Micro-litter pollution in the ascidian Cnemidocarpa verrucosa along the Antarctic Peninsula

Abstract

Antarctic benthic ecosystems are currently threatened by global change and direct human impact. Pollution fromlocal human activities is among the most relevant emerging hazards affecting Antarctic organisms. Micro-litter(ML) has already been found in Antarctic marine ecosystems, including diverse benthic fauna. This studycharacterised and quantified ML in a common soft-bottom filter-feeding solitary ascidian, Cnemidocarpa verrucosa(Lesson, 1830), along the Antarctic Peninsula from 62◦ S to 67◦ S, focusing particularly on Deception Island.Study sites included Johnsons’ Bay (Livingston Island), Deception Island (South Shetland Islands), Uruguay Island(Yalour Islands), and Ryder Buttress (Ryder Bay, Adelaide Island). More than half of the analysed organismscontained at least one ML particle, with an average of 0.14 ± 0.26 items per gram (viscera wet weight) and 1.62± 1.79 items per individual. Microplastics represented 37 % of the total ML items found. Along the AntarcticPeninsula, significantly higher amounts of ML were found in Johnsons’ Bay and Uruguay Island. WithinDeception Island, significantly higher ML abundances were found in Murature, at the innermost part of the island.The most common items found were black or blue cellulosic fibres within the smallest size range analysed(100–500 μm). We suggest that variations in ML among sites could be mainly due to the different intensity ofanthropogenic activities, although environmental characteristics of the locations (i.e. currents, bottom type) alsoplayed a key role in its distribution. To the best of our knowledge, this is the first study to assess ML pollution inan Antarctic ascidian and it also represents the southernmost benthic invertebrate study regarding ML along theAntarctic Peninsula. We believe this research may contribute to the development of policies to protect theAntarctic marine benthos from human pollution and improve their management.