Plastic pollution is a major problem in the marine environment, with an estimated 8 million tons of the stuff ending up in the oceans every year. Much of that takes the form of beads smaller than 5 millimeters (three-sixteenths of an inch) that have been used in commercial products or result from the breakdown of larger chunks.
They’re easily consumed by fish and other sea creatures, so they’re also likely to get passed up the food web to humans. And other recent studies have found them not only bobbing in the waves, but embedded in the sea floor. The Monterey study was aimed at helping figure out how that happened.
“Somehow, someway, these plastics are getting from the surface where we are down to the bottom of the ocean,” Katija said. “That mechanism wasn’t well understood. So what we found was there might be this biological transport mechanism that can aid the transport of these plastics from the near surface to the bottom. Whether that’s a positive or a negative thing, that’s hard to say.”
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Animal species living at the bottom of the ocean eat both the fecal pellets and the larvaceans’ discarded houses, which Katija called “utterly beautiful and structurally complex.”
“What that means is there are these different avenues, these different pathways by which plastics can enter food webs in the ocean,” she said. “The big question that we need to start considering is that if animals are eating these plastics, potentially we could be eating them too, because we eat some of these marine animals.”
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