Ocean depths harbor millions of tonnes of plastic pollution

Ocean depths harbor millions of tonnes of plastic pollution
by Simon Mansfield
Sydney, Australia (SPX) Apr 05, 2024

A landmark study by CSIRO, Australia's national science agency, in collaboration with the University of Toronto, has provided the first quantitative estimate of plastic pollution on the ocean floor, revealing a staggering amount of up to 11 million tonnes.

As plastic consumption is projected to double by 2040, the findings underscore the urgency of understanding plastic's journey to safeguard marine life and ecosystems. Dr. Denise Hardesty, a senior researcher at CSIRO, highlighted the study's groundbreaking nature, offering the initial count of plastic waste settling on the ocean floor, marking it as a significant accumulation point for oceanic plastic.

"This pioneering research offers a glimpse into the magnitude of plastic waste that finds its way to the ocean's depths, lying between 3 to 11 million tonnes," explained Dr. Hardesty. She emphasized the shift from previous focuses on microplastics to now including larger plastic items, ranging from nets to bags, which form part of this underwater waste reservoir.

Alice Zhu, the lead researcher from the University of Toronto, pointed out that the ocean floor's plastic content might be up to 100 times greater than that floating on the surface, stressing the importance of halting oceanic plastic entry to mitigate this deep-sea pollution.

The study leveraged scientific data to develop predictive models, utilizing both remotely operated vehicle (ROV) observations and bottom trawl data, to estimate the spread and quantity of seafloor plastic. The findings suggest a significant portion of plastic pollution clusters around continents, with roughly half discovered at depths above 200 meters, and the rest distributed down to 11,000 meters into the ocean.

Interestingly, inland and coastal seas, despite covering less area, are predicted to contain as much plastic as the entirety of the ocean floor, indicating a pressing need for interventions to curb plastic pollution and protect marine environments.

"Our findings bridge a critical knowledge gap regarding plastic's behavior in marine settings," Zhu noted, emphasizing the importance of these insights for informing both pollution prevention and environmental cleanup efforts to safeguard marine species from plastic's harms.

Research Report:Plastics in the deep sea - A global estimate of the ocean floor reservoir