Surface waters meso- and micro-litter around the Western Antarctic Peninsula: Are the South Shetland Islands a pollution hotspot?

Not even the most remote and pristine oceanic regions, such as the Southern Ocean, are immune to the impacts of marine litter. This study presents novel data on surface waters meso- and micro-litter along the Western Antarctic Peninsula and Livingston Island (South Shetland Islands) across two summer campaigns (2022-2023), providing one of the broadest assessments of marine debris in Antarctica (62° S to 67° S). Litter was detected at all sampling sites, with abundances ranging from 0.019 ± 0.033 to 0.193 ± 0.104 items m^-3 along the Western Antarctic Peninsula (average: 0.086 ± 0.082 items m^-3). The South Shetland Islands exhibited significantly higher litter abundances compared to higher-latitude sites. Our results show that litter distribution correlates with human activity intensity, with latitude and the personnel density of nearby research stations as key influencing factors. The South Shetland Islands emerged as an Antarctic marine litter hotspot, likely driven by the concentration of Antarctic facilities and other anthropogenic activities. Litter was primarily composed of synthetic fibres, especially polyester and nylon, pointing to local human sources. Additionally, a decrease in marine litter was observed at Livingston Island between campaigns, with abundance declining from 0.235 ± 0.152 items m^-3 to 0.116 ± 0.033 items m^-3. This highlights the need for ongoing monitoring to capture interannual variability, avoid seasonal biases, and better understand marine litter dynamics in the Southern Ocean to guide conservation efforts. These findings underscore human impact in Antarctica and the urgent need for better waste management and stricter environmental regulation enforcement.