A new study appearing this week in Science reports the discovery of a startling new role of plastic marine debris — the transport of non-native species in the world’s oceans.
Co-authored by Oregon State University marine scientists John Chapman and Jessica Miller, the study also suggests that expanded coastal urbanization and storm activity, including the recent hurricanes and floods around the world, as well as predicted future enhanced storm activity due to climate change, could mean that the role of marine debris as a novel vector for invasive species may be increasing dramatically.
Between 2012 and 2017, scientists documented nearly 300 species of marine animals arriving alive in North America and Hawaii on hundreds of vessels, buoys, crates, and many other objects released into the ocean by the Japanese earthquake and tsunami of March 2011.
Unexpected was that coastal species from Japan would not only survive the trip through the hostile environment of the open North Pacific Ocean, but continue to survive for many years — four or more years longer than any previous observations of species found living on what are called “ocean rafts.”
Tsunami debris items continued to land in North America and Hawaii as late as spring 2017 with living Japanese species.
Between 2012 and 2014, wood from homes and other buildings in Japan landed in Oregon and other locations bearing Japanese species that included dense populations of wood burrowing marine clams known as shipworms. Shipworms destroy wood. Wood landings declined dramatically after 2014.
The declining wood landings early in the study brought the researchers’ attention to the fact that it was the non-biodegradable debris — plastics, fiberglass, and styrofoam — that was permitting the long-term survival and transport of non-native species.
“Given that more than 10 million tons of plastic waste from nearly 200 countries can enter the ocean every year – an amount predicted to double by 2025 – and given that hurricanes and typhoons that could sweep large amounts of debris into the oceans are predicted to increase due to global climate change, there is huge potential for the amount of marine debris in the oceans to increase significantly,” James Carlton, an internationally known invasive species expert with the Maritime Studies Program of Williams College and Mystic Seaport, and lead author the study, said.
Chapman said that scientists thus far have not documented any Japanese species transported by tsunami debris becoming established on the West Coast. But, Chapman said, it can take years for species to establish and become detected.
“One thing this event has taught us is that some of these organisms can be extraordinarily resilient,” he said. “When we first saw species from Japan arriving in Oregon, we were shocked. We never thought they could live that long, under such harsh conditions. It would not surprise me if there were species from Japan that are out there living along the Oregon coast. In fact, it would surprise me if there weren’t.”
Miller, an OSU marine ecologist who also works at the university’s Hatfield Marine Science Center in Newport noted that “not only were new species still being detected on tsunami debris in 2017 but nearly 20 percent of the species that arrived were capable of reproduction. We were able to not only identify this unique list of species but, in some cases, examine their growth and ability to reproduce which provides useful information on how they fared during their transoceanic voyage.”
Carlton added: “These vast quantities of non-biodegradable debris (plastics), potentially acting as novel ocean transport vectors, are of increasing concern given the vast economic cost and environmental impacts documented from the proliferation of marine invasive species around the world,” Carlton said.
Chapman added: “This has turned out to be one of the biggest, unplanned, natural experiments in marine biology, perhaps in history.”
The research was funded by the Ministry of the Environment of Japan through the North Pacific Marine Science Organization, the U.S. National Science Foundation, and Oregon Sea Grant.
Other authors include Jonathan B. Geller, Moss Landing Marine Laboratories; Deborah A. Carlton and Megan I. McCuller, Williams College; Nancy C. Treneman, Oregon Institute of Marine Biology; Brian P. Steves and Gregory M. Ruiz, Smithsonian Environmental Research Center and Portland State University.
The Smithsonian has also added these observations to the issue of unnatural marine debris that is contaminating the world’s oceans.
Because of its durability, low cost, and our increased use in recent decades, plastic makes up the majority of marine debris seen on shorelines and floating in oceans worldwide. This creates a difficult problem because most plastics are not biodegradable (bacteria don’t break them down into simple, harmless components the way they do paper or wood). Instead, as plastic ages, the sun’s light and heat break it into smaller and smaller pieces.
This tiny plastic confetti, along with larger pieces of floating plastic, creates a big problem. Birds and filter feeders that strain food out of the water may mistake plastic for plankton, fish eggs, or other food. On remote Midway Atoll, Laysan albatross parents accidentally feed their chicks bits of plastic, which fill up their stomachs and cause them to starve. Deep-sea fish living near the garbage patch eat the tiny bits of plastic. Scientists have discovered that microbial ecosystems grow on the floating plastic bits, to unknown effect. Even in the protected waters of the Papahānaumokuākea Marine National Monument along the northwestern Hawaiian Islands, our trash threatens endangered species like Hawaiian monk seals and green sea turtles.
This massive global problem is not hopeless. Some countries and states have banned plastic bags, a trend that will continue with public support. Participating in beach or park clean-ups is an easy way to reduce the amount of trash that reaches natural waters. You can avoid exfoliating soaps and toothpastes with tiny plastic microbeads, and complain to the companies that make them. And you can help every day by avoiding plastic packaging wherever possible, bringing reusable bags to the grocery store, and drinking from reuseable water bottles or coffee mugs.
Scientists with agencies such as NOAA, and other institutions around the world, continue to research the impacts of marine debris, including the emerging area of microplastic debris (plastic that is less than 5mm) and its impacts on our marine ecosystems.
– Smithsonian Institution