## 1 Introduction  
Plastic pollution of the ocean is an aesthetic, economic, and serious environmental problem [1]. Litter pollutes beaches and reduces tourist interest, and plastic waste floating on the ocean surface interferes with shipping and fishing. Plastic drift on the shore destroys habitats for coastal animals and negatively impacts marine biodiversity in general when it accumulates in the ocean. Microplastics (MPs) are particles smaller than 5 mm [2]. They can either directly enter the environment as microfibers from clothing, plastic pellets, cleaning products, etc. (primary microplastics), or as polymer waste resulting from the breakdown of large debris during fragmentation or photodegradation processes (secondary microplastics) [3]. The high scientific interest in marine microplastics is supported by model estimates of plastic particle distributions with different sizes. These take into account fragmentation rates, according to which microplastics, represented by granules, fragments, and fibers, contribute more than 90% of the global particle count in the ocean [4]. The small size and food-like appearance (due to the variety of shapes and colors) of microplastic particles allows them to enter the marine food chain at any level [5, 6, 7, 8]. The propensity of organisms to ingest microplastics has been observed at lower trophic levels (zooplankton, chaetognatha, ichthyoplankton, copepods, and salps) as well as at higher trophic levels, including invertebrates (polychaetes, crustaceans, echinoderms, bivalves)and vertebrates (fish, seabirds, and mammals). Large marine animals are also exposed to plastic pollution through trophic transfer, in addition to direct absorption from the environment. The negative impacts of plastic consumption on marine organisms are manifold (reviews [5; 6; 8] offer insight into laboratory-based and in situ monitoring). These include reduced fecundity, impeded mobility, reduced feeding rates, reduced growth and survival, blockage of both the digestive and gastrointestinal tracts, resulting in internal perforations, and in some cases, death. Furthermore, there is a possibility of toxicological effects resulting from the addition of chemical substances during the production of plastic or the adsorption of heavy metals and environmental pollutants on the surface of microplastics. Further trophic transfer through the food chain results in human consumption of microplastics [9]. Whereas the Arctic as a remote region was previously assumed to be unrelated, in recent years, high levels of plastic pollution have been found there [10]. Pollution enters the Arctic Ocean (Figure 1) both from local sources (fisheries, marine industrial activities, and sewage) and from lower latitudes, transported by ocean currents, atmospheric flows, and rivers [10]. In addition to the presence of microplastics in the ocean [11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21], there is evidence of particles being embedded into Arctic sea ice [22; 23; 24; 25]. The vertical distribution of buoyant microplastics is still a debatable issue since, despite their lightness in relation to seawater, they are found not only in surface waters but also in subsurface layers [12; 14] and even in bottom sediments [11; 15; 16; 19; 21]. Various processes affecting the vertical transport of buoyant microplastics were discussed in [26], but their relative importance in different ocean regions remains unclear. The principal mechanism is usually considered to be biofouling [27; 28; 29; 30], which is the process of the accumulation of organisms on the particle surface. Biofilm growth leads to an increase in the specific gravity of the particle, affecting its buoyancy. Another mechanism for the removal of light microplastics from the ocean surface may be the incorporation into marine aggregates [31; 32] and marine organisms' fecal pellets [33; 34]. The modeling of microplastic transport in the Arctic Ocean, with consideration of biofouling, is a developing field of research, with a limited number of studies currently available.