The Pacific Garbage Patch

Have you heard there's an island of floating garbage the size of Texas in the middle of the Pacific Ocean?

Every coastal country in the world dumps some of its trash at sea, and a lot of that trash is plastic. What happens to all of it? If you've been reading the Internet in the past few years, you've probably been told that it's been accumulating in the middle of the Pacific Ocean, creating a vast, solid island called the Pacific Garbage Patch.

You've probably seen frightening pictures of birds and fish fatally entangled, and great piles of rubbish.

There is some science behind this. Like all oceans in the northern hemisphere, the North Pacific is predominantly a single clockwise current called the North Pacific Gyre. Wind and currents combine to drive floating debris toward the middle. The Hawaiian Islands are right on the southern edge of the Gyre's epicenter.

But if you've ever been to Hawaii, you probably noticed the water's pretty clean. You can't walk from island to island on floating garbage. How can that be? What gives?

What gives is that the stories have been absurdly exaggerated. Photos like this are usually taken along the coasts of developing nations that lack or ignore environmental laws. But all that trash has to go somewhere, and the center of the Gyre is where nature takes it. So why isn't it there?

Well, it's a long journey. Floating plastic takes a full year to reach the Gyre from Asia, and about 5 years from the United States. Plastic in the open ocean becomes very brittle very quickly, from the sun's ultraviolet radiation. Wind and wave motion pulverize it into tinier and tinier pieces. Many plastics degrade completely. Never underestimate the power of our oceans.

Very little plastic survives long enough to make it to the Gyre, and what does is microscopic or granular. The National Oceanic and Atmospheric Administration monitored over 200 basketball-court-sized sample stations in the Gyre for 4 years, and found that half had detectable levels of plastic particles.

But at a certain size, these granules are consumed by plankton and enter the food chain. That's the real problem; not a solid island of trash. Fortunately it's a problem to which there's an easy solution: Stop dumping trash at sea! Our awesome oceans will do the rest, given enough time.

To find real answers, we need to understand the real science, not sensationalized nonsense on the Internet. Good science delivers good solutions.

— Brian Dunning

 

References & Further Reading

Berlofff, Pavel S. et. al. "Material Transport in Oceanic Gyres." Journal of Physical Oceanography. 10 Jun. 2001, Volume 32: 764-796.

Day, R., Shaw D., Ignell, S. "The Quantitative Distribution and Characteristics of Neuston Plastic in the North Pacific Ocean, 1985-88." Technical Memorandums. National Oceanic and Atmospheric Administration, 2 Apr. 1989. Web. 15 Dec. 2008. <http://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-154_P247.PDF>

Kubota, M. "A Mechanism for the Accumulation of Floating Marine Debris North of Hawaii." Journal of Physical Oceanography. 1 May 1994, Volume 24, Issue 5: Pages 1059–1064.

LiveScience Staff. "Mystery of the Sargasso Sea Solved." LiveScience. Tech Media Network, 22 May 2007. Web. 11 Jan. 2010. <http://www.livescience.com/strangenews/070522_sargasso_sea.html>

McGillicuddy, D.J. Jr and A. R. Robinson. "Eddy-induced Nutrient Supply and New Production in the Sargasso Sea." Deep Sea Research Part I: Oceanographic Research Papers. 1 Aug. 1997, Volume 44, Issue 8: Pages 1427-1450.

NOAA. "Great Pacific Garbage Patch." NOAA Marine Debris Program. NOAA, 1 Sep. 2009. Web. 11 Jan. 2010. <http://marinedebris.noaa.gov/info/pdf/patch.pdf>