ALL ISSUES    |    SPRING 2017
Center for Ocean Education and Leadership rendering

Grappling with Ocean Plastic Pollution: Past, Present and Future

The amount of plastic in our ocean can seem hard to fathom—it grows by millions of tons every year. But what exactly is the impact of so much plastic? And what can be done about it? The first crucial step will be understanding the effects in detail.

"This issue is not unprecedented. We've dealt with persistent environmental pollutants before," says Director of Science Kyle Van Houtan.

Plastic in the ocean can break down into tiny fragments that often become food for tiny sea creatures, like small fish. They become food for bigger fishes, which in turn ingest and accumulate the same plastic, carrying it on up the food web—and perhaps back to our dinner plates.

Mapping out future ways to deal with this present problem hinges on understanding the past, Kyle says.

"What's often lacking in environmental management is a baseline of ecosystem health," he says. "To solve a problem, you want to know where you've come from, where you are today, and how fast you got there."

Kyle says one way to set baselines is to gather clues from historical wildlife specimens. One of his current projects examines the heavy metals built up in seabirds, using specimens dating back over 120 years. "We can do the very same thing with plastics," he says, using animals as ocean sensors.

Another key will be refining our knowledge of where ocean plastic pollution ends up, because places where it concentrates—like a subtropical gyre between Hawaii and California (known as the Great Pacific Garbage Patch)—may not be the most vital to ocean health.

Rather, Kyle says it's essential to monitor the ocean's biological hotspots, like a Pacific migratory corridor where cool and warm waters mingle, which is critical for many fish, whales, turtles and birds. Kyle says we need to understand if there's any transfer of plastic contaminants between the gyres and animals in the hotspots.

Plastic pollution infiltrates the ocean's food web in various ways and can inflict harm both chemically and physically. Untangling these impacts is a complex challenge, says Anela Choy, a postdoctoral fellow at the Monterey Bay Aquarium Research Institute (MBARI).

The ocean is full of life, from the surface all the way to the deepest seafloor. Animals are ingesting plastic at all levels, Anela says.

"Not all plastic is buoyant. Some sinks down into the water column," she says. Knowing precisely what that means in terms of impacts and survival for marine animals will require a tremendous amount of scientific legwork.

That may mean ocean monitoring on a vast scale that hasn't seemed possible before, says Chris Scholin, president and CEO of MBARI. Robots may be part of the solution.

The challenge is finding a way to continuously measure plastic debris in a given part of the ocean, as well as any animals there that might ingest it. Having humans attempt this over a long period of time would be costly as well as exhausting. Chris says it's unrealistic—but perhaps not for autonomous robots someday in the future.

MBARI researchers will lay the groundwork this year by deploying remotely operated vehicles to begin sampling plastic from the water column and gaining a better understanding of where and how much is in the ocean.

Those answers and more will ultimately inform the design and function of the robot that will roam the ocean to address the problem of plastic pollution.