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SCIENCE > Environment

Japan’s deep-sea trash ‘exhibition’ is not a pretty sight

  • June 7, 2017
  • , The Asahi Shimbun , 8:00 a.m.
  • English Press

Images and videos shot in deep waters thousands of meters below the ocean surface over more than 30 years show the head of a mannequin, a sandal, a comic book and other pieces of trash have accumulated on the seabed around Japan.


The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) made available footage and photos of the trash on its website in April.


“The problem of trash in the seas has been discussed at summit meetings, meaning it has become an issue states around the world have to tackle together,” said an official of JAMSTEC, which is based in Yokosuka, Kanagawa Prefecture. “I would like people to rethink of the issue of the marine environment after learning about the deep-water trash problem through the images and footage they can rarely view in their daily lives.”


Available at the website are 1,700 videos and 680 images taken during underwater surveys conducted over more than 30 years by research submersibles and other vessels.


One can search the photos and footage by the type of the trash, the location where the debris was found, the depth at which it was photographed, whether there were any living creatures near the object, and other categories on the JAMSTEC database.


While most of the discovered objects are plastic bags or metal cans, a sneaker and other kinds of debris are also included.


Even a mannequin was found in July 1991 in a crack 6,280 meters below the surface in the Japan Trench by a manned research submersible called Shinkai 6500. It was also confirmed to still be there a year later, although soil had accumulated on the mannequin and a deep-sea creature was found near it.


The deepest location on the database was the 10,900-meter-deep seafloor of the Mariana Trench, where what appears to be plastic bags were discovered by the Kaiko remotely operated underwater vehicle in May 1998.


“Plastics, which account for 70 percent of trash found in the seas, cannot be decomposed under natural conditions, so they continue accumulating in waters,” said Atsuhiko Isobe, a physical oceanography professor at Kyushu University’s Research Institute for Applied Mechanics.


Isobe added that it is “not surprising” that large amounts of trash are discovered on the seafloor.


“When plastic products are heavier than water, they gradually move to deeper areas,” he said. “If they reach the deep seabed, they typically stay there.”


Isobe also pointed out that the objects could harm marine ecosystems.


“While there have been few studies themed on trash accumulating on the seafloor so far, benthic creatures may consume such objects when they are broken down into tiny pieces,” he said.


JAMSTEC has been videotaping and photographing living creatures as well as geographical and geological features in deep waters in its studies since the first half of the 1980s. Pieces of debris were found during the research process.


Although the snapped marine creatures and geographical features had already been made accessible to the public, it was the first time for the agency to unveil images and videos of underwater trash alone.


The photos and footage of debris are available on JAMSTEC’s Deep-sea Debris Database (

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