AGI – There are up to 11 million tons of plastic pollution on the ocean floor. This is revealed by new research by CSIRO, Australia’s national scientific agency, and the University of Toronto, Canada, published in Deep Sea Research Part I Oceanographic Research Papers. It is estimated that every minute, a truckload of plastic enters the ocean. With plastic use expected to double by 2040, understanding how and where it travels is critical to protecting marine ecosystems and wildlife.
“The study offers the first prediction of how much plastic waste ends up on the ocean floor, where it accumulates before being broken down into smaller pieces and mixed with ocean sediments,” said Denise Hardesty, senior research scientist at CSIRO. “We know that millions of tons of plastic waste end up in our oceans every year, but we didn’t know how much of this pollution ended up on our ocean floors,” Hardesty explained. “We found that the ocean floor has become a resting place, or sink, for most plastic pollution, with an estimated 3 to 11 million tons of plastic sinking to the ocean floor. ,” Hardesty continued.
“While microplastics on the sea floor have been estimated in the past, this research looks at larger objects, from nets and cups to plastic bags and everything in between,” Hardesty said. “Predictions of plastic pollution at the bottom of the ocean could be up to a hundred times higher than the amount of plastic floating on the ocean surface, according to recent estimates,” said Alice Zhu, a doctoral student at the University of Toronto who led the study. “The ocean surface is a temporary resting place for plastic, so it is expected that if we can stop plastic from entering the oceans, the amount will be reduced,” Zhu continued.
“However,” Zhu added, “our research has found that plastic will continue to end up in the deep ocean, which will become a permanent resting place or sink for marine plastic pollution.” The scientific data was used to build two predictive models to assess the amount and distribution of plastic on the ocean floor, one based on data from remotely operated vehicles, or ROVs, and the other from bottom trawls. Based on ROV data, an estimated 3 to 11 million metric tons of plastic pollution reside on the ocean floor.
The ROV results also reveal that plastic mass is concentrated around continents: approximately half, 46%, of the predicted plastic mass on the global ocean floor resides above 200 meters depth. The ocean depths, from 200 m to 11,000 m, contain the rest of the expected plastic mass, with a percentage of 54%. Although inland and coastal seas cover a much smaller surface area than the oceans, with 11% versus 56% of the entire Earth’s surface, these areas are expected to contain as much plastic in mass as the rest of the ocean floor.
“These findings help fill a long-standing knowledge gap about the behavior of plastic in the marine environment,” Zhu said. “Understanding the driving forces behind the transport and accumulation of plastic in the deeper ocean will facilitate increased actions aimed at environmental cleanup, thus limiting the risks that plastic pollution can pose to marine life” , Zhu concluded.
