The Great Pacific Garbage Patch is a floating vortex of refuse, in the world's largest ocean. Estimates of the size of the whirlpool range between twice the size of Texas, to as large as the continental United States. Scientists studying the feature discovered up to 99 percent of the plastic thought to be present there have vanished. This surprising finding is considered bad news for the environment, as the whereabouts of the material remains a mystery.
The Eastern Garbage patch was the first of several such features discovered, when it was spotted by Charles Moore in 1997. These whirlpools of garbage cannot be seen from aircraft, ships or satellites. The only method to detect these eddies of trash is to collect samples from the ocean.
Andrés Cózar of the University of Cadiz led the Malaspina Expedition in 2010, aimed at sampling these whirlpools. Traveling more than 38,000 miles, his team collected more than 3,000 samples from 141 locations. From their study and previous data, the researchers calculated there is between 7,000 and 35,000 tons of plastics in the global ocean. As large as this number is, it is still just one percent of what the team expected to find. This presents a mystery as to what is happening to the material.
Some marine biologists believe the plastic may be breaking down into tiny pieces, which were not captured by the team. This could present problems to fish that eat the tiny scraps. These fish, or those that eat them, could be part of the human food chain. Debris under one-fifth of an inch in size was especially rare in the samples taken by the team, suggesting ingestion by fish may be a leading cause of the missing garbage.
Biofouling - in which marine plants and animals adhere to debris, pulling the objects underwater, could be another process affecting the plastic waste.
"The deep ocean is a great unknown. Sadly, the accumulation of plastic in the deep ocean would be modifying this mysterious ecosystem - the largest of the world - before we can know it," Cózar said.
The predicted levels of trash were calculated from global production and disposal rates. The amount of plastic produced each year is five times higher than it was in the 1970's.
Whirlpools of plastic were first predicted by the National Oceanic and Atmospheric Administration (NOAA) in 1988.
In Hawaii, rocks have been found fused with plastics, in a formation dubbed plastiglomerates. The prevailing theory is these are formed by people throwing plastic items into campfires.
Investigation of the prevalence of plastics in the Pacific and the mystery of the missing plastic was published in the Proceedings of the National Academy of Sciences.
