World’s oceans hold garbage patches twice the size of Texas

Researchers from the University of New South Wales (UNSW) in Sydney, Australia, estimate that there are at least five huge garbage patches polluting the world’s oceans, some as big as the state of Texas. Using computer modeling, the scientists say they also may be able to determine which nations are the worst polluters—no easy task considering the enormity and complexity of the ocean. The study appears in the journal Chaos, published by the American Institute of Physics (AIP).
“In some cases, you can have a country far away from a garbage patch that’s unexpectedly contributing directly to the patch,” said USNW mathematician and co-author Gary Froyland in an AIP statement. For example, trash from Madagascar and Mozambique would likely flow into the south Atlantic instead of into the Indian Ocean, even though both countries border the Indian Ocean.
Co-author Erik van Sebille, an oceanographer, added, “We can use the new model to explore, for example, how quickly trash from Australia ends up in the north Pacific.”

Ocean garbage patches, which are formed by powerfully rotating ocean currents, raise environmental concerns because broken plastic, which makes up a good deal of the trash, spreads easily and is toxic to marine life.
The five garbage patches are located in the north and south Pacific, the north and south Atlantic, and the middle of the Indian oceans. Although people generally picture them as huge islands of trash, they more resemble a thin soup of plastic, said Froyland in a report by the Christian Science Monitor, as ultraviolet light and churning waters break down the debris into tiny pieces that are easily eaten by fish.
The principal purpose of the research was to find out how well the surface waters of the world’s oceans mix. The new model shows that parts of the Pacific and Indian oceans are actually most closely coupled to the south Atlantic, while another piece of the Indian Ocean really belongs in the south Pacific, the AIP statement said.
“The take-home message from our work is that we have redefined the borders of the ocean basins according to how the water moves,” said van Sebille.
In addition to the ability to track ocean debris, a better understanding of ocean geography could provide fresh insights into ocean ecology, the researchers say. On a smaller and more practical scale, they say their new modeling technique could be used to predict how oil spills might spread in ocean waters.