How does plastic waste get into the ocean’s garbage spots?

Newswise – WASHINGTON, March 2, 2021 – Tons of plastic waste are released into the ocean every day, and most of it accumulates in the center of specks of trash that tend to float on the surface of the oceans in the center of each of its regions . The most infamous, known as the Great Pacific Garbage Patch, is in the North Pacific.

Researchers in the US and Germany decided to investigate the routes by which debris is transported from the coasts to the middle of the oceans, the relative strengths of different subtropical gyres in the oceans, and how they affect the long-term accumulation of debris.

In Chaos, Philippe Miron, Francisco Beron-Vera, Luzie Helfmann and Peter Koltai from AIP Publishing report on the creation of a Markov chain model of the surface dynamics of the oceans from historical trajectories of surface buoys. Your model describes the probability that plastic waste will be transported from one region of the sea surface to another.

“Surface litter is released from the coast and distributed according to its location’s share of global land-based plastic that ends up in the ocean,” said Miron, a research fellow at the University of Miami. “To observe the long-term distribution of floating debris, stranded debris is injected back into the system after the same distribution. We call this model ‘pollution conscious’ because it models the injection, distribution and recycling of waste within the system.”

Transition path theory enables researchers to identify paths or transition paths that connect a source directly to a destination.

“In this work, we focus on coastal-to-subtropical gyres, from one gyrus to another, and from the gyres to the coast,” said Miron.

Researchers deduced debris paths and examined the stability of garbage stains by quantifying the relationship between them and their ability to hold back garbage.

“We have identified a high probability transition canal connecting the Great Pacific Garbage Patch to the coasts of East Asia, indicating an important source of plastic pollution,” Miron said. “And the weakness of the gyrus in the Indian Ocean as a plastic waste trap is consistent with transition paths that do not converge within the gyrus.”

They found that gyres are generally weakly connected or disconnected from each other.

“In fact, one subtropical gyrus is more likely to export garbage towards the coast in unusually strong winds than to another gyrus,” Miron said.

One of the biggest discoveries the group made is that the subtropical gyrus in the North Pacific attracts most of the debris, which is in line with previous estimates. The South Pacific gyrus is the most consistent as debris has fewer routes into and into other gyres.

“Our findings, including prospects for garbage spots that have yet to be directly or reliably monitored in the Gulf of Guinea and Bay of Bengal, have implications for ocean cleanups,” Miron said. “The reactive pollution routes we have found provide targets for this cleanup, aside from the large rubbish spots themselves.”

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The article “Transition Paths of Sea Debris and the Stability of Garbage Spots” was written by Philippe Miron, Francisco Beron-Vera, Luzie Helfmann and Peter Koltai. It will be released in Chaos on March 2, 2021 (DOI: 10.1063 / 5.0030535). After this date it can be accessed at the following address: https://aip.scitation.org/doi/10.1063/5.0030535.

ABOUT THE JOURNAL

Chaos is dedicated to improving the understanding of nonlinear phenomena in all areas of science and technology and describing their manifestations in a way that is understandable to researchers from a wide range of disciplines. See https://aip.scitation.org/journal/cha.

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