Vol 18, No 3 (2022)

In order to study the mechanisms and factors of the formation and transformation of the Sea of Azov spits, as well as to develop tools and approaches to create forecasts for the further development of its coastal zone due to changes in the level regime and climate, in the summer of 2022, the staff of the Southern Scientific Centre of the Russian Academy of Sciences conducted field studies on the northern coast of the Taganrog Bay. On the Beglitskaya Spit area and the adjacent section of the Sea of Azov water area, wells were drilled with core sampling, and the study of soil cover, long-shore currents and the thermohaline structure of coastal waters was carried out. According to the results of drilling 9 wells with a depth of 5.5 to 9.8 m, geological sections were studied in the lower parts of which limestone shells of the middle Sarmatian are deposited. Field studies of the soil cover of the Beglitskaya Spit confirm the development of negative dehumification processes characteristic of the Azov natural and agricultural zone of the Rostov Region, which includes the coast of the Taganrog Bay. The composition of the sediments of the coastal ramparts of the Beglitskaya Spit is explained by differences in the lithodynamic conditions of transportation of sedimentary material. New data of high-precision measurement of elevation marks of the relief surface along the longitudinal profile laid from the base to the distal section of the spit are presented. New data on temperature, salinity, and current velocities of coastal waters are analyzed. Observations carried out at hydrological stations made it possible to build a hypothetical scheme of the modern lithodynamics of the Beglitskaya Spit.

The article presents the results of a study of microplastic pollution of the coastal zone of the Sea of Azov near the city of Taganrog. The level of microplastic content in coast and bottom sediments, water and atmospheric air was estimated. Microplastic includes any type of plastic fragment less than 5 mm in length. It enters the environment from various sources, both industrial and agricultural or domestic. The purpose of the work is to assess the level of microplastic contamination of the Taganrog city environment, to determine morphological and morphometric characteristics, to assess the degree of degradation and the composition of microparticles. In the course of the research, sampling was carried out in the coastal zone of the city of Taganrog and 21 samples of sand sediments, 7 samples of bottom sediments, 14 samples of water and 5 samples of aerosols were taken. A modified NOAA method was used for the received samples; it includes the following manipulations: drying, sifting, filtration, density separation, liquid oxidation, visual sorting using a stereo microscope Micromed MS-1 var. 2C Digital, determination of the degree of microplastic degradation using a microscope VEGA II LMU and identification of the chemical composition of the detected particles using a JASCO FT/IR-6800 IR-Fourier spectrometer. According to the obtained data it was found that microplastics are presented in 100% of samples (sand and bottom sediments, waters, aerosols). In sand sediments, the content of particles reached 154 pcs/m2, in bottom sediments 145 pcs/kg, in water 119 pcs/l. The highest concentrations were recorded in the southern part of the city (Lomakin street). In atmospheric air samples, the largest amount of precipitation was up to 918 particles per 1 m2 per day (Chekhov street).

The research aims determination of peculiar dry land processes in the most fragile systems like pasturelands and forest shelter bands. The research is made for Dubovskoe, Zimovniki, Zavetnoe administrative districts of Rostov Region. For the degression scale of pasturelands and artificial forestry condition determination, remote sensing methods are used. Standard soil observations for soil morphology were performed. Establishment of bench marks were made with geobotanical observation and plant cover determination. The territory of each observation site was mapped using benchmarking method. The derived data processed in ESRI ArcGIS software environment by controlled automatic classification. Pastureland degradation processes are characterized by depletion of turf surface, silt and loam particles removed from the topsoil layer, and decreasing in plant communities’ productivity. Pastureland degradation risk estimation performed according to recently developed scale. Artificial forestry objects in dry semi-arid lands have significant climatic pressure and therefore they haven’t enough resources for self-renovation. Trees of the first forest floor are fading and dying leaving the second floor and forest bed under the sun which is the driver of plant community transformation to ruderal type. The results we reached tell us about uneven use of pasturelands which leads to local soil degradation risk.

The question of the interaction of oil and oil products with a number of microorganisms (pelagic microalgae, ciliates) and their possible role in the destruction of petroleum hydrocarbons remains topical. The aim of the work was to determine the possible impact of petroleum hydrocarbons on the quantitative indicators of some organisms. The experiment used natural marine water with a natural association of pelagic diatoms, dinoflagellates and ciliates. It was shown that this complex of microorganisms is able to participate in the processes of degradation and transformation of hydrocarbons. It is noted that these processes are more intense in the dark. It was revealed that the toxic effect of diesel fuel on diatoms, dinoflagellates and ciliates leads to a decrease in the quantitative indicators of microorganisms (number and biomass). The greatest toxic effect was noted for ciliates, which were not detected in the presence of diesel fuel already on the fifth day of the experiment. For diatoms and dinoflagellates in the presence of diesel fuel, there was a gradual decrease in quantitative indicators relative to a pure environment compared with the reaction to diesel fuel of ciliates. It should be noted that under light conditions, even in the presence of diesel fuel, the abundance of diatoms and ciliates was significantly higher than in the dark. It can be assumed that for diatoms and ciliates, light is a significant factor for maintaining viability (along with the presence/absence of petroleum products). The results obtained allow us to take a fresh look at the possible role of microorganisms in the bioremediation of sea water from oil products in the Arctic region, where the polar night period lasts up to three months (November-January) per year.

The studies were conducted in the places of natural growth of Pinus brutia var. pityusa (Steven) Silba in the Mountainous Crimea. In the western and eastern parts of the southern macroslope of the Main Ridge of the Crimean Mountains, in the natural boundaries of Ayazma, Batiliman, Novy Svet and on Karaul-Oba mountain sampling areas were laid, where taxational features with an assessment of the vital condition of trees were studied, and the floral composition was analyzed. The objective of the research was to assess the condition, bioecological characteristics, phytocenotic structure of natural plantings of P. brutia var. pityusa in the Mountainous Crimea, to analyze the representation of individual ecological groups of plants. As a result of the conducted research, it was found that the natural communities of P. brutia var. pityusa of the Mountainous Crimea in the coastal zone are represented in relatively limited areas. The forest understory is formed by Pistacia atlantica Desf., Juniperus deltoides R.P. Adams, Quercus pubescens Willd.; species of Cotinus coggygria Scop., Ruscus aculeatus L. and Arbutus andrachne L. have isolated occurrences. The projective cover degree of the grass tier varies between 50‒70 %. The floral composition varies from 24 to 37 species of grass tier. The differentiation of the species structure of the studied communities by types of life strategy is revealed. The western part of the distribution of plantings P. brutia var. pityusa of the Mountainous Crimea is dominated by violents and competitive stress-tolerants, while in the eastern one, explerents, stress-tolerantruderal and competitive stress-tolerant-ruderal plant species are more widespread. Based on the analysis of the level of kurtosis of the statistical distribution of species by types of life strategy, a quantitative assessment of the structure dynamics of the grass tier in the studied P. brutia var. pityusa plantings was carried out. The most significant platykurtosis of the distribution of species of different life strategies is noted in the natural boundaries of Batiliman (−2.644) and Karaul-Oba mountain (−2.513). The platykurtosis reflects a decrease in the homogeneity of the phytocenotic structure of the grass tier, which is associated with an increase in the dispersion of ecotopic conditions and an increase in successional processes. It characterizes the pattern structure of the ground cover, the formation of localities in which microstations are dominated by species that are more compliant with the specifics of multifactorial exogenous and endogenous effects. It is shown that a significant fragmentation of plantings P. brutia var. pityusa, deterioration of their condition associated with destructive anthropogenic impact, determine a decrease in the stability of species composition, desertisation of growing conditions and, as a consequence, negative changes in the floral structure of aboriginal forest communities.

A difference in terms of forming seasonal pseudo-populations by ctenophores Mnemiopsis leidyi А. Agassiz, 1865 and Beroe ovata Bruguière, 1789 in the northwestern part of the Caspian Sea is shown. In August 2021, when Beroe ovata had been absent, Mnemiopsis leidyi biomass had been considerably higher, than in November 2020 when both ctenophore species were present in samples. A significant increase in the share of large M. leidyi individuals was recorded. A physiological threshold of vertical distribution of jellyfish is found to coincide with a thermocline border. In August 2021, it was situated at the depths of 20–22 m. Using an on-board telemetric complex significantly enhances the information about peculiarities of vertical distribution of jelly macrozooplankton.