Hydrocarbons at the Water-Atmosphere Border in the Barents and Kara Sea

Abstract

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