Barnacles Plus Plastic Trash Make Rafts for Ocean Animals

By Elizabeth Preston | February 22, 2016 1:39 pm

Plastics at SEA_Marina (1875)aIf you wanted to travel from Japan to California, you could do worse than to hitch a ride on a barnacle-covered buoy. Or maybe a barnacle-covered refrigerator or chunk of foam. Barnacles are turning all kinds of ocean trash into cozy habitats for animals at sea. They might even help some of those animals reach distant shores and become dangerous invasive species.

Flora and fauna have always sailed the sea on rafts such as pieces of wood or pumice, or matted plants. Without flotation devices, some species could never have reached places like the Hawaiian islands. But natural rafts have a limited lifespan before they biodegrade. Plastic objects made by humans, on the other hand, can survive in the ocean for ages.

“Plastics littered in our world’s oceans provide an unprecedented opportunity for rafting organisms,” says University of Florida biologist Mike Gil. Plastic ocean trash is increasing all the time, and it doesn’t break down like natural materials do. Potentially, this means an ordinary piece of garbage could turn a seafaring species into a world traveler.

Plastic debris is often too smooth for wildlife to live on. But gooseneck barnacles are an exception. These crustaceans are experts at gluing themselves to smooth, hard surfaces—natural or artificial—and making a home.

Gil and his colleagues traveled by boat from California to Hawaii, sampling plastic debris in the ocean as they went. Whenever they could haul a piece of trash aboard, they examined it for barnacles, as well as other forms of life.

The researchers found a lot of smooth debris. “Think buoys, drinking bottles, toy balls, pieces of siding,” Gil says. They judged that much of it had been swept off the coast of Japan in the 2011 tsunami. They found a refrigerator holding food with Japanese packaging, for example, and a capsized Japanese boat.

Despite the inhospitable nature of these smooth pieces of debris, they teemed with life. The researchers found clinging masses of gooseneck barnacles all over the place.

Screen Shot 2016-02-22 at 1.58.47 PM

Barnacles cling to a chunk of foam.

The barnacles are “like trees in a rainforest,” Gil says. They provide shelter from predators and the elements for other species. By growing on the plastic trash, barnacles create a new ecosystem. And in these trash ecosystems, the researchers found many other species.

Onboard the boat, they used their hands, knives, spatulas and paint scrapers to pry life forms off the rafts and count them. The more barnacles there were, the more other animals they found living on the trash.

Some of the species living among the barnacles were coastal animals. Some had never been seen on an ocean raft before. And some were very far from home. An Asian crab species turned up on a piece of debris near San Diego, Gil says. One raft held species from opposite sides of the Pacific at the same time.

The study demonstrates that “plastic garbage in the ocean can transport species from coast to coast,” Gil says. “If these species are foreign to the coasts they are transported to, they could become invasive.” That means they could wreak havoc on the ecosystems and economies of the places they land.

As plastic debris continues to fill the ocean, this threat will only get worse. Gil points out that even if humans do their best to keep trash on dry ground, natural disasters like the Japanese tsunami can override our efforts. Reducing the amount of plastic we make in the first place may be the only way to keep joyriding ocean animals from becoming globetrotting nightmares.


Images: Top by Marina Garland (Tyson Bottenus, Mike Gil, and Laura Hansen examine species rafting on a piece of plastic debris). Bottom, Patricia Keoughan.

Gil, M., & Pfaller, J. (2016). Oceanic barnacles act as foundation species on plastic debris: implications for marine dispersal Scientific Reports, 6 DOI: 10.1038/srep19987

MORE ABOUT: Ecology, Ocean, Pollution
  • Uncle Al

    All polymers, polymer constructs, and polymer subassemblies must be denser than seawater. Beltway lobotomites say, “Everything must have a gold-plated lead sufficient weight attached, including (especially!) life vests.

    to keep joyriding ocean animals from becoming globetrotting nightmares.” BBlow Muslim refugees out of the water on their way to Greece, clear Australia of English prisoners’ descendants…repatriate the Irish and African-Americans. Italians go back to Italy, Québécois go back to France, Jews return to Judea, Catholics retake Béziers… and shove Caulerpa taxifolia back up Jacques Cousteau’s Oceanographic Museum of Monaco.

    • MackTheAbsurd

      Way to have no clue about how to stay on topic.

      • OWilson

        Uncle Al was talking about the specific gravity of discarded plastics, and other means of the dispersion, accidental or otherwise, of terrestrial life forms.

        And you ?:)

        • Uncle Al

          Mandate the Department of Education and teachers unions produce the worst possible students. Elevate graduated IQs into triple digits by doing it the other way, All Jetsam to Flotsam!.

        • Mike Johnson

          Super 5*

    • tinfoilhat

      This goes against everything I believe in…. but maybe you should try decaf

  • ameryx

    Why the automatic and unquestioned assumption that the migration of species is bad? Wouldn’t evolution teach that, if the “invasive” species wipes out the native species, the invader is by definition more fit?

    Yet the author assumes that species migration is bad in se. The migration may be the key to survival for species whose native habitats can no longer support them.

    • OWilson

      You should not question the “revealed truth”:)

      You are in a world where the strange belief exists that the world would be a far better place without human beings. Go figure!

      • ameryx

        You nailed it.

    • JAFischer

      All it proves is that the invasive species doesn’t have competition or predators in the new environment.

      Come to the Southeastern United States and tell us that kudzu should be allowed to take over just because it can choke out all the indigenous plant life.

      And tell Australians that rabbits are more deserving than the indigenous animals they’re displacing.

      • ameryx

        Darwin teaches that evolution operates through “survival of the fittest”. In the circular logic which is Darwinism, we know which creatures are fittest, because they survive. I don’t have to tell the Australians anything: Darwin has already established that rabbits survive better in Australia than the indigenous animals; therefore, rabbits are more fit; therefore the indigenous animals deserve to die out.
        Alternatively, one might question the orthodoxy of Darwinism, though one risks being accused of heresy.

        • OWilson

          It is ironic that the side that always throws “Darwinism” in the face of the “Creationists”, are always the ones that seek to play god themselves and meddle with nature (and climate).

          The world is littered with misguided meddling, from the current poisoning of my beautiful Canada Geese by the thousands to the routine killing of starfish on the world’s reefs, presumably to preserve some “balance” that some government agency has ruled a good idea. :)

        • JAFischer

          You just demonstrated your flawed understanding of evolutionary theory. Read books by Dawkins, Gould, and others instead of repeating whatever oversimplifications and lies you’ve heard.

        • JohnnyMorales

          Are you confusing the comics you must read with Darwin again LOL.

          “Survival of the fittest” is the dogma of the X-men arch villain Apocalypse.

          Darwin NEVER summarized his theory like that or used the phrase per se.

          There is NO actual competition in evolution.

          The animal that survives changing environments, is the one that by simple chance has a slight advantage in some way over the others in his environment, and the change is gradual an incremental for the most part.

          This is a great example. Goose neck barnacles seem to make a glue that is better than other barnacles at attaching to smooth plastic surfaces. So they are able to exploit a new niche.

          Are other less glue worthy barnacles losing out, being tossed on the scrap heap headed towards extinction as a result.

          NO they are not. They’re doing just fine.

          It really highlights how describing evolution as the survival of the fittest is utterly absurd.

          The lack of the same sort of glue by non-goose neck barnacles doesn’t equal a loss of fitness in any way to the goose neck barnacles.

          • ameryx

            “Darwin NEVER summarized his theory like that or used the phrase per se.”
            Until the 5th edition, in which he used, with attribution, Herbert Spencer’s phrase.
            “There is NO actual competition in evolution.”



Like the wily and many-armed cephalopod, Inkfish reaches into the far corners of science news and brings you back surprises (and the occasional sea creature). The ink is virtual but the research is real.

About Elizabeth Preston

Elizabeth Preston is a science writer whose articles have appeared in publications including Slate, Nautilus, and National Geographic. She's also the former editor of the children's science magazine Muse, where she still writes in the voice of a know-it-all bovine. She lives in Massachusetts. Read more and see her other writing here.


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