Plastic Ocean: Installation of wasted materials

Why can’t we find the vast majority of ocean plastic?

New research is finding it in unexpected places

Every year, we dump 8 million tons of plastic trash into the ocean. And because most of it floats, you might expect it to amass on or just beneath the water’s surface, similar to the Great Pacific Garbage Patch.

Several recent studies have shown that much of this plastic ends up buried on the seafloor or suspended deep in the water column. This can happen when animals like red crabs and giant larvaceans eat it and poop it out in deeper water—or coat it in heavy mucus, making it sink to the seafloor.

And even more frighteningly, researchers say, some plastic degrades into tiny particles smaller than a cell, called nano plastics, which can accumulate in the tissues of fish and other organisms, sometimes causing neurological or reproductive issues.

This sort of unwitting animal transit has been observed in many species. A 2011 study examining plastic in fish in the north Pacific Ocean estimated that they ingested around 12,000 tons a year. In a later paper Erik Van Sebille’s group, an oceanographer at Utrecht University in the Netherlands noted that if the number held across the entire ocean, 100,000 tons of plastic could be inside animals at any one time.

A lot of the plastic we consume ends up in these patches due to poor waste management practices and natural disasters, among other causes. Marine debris kills hundreds of thousands of sea birds, turtles, and marine mammals each year.

For the past two years, scientists from the nearby Monterey Bay Aquarium Research Institute have been using customized remote-control submersibles to take samples of the near-invisible plastic drifting far below the surface.

“Just because you don’t see it, doesn’t mean it isn’t there,” says Anela Choy, a professor of oceanography at the University of California San Diego, and the lead researcher on the project. Below what she calls the “skin surface” of the ocean, the submersibles carefully filter seawater and take a snapshot of what’s in it.

The conventional view is that it is very hard to track ocean microplastic back to its source. But even very small bits of plastic don’t necessarily look the same. By examining how laser light scatters when it hits different bits of plastic, researchers can create a fingerprint.

The plastic found in Monterey Bay, for example, didn’t resemble the plastics used in local fishing equipment but was mostly Polyethylene terephthalate (PET), a polymer used in disposable packing, indicating it probably came from the land.

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