Agent-Based Marine-Ecosystems Modeling

We propose a new information technology aimed at modeling of biochemical processes in marine ecosystems and based on the use of logical operators of control (intelligent agents) in the dynamic equations of the models. We develop a conceptual model of an ecosystem reflecting the interaction of 17 biochemical processes and 5 external factors. The equations of the model are obtained by the method of adaptive balance of causes (ABC method), which enables one to simulate complex scenarios of the processes running in the investigated systems and guarantees the possibility of robust calculations. Some examples of the behavior of ecosystems under the conditions of deficiency of oxygen caused by the action of natural and anthropogenic factors are presented. As a result, it is possible to make a conclusion that the combined application of the ABC-equations and intelligent agents of control in models of marine ecosystems is quite promising.     

Investigation of the biogeochemistry of methane and mechanisms of its transfer in the Black Sea

We demonstrate the importance of investigation of the behavior of methane as a source of energy and an element of the Black-Sea ecosystem affecting the global behavior of the climate. We describe the genesis of methane and the processes of its aerobic and anaerobic oxidation. An especially important biogeochemical and ecological role is played by the anaerobic oxidation of methane guaranteeing the formation of its effective sink inside the anaerobic zone and preventing its penetration into the atmosphere as a greenhouse gas. On the basis of the analysis of the experimental data available from the literature, we also discuss the principal regularities of the distribution of concentration of methane and its flows. It is shown that the formation of methane hydrates at the bottom in the abyssal part of the Black Sea and the events of jet gas release on the periphery of the basin can be regarded as the components of a single global process of gas release from the bottom of the Black Sea. We present estimates of the components of methane budget in the Black Sea. The results of simulation of the dynamics of methane bubbles and the processes of their gas exchange with the medium are analyzed. The data of hydroacoustic measurements are used to evaluate the distribution of methane bubbles in sizes and the mass transfer of methane through the ocean–atmosphere interface. Finally, we consider the methods of mathematical simulation of the distribution of methane in the ecosystem of the Black Sea. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 40–56, September–October, 2008.     

Basic regularities of the process of sedimentation of suspended organic matter in the shallow-water zones of the seas at middle latitudes

On the basis of analysis of literature data, we consider the regularities of sedimentation of suspended organic matter in shallow waters. The seasonal variability in sedimentation is demonstrated, and its scheme is constructed involving such classes of organic compounds as suspended amino acids, fatty acids, and hydrocarbons. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Analysis of the basic classes of organic compounds dissolved in seawater and their behaviour in the estuaries of rivers and coastal zone of the sea

On the basis of the available literature data, we analyze basic classes of organic compounds dissolved in seawater and study the transformations of proteins, carbohydrates, and lipids produced in the process of photosynthesis in seawater and their behaviour in river water and estuaries of the Black Sea. We also discuss the causes and distinctive features of the processes of production and destruction in the Black Sea. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Peculiarities of oceanographic processes in the north-western Black Sea

The paper examines how various factors affect the intensity of photosynthesis and oxidation reaction in the north-western part of the Black Sea. In the course of the evolution of the basin, natural aspects were widely changing; therefore their role is evaluated by the content of organic matter and diatoms in the bottom sediments. The influence of anthropogenic factors is determined by the current tendencies in the variation of physico-chemical and biological characteristics of the basin. The main factor upsetting steady functioning of the north-western Black Sea ecosystem is the large biogenic influx to the sea. The possible changing of the ecosystem during the nearest few decades is assessed. Translated by Vladimir A. Puchkin.     

Mathematical model for the ecosystem of the Black Sea hydrogen sulphide zone

A model for the ecosystem of the Black Sea hydrogen sulphide zone is suggested which incorporates seven components, namely, the concentrations of hydrogen sulphide, oxygen, dead organic matter, thiosulphates, molecular sulphur, and the biomass of sulphate-reducing and thiobacteria. With the minor terms neglected in the equations governing the system under consideration, the latter was divided into subsystems which allow an approximate calculation of the model components' vertical stationary profiles. The derived components' profiles agree qualitatively with available observations.Translated by V. Puchkin.