In 2017, information was published on the amount of debris seen in the ocean over 30 years of observations. The base was composed of specialists from the Japan Marine Science and Technology Agency.
The database includes photographs and video recordings of plastic fragments taken by deepwater and remotely controlled devices around the world. A total of 5 010 dives were made, during which 3,425 plastic objects were discovered.
Then the scientists analyzed the collected data. It was found out that 33% of the found objects are macroplastic – fragments in the size more than five millimeters. Most of them are disposable items. On average, this category of garbage accounts for 89% of the total pollution, but at a depth of more than six thousand meters, this figure reached 92%. In addition to plastic, the ocean is contaminated with metal and rubber products, as well as remnants of fishing and naval gear.
At a depth of 1092-5977 meters, the debris concentration is from 17 to 335 units per square kilometer. At the same time plastic and other inorganic wastes have already reached the deepest point of the planet, the bottom of the Mariana Trench: at a depth of 10 898 meters, there are bags and cans.
In the study, only deep-sea examples were considered: it is the deep layers of water that became the "final point" of the movement of floating fragments of plastic debris. However, the surface layers are as polluted as they are – not only the oceans, but even the alpine lakes, which were formerly a standard of clean water.