Deep Sea Starfish Have Been Eating Microplastics for 40 Years

Starfish have been eating microplastics for the last four decades, with even those living more than a mile beneath the sea surface ingesting tiny bits of plastic pollution that now permeate the world's marine environments.

Microplastics are tiny bits of plastic, generally less than 5 millimeters in length. They generally come from two main sources—the degradation of larger pieces over time, and health and beauty products that contain polyethylene. The extent of microplastic pollution is becoming increasingly clear—this week it was revealed that human feces samples taken from eight different countries all contained microplastics.

Last year, scientists with the Scottish Association for Marine Science (SAMS) found that half of the creatures living in the North Atlantic at depths greater than 1.2 miles could be eating microplastics. SAMS scientists have now built on this research to find out how long microplastics have been present in this environment since they were first mass produced more than 70 years ago.

In the latest study, published in the journal Environmental Pollution, the team examined two specific species—Ophiomusium lymani and Hymenaster pellucidus—to find out about the abundance of microplastics in deep-sea habitats over the long term. They looked at samples spanning four decades, going from 1976 to 2015.

Across the 39 years, they found half of the specimens sampled had ingested microplastics, with traces of eight different types of plastic identified. They also found that levels of microplastics remained constant across the time—researchers had expected them to increase in line with the amount of microplastics in the ocean.

Hymenaster pellucidus
Hymenaster pellucidus—one of the species studied that was found to have ingested microplastics. Bodil Bluhm and Katrin Iken, University of Alaska, Fairbanks

"Initially we expected the levels of microplastics to decrease as we went back in time, however this was not the case," lead author Winnie Courtene-Jones told Newsweek. "This was somewhat surprising and indicates that microplastics may be present at this deep location earlier than 1976.

"The research suggests that microplastics have been present in our environment longer than we perhaps thought. Little is known about the time scales over which plastics and microplastics sink to the sea floor; given that mass production of plastics began in the 1940s and '50s, our research suggests the relatively rapid sinking of microplastics to the deep sea. We as yet don't know what the consequences of this may be to the animals which live here."

The next phase of the research involves assessing the amount of microplastics in different parts of the ecosystem. Discussing how people can prevent making the problem worse, Courtene-Jones said: "Tackling microplastics directly is challenging, as they are so small, however larger plastic items fragment to form microplastics. So, reducing our use of disposable plastics—for example, coffee cups, drinks bottles—is one way we can all help."