More than 8.3 billion tons of plastic waste enter the oceans each year, equivalent to a garbage truck dumping its contents into the sea every minute of the day, according to a report by the World Economic Forum. Anything more than 5 millimeters in size, about a fifth of an inch, is generally considered to be “macroplastic,” while anything below that size is “microplastic.”
Biermann and a team of colleagues embarked on their own study of detecting ocean plastic through satellite imagery, and recently published their findings in Scientific Reports. First, they obtained high-resolution optical data from the European Space Agency (ESA), which is gathered by the Sentinel-2 Earth observation satellite. Second, they used the plastic target data from the University of the Aegean to help differentiate plastic debris from natural objects like driftwood and seaweed.
Then the researchers employed an algorithm to develop a “floating debris index” (FDI) that would identify macroplastics, like plastic water bottles and plastic bags, bobbing on the surface of the sea. While plastic tends to get pushed around in the ocean, winds and ocean currents will propel it into clusters that stay in one place. Biermann says she hopes that optical satellite data can help identify these aggregates, and that people and organizations can use this information to work on solutions. “There will be cleanup operations like the Ocean Voyages Institute, which we’d like to work with. They would then go to where we spotted things, and they would be able to remove tons of plastic at a time,” Biermann said. “This really is the first technical exercise, but we would then like to apply the method, far more broadly … to rivers and open waters.”
Source: Mongabay
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