Humans have dumped tons of plastic into oceans. Now it’s reached the deepest depths, study finds

Man-made plastic has made its way into the stomachs of crustaceans living miles below the ocean surface in deep trenches, a “worrying” new study finds.
Man-made plastic has made its way into the stomachs of crustaceans living miles below the ocean surface in deep trenches, a “worrying” new study finds. AP

The crustaceans crawling through the deepest, darkest depths of the ocean are almost like aliens: We know little about them, they’re otherworldly-looking — almost shrimp-like — and they exist in an environment that we can hardly imagine.

But the real aliens in these unthinkably deep corners of the ocean, like the Mariana Trench, aren’t the animals at all. Instead, the aliens here are human-made plastics like rayon and nylon.

The oceans are filled with 300 million tons of plastic litter, all of it produced by humans. And now, scientists say they have found those foreign, human-created plastics inside the stomach of some of least understood animals on the planet — the crustaceans who live on the deepest ocean floors.

“Litter discarded into the oceans will ultimately end up washed back ashore or sinking to the deep-sea,” Dr. Alan Jamieson, who led the research at Newcastle University in the United Kingdom, said in a statement. “There are no other options.”

His research confirms that plenty of that human-generated plastic has already ended up in the deep sea. But the plastic isn’t just there, sitting on the ocean floor, the study says — it’s made its way into the bodies of the animals who call the deep sea home.

Every animal the Newcastle team analyzed from the Mariana Trench, the deepest in the world at seven miles, had ingested plastic, the study found. In the New Hebrides Trench, 50 percent of the animals had plastic in their stomachs.

But why is the plastic ending up inside these deep-dwelling critters?

“The deep sea is not only the ultimate sink for any material that descends from the surface, but it is also inhabited by organisms well adapted to a low food environment, and these will often eat just about anything,” Jamieson said.

Until about 60 years ago, humans weren’t even mass producing plastic, National Geographic reports. But now, rayon, nylon and all sorts of other plastics are produced at a record pace to make clothes and coke bottles and more. As a result, there’s about 8.3 billion metric tons of plastic on the planet.

Most of that plastic isn’t recycled, either. In fact, reports National Geographic, 91 percent of the world’s plastic ends up as waste that threatens fish, birds, mammals and even the crustaceans seven miles below the ocean’s surface.

Given that plastic has made it so deep, Jamieson added, “it is highly likely there are no marine ecosystems left that are not impacted” by human-made debris.

The study tested 90 animals found in a handful of super-deep trenches across the Pacific Ocean, including the Mariana, Japan, Izu-Bonin, Peru-Chile, New Hebrides and Kermadec trenches. It follows up on earlier research Jamieson and his colleagues published in February in the science journal Nature, which found “extraordinary levels of persistent organic pollutants” in two deep ocean trenches.

As the Los Angeles Times reported in February, those pollutants can have “devastating effects on the hormonal, immune and reproductive systems,” according to Katherine Dafforn, an scientists at the University of New South Wales.

Jamieson and his colleagues dropped a so-called “lander” to the ocean floor to collect the samples, the researchers said.

Eight million tons of plastic are added to the ocean each year, according to the researchers.