Optimal control of sustainable development in the biological rehabilitation of the Azov Sea

The article is devoted to the application of the concept of sustainable development management to the task of combating the eutrophication of shallow water bodies (by the example of the Azov Sea). To describe the state dynamics of the water body, partial differential equations solved numerically by the finite difference method have been used. The dynamic problem of minimizing costs for the maintenance of the ecosystem of the water body in the defined condition, which is interpreted as the requirement for sustainable development, has been solved. The research and forecast complex, including the mathematical models of the hydrobiology of the shallow water body, environmental databases, and program library used to design scenarios of the ecological situation in the Azov Sea, has been worked out. Changes in the concentration of malicious blue-green algae due to water pollution by biogenic substances causing the rapid growth of these algae have been forecast. The influence of the spatial distribution of the temperature and the salinity on the biological treatment of the Azov Sea though the introduction of green algae, which displaced the toxic blue-green algae, has been studied. Using the designed research and forecast complex based on the materials of expeditions it is possible to investigate the key mechanisms of formation of vertical and horizontal zones in the distribution of biogenic substances, oxygen, and planktonic populations, to set the values of the parameters for management of the amount of hydrogen sulfide and hypoxemic zones, to evaluate the possibility of the biological treatment of the Azov Sea waters with the help of the introduction of the green alga Chlorella vulgaris BIN, followed by displacement of the toxic blue-algae that are most common in shallow water bodies such as Aphanizomenon flosaquae, and to rank the ecological efficiency of the factors for the management of the stability of the composition of the phytoplankton species, including the blooming of microalgae. Examples of the numerical calculations have been provided. The obtained results have been analyzed.