Modeling the Accumulation and Transport of Microplastics by Sea Ice

Plastic pollution is ubiquitous within the marine environment. Despite increasing public and scientific attention to the issue, there still remain gaps in the knowledge of the full global extent of the distribution of this microplastic pollution. The presence and transportation of microplastics in sea ice is an emerging area of research, particularly with regards to sea ice in the Southern Ocean. This study uses numerical modeling to explore the accumulation and transport of positively and neutrally buoyant microplastics in both Arctic and Southern Ocean sea ice. In general, sea ice may be an important seasonal sink for microplastics pollution in both the Arctic and the Antarctic. Positively buoyant microplastics dominate in Arctic sea ice, whereas in the Southern Ocean, neutrally buoyant plastics, which arrive in the region through deep-water transport, appear to be dominant. The overall distribution of microplastics in the Arctic is in keeping with the current literature, although direct comparisons between the results of this model and observational data should be made with caution. There is a clear need for further observational data in the Southern Ocean to elucidate both the transport mechanisms and accumulation of microplastics in Southern Ocean sea ice.