Peculiarities of the Distribution of Particulate Matter at the Water–Atmosphere Geochemical Barrier in Transoceanic Sections

Аннотация

The article presents the results of studies on the grain size distribution of aerosols and surface waters (cruise 31 of the R/V Akademik Nikolay Strakhov in December 2015–January 2016 and cruise 42 of the R/V Akademik Boris Petrov in January–April 2017). It was found that the average quantity of 0.3–0.5-µm aerosol particles per L decreased during 2017 as follows: Bab El-Mandeb Strait (135 190) > Gulf of Aden (102 854) > Red Sea (91 612) > North and Baltic seas (76 468) > Indian Ocean (64 113) > Malacca Strait (46 491)> Mediterranean Sea (28 397) > East Atlantic Ocean (14 803). The biotic factor prevails in the distribution of particulate matter and organic compounds in open waters of the Indian Ocean and in the northeast Atlantic Ocean, as well as in areas of high productivity (the Arabian Sea). Circumcontinental zoning results in a prevalent terrigenous component in particulate matter of coastal waters. The transformation from the winter (2016) to the spring (2017) phytoplankton community resulted in a decrease in particulate matter content by an average factor of 8. The lack of a correlation between the concentrations of particulate matter and organic compounds in some regions points to different sources of their formation. Despite the high concentrations of hydrocarbons in several samples in 2016 (up to 50–70 µg/L), the average concentrations were practically unchanged: 10.5 and 8.7 µg/L in 2016 and 2017, respectively. The presence of weathered oil alkanes in the composition of hydrocarbons points to the influence of oil pollutants.