Science

The first global view shows seasonal changes and sources

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Each year, an estimated 8 million tonnes of plastic waste flow into the ocean, most of which is shattered by the sun and waves into microplastics (small spots that can ride in ocean currents hundreds or thousands of miles from the point of entry).


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

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 have entered the water, how they are moved, and their tendency to collect.

This approach relies on the Cyclone Global Navigation Satellite System (CYGNSS) and Global view Or magnify a small area to display a high resolution image. Microplastic Release from a single location.

This approach is a significant improvement over current tracking methods that rely primarily on uneven reporting from plankton trawlers that net microplastics with catches.

“We are still early Research processHowever, I hope this will be part of a fundamental change in the way tracking and management is done. Microplastic pollutionChris Ruff, UM’s professor of climate and space sciences at Frederick Baltmann University, a principal investigator at CYGNSS, and a senior author of a newly published treatise on this study, said.

Their first observations are clear.

Seasonal changes in the Great Pacific Garbage Patch

The team found that global microplastic concentrations tend to fluctuate seasonally, peaking in the North Atlantic and Pacific during the Northern Hemisphere summers. 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.

Southern hemisphere concentrations peak in the summer months of January and February. Researchers believe that the combination of strong currents breaking the microplastic plume and an increase in vertical mixing that pushes the microplastic plume below the surface of the water.

The data also showed some short spikes in the concentration of microplastics in the mouth Yangtze River— Long suspected to be the primary source of information.

“It’s one thing to suspect the source of microplastic pollution, but it’s a completely different thing to see it happening,” Ruf said. “The data on microplastics available in the past are very sparse and are just short snapshots that are not reproducible.”

Researchers have created visualizations that show the concentration of microplastics around the world. Sedimentary areas are often due to local water flow and convergence zones, with the Great Pacific Garbage Patch being the most extreme example.

“What’s remarkable about plumes from major estuaries is that they are sources of sea emissions, as opposed to where microplastics tend to accumulate,” Ruf said.

This information could help organizations that remove microplastics deploy ships and other resources more efficiently, Ruf says. Researchers have already talked to the Dutch cleanup organization The Ocean Cleanup and are working together to validate the team’s first findings. Single-point emission data for microplastics into the world’s waters. It may also be useful for UNESCO, a UN agency sponsoring a task force to find new ways to track emissions.

Hurricane tracking satellite aimed at plastic pollution

Developed by Ruf and UM undergraduate 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 predictions of its severity. Raff leads the CYGNSS mission.

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

“I used to take radar measurements of surface roughness and use it to measure wind speeds, but I knew that the presence of objects in the water would alter the response to the environment,” Ruf said. I will. “Therefore, I got the idea of ​​doing everything in the opposite direction, using responsive changes to predict the presence of objects in the water.”

Using independent wind speed measurements from NOAA, the team looked for places where the ocean looked less rough than it should be. wind speedThey then compared those areas with actual observations from plankton trawlers and current models that predict the movement of microplastics. They found a high correlation between smoother areas and areas containing more microplastics.

Raff’s team said that changes in ocean roughness could not 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 in water to collect in the same way.


Studies reveal the complexity of microplastic contamination


For more information:
Madeline C. Evans et al. For the detection and imaging of marine microplastics with space-borne radar IEEE Transactions on Earth Sciences and Remote Sensing (2021). DOI: 10.1109 / TGRS.2021.3081691

Quote: Marine Microplastics: The first global view showing seasonal changes and sources (June 10, 2021) was on June 10, 2021 https://phys.org/news/2021-06-ocean-microplastics- Obtained from global-view-seasonal.html.

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https://phys.org/news/2021-06-ocean-microplastics-global-view-seasonal.html The first global view shows seasonal changes and sources

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