Less than approximately 10% of plastic that enters the ocean can now be accounted for, probably due to fragmentation into small microplastics (PM) not quantified by modern techniques or to ocean surface export. It is not known how much plastic debris actually floats on the ocean’s surface, what mechanisms control the transport and fate of plastic from land to deep sea, and what ecological impact this might have.
The HOTMIC project aims to address these knowledge gaps by focusing on a land-ocean linkage model between Western Europe and the North Atlantic Ocean current. The goal of HOTMIC is to map the distribution of PM, including <10μm particles and microfibers, in water, sediments and biota from the coastal ocean to the open ocean gyrus and deep sea. This project will quantify the processes that control the lateral and vertical transport of PM, including biofouling, (bio)aggregation and deposition, for incorporation into global ocean models. To understand the fate of PM in the ocean, HOTMIC will examine microplastic weathering signatures during shipping and will assess the predominant mechanisms that create the weathering signature, including the biological effects of bioestruction and ingestion.