The Arctic Is a 'Dead End' for Ocean Plastic

The Arctic isn't exactly on top of the world right now. Aside from its literal setting in the northernmost limits of Earth, the sparsely populated region has faced a spate of human-induced misfortune lately. It's being rapidly reshaped by our greenhouse gas emissions, for example, and now it's filling up with our garbage, too.

Plastic trash is a growing threat to oceans around the planet, and research on the Great Pacific Garbage Patch — plus similar messes in the Atlantic, Indian and Southern oceans — has drawn widespread public attention over the past decade. But since the Arctic Ocean is so remote and largely buffered by land, it has seemed safer from the plastic debris plaguing so many ocean gyres farther south.

According to a new study, however, the Arctic not only shares this global plastic problem, but serves as a "dead end" for hordes of marine debris drifting through the North Atlantic. Even though very little plastic waste is discarded within the Arctic itself, it's still carried there — and then stranded — by ocean currents.

'Conveyer belt of plastic'

As the study's authors report in the journal Science Advances, roughly 300 billion pieces of plastic debris are now swirling around the Arctic Ocean's Barents and Greenland seas. Most of these are rice-sized microplastics, which can be especially bad for wildlife, and the vast majority apparently came from the North Atlantic.

The study revealed plastic riding into the Arctic via the Gulf Stream, a major ocean current that also brings warm water from the Gulf of Mexico to Northern Europe and the U.S. East Coast. Once this current reaches the Arctic Ocean, it sinks deeper and begins a long journey back to the equator — but without its plastic hitchhikers.

Plastic still seems relatively scarce in most of the Arctic, but the researchers say they found "quite high concentrations" in the Barents and Greenland seas. "There is continuous transport of floating litter from the North Atlantic," explains lead author Andrés Cózar, a biologist at the University of Cadiz in Spain, "and the Greenland and Barents seas act as a dead end for this poleward conveyor belt of plastic."

To illuminate this, Cózar and his colleagues took a five-month voyage around the Arctic Ocean, creating a map of floating plastic debris. They also used data from more than 17,000 satellite-tracked buoys floating on the ocean surface, and modeled how ocean currents move those buoys to help them retrace the Arctic's plastic stream.

Already on thin ice

Oceanic trash may not rival the sweeping dangers of dwindling Arctic sea ice, but it still poses a grave threat to the region's already embattled ecosystems.

"The Arctic is one of the most pristine ecosystems we still have," says study co-author Erik van Sebille, an oceanographer and climate scientist at Imperial College London, in a statement about the study. "And at the same time it is probably the ecosystem most under threat from climate change and sea ice melt. Any extra pressure on the animals in the Arctic, from plastic litter or other pollution, can be disastrous."

Roughly 8 million metric tons of plastic enter Earth's oceans every year, according to a 2015 study, and they can kill or sicken wildlife in a wide range of ways. Discarded plastic netting entangles seals, dolphins and whales, for instance, while plastic shopping bags clog the digestive systems of sea turtles hungry for jellyfish. Plus, unlike more biodegradable debris, plastic doesn't easily break down in seawater — it mainly just "photodegrades" under sunlight into smaller and smaller microplastics. These pose a more insidious ecological threat, forming toxic specks that look like food to seabirds, fish and other marine animals.

The coast isn't clear

There may be no practical way to clean up ocean plastic on a large scale, especially microplastics in remote, turbulent places like the Arctic. But thanks to research like this, we're at least learning how ocean plastic travels and where it originates. The next step is translating that into better plastic recycling on land.

"What is really worrisome is that we can track this plastic near Greenland and in the Barents Sea directly to the coasts of northwest Europe, the U.K. and the East Coast of the U.S.," van Sebille says. "It is our plastic that ends up there, so we have a responsibility to fix the problem. We need to stop the plastic from going into the ocean in the first place. Once the plastic is in the ocean, it's too diffusive, too small and too intermingled with algae to easily filter out. Prevention is the best cure."