As the Russian part of the recently completed international PLUMPLAS project, we  implemented in situ measurements of microplastic and plastic litter in the Russian seas, including the Black and Kara seas, as well as the White, Barents, Laptev and East Siberian seas. For all study areas, maps of plastic pollution were developed, as well as maps of hydrophysical fields marking river plumes. In the Black Sea, research covered the entire Russian sector of the sea from Sochi and the border with Abkhazia to the Kerch Strait. In the Kerch Strait itself, simultaneous measurements of the flow velocity and microplastics were implemented, which made it possible to estimate the transport of plastic through the Strait. Plumes of the Yenisei, Ob, Lena, Indigirka, and Kolyma have been studied in the Arctic seas. Data were obtained on the runoff of microplastics from the Northern Dvina rivers in the White Sea and the seasonal cycle of this runoff, including runoff during the winter ice period.

A technique for mapping floating plastic debris using shipboard remote laser sensing has been developed and successfully tested in the Black Sea, although some additional validation in other regions and further development of the methodology will be needed.
With the help of numerical modeling, the influence of various types of wind impact on the incidence and temporal variability of plumes of small rivers in the northeastern parts of the Black Sea and the transport of microplastics and other pollution by them was revealed.
The analysis of the extensive material collected during the project implementation has revealed new features of the taxonomic composition of biofouling, characteristic of marine plastics depending on the origin of the floating fragments, including those discharged by rivers. Most of the latter are characterized by fouling with diatoms and green filamentous algae against the background of saprophytic bacterial films.

river plumes, plastic litter, microplastic