Though it’s existed for decades, the Great Pacific Garbage Patch is attracting renewed attention from scientists and environmental experts with the return of a research vessel that has been collecting data for the last several months.

The Great Pacific Garbage Patch is one of five major garbage patches drifting in the oceans north and south of the Equator at the latitude of terrestrial deserts.

Charles Moore, who is credited with discovering the gyre — a circular system of rotating currents—on a yachting race in the North Pacific, led a team of scientists on a two-month expedition to the heart of the Garbage Patch, beginning in July.

Moore wrote an op-ed in The New York Times Monday called “Choking the Ocean With Plastic,” saying that although it was his 10th voyage to the area, he was “utterly shocked” to see the enormous increase in the quantity of plastic waste since his last trip in 2009.

“Plastics of every description, from toothbrushes to tires to unidentifiable fragments too numerous to count, floated past our marine research vessel Alguita for hundreds of miles without end,” Moore wrote. “We even came upon a floating island bolstered by dozens of plastic buoys used in oyster aquaculture that had solid areas you could walk on.”

“Plastics are now one of the most common pollutants of ocean waters worldwide,” Moore wrote. “Pushed by winds, tides and currents, plastic particles form with other debris into large swirling glutinous accumulation zones, known to oceanographers as gyres, which comprise as much as 40 percent of the planet’s ocean surface — roughly 25 percent of the entire earth.”