Nasa-funded mission tracks ocean microplastics from space

Microplastics are extremely difficult to track and clean up through conventional methods

The microplastics that choke ocean life will soon be tracked from space as part of a Nasa-funded research programme.

Researchers at the University of Michigan discovered satellites can spot the soapy or oily residue to which microplastics attach themselves with ease.

Microplastics are tiny flecks that can ride ocean currents hundreds or thousands of miles from their point of entry and can harm sea life and marine ecosystems.

They’re extremely difficult to track and clean up, but a 2021 discovery raised the hope that satellites could offer day-by-day updates on where microplastics enter the water, how they move, and where they collect.

The team noticed that data recorded by the Cyclone Global Navigation Satellite System (CYGNSS), showed fewer and smaller waves in areas of the ocean that contain microplastics.

They used the technique to spot suspected microplastic releases at the mouth of China’s Yangtze River and to identify seasonal variations in the Great Pacific Garbage patch, a convergence zone in the North Pacific Ocean where microplastics collect in massive quantities.

It emerged that the wave activity is not caused by the plastics themselves, but by surfactants — soapy or oily compounds that are often released along with microplastics and that travel and collect in similar ways once they’re in the water.

Professor Chris Ruf, said that a satellite-based tracking tool was a major improvement on current tracking methods, which rely mainly on reports from plankton trawlers that net microplastics along with their catch.

He said: "NOAA, the Plymouth Marine Lab in the UK and other organisations are very aware of what we’re doing, but we need to be cautious and fully understand the system’s limitations before putting it into widespread use.

“These new findings are an important step in that process."

Corresponding author Yulin Pan said: "We can see the relationship between surface roughness and the presence of microplastics and surfactants," Pan said. "The goal now is to understand the precise relationship between the three variables."