Abstract
The paper presents the results of hydrochemical observations obtained during the expedition on the scientific-research vessel “Deneb” in the Eastern part of the Azov Sea and the Taganrog Bay in July 2017. In the ecological and hydrophysical researches we have found abnormally low levels of dissolved oxygen in the bottom layer of the Azov Sea. Among the various approximations of the vertical turbulent exchange coefficient, the algebraic subgrid models are the most applicable. These models are based on the determination of turbulent flows as averaged multiplication of deviations over space or time (correlation) of the velocity components of the currents and a transferring physical quantity. The numerical experiment for determination of vertical turbulent exchange coefficient for some points of the Azov Sea was performed. Direct dependence between values of the vertical turbulent exchange coefficient and the concentration of dissolved oxygen in the bottom layer was obtained.
Highlights
Human impact on nature along with the abnormal climate changes lead to the violation of the natural functioning of the hydro-ecosystems, eutrophication, decreasing of biological diversity
The decomposition of huge amounts of organic matter in a short time period leads to a significant reduction in the concentration of dissolved oxygen in the water, causing fish kills and, as a result, leads to water quality deterioration
Among all hydrochemical parameters influencing on the biological productivity of the Azov Sea, the dissolved oxygen has a special attention as the source of the respiration of aquatic organisms and the factor determining the speed and completeness mineralization of organic matter in the water
Summary
Human impact on nature along with the abnormal climate changes lead to the violation of the natural functioning of the hydro-ecosystems, eutrophication, decreasing of biological diversity. Among all hydrochemical parameters influencing on the biological productivity of the Azov Sea, the dissolved oxygen has a special attention as the source of the respiration of aquatic organisms and the factor determining the speed and completeness mineralization of organic matter in the water. The concentration of dissolved oxygen in sea water depends on several factors, the main ones are: the gas exchange between water and atmosphere; the intensity of the photosynthesis process; the process by which bacterial and chemical oxidation metabolites of marine organisms, remains of dead organisms of plant and animal origin; the intensity of convective mixing and the flow of oxygen-depleted waters; water advection of masses, biochemical oxygen demand of bottom sediments [1]. The leading factors of formation of the oxygen regime in surface waters are primarily production processes, in the bottom – the biochemical decomposition of bottom sediments. The hydrochemical laboratory is located on the board of the vessel "Deneb" due to which we can performed all complex of fiend analyzes (oxygen, nutrients, pH, sulfide, plant pigments, production-destruction)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call