Even as public awareness grows about the accumulation of plastic waste in our food systems and natural environments, scientists continue to make surprising discoveries about just how ingrained plastic is at the farthest reaches of our planet.
The latest habitat that’s been shown to be riddled with tiny particles known as microplastics is the deep ocean. The prevaling thought had been that plastic tends to float and concentrate at the surface, like with the so-called Great Pacific garbage patch. But we only held onto that optimistic belief because we hadn’t gotten around to checking.
A team of scientists realized that the unique underwater topography of the Monterey Bay offers the ideal setting to study plastic concentrations at various depths, thanks to the deep submarine canyon. So they did just that and published the results on June 6 in the journal Scientific Reports.
Using a multimillion-dollar underwater robot from the Monterey Bay Aquarium Research Institute in Moss Landing, the researchers surveyed the mile-deep submarine canyon that runs through the middle of the bay all the way to the coastline. The robot collected water samples at depths ranging from 5 to 1,000 meters. Microplastics were disturbingly abundant in the midsection, at 200 to 600 meters of depth.
Scientists also wanted to learn whether the particles were getting eaten by sea creatures and introduced into the food chain. One of the organisms examined were filter feeders called giant larvaceans, though they are actually as tiny as insects. Larvaceans eat by building mucous mesh structures around their bodies that capture floating plankton. The research team’s robot collected filters that had been discarded. On shore, the scientists also gathered beach-stranded pelagic red crabs. In the cases of both species, large amounts of microplastics had invaded their bodies.
“This study provides direct evidence that a potentially large pool of marine microplastics may exist within the largest living space on Earth, the deep-sea water column,” the scientists wrote in conclusion.
Adding that more research is necessary, they wrote, “Intensive sea-going surveys are logistically demanding and very costly, but increased technology investments are necessary for advancing our understanding of global marine ecosystems.”