Monterey Bay Is Filled With Microplastic From Human Waste—Even at Its Deepest Points

Plastic pollution pervades California's Monterey Bay, even at its deepest points, with microplastic particles found to be at the same concentration at the surface as at the seafloor, scientists have discovered.

Researchers from the Monterey Bay Aquarium Research Institute and Monterey Bay Aquarium have carried out a systematic study of the area's National Marine Sanctuary by repeatedly sampling the water from the same locations down to depths of over 3,200 feet.

Microplastics are tiny bits of plastic created from industrial waste and the breakdown of consumer products. A number of recent studies have highlighted their pervasiveness—they have been found in the Arctic sea ice, in Swiss mountains and in the deepest parts of the sea. Microplastics are so abundant they have even been found in human feces across the globe.

Anela Choy, lead author of the latest study, published in Scientific Reports, said that because of previous research they had expected to find microplastics in the deepest parts of Monterey Bay, "we just didn't know the extent of the absolute amounts that we would find and how they would vary with ocean depth," she told Newsweek.

Researchers used underwater robots to collect the samples from different depths around the Bay. They then filtered the microplastic parts and worked out the concentrations at the different locations. Findings showed the level of microplastics at the surface was the same as at the deepest locations sampled. They also found concentrations were highest at a range of between 650 and 2,000 feet beneath the surface.

Findings also showed microplastics were present in the marine creatures sampled as part of the study. They looked at two species—pelagic red crabs and giant larvaceans—and found microplastics were present in every individual sampled. This adds to the evidence that microplastics are entering the food chain via marine environments.

Monterey Bay
A whale in California's Monterey Bay. EVA HAMBACH/AFP/Getty Images

Most of the microplastic was that used to make consumer products, such as single use drink bottles and food packaging. "We hypothesize that there were both land-based sources and open ocean sources from outside of Monterey Bay," Choy said of the sources of the microplastics.

"We looked at the kinds of plastic we sampled from the ocean and two species of marine animals and found they did not match the types of plastic used by local fishery operations, and instead resembled things like PET, from human-derived single use products for example."

The research comes as news stories highlight the huge problem of plastic waste. In May, a new island of plastic waste dozens of miles long was discovered floating in the Mediterranean Sea. Researchers also recently discovered that barely inhabited Indian Ocean islands are now swamped in plastic waste.

Choy said the next step in their research is to find out how microplastics are moving through marine food webs. "We would like to know the fate and transport of this material, and take steps forward to understand what this all means for healthy marine ecosystems that humans all around the world rely upon every day," she said.

Despite the severity of the problem of plastic pollution, she said she is still hopeful we can make a change: "As with all environmental problems, it is never too late to modify our behavior and attempt to take effective corrective action ... Our findings can be used to encourage positive community action, and to motivate individuals and corporations to be more responsible partners in helping to solve this problem. I am optimistic we can do better."