Plastic at the bottom of Mariana Trench

| 31st May 2019
Plastic waste deep underwater
Sustainability Times
The journey to extreme depths of the Mariana Trench encountered new species of sea creatures - as well as a plastic bag and sweet wrappers.

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The Mariana Trench, located in the western Pacific ocean, is the deepest point in the world. Its underwater valley - known as Challenger Deep - reaches a known depth of 10,994 metres.

To put this mind-boggling depth in to perspective: if you placed Mount Everest in Challenger Deep, its peak would still be over two kilometres (1.2 miles) under water. 

This ecosystem is so far removed from the rest of the world that no sunlight can penetrate it and nutrients from the surface seldom make it this far. It would not be a stretch it say that the deepest parts of our oceans are as unfamiliar as alien worlds.

Toxic chemicals

The only connection between the trench and the outside world are the submersibles that conduct research missions and, unfortunately, man-made chemicals and plastics. 

The first indication of pollutants in the trench came in a 2016 study published in the journal Nature Ecology & Evolution that described how PCB (polychlorinated biphenyl), a highly toxic chemical that was banned internationally in 2001, was reported in crustaceans at depths of up to 10,250 metres.  

In a recent trip to the trench by American explorer Victor Vescovo, four new species of amphipods were discovered. Vescovo also found a plastic bag and sweet wrappers nearly seven miles down.

study published early this year in the journal Royal society Open Science looked at the gut contents of amphipods from six deep sea trenches around the Pacific Rim (including the Mariana Trench).

The researchers discovered that over 72 percent - 65 out of 90 – of amphipods contained at least one microplastic particle, the first record of microplastics being ingested by hadal organisms. All of the collected amphipods from the Mariana Trench contained microplastics. 

This Author 

Jack Wilkin is a graduate research student at the Camborne School of Mines in the United Kingdom. His research focuses on the isotopic geochemistry of fossils from the Jurassic of Germany for paleoclimate studies.

Image: Sustainability Times. 

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