The results of the study of hydrocarbons (HCs): aliphatic (AHCs) and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments (2019 and 2020, cruises 75 and 80 of the R/V Akademik Mstislav Keldysh) in the Norwegian-Barents Sea basin: Mohns Ridge, shelf Svalbard archipelago, Sturfiord, Medvezhinsky trench, central part of the Barents Sea, Novaya Zemlya shelf, Franz Victoria trough are presented. It has been established that the organo-geochemical background of the Holocene sediments was formed due to the flow of sedimentary material in the coastal regions of the Barents Sea on shipping routes. The anthropogenic input of HCs into bottom sediments leads to an increase in their content in the composition of C_org (in the sandy sediments of the Kaninsky Bank at an AHC concentration up to 64 μg/g, when its proportion in the composition of C_org reaches 11.7%). The endogenous influence on the of the Svalbard archipelago shelf in Sturfiord and in the Medvezhinsky Trench determines the specificity of local anomalies in the content and composition of HCs. This is reflected in the absence of a correlation between HCs and the grain size composition of sediments and C_org content, as well as a change in hydrocarbon molecular markers. At the same time, the sedimentary section is enriched in light alkanes and naphthalene’s that may be due to emission during point discharge of gas fluid from sedimentary rocks of the lower stratigraphic horizons and/or sipping migration.

The concentrations and composition of hydrocarbons (HCs), aliphatic (AHCs), and polycyclic aromatic hydrocarbons (PAHs) in the Barents and Kara seas were determined in the surface microlayer (SML, about 300 µm thick), melting ice, and surface waters. Field material was collected on cruises 80 and 83 of the R/V Akademik Mstislav Keldysh in August 2020 and June 2021, respectively. In the SML, HCs occur primarily in suspension. In the Barents Sea, the AHC content in suspension was lower (31–96, 68 µg/L on average) compared to the Kara Sea (187–1051, 693 µg/L on average), where research was carried out in early summer. In the Kara Sea, the AHC concentrations in the SML were 3.6 times higher than in dissolved form (89–270, 158 μg/L on average), while compared to the suspension of surface waters, they were almost 15 times higher. Organic compounds also accumulate in ice, but to a lesser extent than in the SML. From the alkane composition, the influence of autochthonous processes on HC generation in melting ice is insignificant. The PAH contents in suspension were also 4.8 times higher on average than in dissolved form. The influence of the combustion products of ship fuel on the PAH composition was traced by markers, which showed that, in addition to phenanthrene, fluoranthene and pyrene dominated in all samples.