The health of oceans in the face of massive pollution has been a topic of this blog on multiple occasions, and we’re always interested in learning more about the efforts to clean up the incredible amounts of waste, especially plastic, in one of the most–if not the most–important global ecosystems. New models by researchers at Imperial College London are hypothesizing that, rather than targeting sites like the great Pacific garbage patch, trash pick-up by floating microplastic collectors should be more effective near the coasts, where the rubbish originates. Sarah DeWeerdt reports for Conservation Magazine:
Cleanup efforts for ocean plastics should be concentrated close to shore, at the source of the problem, rather than in areas of open ocean where plastic tends to accumulate, according to a study recently published in the journal Environmental Research Letters. Ideally, if plastic collectors were placed offshore near coastal population centers, they could remove nearly one-third of plastic in the ocean over the next 10 years.
In the study, oceanographer Erik van Sebille and undergraduate physics student Peter Sherman, both at Imperial College London, used data on ocean currents and waste management practices in different countries to simulate the entry and circulation of plastic in the oceans from 2015 to 2025.
Then they modeled how much plastic could be removed by floating plastic collectors that sieve out tiny pieces of plastic, or microplastic, drifting on the surface of the ocean. The analysis assumed that each of 29 collectors would capture 45 percent of the plastic bits passing through its vicinity. These parameters are based on a previous study by an organization known as The Ocean Cleanup, which is developing the devices.
The Ocean Cleanup has proposed deploying plastic collectors in subtropical gyres, which are circular currents that tend to trap and concentrate floating plastic. The largest and most dramatic of these is the Pacific Garbage Patch, a conglomeration of plastic that covers a stretch of ocean more than twice the size of the United Kingdom between Hawaii and California.
That proposal has intuitive appeal: if you see a bunch of garbage, pick it up.
But according to the new analysis, cleaning up the Garbage Patch isn’t the most efficient way to get the most plastic out of the ocean, nor the best way to minimize plastics’ harm to marine life.
The best places to put plastic collectors are areas where the most plastic is moving through, not the places where the most plastic ends up, the researchers found. They identified a set of locations for the devices that would result in removal of 31 percent of the ocean’s microplastics by 2025. In contrast, putting all the collectors in the Pacific Garbage Patch would only reduce plastic in the oceans by 17 percent.