The Great Pacific Garbage Patch, a massive ocean-going island of floating waste plastic, is far bigger than previously thought.
More than 79 thousand tonnes of plastic are floating inside the mass, a figure up to 16 times higher than previously estimated, according to a study published in the journal Scientific Reports.
Laurent Lebreton of the Ocean Cleanup Foundation and colleagues examined the major ocean plastic accumulation zone between California and Hawaii known as the Great Pacific Garbage Patch.
The results suggest that microplastics are rapidly accumulating and that plastics made up 99.9% of debris.
Based on data from sea and air surveys, the model predicts there are between 45 and 129 thousand tonnes of plastic floating in an area of the ocean covering 1.6 million km2.
The big patch:
At least 46% of plastic consisted of fishing nets, and over three quarters of the plastic was debris larger than 5cm, including hard plastics, plastic sheets and film.
Microplastics accounted for 8% of the total mass of plastic but 94% of the estimated 1.8 trillion pieces floating in the area.
Although most large items had broken down into fragments, the researchers were able to identify containers, bottles, lids, packaging straps, ropes, and fishing nets.
The authors assessed aerial images alongside data from 652 net tows carried out by 18 vessels.
The aerial imaging allowed for a more accurate count and measurement of larger debris than previous studies which used only vessel-based visual surveys.
The authors say more research is needed to quantify sources of ocean plastics in the Great Pacific Garbage Patch and to better assess how long plastics stay in this area.