Occurrence, relative abundance and spatial distribution of microplastics and zooplankton NW of Sardinia in the Pelagos Sanctuary Protected Area, Mediterranean Sea

Environmental context Plastic materials are accumulating in the marine environment where they can now be found in the remotest areas of the world's oceans. Microplastics (plastic particles =5 mm), abundant in marine surface waters, are also found in neritic and pelagic waters of Mediterranean marine protected areas. Microplastics can accumulate along marine food chains, having noxious effects on marine organisms at different trophic levels and creating a serious threat to marine ecosystems. Abstract Floating plastic debris tends to fragment into smaller pieces, termed microplastics, which may increase the likelihood of ingestion of plastics by marine organisms entering the food web. This study analyses the amount and spatial distribution of microplastics and zooplankton in an area near Asinara National Park (NW Sardinia) and overlapping the Pelagos Sanctuary (Mediterranean Sea). Analysis showed microplastics in 81 % of the 27 samples analysed, with a mean value of 0.17 ± 0.32 items m–3. From geographic information system processing of the data, microplastics appeared more abundant (by a factor of four) in the pelagic than in the neritic environment, and showed a size range of the same order as major zooplanktonic taxa determined in the area. These findings suggest a potential risk of mesozooplankton and species preying on plankton mistaking microplastics for food. Further functional and toxicological studies are therefore necessary to assess the hazard associated with microplastics in the marine food web.