Thursday, August 26, 2010

Oceanic Garbage Patches may number five

Researchers who have deployed thousands of drifting buoys in the oceans are predicting that every major ocean has a vast debris field, like the Pacific's “Great Garbage Patch.”

This massive region of the Pacific is filled with the refuse of humanity, much of it plastic. Bottle caps, toothbrushes, fishing nets, cigarette lighters, and uncountable shards, slabs and specks of unidentifiable plastic, colored blue and red, white and yellow, brown and black, green and aqua. It is a toxic rainbow hat threatens marine life in many ways.

Nikolai Maximenko, an oceanographer and senior researcher with the University of Hawai'i's International Pacific Research Center, is co-author of a report in Science on a vast study by researchers from the Sea Education Association, Woods Hole Oceanographic Institution and University of Hawaii at Mānoa.

That team, working with plankton nets deployed from a sailboat, located the Atlantic's version of the Garbage Patch—a patch that is predicted by Maximenko's computer model of how converging currents cause oceanic trash to collect in specific regions.

“The study is so exciting because it validates the computer model we’ve developed using more than 15,000 trajectories of drifting buoys,” Maximenko said.

“The purpose of the model is to track long-living objects that float on the ocean surface. Our model has already successfully reproduced the location of the ‘Great Pacific Garbage Patch.’ That now the debris in the North Atlantic collects mostly where our model predicts is further evidence that plastic moves in a similar way that drifters do. We can now expect that our model will be very useful in coordinating debris detection and clean up operations.”

The cool thing about the model is that it explains where the debris can be found, but also why it ends up there, said Sea Education Association researcher Kara Lavender Law, the lead author of the Science paper.

"Not only does this important data set provide the first rigorous scientific estimate of the extent and amount of floating plastic at an ocean-basin scale, but the data also confirm that basic ocean physics explains why the plastic accumulates in this region so far from shore,” Law said.

Now that the Pacific and Atlantic Garbage Patches are located, are there more? Maximenko's model suggests there ought to be similar patches in the south Atlantic, the South Pacific and the South Indian Ocean. All are in remote parts of those oceans where ship traffic is light. That may explain why they haven't yet been found.

But if they exist they also may simply have a lot less trash in them, since the Southern Hemisphere produces less plastic trash than the Northern Hemisphere.

For more information see NOAA's page on marine trash, or see here for more about Maximenko’s model.

The paper: Kara Lavender Law, Skye Morét-Ferguson, Nikolai A. Maximenko, Giora Proskurowski, Emily E. Peacock, Jan Hafner, and Christopher M. Reddy: Plastic accumulation in the North Atlantic subtropical gyre, Published Online August 19, 2010, Science DOI: 10.1126/science.1192321.

© Jan TenBruggencate 2010

1 comment:

Susie said...

Aloha Jan,
Thought you might like to link your article to this non-profit's website that will be running a research cruise in January 2011 to the South Atlantic gyre: Your readers might find it interesting.