Tiny Invaders

Marine scientists can identify beached objects that came from Japan by their markings, carpentry styles and the organisms clinging to them.

In June 2012, a 60-foot vessel packed with foreigners landed on the shore of Newport, Oregon. Officials from several agencies quickly came up with a plan to deal with the invaders before they caused more damage.

The vessel: a floating dock that had broken from Japanese coastline during the March 2011 tsunami. The stowaways: several tons of organisms that had survived the voyage across the Pacific.

Marine scientists identified dozens of species not native to the U.S. coast, including North Pacific sea stars, Japanese shore crabs and brown algae called Undaria pinnatifida, orwakame – delicious in miso soup, disastrous in habitats like Monterey Bay.

The dock in Oregon was just the beginning of what would become a stream of Japanese tsunami debris arriving on the U.S. West Coast.

“We were anticipating the arrival of this material,” says Jonathan Geller, a faculty member at Moss Landing Marine Laboratories. “We want a DNA sequence on all these organisms so we can monitor the environment here.”

Geller and his collaborators landed a National Science Foundation grant to study the “biofouling.” Tsunami debris reported by beach-walking citizen scientists includes boats, lumber and two more floating docks. (A fourth is still at sea.)

Most of the stuff is washing up in Oregon and north, Geller says, but the team is looking in California, too.

Geller says he didn’t expect so many creatures to survive the trans-Pacific voyage through the nutrient-poor high seas. But the biota covering tsunami debris often comprise mini food webs, so creatures like crabs, mussels and snails have enough to eat onboard.

“These are little dynamic communities,” he says.

Invasive marine species can harm native species by eating them, disrupting their food supplies or introducing parasites and pathogens. They can hitch rides on things like cargo ships and plastic garbage. But Geller says the difference, when it comes to tsunami debris, is the scale.

Study lead James Carlton, a professor of marine science at Williams College, says his team has counted more than 250 species on the debris set loose from Japan almost four years ago.

“Millions of items were ejected into the North Pacific from a known area at the same time,” he says. “It’s been a really interesting and extremely rare [research] opportunity.”

The next step, Carlton says, is to monitor the U.S. West Coast to see if any of the invaders are establishing a toehold here – giving marine scientists a distinct advantage in what is often an uphill battle.

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