Gas - Geochemical, Hydrological, and Biooptical Characteristics of the Shallow Northeastern Shelf of Sakhalin Island

The paper discusses the theoretical and practical aspects of the relationship between bio-optical parameters (chlorophyll-a concentration, colored dissolved organic matter, turbidity) and the distribution of dissolved gases (methane, helium, hydrogen, hydrogen sulfide) in seawater. Comprehensive studies of the gas geochemical, hydrological, and bio-optical parameters of the shallow northeastern shelf of Sakhalin Island (Sea of Okhotsk) are based on data obtained during cruise No. 68 of the RV “Akademik Oparin” in August 2023. It has been shown that during the warm period of the year, the study area includes waters with various bio-optical characteristics, influenced by river runoff, hydrocarbon-rich shelf areas, active phytoplankton development, and water dynamics. Bio-optical measurements allow for distinguishing the main branch of the East-Sakhalin Current and its shelf branch, in which increased concentrations of dissolved gases are present, emanating from benthic sources on the eastern shelf of Sakhalin Island.