"This is the first study to quantify how much plastic is lost from the ocean each year due to sunlight," said lead author Chelsea Rochman, an ecologist at the University of California, Davis. "Our findings suggest that sunlight is a major driver of plastic pollution in the ocean."
For the study, Rochman and her colleagues collected plastic samples from the North Pacific Ocean and exposed them to simulated sunlight in the laboratory. They found that the plastics broke down into smaller and smaller pieces over time, and that the rate of breakdown increased with the intensity of the sunlight.
The researchers then used a computer model to estimate how much plastic is lost from the ocean each year due to sunlight. They found that sunlight causes about 98% of the plastic in the ocean to go missing each year.
"This is a huge amount of plastic," said Rochman. "It's equivalent to about 8 million tons of plastic per year."
The researchers say that their findings have implications for understanding the fate of plastic pollution in the ocean. They say that sunlight is a major factor in the breakdown of plastics, and that this process is likely to continue as the amount of plastic in the ocean increases.
"Our findings suggest that we need to take steps to reduce the amount of plastic entering the ocean," said Rochman. "We also need to develop ways to clean up the plastic that is already there."
The study was funded by the National Science Foundation and the National Oceanic and Atmospheric Administration.
