There’s enough plastic waste in the ocean to support the evolution of entire species and potentially harm others, according to a new study.
Published on Thursday in the peer-reviewed journal Nature Communications, the report documents the emergence of “neopelagic” communities—those that have evolved to live on plastic waste in the ocean.
The study, conducted by researchers at the Smithsonian Environmental Research Center, Williams College, and a number of other oceanic research institutions, builds on existing understanding of the ways oceanic species transport along coasts on floating debris, like plastic, seeds and seaweeds. This process is known as “ocean rafting,” and it’s well-studied, but it was long assumed to be an ephemeral process, and past research focused on the transient movement of coastal wildlife via rafts rather than their sustained residency on them.
According to the paper, the exponential increase in plastic pollution in the ocean has created permanent opportunities for coastal species to exist in the open ocean by colonizing floating debris.
In partnership with the nonprofit Ocean Voyages Institute, researcher Linsey Haram—who was was first author on the study as a postdoctoral research fellow at the Smithsonian Environmental Research Center—analyzed 103 tons of plastic from the North Pacific Subtropical Gyre, a region of the pacific ocean between California and Japan, and found a number of coastal species, like anemones and shrimp-like amphipods thriving on the debris.
“The issues of plastic go beyond just ingestion and entanglement," Haram said in a press release. “It's creating opportunities for coastal species' biogeography to greatly expand beyond what we previously thought was possible.”
Researchers first observed this phenomenon after the earthquake and tsunami that struck Japan in 2011, in which a large swath of debris was shuffled into the North Pacific Ocean, near Hawaii and the west coast of North America. “Hundreds of coastal Japanese marine species” were found alive on debris that had travelled 6,000 kilometers—and many of these species were found to have grown and reproduced for years at sea,” the study says.
Though the data analyzed for their paper only ranged until 2017, Haram told Motherboard that she’s continued to keep an eye on waste that’s arrived on North American shores in the years since. She’s continued to see plastic travel across the Pacific well into 2021, but lumber stopped arriving within a few years of the tsunami.
“This has led us to think that the exceptional durability and buoyancy of floating plastic debris may provide a unique, long-lasting habitat structure in the open ocean where coastal species are able to survive,” Haram said in an email.
This discovery carved a path for questions around how these communities have evolved to survive specific conditions at the surface of the ocean atop plastic debris. Haram and her co-authors coined the term “neopelagic”—“neo” meaning “new” and “pelagic” referring to the open ocean—to refer to these species, encompassing both rafting species and neuston, a category of oceanic species that live at the water’s surface and have evolved unique mechanisms to survive the “sea-air interface,” like air sacs that catch the wind.
Floating plastic could also provide a vector for the movement of invasive species, the study says; so, while plastic garbage has led to the proliferation of some species, it could prove to be the downfall of others, which will compete for resources in coastal regions where neopelagic ecosystems land after travelling from the open ocean.
“Coastal species are directly competing with these oceanic rafters," Haram said in the release. "They're competing for space. They're competing for resources. And those interactions are very poorly understood."
The researchers hope their paper will lay ground for future research on this and other biological consequences of the global plastic problem.
“The global plastic pollution crisis is reconfiguring seaweed and animal communities in the open ocean,” Haram told Motherboard. “The downstream effects of this reconfiguration on ocean ecosystems is unknown.”
Update: This article has been updated with comment from study co-author Linsey Haram.