Oyster buoys and refrigerator parts set adrift by the 2011 Japan tsunami are now rolling in with the tide on Hawaii's beaches, a new field survey reveals.
Black oyster buoys and refrigerator parts — and even a full refrigerator — that trace back to Japan have shown up on the islands of Oahu and Kauai, said Nicholas Mallos, a conservation biologist and ocean debris specialist at the nonprofit Ocean Conservancy. Also on Oahu, researchers found a large 4-foot by 4-foot (1.2 by 1.2 meters) chunk of housing insulation framed in wood, a piece almost certainly sent into the sea by the devastating tsunami.
"These items have never before been seen on these beaches," Mallos told LiveScience.
The Japanese government has estimated the tsunami, which was triggered by an underwater earthquake in March 2011, swept about 5 million tons of wreckage out to sea. While 70 percent appears to have sunk offshore, the rest is floating in the Pacific Ocean. The first bit to show up in Hawaii, in September, was a barnacle-covered seafood storage bin.
Exposed to ocean currents on every side, the Hawaiian Islands are a hotspot for Pacific junk. Some of this ocean litter originates from the fishing industry; most of the rest is consumer garbage from soda bottles, toys and other plastic goods, much broken down by the waves beyond recognition. [In Photos: Tsunami Debris & Ocean Trash in Hawaii]
At Kimalo Point on Hawaii's Big Island, tiny fragments of plastic penetrate as much as 3 feet (0.9 meters) below the beach surface.
"Many places on the beach, it's hard to differentiate the sand from the plastics on the surface," Mallos said.
The tsunami debris is different. For one thing, it tends to be larger, having only been in the ocean since March 2011, Mallos said. The debris also comes ashore in surprisingly homogenous waves. This summer, it was oyster buoys, Mallos said. Now, it's refrigerator parts.
The reason? Wind acts on similar objects in similar ways, according to research by Nikolai Maximenko of the University of Hawaii at Manoa's International Pacific Research Center. All of the tsunami debris went into the ocean at the same time, but some objects drift across the Pacific faster than others. That results in clusters of similar objects showing up in Hawaii and along the North American West Coast at the same time. (Tracking Tsunami Debris Infographic)