To deter the dock's non-native hitchhikers from establishing a foothold on Agate Beach, volunteers and staffers with the Oregon Department of Fish and Wildlife scrape the structure clean with rakes and shovels on June 7.
All the marine organisms were to be buried at elevations above storm-surge water lines—the lack of salt water will ensure that the life-forms will break down.
Invasive species biologist John Chapman said that, while invasives sometimes find their way across oceans, the journey of this "floating island" was unprecedented. So was the idea that hundreds of millions of organisms could survive in relatively food-poor, open-ocean waters without being picked clean by predators.
"We were caught flat-footed," said Chapman, of Oregon State University. "This was a close-encounter-of-the-fourth-kind type of event, where an alien mother ship from outer space lands on our shores."
(Related: "Japan Tsunami, Before & After: Zoomable Satellite Images.")