Invaders by Tsunami
Crabs and Gooseneck barnacles colonize ocean plastic (credit: Sea Education Association)
Invasive species have utilized a myriad of ways to move from one place to another: Quagga Mussels invaded North America through the Great Lakes on container ships; Burmese pythons were released by clueless owners and then invaded the Florida Everglades; Long-horned beetles arrived as larvae inside untreated lumber from China and now attack timber trees: and the Asian Jumping Carp, raised in Louisiana aquaculture farms, escaped from their ponds to enter the Mississippi River during a hurricane. They carp now threaten the Great Lakes ecosystem if they make it past barriers.
Besides causing ecological havoc, invasive weeds, bugs, reptiles, fish, and other critters cost billions of dollars in pest control. Eliminating invasive species in the US has already been estimated to exceed $21 billion/year. One study of invasives conducted by Oregon State University and published in Science Magazine. Itdescribed a new mechanism for invasives to disperse: floating to coastlines on various floating materials and driven by tsunami waves. In their report, the OSU investigators determined one Japanese earthquake had generated a tsunami that:
"launched a trans-oceanic biological rafting event with no known historical precedent."
According to the announcement, nearly 300 species were documented being transported on non-degradable plastic items which traveled across the Pacific Ocean to North America and Hawai‘i over a period of six years. Recognizing that wooden materials were declining as an ocean pollution problem this brought attention to the fact that non-biodegradable garbage---plastics, fiberglass, Styrofoam---permitted the long-term survival and transport of non-native species just as well. The investigators never expected live coastal species from Japan could not only survive the hostile environment of the open ocean but also could thrive for years living happily on their 'ocean rafts'. The article's lead author, James Carlton noted:
“Given that more than 10 million tons of plastic waste from nearly 200 countries can enter the ocean yearly and given that hurricanes and typhoons, could sweep large amounts of debris into the oceans, that are predicted to increase due to climate change, there is a huge potential for the amount of marine debris to significantly increase”.
The article concluded that expansion of coastal developments, increased availability of ocean plastics available to colonize, and the increase of climate change-induced storm intensities will likely expand the rafting of invasive species as well. The costs associated with removing discarded plastic waste from the oceans isn't known but it is unlikely to be cheap. Expect more invaders to hitch rides on discarded plastic bottles and broken toys to arrive along your shorelines. WHB