The ocean is littered with plastic. A new study suggests some 88 percent of the open ocean features tiny pieces of plastic debris called microplastics. But surprisingly -- and problematically -- during a massive survey and study of Earth's oceans, scientists found fewer and smaller large accumulations of trash than they expected.

"Based on trends in plastic pollution we expected to find about 100 times more plastic than we actually found," explained study co-author Carlos Duarte, a professor of plant biology at the University of Western Australia. "But the reason is probably because it is being removed by fish and entering the ocean food web."

The two revelations from the study -- the expanse of microplastics and the disappearance of larger accumulations -- seem to tell a worrisome tale, a tale of large debris being broken down and incorporated into the marine ecosystem, likely entering the food chain.

Duarte and his fellow researchers undertook the task of mapping the ocean's plastic accumulation by collecting some 3,070 separate surface water samples during the 2010 Malaspina Circumnavigation Expedition funded by the Spanish Research Council. These samples revealed that these broken-down microplastics were detectable in 88 percent of all the world's ocean water. All totaled, researchers estimate that some 10,000 to 40,000 tons of plastic debris is drifting through the open oceans.

All of this news is disheartening for several reasons. For one, scientists say its much more difficult to track the negative consequences of trash once it's disappeared beneath the ocean surface. "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," explained study co-author Andres Cozar, a researcher from Spain's University of Cadiz.

Maybe more significantly, the diminishing trash heaps suggest fish are eating it. And humans eat fish -- and all the contaminants that come with them.

"There is potential for this plastic to enter the global ocean food web," explained Duarte. "And we are part of this food web."

The full survey and study of the ocean's plastic pollution was published this week in the Proceedings of the National Academy of Sciences.