Content and Composition of Organic Compounds in Suspended Particulate Matter and Bottom Sediments in the Kara Sea during the Period of Seasonal Ice Melting

摘要

The first data on the content of organic compounds (OCs), i.e., C_(org), lipids, and hydrocarbons (aliphatic (AHCs) and polycyclic aromatic (PAHs)) in the suspended particulate matter of the surface waters and bottom sediments in the western Kara Sea and the Gulf of Ob during the period of seasonal ice melting (July 2019) are considered. The highest content of OCs and suspended particulate matter in surface waters was found in the Gulf of Ob: AHCs up to 325 μg/L, PAHs up to 15 ng/L, and suspended particulate matter up to 15.5 mg/L. In the sea basin, the AHC concentrations increased, on average, from 20 to 59 μg/L, which was associated with flooding. A sharp decrease in all OC components supplied by the river runoff is observed 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. The decomposition of autochthonous suspended particulate matter including the suspended OCs during sedimentation leads to the absence of increasing concentrations of C_(org), AHCs, and PAHs in the bottom sediments, unlike those in the surface waters.