Features of the Behavior of Organic Compounds in Water and Bottom Sediments in the Kara Sea during Seasonal Ice Melting

The article presents the first data on the content of organic compounds (OCs): C-org, lipids, and hydrocarbons (aliphatic-AHCs) and polycyclic aromatic (PAHs)) in suspended particulate matter of the surface waters and bottom sediments in the western Kara Sea and Gulf of Ob during the period of seasonal ice melting (July 2019). The content of OCs and suspended particulate matter in surface waters was the highest in the Gulf of Ob: up to 325 mu g/L for AHCs, 15 ng/L for PAHs, and 15.5 mg/L for suspended particulate matter. The concentration of AHCs in the sea basin increased on average from 20 to 59 mu g/L, which was related to ice melting and flooding. The concentration of all OC components supplied by river runoff sharply decreases at the geochemical barrier between the Gulf of Ob and the Kara Sea. The production of hydrocarbons and intensification of navigation in the southern part of the Kara Sea affect the AHC and PAH composition. Decomposition of autochthonous suspended particulate matter, including suspended OCs, during sedimentation leads to the absence of an increase in the concentrations of C-org, AHCs, and PAHs in bottom sediments in contrast to those in the surface waters.