A Japanese national research institute says it will launch a major research project on how plastic waste is contaminating the ocean depths and affecting the ecosystem.
The Japan Agency for Marine-Earth Science and Technology set up a group in April to study marine pollution caused by plastic waste.
The three-week project starts on August 28. It will take place in Sagami Bay, south of Tokyo, and in the waters off the Boso Peninsula, east of Tokyo.
Researchers will measure the amount of micro plastic contained in sediment extracted from the seabed at depths of between 1,200 and 9,200 meters. They will look into when it accumulated, and whether it can be found in the stomachs of marine animals.
Micro plastic is smaller than 5 millimeters and affects the ecosystem.
The group will also carry out an experiment to see how plastic breaks down over time in the deep sea environment.
It says pieces of plastic will be placed at a depth of 1,200 meters for three years. Some pieces will be ordinary plastic used in consumers products. Others will be a special plastic designed to break down with the help of microorganisms, turning into water and carbon dioxide.
The group's deputy leader, Masashi Tsuchiya, says much remains unknown about how far plastic waste has spread, and how much has accumulated in the deep sea.
He says he hopes the project will raise awareness of the issue, and make people realize their discarded waste could end up in the Mariana Trench, the deepest natural trench in the world located in the western Pacific.