Trip on a discarded Happy Meal toy at the beach? You may have just disturbed an entire community of microbes that have found thriving new worlds on the ocean’s plastic.
Globally, we produce some 250 million tons of plastic per year, and about 4.7 million tons of it gets dumped into the ocean annually, according to Plastic Oceans, a UK nonprofit. But while much research has been dedicated to how ocean plastic can trap, suffocate, and poison marine animals, little had looked at the animals living on the plastic itself. A new study from the Sea Education Association (SEA), Woods Hole Oceanographic Institution, and the Marine Biological Laboratory (MBL) finds that ocean plastic now functions as "artificial microbial reefs," an ecosystem—a "plastisphere," unto itself.
"We saw that nobody had done this before and had a good idea that there could be an interesting signal there," Tracy Mincer, a microbiologist and one of the authors of the report said. "We found some things that were very different from what other people have seen."
The researchers, including Mincer, the SEA’s Erik Zettler, and the MBL’s Linda Amaral-Zettler, found 1,000 different types of bacteria on ocean plastic samples, including plants, algae, autotrophs, and predators. But plastic also serves as a new kind of transportation for potentially harmful bacteria looking to hitch a ride across the ocean. A quarter of the microbes researchers found on one piece of plastic were Vibrios, a bacteria family that includes cholera-causing pathogens.
"To see that kind of bias toward one type of bacteria group was surprising to us," Mincer said. "Some of the work in my lab has looked at the mechanism of how Vibrios are attaching to plastic. We’re finding some super aggressive colonies that are attaching to plastic very well."
Another surprising finding from the initial investigation showed that these microbes were actually etching away at the plastic, and helping it break down into smaller particles. Still, this doesn’t necessarily mean that ocean germs are helping plastic biodegrade. The microbes may be breaking up our waste, Mincer points out, but plastic never really disappears.
Researchers attributed the "plastisphere" directly to the steady buildup of plastic in the oceans over the last half-century. But despite an international ban on dumping plastic in the ocean, debris is still making its way into the water—enough, apparently, to attract its own unique life-forms.
"I think we need to take this really holistic approach and use plastic as necessary," Mincer said, noting plastic’s abysmal recycling rates and the proliferation of single-use packaging. Still, some cities have made progress in banning plastic bags—like Portland, Washington, D.C., San Francisco, and most recently, Los Angeles.
A handful of companies have also promised to reduce their product packaging. Wal-mart, for example, has pledged to go "packaging neutral" in the next 12 years. Method, a cleaning supply company, also has a line of soaps placed in recycled plastic containers sourced from ocean debris.
"Plastic has its place," Mincer notes. "But do we need yogurt cups that last 10,000 years?"