When the powerful tsunami that devastated portions of Japan on March 11th, 2011 receded, it carried with it all kinds of debris - Ranging from over 200,000 buildings complete with belongings, to countless cars. Among the biggest, were four dock floats - the size of freight train boxcars, that were ripped off intact from the fishing port of Misawa.

One the barges was recovered shortly after off a nearby island. However, the other three were not seen until this week, when one suddenly washed ashore on the white sands of Oregon's Agate Beach. Not only had the 165-ton concrete and steel dock made an astonishing 5,000 mile journey across the world, but it had also carried with it, a diverse community of organisms ranging from algae to mussels, crabs and even starfish.

The problem with the arrival of these unexpected visitors is that they are all native to Japan. If allowed to live, they could threaten the local species and even topple the existing eco-system irreversibly. In order to prevent the aliens from taking over, the scientists had to scrape the dock clean, sterilize it with torches and even, bury the one and half ton material that was clinging to it, above a high-water line.

While that averted this particular threat, others may not be as easy to get rid of. Wakame, a species of seaweed that was previously found only in Japan has now been spotted in Southern California, as has a new species of algae. In addition to that, a never-been seen before tiny species of crab is making rapid inroads around New York, whilst a new kind of starfish has been spotted all along the US coast. What other surprises will the after-effects of the Japanese tsunami bring? Only time will tell!

Resources: news.discovery.com,news.yahoo.com,