Wednesday, May 9, 2012

Plastic in 'Great Pacific Garbage Patch' increases 100-fold

This map shows the North Pacific Subtropical 
Convergence Zone within the North Pacific Gyre.

The amount of plastic trash in the "Great Pacific Garbage Patch" has increased 100-fold during the past 40 years, causing "profound" changes to the marine environment, according to a new study.
Scientists from Scripps Institution of Oceanography in San Diego found that insects called "sea skaters" or "water striders" were using the trash as a place to lay their eggs in greater numbers than before.
In a paper published by the journal Biology Letters, researchers said this would have implications for other animals, the sea skaters' predators -- which include crabs --  and their food, which is mainly plankton and fish eggs.

The scientists also pointed to a previous Scripps study that found nine percent of fish had plastic waste in their stomachs.
The "Great Pacific Garbage Patch" -- which is roughly the size of Texas -- was created by plastic waste that finds its way into the sea and is then swept into one area, the North Pacific Subtropical Convergence Zone, by circulating ocean currents known as a gyre.
The Scripps Environmental Accumulation of Plastic Expedition, known as SEAPLEX, traveled about 1,000 miles west of California in August 2009.
A statement on Scripps' website said the scientists had "documented an alarming amount of human-generated trash, mostly broken down bits of plastic the size of a fingernail floating across thousands of miles of open ocean."
Scripps graduate student Miriam Goldstein, SEAPLEX’s chief scientist, said that plastic had arrived in the ocean in such numbers in a "relatively short" period.
"Plastic only became widespread in late '40s and early '50s, but now everyone uses it and over a 40-year range we've seen a dramatic increase in ocean plastic," she said. "Historically we have not been very good at stopping plastic from getting into the ocean so hopefully in the future we can do better." 
Sea skaters -- relatives of pond water skaters -- normally lay their eggs on flotsam such as seashells, seabird feathers, tar lumps and pumice. The sharp rise in plastic waste had led to an increase in egg densities in the gyre area, the study found.
"We're seeing changes in this marine insect that can be directly attributed to the plastic," Goldstein said in a statement.
She told BBC News that the addition of "hundreds of millions of hard surfaces" to the Pacific was "quite a profound change."
"In the North Pacific, for example, there's no floating seaweed like there is in the Sargasso Sea in the North Atlantic. And we know that the animals, the plants and the microbes that live on hard surfaces are different to the ones that live floating around in the water," she added.
A garbage patch has also been found in the Atlantic Ocean, lying a few hundreds miles off the North American coast from Cuba to Virginia.
Oceanographer Curtis Ebbesmeyer, who said he coined the phrase the "Great Pacific Garbage Patch," told by phone that the only solution was to switch to using biodegradable plastic and let the plastic gradually disperse.
"We can't clean it up. It's just too big. You'd have to have the entire U.S. Navy out there, round the clock, continuously towing little nets. And it's produced so fast, they wouldn't be able to keep up," he said.
Ebbesmeyer said in 10,000 years scientists might find a layer of plastic in the ground and use this as evidence of "the plastic people."


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