'Pieces of human society': deep ocean may be riddled with microplastics

Quantity of particles hundreds of meters underwater off California is on par with Great Pacific Garbage Patch, study finds

Anela Choy, a biological oceanographer, had been noticing something odd while studying the diets of tuna and other deep-diving fish. Though they lived at average depths of 1,000ft, their stomachs routinely contained bottle caps, trash bags, and light sticks. "It was so strange," says Choy, who works at the Scripps Institution of Oceanography at the University of California, San Diego. "We were seeing recognizable pieces of human society."

Her concerns about plastic pollution inspired a study of waters off the coast of northern California, conducted by Choy and a team of other scientists. The findings, released today in Nature Scientific Reports, reveal a proliferation of microplastic particles, the tiny fragments left over when larger plastics break down. Most remarkably, the highest concentrations of microplastics were found about 200-300 meters (650-1,000ft) down - four times more plastic than was found in samples at the surface. That's on par, or higher, with quantities found at the surface of the Great Pacific Garbage Patch.