Photo: Brian Yurasits
A new study has come up with the first estimate of how much plastic waste actually ends up on the ocean floor. The study, conducted by Australia’s national science agency CSIRO and the University of Toronto in Canada, found that there could be up to 11 million tons of plastic pollution resting at the bottom of the ocean.
“We know that millions of tons of plastic waste enter our oceans every year but what we didn’t know is how much of this pollution ends up on our ocean floor,” said Dr Denise Hardesty, Senior Research Scientist with CSIRO and co-author of the study, in a press release. She added that difference between this study and previous efforts is that it looked at more than just microplastics on the ocean floor – larger items, such as nets, cups and plastic bags, were also included.
To estimate the amount and distribution of plastic on the ocean floor, the team created two predictive models. One model was based on data from remote operated vehicles (ROVs) and the other from bottom trawls. Using the model based on ROV data, they estimated that 3-11 million tons of plastic was on the ocean floor as of 2020. They also found that the macroplastic clusters around continents, close to human populations.
That number could be up to 100 times more than the amount floating on the surface, according to Alice Zhu, a PhD Candidate from the University of Toronto who led the study. “The ocean surface is a temporary resting place of plastic so it is expected that if we can stop plastic entering our oceans, the amount would be reduced,” she added. “However, our research found that plastic will continue to end up in the deep ocean, which becomes a permanent resting place or sink for marine plastic pollution.”
Zhu and her colleagues hope that this new knowledge will help inform efforts to reduce the amount and impact of marine plastic debris.
