Every year, millions of tons of plastic are thrown away, and only a tiny fraction of this waste is properly recycled.
What happened?
To understand how plastic pollution affects the marine environment, researchers at the Woods Hole Oceanographic Institution searched beneath the ocean’s surface.
They found that microplastic particles accumulate in ocean eddies, causing water masses to swirl.
In a study published in the journal Chaos, researchers Larry Pratt and Irina Rypina developed 3D models to better understand underwater collections of microplastic particles.
The pair used a rotating cylinder filled with water to simulate how the ocean and atmosphere move on a large scale. In their setup, the cylinder rotates at a steady speed, while the lid on top can rotate at different speeds.
They determined that vortices typically follow stable, repeating paths, circulating in circles. As Popular Mechanics observes, these vortices are essentially like tornadoes in the water.
“If you just throw a small particle into water at any speed, viscous drag will quickly cause its motion to approximate that of a fluid,” Pratt explained in a statement. “So, a preliminary estimate is that the microplastic particle is simply moving along the fluid trajectory.”
Why are these findings important?
While Platt and Lipina were able to accurately replicate ocean eddies, there’s a complication: Microplastics don’t necessarily move in the same way as water.
Due to their mass and size, they may lag slightly as they move and disrupt the flow of water. This causes them to slowly deviate from the path that a pure water block would normally follow.
“The main thing we need to consider is the effect of small-scale turbulence,” Platt said. “This theory is valid for spherical particles, but most microplastics in the ocean have very irregular shapes.”
“In the near future, we hope this theory will inform sampling strategies and help provide a better understanding of where plastics may be accumulating.”
What measures are being taken to combat plastic pollution?
According to the OECD’s Global Plastics Outlook, the world’s annual plastic production is increasing rapidly.
Only 9% of all plastic waste is properly recycled, with the rest ending up in landfill or littering our environment. But there are ongoing global efforts to combat plastic pollution, including ongoing efforts to pass a United Nations global plastics treaty.
Countries have also developed regional policies to reduce the prevalence of single-use plastics.
“In recent years, growing awareness of plastic pollution has captured the attention of public opinion and paved the way for greater policy intervention,” said OECD Secretary-General Matthias Koeman.
“Many OECD countries and emerging economies have been implementing policies specifically aimed at reducing the negative environmental impacts associated with different stages of the plastic life cycle.”
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