The study reveals that the ocean floor has become a reservoir for most plastic pollution, with between 3 to 11 million tonnes of plastic estimated to be sinking to the ocean floor. This estimate is up to 100 times more than the amount of plastic floating on the ocean’s surface based on recent estimates. The research focuses on larger items, from nets and cups to plastic bags and everything in between, rather than microplastics.
The study also found that plastic mass clusters around continents, with approximately half (46%) of the predicted plastic mass on the global ocean floor residing above 200 m depth. The ocean depths, from 200 m to as deep as 11,000 m, contain the remainder of the predicted plastic mass (54%). Interestingly, inland and coastal seas, which cover much less surface area than oceans (11% vs. 56% out of the entire Earth’s area), are predicted to hold as much plastic mass as the rest of the ocean floor does.