HYDROCARBONS IN THE SURFACE MICROLAYER AND ICE OF THE KARA SEA

Abstract

Concentrations and composition of hydrocarbons – HCs (aliphatic – AHCs and polycyclic aromatic hydrocarbons – PAHs) in the Kara Sea (cruise 83 of the R/V Academic Mstislav Keldysh, June 2021) in the sea surface microlayer – SML (about 300 µm thick), ice and surface waters weree defined. The concentration of AHCs in SML occurs in suspended particulate matter (SPM), where their content varied in the range of 197–1051 µg/l, on average 621 and was almost 4 times higher than in the dissolved form: 89–270, on average 158 µg/l, and according to compared with the suspended form of surface waters – almost 22 times higher (on average 33 µg/l). The accumulation of organic compounds also occurs in ice, but to a lesser extent than in the SML. According to the composition of alkanes, the influence of autochthonous processes on the formation of AHCs in surface microlayer and melting ice is mostly insignificant, and this distinguishes their behavior from the ice that forms. The content of PAHs in surface microlayer in SPM was also 4.8 times higher on average than in the dissolved form. Despite the different sources of these hydrocarbon classes, for all samples taken, a dependence was observed in the distribution of AHCs and PAHs in SPM (r = 0.79, n = 52, at p 0.01). In the composition of PAHs, according to the markers, the influence of combustion products of marine fuel is traced, since, in addition to phenanthrene, fluoranthene and pyrene dominated in all samples.