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Citizen of the Planet/Education Images/UIG via Getty Images
The patch is in an area of ocean between California and Hawaii called the North Pacific Subtropical Gyre — a kind of swirling dead end for Pacific currents, which have been depositing floating plastic trash there for decades. Now, an extensive survey of the region estimates it holds about 79,000 metric tons of floating plastics — everything from thick tangles of fishing line to tiny fragments of old soda bottles.
Laurent Lebreton, an oceanographer and lead author of the new study, told Seeker the survey also provides new insight into the makeup of the patch.
“It’s mostly made of tiny microparticles, but this is only if you talk about the number of pieces,” said Lebreton, who leads plastic research at the Netherlands-based Ocean Cleanup Foundation. “Most of the mass, most of the matter available, is carried by large debris. I think that was quite a big finding there.”
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National Oceanic and Atmospheric Administration
But those pieces make up less than 10 percent of the total weight of the garbage patch. Nearly half of the mass comes from fishing nets and line lost or jettisoned by trawlers, which clump together and collect other floating trash along the way. The trash is spread over an area about 1.6 million square kilometers — roughly 1,300 by 1,300 km (800 by 800 miles) — with the bulk of it concentrated toward the center.
The findings, published March 22 in the research journal Scientific Reports, were based on surface sampling and aerial surveys conducted over a 14-month period in 2015 and 2016, as well as computer modeling. The new estimate is four to 16 times bigger than previous calculations, including one Lebreton produced himself. But he said earlier studies were conducted from the surface and likely underestimated the amount of large debris.
“We said, ‘Instead of trying to observe large debris from observers on vessels, let’s try to fly above it and get pictures and come back with a more precise estimate of the large debris,’ ” he said.
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And some of the larger items, like crates or bottles, appear to be durable. Sweeps of the water turned up debris that dated back decades — a crate from 1977, a hardhat from 1989, the back of a Nintendo Gameboy from 1995. Lebreton said the study couldn’t determine precisely how long those items had been floating around, but “You can tell it’s spent some time in the water, because it’s degraded.”
The patch is growing as up to eight million tons of plastic washes into the world’s oceans a year, the United Nations estimates. That plastic is a hazard to marine life: Fish and other sea creatures can mistake the indigestible polymers for food, while hazardous chemicals can latch onto plastics and accumulate up the food chain when they’re consumed.
Lebreton said he hopes the findings will help convince people to take action to reduce their consumption of plastic, particularly those items that are discarded after a single use.
“I’m not saying we should move away from plastics,” Lebreton said. “I don’t think that is going to happen, because plastic is very useful in many applications. But I think there are some plastics that could actually not be there in the first place, and single-use plastic is definitely one of them … if you buy something, open the package and just throw it away, those are the type of things that end up in the ocean very quickly.”