This article first was published online by DFM News on May 2, 2012.

Photo Credit: Sea Education Association, Marilou Maglione

Surface trawling has long been used to estimate the level of plastic pollution in the ocean, from plastic soda bottles to disposable bags, but it turns out this method of measurement only scratches the surface of the problem… quite literally.

High winds cause plastic debris to mix well below the surface where more than half of the ocean’s plastic pollution has swirled about, uncounted, according to Tobias Kukulka, a University of Delaware assistant professor of physical ocean science and engineering.

In still water, plastic is buoyant, inevitably rising to the ocean surface, Kukulka explained in an email interview. “However, in a wind-driven turbulent ocean, this buoyant upward transport is balanced by a downward transport because plastic particles “catch a ride” with the turbulent motion,” he said.

Kukulka and co-lead author Giora Proskurowski, oceanography scientist at the University of Washington, published the results of a study of plastic pollution of the world’s oceans in the latest issue of Geophysical Research Letters.

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