The surface of these garbage gyres may be unsightly, but what happens beneath is what disturbs researchers the most. "One study collected surface samples of the NPG over a 22-year period (1986-2008), and found that despite the steady increase in global plastic production and disposal, the concentration of plastic debris in the NPG had not increased," says Baechler. "This may be because floating plastic does not sit at the surface forever. It has been found that floating plastic debris that aggregates in the gyre also sinks down through the water column into the deep sea."