Litter trends at three stations of the HAUSGARTEN observatory

The deep sea is considered a major sink for debris even in regions as secluded as the Arctic Ocean. Here, we assess the variability of litter over a latitudinal gradient at the HAUSGARTEN observatory by adding imagery from the southernmost station S3 to previously published data from the northernmost station N3 and the central station HG-IV. The analysis includes footage of the seafloor from 2002 to 2017. Photographic surveys were analyzed to determine litter density, material composition, size and interactions with epibenthic fauna. Litter density clearly increased over time ranging between 813 ± 525 (SEM) and 6,717 ± 2,044 (SEM) items km-². The dominant material was plastic and small-sized items accounted for 63% of the litter in the observatory. N3 experienced the strongest increase in litter dominated by dark pieces of glass (41%). Interactions between litter and epibenthic megafauna were frequently observed (45% of items) in the form of entanglement with sponges or colonization by sea anemones.