There’s a vast ecosystem stretching far below the ocean’s surface — one where the light dims, the pressure mounts, and life takes on forms that can seem downright alien. But even there, a place that seems a world apart from human society, our plastic trash is building up.
In the deep sea, it’s a challenge to study where that plastic accumulates and how it affects animals. So scientists at the Monterey Bay Aquarium and our partners at the Monterey Bay Aquarium Research Institute (MBARI) launched an ambitious collaboration.
The resulting study, which examined microplastic in the waters of Monterey Bay, was published June 6 in the journal Scientific Reports.
“We designed this study to answer a fundamental gap in our knowledge of marine plastic once it reaches the ocean,” says lead author Anela Choy, a former MBARI researcher and now a professor at the Scripps Institution of Oceanography in San Diego.
The research team gathered data by using remotely operated vehicles (ROVs), robotic submarines designed by MBARI engineers, to collect water samples at depths from 200 to 600 meters (about 650 to 2,000 feet).
They also searched for plastic in animals with important roles in the marine food web: pelagic red crabs; and tadpole-like creatures called giant larvaceans, which surround themselves with clouds of mucus that capture food — and, as the researchers discovered, plastic.
Until now, little has been known about how microplastics move in the ocean. A new paper by our colleagues at the Monterey Bay Aquarium Research Institute (MBARI), just published in the journal Science Advances, shows that filter-feeding animals called giant larvaceans collect and consume microplastic particles in the deep sea.
Larvaceans are transparent tunicates that live in the open sea and capture food in sticky mucus filters. Plastic particles accumulate in the cast-off mucus feeding filters and are passed into the animals’ fecal pellets, which sink rapidly through the water, potentially carrying microplastics to the deep seafloor.
Despite their name, giant larvaceans are less than 10 millimeters (4 inches) long, and look somewhat like transparent tadpoles. Their mucus filters—called “houses” because the larvaceans live inside them—can be more than 1 meter (3 feet) across. These filters trap tiny particles of drifting debris, which the larvacean eats. When a larvacean’s house becomes clogged with debris, the animal abandons the structure and it sinks toward the seafloor.
In early 2016, MBARI Principal Engineer Kakani Katija was planning an experiment using the DeepPIV system to figure out how quickly giant larvaceans could filter seawater, and what size particles they could capture in their filters. Other researchers have tried to answer these questions in the laboratory by placing tiny plastic beads into tanks with smaller larvaceans. Because giant larvacean houses are too big to study in the lab, Kakani decided to perform similar experiments in the open ocean, using MBARI’s remotely operated vehicles (ROVs).
“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.
Plastic is one of the most common materials in our daily lives. We drink from plastic cups, wear clothing made of plastic fibers and buy products sealed in plastic packaging. We’re surrounded by these petrochemical-based polymers, but we don’t yet fully understand them. Especially when it comes to questions about how plastic trash affects the ocean environment — and our own health.
Dr. Roland Geyer, associate professor of industrial ecology at the University of California, Santa Barbara, has investigated just how much plastic is flowing to the sea, and where it’s coming from.
Using solid waste data from 2010, he calculated that 192 coastal countries produced 275 million metric tons of plastic waste that year. Of that amount, he estimates 8 million metric tons entered the ocean — enough to cover an area 34 times the size of Manhattan ankle-deep in plastic marine debris. And that input rate is likely increasing each year.
What can we do about it? Roland sees two big opportunities for change in California: Reducing litter, and producing less plastic waste in the first place.
The California State Capitol is 75 miles from the coast, but the laws forged there can have big impacts on the health of the ocean. That’s why the Monterey Bay Aquarium supported a half-dozen ocean-related bills during the 2015 legislative session. Many were signed into law.
The Aquarium also hosts the annual Ocean Day California reception in Sacramento, bringing together California legislators, state administrators, businesspeople and ocean conservation leaders to celebrate conservation of the ocean. Each year we honor California ocean champions who took action to advance marine and coastal health – including backers of important legislation.
Here’s our final scorecard for the 2015 legislative session.
Ocean plastic pollution is a problem–a big problem– for the health of the ocean and ocean wildlife. In California, we’re making progress by tackling it on several fronts.
Right now, the Legislature isclose to passing the nation’s strongest law to eliminate the use of non-biodegradable microbeads in consumer products. In recent years, cities and counties throughout California have banned single-use plastic bags. And in 2014, California enacted astatewide ban on disposable plastic shopping bags, authored by three of the Aquarium’s 2015 Ocean Champion Award winners– Secretary of State (and former state senator) Alex Padilla, State Senate President Pro Tem Kevin de León and State Senator Ricardo Lara.
That law established California as a leader in the fight against the growingtide of ocean plastic pollution. It was supposed to take effect on July 1– untilout-of-state plastic bag companies spent millions of dollars to force theissue onto the November 2016 ballot. Without the law, each year as many as 13 billion plastic bags will be sold in California that would otherwise not be sold. Every bag could potentially make its way to the ocean.
Implementation ofa statewide ban on single-use bags has been delayed, but not derailed. Victory over the effort to repeal this law is a top Aquarium priority, as taking steps backward is unacceptable. We’re asking you join us and Say Yes on the referendum to keep this law: Say Yes to a plastic-free ocean. Say Yes to reusable shopping bags. Say Yes to California’s leadership on this critical issue.