The "garbage patch" is not an island nor a single mass, leading some scientists to object to the name (which the current study uses). Instead, it's a large area with high volumes of plastics, one in which concentrations increase markedly as you move towards its centre. The debris ranges from tiny flecks to enormous discarded fishing nets, which make up 46 per cent of the material, the study found. The study was led by the Ocean Cleanup Foundation and researchers at institutions in New Zealand, the United States, Britain, France, Germany and Denmark, who published the findings in the journal Scientific Reports. Rubbish in the Great Northern Pacific Patch.

There's a key distinction between the mass of plastic within the patch increasing - which it is - and the overall size of the patch, which does not seem to be changing. Rather, it's just that trash within the patch seems to be accumulating, or growing denser. The plastic is probably mostly coming from Pacific countries, Lebreton said. But it could be coming from anywhere, since plastic now travels across the entirety of the ocean and has even shown up in Arctic waters, where very few humans live. That suggests the plastic travelled there from elsewhere, riding the ocean currents. Loading Replay Replay video Play video Play video Some of the debris probably also came from the 2011 tsunami that devastated Japan and washed large amounts of waste out to sea, the study said. The location of the patch is in a zone of slack currents where debris arrives and then lingers, increasing in the calm waters.

Loading The study finds that, based on prior examinations dating back to the 1970s, the amount of plastic in the patch is growing steadily as more flows in than flows out. "We think there's more and more plastic basically accumulating in this area," Lebreton said. The most striking aspect of the findings - and perhaps the most damaging - was the large volume of fishing nets or "ghost nets", said Chelsea Rochman, an assistant professor at the University of Toronto, who studies marine plastic but was not part of the current study. "This suggests we might be underestimating how much fishing debris is floating in the oceans," she said in an emailed comment. "Entanglement and smothering from nets is one of the most detrimental observed effects we see in nature."

Loading The fact that the plastic content of the patch is increasing is consistent with research that has been conducted on land, showing that waste volumes entering the ocean are large and increasing, said Jenna Jambeck, an environmental engineer at the University of Georgia who has studied plastic waste processes. She was not involved in the new study. In a 2015 study, Jambeck found that humans are filling the oceans with an estimated 8 million tonnes of plastic every year, and that is expected to increase by 22 per cent by 2025. That matches what is now being seen in the ocean, in the form of the ever-accumulating garbage patch in the Pacific, though Jambeck also noted that much plastic sinks to the ocean bottom, and the fishing nets are being tossed in from boats, rather than dumped from the shore.

"The logic plays out that if we projected it to be increasing, every year in terms of input, that you would see some potential increase in the ocean," Jambeck said. Jambeck and the research team agree far less plastic is accumulating in the Pacific patch than is going in the ocean - and the study itself says that, in light of how much plastic is being dumped, they would have expected volumes to be even higher. Clearly, much plastic is sinking and doing its damage at the sea floor, or in lower depths of the ocean. In this sense, the Great Pacific Garbage Patch is, in the end, merely the most dramatic outward symptom of a far deeper problem of enormous volumes of human waste reaching places where it was never intended to be. "The results are alarming; it really shows the urgency of this situation," Lebreton said.

The Washington Post