These synthetics, the use of which has taken off around the world, can stay afloat for years or even decades. The debris that was dragged out to sea by the 2011 tsunami formed an unsinkable flotilla capable of transporting a large population of organisms across the world’s largest ocean.
“We have created a new ecological process, the process of mega-rafting,” said Steven L. Chown, a professor of biology at Monash University in Australia, who was not involved in the report, but wrote a commentary that also appeared in Science. “The development of materials that can float for ages, and the rising levels of seas due to climate change, make the possibility of these events larger and larger.”
This flotsam ranged in size from coolers and motorcycle helmets to entire fishing boats and even larger objects, teeming with living sea animals that were native to the coastal waters of Japan, but foreign to North America.
The larger the object, the more animals it carried. One of the first pieces of tsunami debris that appeared was a 180-ton floating dock that washed ashore in Oregon in June 2012. It was carrying a diverse mini-ecosystem of more than 120 different species.
“This was our first head’s up, that this was the vanguard of what might be coming from Japan,” said one of the report’s co-authors, James T. Carlton, a professor emeritus of marine sciences at Williams College….