Biohydrochemistry of marine environment and transformations of biogenic substances and oil hydrocarbons on the southeastern Sakhalin shelf

Mathematical simulation is used to study the biotransformation conditions of compounds of organogenic elements (C, N, P, Si) and oil hydrocarbons in the water of southeastern Sakhalin shelf. The input data for calculations were evaluated with the use of Sakhalin Shelf GIS or taken from the reference literature and materials of expedition studies. The values of water discharges through the boundaries of the zones chosen within the shelf water area and through the interface with the Sea of Okhotsk were derived from the characteristics of currents estimated by means of Bergen University oceanic model based on normal long-term monthly thermohaline parameters obtained from the Sakhalin Shelf GIS. The intraannual variations of the concentrations of organic and mineral compounds of C, N, P, and Si, as well as oil hydrocarbons because of biotransformation of substances by organisms of the community (bacteria, phytoand zooplankton) were evaluated in calculations with CNPSi-model. The results of calculations, revealing the features of the dynamics of substances, the biomass of organisms, and their activity in matter biotransformations were analyzed.