Drowning in garbage

Litter — from sea glass to bottle caps to remnants of fishing lines — washing up on our beaches has become a familiar sight. It's easy to think that that debris must be all of the marine litter out there, which eventually makes its way back to shore.

We like to imagine the world's oceans to be pristine and unsullied. But the reality is that the seas are not free from the same litter and pollution we see on land.

In the middle of the Pacific, a circular ocean current called the Pacific Gyre swirls around a region about the size of Africa. Long avoided by sailors for stranding ships in its doldrums, today the spiraling current collects a different cargo: Plastic.

Everything that floats is drawn into this vortex, creating a marine dead zone twice the size of Texas, now commonly known as the Great Pacific Garbage Patch.

Plastic makes up 90% of marine litter and does not biodegrade. Instead, it slowly breaks down into smaller bits of plastic that never disappear. Eventually it becomes tiny pellets called "nurdles," which cannot be digested — but that doesn't stop animals from eating them.

Birds, fish, and marine mammals in the middle of this toxic zone have a steady diet of plastic litter — which turns deadly when sharp pieces of debris rupture their stomachs or when the mass of cigarette lighters, bottle caps, and fishing nets grows too large and causes starvation. In the Great Pacific Garbage Patch, uncontaminated food can be hard to find: Researchers estimate there are six pounds of plastic for every pound of plankton.

But it's not just distant sea creatures that suffer the consequences. The floating plastic mass also collects chemicals that don't break down in seawater, like DDT, PCBs, and nonylphenols, which cause hormonal disruptions in the animals that eat them -- and the ones that eat those animals.

Those of us at the top of the food chain ought to start worrying.

Suggested sites:

• Trashed - Charles Moore, leading researcher of the Great Pacific Garbage Patch, explains how it works and what we can do about it.
• Our oceans are turning into plastic ... are we? - A look at the possible human side effects of marine pollution, including obesity and infertility.
• The trash vortex - Greenpeace, unsurprisingly, is opposed.
• Why is the world's biggest landfill in the Pacific Ocean? - HowStuffWorks looks into the origins of the trash vortex.
• Albatross necropsy video - 306 punches - Warning: This graphic video shows the plastic objects that killed an albatross.