Specific features of water circulation and biogenic substance transformation and transport in Tatar Strait (Sea of Japan): Assessment based on the results of mathematical modeling

This study has no analogues in terms of methodology, as it uses three electronic instruments for studying the oceanographic regime of Tatar Strait. GIS “Sakhalin Shelf” was used to reconstruct annual variations in hydrological and hydrochemical characteristics of the marine environment at standard horizons of oceanographic stations in fixed geographic coordinates. An adapted version of the Oceanic Model created in Bergen University was used to reconstruct the spatial and temporal distribution of seawater temperature and salinity, to calculate the density and the circulation rate of water masses and water exchange parameters between the strait and nearby water areas and between regions within the strait. The hydroecological CNPSi-model was next used to assess the annual dynamics of concentrations of biogenic element compounds; the biomasses, biohydrochemical activity, and bioproductivity of microorganisms (heterotrophic bacteria, three phytoplankton and two zooplankton groups), involved in transformation of biogenic substances, as well as the internal fluxes of biogenic substances, governed by microorganism activity and the external load onto the marine ecosystem. Analysis of calculation results made it possible to reveal new features in water circulation in the strait (including those for winter) and, for the first time, to analyze the transport regime of biogenic substances through the external boundaries of Tatar Strait and through the boundaries of three regions identified within the strait.