Imagine motoring from Hawaii to California through the North Pacific subtropical gyre, an immense region of the ocean where high pressure rules, trade winds fail, and currents trace a circle many hundreds of miles across, corralling anything that floats into a slowly rotating vortex. A few days off Hawaii, you notice something odd about the sea around you: it is laden with a subsurface "soup" of plastic trash, from soccer balls and kayaks to water bottles, snarls of polypropylene rope, and bladder-like shopping bags. This layer of human-produced detritus extends thirty feet deep, is in constant motion, and you pass through it for days.
You've encountered the Great Pacific Garbage Patch, an enormous and accidental floating dump first described in 1997 by George Moore, heir to an oil fortune and founder of the Algalita Marine Research Foundation. At that time, Moore estimated this floating soup of plastic debris covered an area of ocean the size of Texas. This spring, however, after returning from their most recent survey, Algalita researchers report that the drifting trash vortex is now two vortexes, one on either side of Hawaii. Together they cover an area twice the size of the continental United States, containing an estimated 100 million tons of flotsam.
This immense gyre of plastic is deadly: seabirds and marine mammals mistake the plastic fragments for food. (Algalita researchers estimate that plastic fragments outweigh surface zooplankton in the North Pacific by 6 to 1, or six pounds of plastic to every pound of food.) More than 1 million seabirds die from ingesting this trash each year, and upwards of 100,000 marine mammals.
Plastic never completely decays, and its synthesized molecules sop up some of our worst pollutants, accumulating non-water-soluble compounds including DDT and PCBs at up to one million times the levels they normally occur in the ocean. Jellies and other organisms that "vacuum-feed" ingest the pollutant-laden fragments, fish and sea turtles eat the jellies, and so on. Eventually, humans may eat the fish.
So next time you find yourself tempted to buy what singer Nancy Griffith calls "unnecessary plastic objects," imagine those twin vortexes of discarded plastic slowly rotating in the Pacific Ocean, and think again.
(This article in the UK Independent includes a striking and depressing illustration of the North Pacific subtropical gyre's floating plastic "soup.")