An amazing level of contaminants are detected from deep-sea creatures

ByNOAA Ocean Exploration & amp; Research

Marine pollution caused by waste discharged due to human activities of drifting waste and harmful substances is an environmental problem occurring throughout the Earth and it is currently difficult for each country to resolve it even if measures are taken. As it is difficult to prevent marine pollution, harmful substances were also discovered in the Mariana Trench and the Kermadec Trench, where people have hardly entered.

Marine, extreme, but not pristine: Anthropogenic pollution in the deepest ecosystem on Earth | Nature Ecology & Evolution Community
https://natureecoevocommunity.nature.com/users/27531-alan-jamieson/posts/14982-marine-extreme-but-not-pristine-anthropogenic-pollution-in-the-deepest-ecosystem-on-earth

The world's deepest ocean trenches are packed with pollution | The Economist
http://www.economist.com/news/science-and-technology/21716891-nasty-chemicals-abound-what-was-thought-untouched-environment-worlds

The trench is a place where the sea floor is like an elongated valley. The Mariana trench, which is said to be the world's largest, has a length of 2550 km and the deepest part found by the survey up to the present is called Challenger ocean It has a depth of 19,11 m. This is an unimaginable depth that it is about 2,000 m from the summit to the sea surface even if you sink Everest at an altitude of 8848 m.

In the relatively shallow part of the ocean, sunlight promotes the growth of plants and forms almost the same ecosystem as the ground that creatures such as fish and shellfish consume plants. In the deep sea where sunlight does not reach, ecosystems are formed around the hydrothermal vents that release chemical substances. However, the existence of hydrothermal vents has not been confirmed on the seabed at 5000 m or less, and organisms inhabiting less than 5000 m live in harsh environments with organic matter contained in dead bodies of organisms falling from the shallow ocean as important nutrients It is.

ByUSFWS - Pacific Region

Organic matter that has fallen into the trench never goes out of the trench again. Dr. Alan Jamieson of the University of Newcastle thought that organic matter accumulated in the trench contains human origin, that is, pollutants produced by human activities. Dr. Jamieson hypothesized that contaminants such as polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) might not invade into the body of organisms in the trench.

In fact, Dr. Jamieson formed a survey team and conducted a survey to capture the legs by sinking the unmanned aircraft between 7000 m and 10 000 m in the Mariana Trench and the Kermadec Trench. As a result of investigation, PCB and PBDE were detected from captured end legs. Although the concentration of PBDE was moderate and not a big problem, the problem is PCB concentration.

ByNOAA Ocean Exploration & amp; Research

The PCB detected from organisms on the coast without contamination is less than 1 nanogram per gram of tissue, but in contaminated areas it exceeds 100 nanograms. 495 nanograms of PCB per gram was detected from the end legs collected at the site of the Mariana Trench at 10,250 meters, 800 nanograms per gram at 8942 m location, 1900 per gram at the end legs collected at 7841 m Nanogram PCB was detected. In the Kelmadec Trench there were fewer PCBs detected than the Mariana Trench, but still it was a high number of 50 to 250 nanograms per gram.

The exact cause is unknown why the PCB level of the Mariana Trench was high, but Dr. Jamieson said "The ocean current of the North Pacific is formingNorth Pacific RoundThere is a possibility that plastics decomposed into the Mariana Trench may have entered from here, as a large amount of plastics are accumulated. "