A torrent of plastic pollution flows into the ocean each year—stuff like discarded drink bottles, food wrappers, cigarette butts and straws. California voters are about to decide whether to uphold a statewide ban on single-use carryout shopping bags, which rank fourth among the types of trash found in coastal cleanups.
Top ocean scientists recently put the scope of the challenge in perspective. The UC-Santa Barbara Benioff Ocean Initiative and the Monterey Bay Aquarium collaborated on a half-day plastic pollution science summit at the University of Southern California.
“We have to get our heads collectively around how much [plastic] might be entering the ocean every year,” said Dr. Roland Geyer, an associate professor of industrial ecology and green supply chain management with the Bren School at UCSB.
Global plastic production has far surpassed the production of metals like aluminum and steel. Globally, people have created and used 7 billion metric tons of plastic over the past 65 years—half of that in just the past 15 years.
Like eating LEGOs
Roland and his colleagues estimate 8 million metric tons of plastic waste finds its way to the ocean each year. That’s enough to cover 34 Manhattan Islands ankle-deep in plastic—or the equivalent of dumping five grocery bags full of plastic on every foot of shoreline in the 192 coastal nations he surveyed.
Most of the plastic is used as packaging, for everything from bottles to bags. Much of it ends up “escaping” to the ocean—either because people litter, or because it leaks out of waste-management systems—rather than being recycled or disposed of in landfills. (Europe recycles about 26 percent of its plastic; in the U.S., the figure is only 9 percent.)
Once in the ocean, most plastic sinks, Roland said, so it’s near impossible to clean up. The solution to ocean plastic pollution must include generating less waste to begin with, and stepping up recycling and reuse, he added. That includes investing in waste management systems in the developing world, where the use of disposable plastics is rising most rapidly.
Aquarium Science Director Dr. Kyle Van Houtan has seen the direct effects of plastic debris on marine animals, like the Pacific sea turtles and seabirds he studies.
“We found 41 bits of plastic in one tiny turtle, because at that size, turtles can’t dive for food,” he said. “They eat debris that’s floating on the surface—microplastics less than a millimeter in size. In the ocean, they’re pervasive, and they’re food.”
“It’s like eating LEGOs,” Kyle said. “They’re not getting any caloric benefit from their food.”
The secret ingredient in your chicken
Plastics threaten marine animals in other ways. Sea lions, whales and turtles can become entangled in plastic debris like six-pack rings and abandoned fishing gear. Large plastic pieces they swallow can rupture their intestines. Plastics also act like sponges for chemicals in the ocean, and leach toxins into animals that eat them.
People can be affected as well, Kyle added, because many small fish are processed into fishmeal, which is fed to pigs and poultry that we eat. “The contaminants go all the way up the food web,” he said. “Even if you don’t eat fish, you could still get ocean pollution in your diet through your chicken.”
It’s difficult to fully understand how plastics affect ocean food webs, Kyle said, because those food webs are so complex. The Aquarium is now collaborating with colleagues at the Monterey Bay Aquarium Research Institute to deploy autonomous underwater vehicles—programmable ocean-going robots that can sample the waters in zones where both marine life and plastic debris are abundant.
Ultimately, he said, the lesson we learned decades ago from marine biologist and conservation pioneer Rachel Carson is this:
“There is no such thing as ‘away.’ To say you’re throwing something away is just fiction. And, the distance between the event of the pollution and the outcome can be very far. If we turned off the spigot [of plastic] today, we’d still be dealing with this for decades to come.”
Plastic pollution under the microscope
“Rivers and harbors can be heavily polluted,” she said. “The mid-Pacific is blue as far as you can see—and then you see floating trash, and tiny bits of microplastic. Ninety percent [of ocean plastic] is less than a quarter-inch long—less than the size of an M&M.”
On one expedition to the North Pacific gyre between California and Hawaii, Jennifer and her team collected more than 32,000 pieces of microplastic.
Gooseneck barnacles, which attach to floating objects at the surface and filter plankton from the water, are even more profoundly affected. More than a third of the barnacles Jennifer sampled had plastic in their gut.
This only scratches the surface of the problem, because her team wasn’t able to sample even tinier nanoplastic particles.
California leads the world
Science can identify the scope of the problem, Kyle said, but it will take a number of creative solutions to turn the tide.
Roland noted that California, the world’s sixth-largest economy, is a global leader in environmental policy. What California does, he said, “can go a long way to change mindsets—and industrial patterns—around the world.”
Featured photo: Plastic debris breaks down in the ocean, but it never goes away. Many particles wash up on beaches; others remain in the water as tiny microplastics or nanoplastic pieces. Photo: Algalita Marine Research Foundation.