for National Geographic News
Beaches worldwide bear witness to the ugly impact of plastic debris on our oceans. Milk jugs, water bottles, cigarette lighters, diaper liners, jar lids, cheap toys, and goodness knows what else festoon tide lines today. But this may just scratch the surface.
A new study suggests that microscopic bits of plastic have sifted, unseen, throughout the marine environment. The plastic not only litters the beach, it islike fine bits of sandbecoming the beach.
U.K. researchers in Plymouth and Southampton, England, found that microscopic fragments of nylon, polyester, and seven other types of plastic are widespread in sediments around British shores.
The sediments were collected from beaches, estuaries, and shallow waters. "Everything that didn't look like a piece of natural organic debris was then identified," said Richard Thompson, a senior marine ecology lecturer at the University of Plymouth, who led the study. Up to a third of this material was later identified as synthetic polymers used in plastics.
Even so, the scientists write in the research journal Science: "We believe that these [fragments] probably represent only a small proportion of the microscopic plastic in the environment."
Thompson says the amount is probably greater, but they currently lack the technology to accurately distinguish plastic debris less than 20 microns in diameter (a width thinner than a human hair).
Beyond plastic-enriched shorelines, the team found that plastic particles are now common in the high seas.
To gauge long-term trends, the scientists examined plankton samples collected over the past 40 years in shipping lanes between Iceland and Scotland. Results showed there was approximately three times more plastic in the water column in the 1990s compared with the 1960s.
"Estimates for the longevity of plastic range from a hundred to a thousand years," Thompson said. "Since we've only been [mass producing] plastics for 40 years, we still don't have a full handle on their longevity."
The impact of larger plastic flotsam on marine wildlife is well documented. According to the U.K.'s Marine Conservation Society, a national environmental nonprofit, more than a million seabirds and 100,000 mammals and sea turtles die globally each year from entanglement in, or ingestion of, plastics.
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