Dear EarthTalk: Recent news coverage of the disappearance of Malaysian Airlines Flight 370 reminded us all again of how much debris, including plastic, is in our oceans. To what extent is this a real problem that threatens ocean or human health? -- Margaret Ainsworth, Philadelphia
The so-far in vain search for Flight 370 has indeed stirred up interest in the growing problem of ocean debris as objects thought to possibly be plane parts have repeatedly turned out to be just floating trash.
"The ocean is like a plastic soup, bulked up with the croutons of these larger items," Charles Moore, the captain who discovered an ocean trash gyre roughly the size of Texas swirling around in the deep ocean currents between Hawaii and California, told the Associated Press. "It's like a toilet bowl that swirls but doesn't flush."
Moore's "Great Pacific Garbage Patch" is one of five such debris vortexes in the world's oceans. Last April, searchers for MH370 stumbled onto the eastern edge of one of them in the Indian Ocean, at first mistaking some of the larger bobbing objects for airplane wreckage.
While this floating flotsam may be a time-wasting distraction for MH370 searchers, green leaders are worried about it for other reasons. According to the U.S. Environmental Protection Agency, trash and other ocean debris can cause direct harm to wildlife that ingests or gets caught in it and can break or suffocate coral reefs that are key habitat for many of the world's marine species. Marine debris can also contribute to the movement of harmful invasive species that hitch rides from one body of water to another.
Another issue is that so much marine debris is comprised of plastic, much of which takes hundreds of years to break down and ends up in the digestive systems of everything from whales to plankton, including much of the seafood that ends up on our dinner plates.
The 2011 report, "Plastic Debris in the California Marine Ecosystem," by the California Ocean Science Trust, California Ocean Protection Council and Sea Grant found that plastic debris in the ocean not only leeches some chemical pollutants that were added during manufacture but also absorbs and accumulates others. This includes many persistent organic pollutants (so-called POPs that have been used extensively for things like pest control, crop production and industrial manufacturing) from surrounding seawater and marine sediments. These POPs have been linked to population declines, diseases and behavioral or physical abnormalities in many wildlife species. Researchers are still not sure how these chemicals, as well as others (Bisphenol A, phthalates, phenanthrene, etc.) may affect marine ecosystems in the long run.
In the meantime, we can all play a role in reducing the amount of plastic and other debris that end up in our oceans.