Hydrocarbons in the Water and Bottom Sediments of the Barents Sea during Ice Cover Variability

Aliphatic hydrocarbons (HCs) were studied in water and bottom sediments sampled during cruises 67 th and 68 th (August–September 2016 and July–August 2017, respectively) of the R/V Akademik Mstislav Keldysh in the Barents Sea to determine the lateral and interannual variability of their concentrations and composition. It has been established that the HC distribution in water was mainly determined by natural factors and depended on the hydrological peculiarites in different areas of the sea. From autumn 2016 to summer 2017, hydrocarbon concentrations slightly increased (on average, from 3 to 5 µg/L), which was related to a change in the biochemical composition of organic matter likely owing to the decrease of ice area. The content of HCs decreased mainly with the depth. An exception was observed in the area of troughs and deposits, where nepheloid bottom layers demonstrated an increase of HC concentration in suspended matter and in the surface layer of bottom sediments, whereas sedimentary sequence showed no correlation between HC distribution and organic carbon.