Density and distribution patterns of seafloor macrolitter in the eastern Red Sea.

The constant production of plastic and incessant growth of waste pollution continues to alter the marine environment from the coasts and surface waters to the deep sea. The quantification and investigation of macrolitter on the vast seabed of the ocean are challenging tasks that must be undertaken to elucidate the impact of anthropogenic activity on the marine environment and facilitate subsequent implementation of legally binding waste management regulations. In this study, we analyzed >60,000 images collected during 84 dives surveying 62.1 km of seabed in the eastern Red Sea to quantify the abundance and density of seafloor macrolitter. The surveyed depth of the seabed varied between 35 and 2415 m, and litter was observed at depths ranging from 93 to 2415 m. The litter density varied between 0 and 73,798 items km, with the mean (± SE) and median densities of 4069 ± 1188 and 1371 items km, respectively. Plastic was the main litter category, comprising 46 % of all litter. The density of litter was higher at deeper depths (>1400 m) and increased significantly at distances farther from the shore. The results of this study suggest that maritime traffic and the possible direct litter discharge from vessels are the main anthropogenic sources of seafloor litter in the eastern Red Sea. Thus, we emphasize the urgency of conservation efforts and strict waste regulations to preserve the marine ecosystem of the Red Sea.