User:Cosettepatterson/Deep-Sea Debris

Deep-Sea Debris
Although an increasing number of studies have been focused on plastic debris accumulation on the coasts, in off-shore surface waters, and that ingested by marine organisms that live in the upper levels of the water column, there is limited information on debris in the mesopelagic and deeper layers. Studies that have been done have conducted research through bottom sampling, video observation via remotely operated vehicles (ROVs), and submersibles. They are also mostly limited to one-off projects that do not extend long enough to show significant effects of deep-sea debris over time. Research thus far has shown that debris in the deep-ocean is in fact impacted by anthropogenic activities, and plastic has been frequently observed in the deep-sea, especially in areas off-shore of heavily populated regions, such as the Mediterranean.

A Deep-sea Debris database by the Global Oceanographic Data Center of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), showing thirty years of photos and samples of marine debris since 1983, was made public in 2017. From the 5,010 dives in the database, using both ROVs and deep-sea submersibles, 3,425 man-made debris items were counted. The two most significant types of debris were macro-plastic, making up 33% of the debris found, and metal, making up 26%. Plastic debris was even found at the bottom of the Mariana Trench, at a depth of 10,898m, and plastic bags were found entangled in hydrothermal vent and cold seep communities.

Plastics that are less dense than seawater and float have historically garnered more attention because they can accumulate on shorelines, within sight of people. However, these positively buoyant plastics can sink due to the adherence of particles, leading to their accumulation in the deep-sea.