DATE: June 6, 2019
SNIP: Monterey Bay is one of the most beautiful and pristine-looking places on earth, but look below the surface and researchers have found evidence it’s teeming with microplastic.
The tiny pieces are smaller than a grain of rice and have been discovered floating through water columns as deep as 3,800 feet and in the guts and discharge of different sea creatures.
Today in the journal Nature Scientific Reports, researchers present a torrent of horrifying findings about just how bad the plastic problem has become. For one, microplastic is swirling in Monterey Bay’s water column at every depth they sampled, sometimes in concentrations greater than at the surface of the infamous Great Pacific Garbage Patch. Two, those plastics are coming from land, not local fishing nets, and are weathered, suggesting they’ve been floating around for a long while. And three, every animal the researchers found—some that make up the base of the food web in the bay—were loaded with microplastic.
“What we found was that microplastic is actually pretty pervasive,” said Anela Choy, lead author and assistant professor at the Scripps Institution of Oceanography, who was a postdoc with MBRI at the time.
“We found microplastics in 100 percent of our water samples and 100 percent of our animal samples that we looked at,” she said.
The researchers found the amount of microplastic captured at the surface is about the same as it is down at 3,200 feet. But between 650 and 2,000 feet, the counts skyrocket.
Scientists have suspected that ocean plastics aren’t necessarily concentrated at the surface, contrary to what you’d assume given the Great Pacific Garbage Patch. This is one big reason why they’ve scoffed at the idea of the Ocean Cleanup project, which is essentially a giant tube for catching surface plastic. It snapped shortly after its deployment in the Patch. But until now no one has gathered good data on what that distribution of plastic looks like up and down the water column.
A still outstanding piece of that puzzle, though, is where this microplastic is coming from. By running tests in the lab, the researchers found that most of the particles they collected were PET, a component of single-use plastics. Then the question becomes, where are things like plastic bottles breaking down into microplastic in the sea? Does it happen at the surface, or do the bottles sink and then break down? How do the tiny particles swirl in currents? All important questions for future research.
What was clear from this work, though, is that the microplastic is weathered, suggesting particles had been floating around for perhaps years.
These old plastics aren’t just floating around harmlessly—they’re making their way into animals. The researchers concentrated on two species, pelagic red crabs and giant larvaceans, bizarre critters that make mucus nets to catch food. They found that all specimens carried microplastic, suggesting that both currents and animals transport plastic around the ecosystem.