Invasive species ride tsunami debris to US

When a floating dock the size of a boxcar washed up on a sandy beach in Oregon, beachcombers got excited because it was the largest piece of debris from last year's tsunami in Japan to show up on the US West Coast.

But scientists worried it represented a whole new way for invasive species of seaweed, crabs and other marine organisms to break the earth's natural barriers and further muck up the West Coast's marine environments. And more invasive species could be hitching rides on tsunami debris expected to arrive in the weeks and months to come.

"We know extinctions occur with invasions," said John Chapman, assistant professor of fisheries and invasive species specialist at Oregon State University's Hatfield Marine Science Center. "This is like arrows shot into the dark. Some of them could hit a mark."