЛОЯ НА ШЕЛЬФЕ–КОНТИНЕНТАЛЬНОМ СКЛОНЕ В ЧЕРНОМ МОРЕ

The preliminary results of an experimental study of a mechanism of the Black Sea anoxic layer ventilation related with the descent of oxygen-containing water down the bottom slope in Ekman boundary layer are presented. To study this mechanism, several automatic measuring stations were installed at the bottom of the shelf-continental slope zone in the depth range from 80 to 243 m, on the cross-section abeam of the Gelendzhik Bay. The observations that lasted for 1.5–2 months were fulfilled during two periods in the beginning and the end of 2018. The stations were registering hydrophysical (temperature, salinity, pressure and current velocity) and hydrochemical (dissolved oxygen concentration) parameters at a 0.5–2.5 m distance from the bottom. The acquired data are suitable for estimation of spatio-temporal parameters of water transfer in the bottom layer up and down the slope, depending on direction and intensity of alongshore current. Preliminary analysis of the first installation data confirmed the presence of bottom water transfer along the slope perpendicular to the shore. Also, in case of intense alongshore north-western current, a descent of the bottom layer water was observed. Such manner of water transfer conforms to both geostrophic adjustment and dynamics of the bottom Ekman boundary layer. However, variability of water density in the bottom layer, caused by vertical water transport, had about the same range as density fluctuations in the water column on the same depths. This fact disputes the effectiveness of Ekman transfer in the bottom layer as a water ventilation mechanism for the upper part of continental slope of the Black Sea (Zatsepin et al., 2007; Elkin, Zatsepin, 2017).

Engineering geophysical studies in the Black Sea from onboard the R/V Ashamba during 2017

In May and October 2017, expeditionary research was carried out in the area of Gelendzhik in the Black Sea at the R/V «Ashamba». The main tasks were the mapping of the seabed and the search for small-sized objects at the bottom of the water area using a WASSP WMB-3250 multibeam echo sounder. Surveys included areal surveying and drawing up bathymetric maps of test sites in Gelendzhik Bay and in the transition zone from the shelf to the continental slope. In addition, the echo sounder was used to search and determine the exact coordinates of the bottom seismograph installed at the seabed near the Divnomorskoye village in May 2016. The article presents the results of the work carried out.

Detection and Evaluation of Anthropogenic Pollution on the Basis of Geochemical Study of the Interstitial Waters of Marine and Freshwater Sediments

The chemical composition of interstitial waters from several inland seas and or water system (NPWS) exposed to anthropogenic pollution was studied. The patterns of the distribution of pollution in the Dnieper–Bug Estuary, Gelendzhik Bay of the Black Sea and in the Alexandria’s Eastern Harbor of the Mediterranean Sea were found. Most of the contamination occurs in the upper layers of bottom sediments and near mouth zones. A significant role is played by secondary contamination related to the dissolution and accumulation of metals and nutrients in the interstitial water and their migration to the water column. The estuary factor of anthropogenic pollution takes center stage according to a factor analysis for the combined impacts of potentially mobile forms of metals in the Dnieper–Bug Estuary. Studies of the Lake Pyasino pollution near Noril’sk were carried out.

Technique for Simulation of Black Sea Circulation with Increased Resolution in the Area of the IO RAS Polygon

A numerical technique is presented for simulating the hydrophysical fields of the Black Sea on a variable-step grid with refinement in the area of IO RAS polygon. Model primitive equations are written in spherical coordinates with an arbitrary arrangement of poles. In order to increase the horizontal resolution of the coastal zone in the area of the IO RAS polygon in the northeastern part of the sea near Gelendzhik, one of the poles is placed at a land point (38.35° E, 44.75° N). The model horizontal resolution varies from 150 m in the area of the IO RAS polygon to 4.6 km in the southwestern part of the Black Sea. The numerical technique makes it possible to simulate a large-scale structure of Black Sea circulation as well as the meso- and submesoscale dynamics of the coastal zone. In order to compute the atmospheric forcing, the results of the regional climate model WRF with a resolution of about 10 km in space and 1 h in time are used. In order to demonstrate the technique, Black Sea hydrophysical fields for 2011–2012 and a passive tracer transport representing self-cleaning of Gelendzhik Bay in July 2012 are simulated.

Reveal appraisement level of anthropogenic pollution on the basis of geochemistry studying the interstitial waters of marine and freshwater sediments

The chemical composition of interstitial waters from several of inland seas and NPWS, exposed to anthropogenic pollution. The regularities of distribution of pollution in the Dnieper-Bug estuary and Gelendzhik Bay of the Black sea in the Eastern Harbor of Alexandria Mediterranean Sea. Most of the contamination confines to the upper layers of sediments and near mouth zones. A significant role is played by secondary contamination related to the dissolution and accumulation of metals and nutrients in the interstitial water and their migration in the water column. When factor analysis for the aggregate impact of potentially mobile forms of metals in the Diepr-Bug estuary factor of anthropogenic pollution came in first place. Studies pollution in the Pjasino Lake near town Norilsk.

Intense ventilation of the Black Sea pycnocline due to vertical turbulent exchange in the Rim Current area

This paper presents new observational data, which indicate that deep ventilation events in the aerobic zone extending across the upper part of the permanent pycnocline may occur sporadically in the Rim Current area, even during relatively warm seasons, when the seasonal thermocline is still notable. The strongest observed event of this type occurred on November 2014 off the continental shelf break near Gelendzhik Bay. Vertical profiles of dissolved oxygen were accurately measured using an SBE 52-MP Conductivity, Temperature, Depth (CTD) probe equipped with a fast-response SBE 43F oxygen sensor mounted on a moored Aqualog automatic mobile profiler. The analysis of the profiling data from October 6 through December 16, 2014, from depths between 35m and 215m revealed an anomaly on November 6–7. The dissolved oxygen exceeded the background levels by more than 0.2ml/l (8.9μM) at the 14.9–15.7kg/m3 isopycnals in the pycnocline and reached approximately 1ml/l (44.66μM) for short periods. The peak absolute value of the dissolved oxygen reached an exceptionally high value of approximately 0.3ml/l (13.4μM) at the 15.9kg/m3 isopycnal. The ventilation event increased the temperature by ~0.2°C at depths of 120–160m. The simultaneous observations of both the thermohaline stratification and the ocean currents suggest that the ventilation event was associated with the sinking of pycnocline waters in the near-bottom Ekman layer along the continental slope and intense vertical turbulent exchange in the Rim Current area near the continental slope. The ventilation of the pycnocline when the overlaying upper ocean is stably stratified sharply differs from the convection reaching the Cold Intermediate Layer during extensive cooling of the sea surface. Indications of such ventilation events were also found in the Aqualog mooring data archive from 2012.

Heterotrophic bacteria, zooflagellates, and ciliates in coastal waters of northeastern Black Sea

According to the parameters of density and biomass of heterotrophic bacterioplankton, waters in the ports of Novorossiysk and Tuapse were eutrophic-hypereutrophic and in the resort cities of Gelendzhik and Anapa they were hypereutrophic. The abundance of heterotrophic bacteria reached maximum values of 12.7–14.2 million cells/mL during the period of abnormally high water temperatures (August 2010) in recreational zones. Chainlike and filamentous forms (57–65%) of bacteria, which were typical for the strong coastal pollution of waters, prevailed. The abundance of zooflagellates (kinetoplastids) in semi-isolated water areas (port of Novorossiysk and Gelendzhik Bay) reached the level of highly eutrophic waters, 6.2–9.7 million ind/m3. However, the biomass of naked ciliates was 1.5 times lower than their maximum values earlier registered in coastal waters of the northeastern shelf. The peak of abundance of alien tintinnids of the genera Eutintinnus, Tintinnopsis, and Amphorellopsis, which were introduced via ballast waters of ships, was recorded in Novorossiysk Bay. The ratio of titinnids to the total abundance of ciliates increased 5 times and reached 25–40%. Protozoans developed poorly in the oil-polluted port of Tuapse and the open Anapa Bay.

Study of fields of currents and pollution of the coastal waters on the Gelendzhik shelf of the Black Sea with space data

This paper presents the results of hydrophysical measurements and processing of space imagery of the fields of currents and pollution of the coastal waters on the Gelendzhik shelf of the Black Sea. The results of measurements with a towed acoustic Doppler profiler reveal the strong spatial and temporal variability of the fields of near-surface currents and impact of the deep discharge on the dynamics of coastal waters. The characteristics of the near-surface seawater pollution are studied under the influence of the submerged outfall. The analysis of space imagery of high spatial resolution reveal small-scale optical seawater heterogeneities caused by intense anthropogenic impact directly on the Gelendzhik Bay, the surface influence of the submerged outfall on the coastal waters, and the pollution jet area.

Oithona brevicornis Giesbrecht (Copepoda: Cyclopoida), invader into the Black Sea and in the Sea of Azov

The pattern of distribution and biology of a cyclopoid copepod Oithona brevicornis new to the northeastern shelf of the Black Sea was studied. Penetration of this species will probably change the trophic structure of mesozooplankton in the neritic zone. From late August to November 2010, O. brevicornis was a predominant species in mesozooplankton, reaching 80–85% of its total amount. In September, its maximum density in Novorossiysk Bay reached 30 000 ind./m3; in Gelendzhik Bay and Anapa Bay and in Lake Zmeinoe (Big Utrish), it was 22 000–27 600 ind./m3. In August 2010 O. brevicornis was recorded in the Sea of Azov. In the period of peak of reproduction of the pelagic predator ctenophore Mnemiopsis leidyi A. Agassiz in the Temryuk Gulf, its abundance varied from 4 to 600 ind./m3.

Fine vortex columns on the shelf in the area of bottom convection influence

This paper analyzes the results of investigations into extremely large releases of current velocities registered by an acoustic Doppler profiler during experiments performed on the Hawaii shelf. An integral analysis of the variability of current fields relies on the profile data of current velocities, temperature, and acoustic-scattering layers. Based on these investigations, we proposed a hypothesis stating that the small-scale variability of currents in profiler data is conditioned by the passage of fine vortices emerging in the outflow and rise of freshened waters from a subsurface sink near the shelf edge. To confirm this hypothesis on the emergence mechanism of the observed releases of current velocities, we conducted a mathematical simulation of the response that the Doppler meter has to the passage of fine vortex, which revealed a good agreement between model calculations and experimental data. Similar phenomena were also found in the Gelendzhik Bay of the Black Sea.