Since the mid-20th century more than 8.3 billion tonnes of plastic has been produced, and at least 60 per cent of that plastic has ended up in either sea.
In just a few decades, the spiralling levels of waste have created vast, spiralling, “gyres” of plastic waste measuring hundreds of thousands of square miles out in the open ocean.
New research has now revealed that these plastic gyres are host to a surprising array of plants and animals normally associated with coastal waters rather than the remote open ocean.
The scientists studying this phenomenon have warned that this rapid change could upend ecosystems which have been stable for thousands of years.
Scientists studied the species living among the plastic debris in the North Pacific Subtropical Gyre, more commonly known as the “Great Pacific Garbage Patch”.
After picking up more than 100 tonnes of plastic which was then analysed, they discovered coastal species including anemones, hydroids and shrimp-like amphipods, not only surviving, but thriving, on marine plastic hundreds of miles from their usual coastline environments.
“The issues of plastic go beyond just ingestion and entanglement,” said Linsey Haram, lead author of the research and a former postdoctoral fellow at the Smithsonian Environmental Research Centre (Serc) in Maryland in the US.
“It’s creating opportunities for coastal species’ biogeography to greatly expand beyond what we previously thought was possible.”
The world now has at least five giant plastic-infested gyres, or “garbage patches”, spiralling around its oceans. The Great Pacific Garbage Patch between California and Hawaii, holds the most floating plastic, with an estimated 79,000 metric tons of plastic floating in a region over 610,000 square miles.
For marine scientists, the existence of a new community of open ocean-dwelling species is a complete paradigm shift.
“The open ocean has not been habitable for coastal organisms until now,” said Serc senior scientist Greg Ruiz, who leads the Marine Invasions Lab where Dr Haram worked.
He said this was “partly because of habitat limitation, there wasn’t plastic there in the past, and partly, we thought, because it was a food desert.”
But plastic waste is now providing a habitat for these species, and somehow, these once coastal creatures are finding food on the high seas.
Dr Ruiz said scientists are still speculating exactly as to how these creatures’ diet is supported, suggesting food could drift into existing hot spots of productivity in the gyre, or that the plastic itself acts like a reef attracting more food sources.
A key concern is the impact the new plastic-rafting species may have on the marine environments they now find themselves in.
The open ocean already has plenty of its own native species, already adapted to colonising floating debris.
The scientists said “the arrival of new coastal neighbours could disrupt ocean ecosystems that have remained undisturbed for millennia”.
Dr Haram said: “Coastal species are directly competing with these oceanic rafters.
“They’re competing for space. They’re competing for resources. And those interactions are very poorly understood.”
The authors said increasing our understanding of the impact on ecosystems was increasingly important as humanity’s burden on the natural world grows.
Cumulative global plastic waste could reach over 25 billion metric tons by 2050, and with fiercer and more frequent storms on the horizon caused by the worsening climate crisis, the authors said they expect even more of plastic will get pushed out to sea.
“Colonies of coastal rafters on the high seas will likely only grow”, they said and this side effect of plastic pollution “could soon transform life on land and in the sea”.
The research comes as new figures from the US’s National Academies of Sciences, Engineering and Medicine warns the US has the world’s highest level of plastic waste per capita. The country generated 42 million metric tonnes of plastic waste in 2016, working out to around 130 kg per person per year.