MONTEREY — A recent study concluded that an estimated seven trillion pieces of microplastic flow with stormwater into the San Francisco Bay each year. No similar estimates exist for Monterey Bay. Instead, two major studies in the area are helping scientists understand the origins and fates of these microplastic pollutants.
Far from unique to San Francisco Bay, microplastics plague nearly all marine areas. These tiny plastic particles, 5 mm or less in diameter, come from tires, synthetic fabrics, plastic packaging, cosmetics and a number of other daily objects. They make their way from washing machines and curbsides into coastal waters and beyond.
Researchers at the Monterey Bay National Marine Sanctuary spent the last three summers collecting these microplastics in funnel-shaped mesh nets called manta trawls at four locations around the bay. Attaching flow meters to the trawls allows them to calculate the amount of plastic per square kilometer.
Chad King, a lead researcher on the project, says there’s more than expected. He recounts being able to see some of the plastic filaments in the water with the human eye. King and partners at CSU Monterey Bay and Stanford’s Hopkins Marine Station study those filaments in hopes of gaining clues about the sources of the plastics. They plan to have answers within the next few months.
While the sanctuary researchers monitor the problem at the surface, scientists at the Monterey Bay Aquarium Research Institute and the Monterey Bay Aquarium explore the issue in depth — literally.
“Most of the story is below the surface,” says Dr. Kyle Van Houtan, chief scientist at the Monterey Bay Aquarium. Van Houtan joined colleagues from MBARI to study the prevalence and distribution of microplastics in the deep. They published a paper in June that highlights large amounts of plastic in the midwater — the region of water between the surface and the sea floor.
Dr. Anela Choy, the lead author of the paper, emphasizes how common microplastics have become across ecosystems. “They’re pervasive and widespread — a dynamic thing that’s constantly changing as these plastics break down.”
As scientists continue to study how these tiny particles move through the bay, it will take innovation. “A lot of researchers in different fields are working together,” Choy says. Whether ecologist or engineer, “all types of people have something to offer this new field.”
Including citizens; Choy says people can minimize their impact by making conscientious choices about things like single-use plastics. “Water bottles, take-out containers … those were the types of plastics found,” she says.
Researchers at the national marine sanctuary give similar recommendations. King encourages people to read more about the sources of microplastics and to consider making slight alterations to their behavior.
“Everyone could make small changes,” he says.
