Plastic in the ocean helps transport invasive marine species

When we think about the potential environmental impact of the mind-boggling amount of plastic waste that litters our oceans, we often think of it as useless trash. However, a new study published in the journal Science reports that plastic marine debris has a previously unmentioned role: transportation for non-native marine species.

Between 2012 and 2017, researchers found nearly 300 species of marine animals landing alive on shore in North America and Hawaii. These species clung to everything from ships to buoys and crates. They believe many of these objects were released into the ocean by the Japanese earthquake and tsunami back in March of 2011.

The scientists were surprised that coastal species from Japan could survive for years on this trip through the hostile open North Pacific Ocean. In fact, many of these species survived for at least four years longer than any previous observations found living on these “ocean rafts.”

Researchers believe that a major part of this increased survival rate has to do with the fact that these species were attached to non-biodegradable debris, such as plastic, fiberglass, and styrofoam. This study also suggests that factors such as expanded coastal urbanization and storm activity – particularly an increase in recent hurricanes as a result of climate change – could further increase the role of marine debris as a transport for these invasive 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 increase by an order of magnitude 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,” says James Carlton, lead author of the study and an internationally known invasive species expert at the Maritime Studies Program of Williams College and Mystic Seaport.

Luckily, so far scientists have not found that any of these Japanese species have become established in the ecosystems on the West Coast, but they acknowledge that it can take years for species to drop anchor – so to speak – and be detected by scientists.

“One thing this event has taught us is that some of these organisms can be extraordinarily resilient,” says John Chapman, co-author of the study and a marine scientist at Oregon State University. “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.”

It may be just a matter of time before these invasive species are found in ecosystems along the West Coast. This study, which Chapman describes as “one of the biggest, unplanned, natural experiments in marine biology, perhaps in history,” shows not only how resilient marine species can be, but how unrelenting our plastic waste is as well.

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By Connor Ertz, Earth.com Staff Writer