"There are many "garbage patches," and by that, we mean that trash congregates to various degrees in numerous parts of the Pacific and the rest of the ocean. These natural gathering points appear where rotating currents, winds, and other ocean features converge to accumulate marine debris, as well as plankton, seaweed, and other sea life. (Find out more about these "convergence zones" in the ocean and a NOAA study of the North Pacific Subtropical Convergence Zone [PDF].)"
http://response.restoration.noaa.gov/ab ... -myth.html