Microplastics rife in Monterey fish, seabirds
Microplastic particles are widespread in Monterey Bay anchovies and the diving seabirds that eat them as a main food source — which could possibly impact the birds’ reproductive systems, according to a new study.
Scientists at UC Santa Cruz, UC Davis and the San Diego Zoo Wildlife Alliance studied microplastic pollution in Monterey Bay by testing microplastic particles in the water and in anchovies and common murres, a bird species found in abundance in the region.
They found that 58% of anchovies and 100% of murres had microplastic particles in their digestive tracts, according to the study published Nov. 4 in the Environmental Pollution journal.
The study is believed to be the first time researchers have looked into whether microplastics can impact the reproductive systems of marine life, according to Christopher Tubbs, associate director of reproductive sciences at San Diego Zoo Wildlife Alliance — though the extent of any potential effects has yet to be determined.
The study also comes two months after California became the first state in the United States to begin requiring water agencies to test for microplastics, which can be found everywhere from clothing, food packaging, drinking water and the ocean. Another recent study by Stanford University scientists found that whales are ingesting “colossal” amounts of microplastics that mainly come from the fish they feed on.
The microplastic particles found in 23% of murres revealed estrogenic activity, which can disrupt hormones and “have cascading effects on reproductive and immune functions,” Myra Finkelstein, the study’s senior author and professor at UC Santa Cruz, said in a news release.
Scientists used an optical method called Raman spectroscopy to identify the specific microplastics: About 78% were fibers and 57% were plastic.
“When you’re looking at tiny fibers under the microscope, you can’t always tell if it’s cotton or polyester, so we took that next step to determine what it was, and then took the further step of testing them for estrogenic activity,” explained Finkelstein.
Water samples taken from Santa Cruz and Moss Landing revealed they contained approximately 2 microplastics per 1,000 liters, according to the researchers. Scientists predicted that the anchovies are likely “a major source” of microplastics in murres because their diet mainly consists of fish such as anchovies, which feed on tiny plankton.
On top of that, many seabirds are mistaking big pieces of plastic as food, known as macroplastics, which Finkelstein says is a “major concern” as it could be extracting toxic compounds.
Scientists did not look at how the microplastics are affecting anchovies and murres in the recent study, though Finkelstein and researchers at the San Diego Zoo Wildlife Alliance are working to identify the impacts, according to university officials.
“With microplastics, it seems we are finding them anywhere we look,” said Finkelstein. “But we need to do more work to find out what the biological impact is.”