Elizabeth Lopez maneuvered a massive steel claw over the side of a 134-foot sailboat and guided its descent through swaying kelp and schools of fish 10 miles off the coast of San Diego. She was hoping to catch pieces of a mysterious marine ecosystem that scientists are calling the plastisphere.

This biological community starts with particles of degraded plastic no bigger than grains of salt. Bacteria take up residence on those tiny pieces of trash. Then single-celled animals feed on the bacteria, and larger predators feed on them.

"We've created a new man-made ecosystem of plastic debris," said Lopez, a graduate student at the University of San Diego, during the recent expedition.

The plastisphere was six decades in the making. It's a product of the discarded plastic flip-flops, margarine tubs, toys, toothbrushes that gets swept from urban sewer systems and river channels into the sea.

When that debris washes into the ocean, it breaks down into bits that are colonized by microscopic organisms, many of them new to science. Researchers suspect that some of the denizens may be pathogens hitching long-distance rides on floating junk.

Scientists also fear that creatures in the plastisphere break down chunks of polyethylene and polypropylene so completely that dangerous chemicals are leached into the environment.

"This is an issue of great concern," said Tracy Mincer, a marine geochemist at the Woods Hole Oceanographic Institution in Massachusetts. "Microbes may be greatly accelerating the weathering of plastic debris into finer bits. If so, we aren't sure how zooplankton and other small creatures are responding to that, or whether harmful additives, pigments, plasticizers, flame retardants and other toxic compounds are leaching into the water."

PHOTOS: Gathering samples at sea to study the 'plastisphere'

About 245 million tons of plastic is produced annually around the world, according to industry estimates. That represents 70 pounds of plastic annually for each of the 7.1 billion people on the planet, scientists say.

The waste gathers in vast oval-shaped ocean "garbage patches" formed by converging currents and winds. Once trapped in these cyclonic dead zones, plastic particles may persist for centuries.

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An ecosystem of our own making could pose a threat - latimes.com