August 17, 2007

Little Plastic Crumbs

Judging from his Amazon sales rankings, Alan Weisman certainly doesn't need me to hype his new book, The World Without Us. But it's an excellent read, and much recommended all the same. Just about every page would make for great blog fodder, but let's go with the part about a sailor who finds a massive floating whirlpool of garbage in the middle of the Pacific:
Capt. Charles Moore of Long Beach, California, learned that the day in 1997 when, sailing out of Honolulu, he steered his aluminum-hulled catamaran into a part of the western Pacific he'd always avoided. Sometimes known as the horse latitudes, it is a Texas-sized span of ocean between Hawaii and California rarely plied by sailors because of a perennial, slowly rotating high-pressure vortex of hot equatorial air that inhales wind and never gives it back. Beneath it, the water describes lazy, clockwise whorls toward a depression at the center.

Its correct name is the North Pacific Subtropical Gyre, though Moore soon learned that oceanographers had another label for it: the Great Pacific Garbage Patch. Captain Moore had wandered into a sump where nearly everything that blows into the water from half of the Pacific Rim eventually ends up, spiraling slowly toward a widening horror of industrial excretion.

For a week, Moore and his crew found themselves crossing a sea the size of a small continent, covered with floating refuse. It was not unlike an Arctic vessel pushing through chunks of brash ice, except what was bobbing around them was a fright of cups, bottle caps, tangles of fish netting and monofilament line, bits of polystyrene packaging, six-pack rings, spent balloons, filmy scraps of sandwich wrap, and limp plastic bags that defied counting.
In 2005, the gyre was estimated to be 10 million square miles—roughly the size of Africa. Moore has calculated that there's about 3 million tons of plastic junk floating on the surface of the gyre, with nearly six times that much bobbing underwater, weighted down by barnacles and algae. And there are apparently six other major tropical gyres filling up with plastic debris. (See here for an earlier article on Moore's research.)

As unsightly as it is, though, the floating garbage is less troublesome than the fact that so much plastic in the ocean keeps crumbling into tinier and tinier particles without ever biodegrading. The particles then get eaten by various sea creatures—when they get small enough, even zooplankton will swallow them—and no one quite understands what effect that has on sea life, although the fact that plastics act as "sponges" for toxins offers one hint. These particles are literally everywhere in the ocean, and they'll remain for hundreds of thousands of years, until some super-microbe comes along that can actually digest plastic.
-- Brad Plumer 6:57 PM || ||