Recent research spearheaded by Australia’s national science agency, CSIRO, in collaboration with the University of Toronto, estimates that up to 11 million metric tons of plastic pollution currently reside on the ocean floor. This research, published in the Deep Sea Research Part I: Oceanographic Research Papers, marks a significant milestone in understanding the full scope of marine plastic pollution.
The ocean ingests enough plastic every minute to fill a garbage truck. With global plastic consumption projected to double by 2040, the fate of this plastic is a critical concern for marine conservation efforts. Dr. Denise Hardesty, a Senior Research Scientist at CSIRO, indicated that this is the first estimate of how much plastic waste accumulates on the ocean floor before being broken down into smaller pieces and mixed into ocean sediment.
Unlike prior estimates focused on microplastics, this study examines larger debris, ranging from fishing nets to plastic bags, revealing that the ocean floor is a primary repository for these pollutants: Alice Zhu, a Ph.D. Candidate at the University of Toronto and lead researcher of the study notes that the volume of plastic on the ocean floor could be up to 100 times greater than that floating on the surface.
The findings underscore the importance of halting plastic entry into oceans to reduce surface pollution. However, as Zhu points out, plastic will continue to migrate to the deep sea, necessitating a focus on prevention and remediation strategies that address the entire marine environment.
To estimate the distribution and volume of seafloor plastic, the team employed predictive models based on data from remote-operated vehicles (ROVs) and bottom trawls. Analysis of that data estimated that between 3 and 11 million metric tons of plastic pollution have settled on the ocean’s bed. Furthermore, the ROV findings shed light on the distribution of this plastic mass, indicating a significant accumulation near continental regions. Specifically, nearly half (46%) of the total estimated plastic mass found on the global ocean floor is concentrated at depths shallower than 200 meters. The remaining portion, which accounts for 54% of the plastic mass, is dispersed across deeper oceanic regions, extending from 200 meters down to profound depths of 11,000 meters.
Understanding the mechanisms of plastic accumulation in deep-sea environments is critical for developing effective source reduction and environmental remediation strategies. This research fills a significant knowledge gap and supports initiatives like CSIRO’s Ending Plastic Waste Mission, which aims to transform plastic production, usage, recycling, and disposal practices. The study’s findings highlight the critical need for businesses and policymakers to intensify waste management and marine protection efforts, ensuring the preservation of aquatic ecosystems for future generations.
