Each year, about 8 million tonnes of plastic waste goes into the ocean, most of which is broken by the sun and waves into microplastics (small specks that can travel in ocean currents hundreds or thousands of times). kilometers from the entry point).

Debris can harm marine life and marine ecosystems and is extremely difficult to track and clean up.

Researchers at the University of Michigan are now discovering marine microplastics around the world and developing new ways to track them over time. This provides a daily timeline of where microplastics enter the ocean, how they move, and their tendency to accumulate.

This approach is based on the Cyclone Global Navigation Satellite System (CYGNSS) and Overview Or enlarge a small area to display a high resolution image. Microplastic Release from one place.

This technique is a significant improvement over current monitoring methods which rely primarily on the uneven ratios of plankton trawlers cleaning up microplastics with the catches.

“We are still ahead Research processHowever, I hope this will be part of a fundamental change in the way monitoring and management is done. Microplastic pollutionChris Ruff, UM professor of climate and space science at Frederick Baltmann University, senior researcher at CYGNSS and lead author of a recently published treatise on this study, said.

Their first observations are clear.

Seasonal changes in the Great Pacific Garbage Patch

The team found that global concentrations of microplastics tend to fluctuate seasonally, peaking in the North Atlantic and Pacific during summers in the northern hemisphere. For example, June and July are the peak months of the Great Pacific Garbage Patch, a convergence zone in the North Pacific where a large amount of microplastics are concentrated.

Concentrations in the southern hemisphere peak during the summer months of January and February. The researchers believe that the combination of a strong current breaking the microplastic plume and an increased vertical mixing that pushes the microplastic plume below the surface of the water.

The data also showed short spikes in the concentration of microplastics in the mouth Yangtze river– Long suspected of being the main source of information.

“It’s one thing to suspect the source of microplastic pollution, but it’s a completely different thing to see it happen,” Ruf said. “Data on microplastics available in the past. Is just a very sparse, non-reproducible, short snapshot. “

Researchers have created visualizations that show the concentration of microplastics in the world. Often times, the storage area is due to local water flow and convergence areas, with the Great Pacific Garbage Patch being the most extreme example.

“What is remarkable about plumes in large estuaries is that they are sources of marine emissions, as opposed to places where microplastics tend to accumulate,” Ruf said.

This information could help organizations that remove microplastics to deploy ships and other resources more efficiently, Ruf says. The researchers have already spoken to the Dutch cleaning organization The Ocean Cleanup and are working together to validate the team’s early findings. Single point emission data reveals the emissions of microplastics to the world’s waters. It could also be useful for UNESCO, a United Nations agency sponsoring a working group, to find new ways to follow.

Plastic pollution hurricane satellite

Developed by UM undergraduate Ruf and Madeline Evans, this tracking method uses existing data from CYGNSS, eight microsatellite systems launched in 2016, near the center of a large storm system. Monitor your weather and strengthen your forecast of its severity. Raff leads the CYGNSS mission.

Key to the process is the roughness of the sea surface, which CYGNSS has already measured using radar. The measurements were primarily used to calculate the wind speed near the eyes of a hurricane, but I suspected that Ruf might have other uses as well.

“I used to take radar measurements of surface roughness and use it to measure wind speed, but I knew that the presence of objects in the water would alter the response to the environment. “said Ruf. .. “Therefore, I came up with the idea of ​​doing everything in reverse, using reactive changes to predict the presence of objects in the water. “

Using independent measurements of NOAA wind speed, the team searched for a less rugged location. wind speedThey then compared these areas with actual observations from current models that predict the movement of plankton trawlers and microplastics. They found a strong correlation between smoother areas and areas with more microplastics.

Raff’s team said changes in ocean roughness cannot be caused directly by microplastics, but by surfactants, a type of oily or soapy compound that reduces the surface tension of liquid surfaces. I think there is. Surfactants tend to accompany microplastics. oceanThis is because it is often released with microplastics and travels through water to be collected in the same way.