OIL HYDROCARBONS IN SHELF WATERS OF THE EASTERN PART OF THE SAKHALIN ISLAND: THEIR INPUTS, TRANSFORMATIONS AND CONTENTS

Abstract

On the basis of the methodology of mathematical modeling, the development of the transformation of oil hydrocarbons in the waters of the eastern shelf of Sakhalin Island is considered. Three electronic instruments for the analysis of oceanographic information were used: 1. GIS “Sakhalin shelf” (for processing and systematization of thermohaline observed parameters); 2. The oceanic model of the Bergen University (for calculating the velocities and directions of currents, and also flow rates of water exchange between the individual regions on the Sakhalin Shelf); and 3. CNPSi-model (for calculating the biotransformation of oil hydrocarbons taking into account the intra-annual changes of the long-term marine environment parameters and features of the substance transfer at the water exchange). The entire eastern shelf of the Sakhalin Island was subdivided on two Water Areas (1. southeastern and 2. northeastern ones), where Regions 1–3 and 1–4 were respectively allocated. Using the methodology of mathematical modeling, the CNPSi-model reproduces the interactions of the changing environmental factors during a year (temperature, light intensity, water transparency, oil hydrocarbon inputs from external sources, conditions of the water regime) and their influence on the biotransformation of oil hydrocarbons in two-layer marine environment. The model calculates the changes during a year of the oil hydrocarbon concentrations, the biomass of B2 bacteria (they oxidize of the oil hydrocarbons) and their activity indexes (the specific growth rate, the total biomass turnover time and the biomass production). An analysis is made of the changes in these parameters depending on environmental factors and conditions of substance transport during water exchange across the boundaries of regions and with open water areas of the Sea of Okhotsk. For each region studied, the characteristic values of these parameters were revealed for specific periods of a year. Calculations show that there are different conditions for the formation of B2 bacteria biomass and their production on the south and north regions of the eastern shelf of the Sakhalin Island. In Regions 1–3 of the southeastern part of the shelf (Area 1), a significant effect of water dynamics was found on the development of the biomasses of organisms and, in particular, on the B2 biomass.