Wednesday, October 11, 2006

Central Pacific Gyre -- World's Largest Landfill

'Twas brillig, and the slythey toves
did gyre and gimble in the wabe.

You may remember these lines from your youth -- they're the first two lines of Jabberwocky from Through the Looking Glass. There aren't too many recognizably familiar words in those two lines but 'gyre' is at least a legitimate word.

So, what is a gyre? Simply put, a gyre is a swirling vortex.

And there's a big one in the north/central Pacific. How big? Oh, about 10 million square miles -- that's about the size of Africa. What causes it? Hot equatorial air descends in a clockwise rotation as it moves north toward the pole, producing circular ocean currents which actually spiral downward,creating a slight down-welling like the one you see when you empty your bathtub.

It's a place to avoid. There's no wind, so sailing through it is not recommended. It's singularly lacking in nutrients, so fishing is pointless. If that's not enough, then what makes it a particularly unpleasant place is that it has become a huge garbage dump for plastic products.

Much of the garbage that gets dumped, dropped or spilled into the ocean is biodegradable. Plastic, on the other hand, is not. And plastic from all over the world finds its way to the north Pacific gyre. It is estimated that about 3 million tons of plastic currently float in the gyre, and it is unknown how much has been sucked down as deep as 30 meters below the surface of the water.

While is doesn't biodegrade, plastic does photodegrade, meaning that sunlight breaks it down into smaller and smaller parts which never become small enough to digest. Confused plankton-eating fish and birds end up eating the plastic particles. Not only is there no nutrition, but the plastic acts as sponges, absorbing toxins such as DDT and PCBs which are not soluble in salt water, causing genetic damage to the animal's offspring. It is estimated that there are six pounds of plastic for every pound of plankton.

Reference:; CBS news


Anonymous Ramesh said...

Thanks for your valuable information.

It was really of use to me.

7:31 PM  

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