No marine ecosystem is spared from plastic pollution: researchers have for the first time discovered microplastics in the bowels of mini crustaceans living at nearly 11 km deep. The authors of this study published Wednesday in the journal Royal Society Open Science have dissected 90 specimens of Lysianassidae amphipods, tiny shrimps, harvested from the bottom of six of the deepest ocean trenches around the Pacific Belt.
Nylon, polyethylene, PVC, synthetic silk … 65 individuals (more than 72%) contained at least one microparticle. And the contamination concerns all the sites, with a minimum of 50% of the specimens collected at nearly 7000 meters deep in the New Hebrides fossa having ingested plastic, to 100% in those captured at nearly 11 000 meters in the Mariana Trench, the deepest known.
"Part of me was expecting to find something, but not to the point of having 100% of the people in the deepest place in the world with fibers in their bowels. It's enormous", says AFP Alan Jamieson, researcher in marine ecology at the British University of Newcastle. The scientist, a specialist in underwater exploration who has discovered several species of the abyss, does not usually study plastic pollution issues.
Swallow a rope of 2 meters
But he and his team had amphipods of several species of the family Lysianassidae (Hirondellea, eurythenes gryllus) harvested between 2008 and 2017 by traps placed on the bottom of the oceans by submarine vehicles. An incomparable collection that they wanted to exploit to contribute to the knowledge on the "Hot topic" from pollution to microplastics, he says. More than 300 million tons of plastic are produced each year, some of which end up in the ocean.
According to scientific estimates, some 5,000 billion pieces of plastic weighing more than 250,000 tons float on the surface, the material eventually degrade into microparticles that sink to the bottom of the sea. Previous studies have documented the presence of microplastics in marine sediments at nearly 7,000 meters near the Kuril Pit, and in organisms at 2,200 meters deep in the North Atlantic. But most studies focus on the surface.
With this new data, "The essential point is that we find (The microplastic) systematically in animals all around the Pacific at extraordinary depths. It's everywhere. It's time to accept that plastic microparticles are everywhere ", laments Alan Jamieson. Some of the pits in which the individuals studied lived are indeed several thousand kilometers apart from each other. And the pollution of the depths is not new, the first samples going back to 2008. The impact of the ingestion of the microparticles by these organisms which are the beginning of the food chain of the abyss is not known. But there is probably a risk of obstruction.
Our garbage cans in the abyss
"It's like you're gulping down a 2 meter polypropylene rope and you're hoping it does not impact your health."says the researcher, who also notes the risk of chemical contamination by some compounds. And once entered the food chain, "There is a high probability" a "Perpetual cycle" transfer of these microplastics from an animal to its predator.
The UN and NGOs have declared war on plastics to try to dry up pollution at the source by fighting against the all-disposable culture. But the hope of cleaning up the sea with gigantic waste volumes is more than weak. And the prospect is even darker for the bottom of the oceans where the decomposed particles will eventually land. "We bunch our garbage cans in the place we know the least in the world", laments Alan Jamieson.
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RELEASE With AFP