According to foreign media new atlas, millions of tons of plastic waste are discharged into the world's oceans every year, but a new study shows that not all waste plastics pass through the sea in the same way. Scientists studying the movement of seafloor sediments have found that so-called underwater "avalanches" are bringing microplastics into the deep sea, which may help researchers better map the distribution of waste in the whole marine environment and help determine the "microplastics hot spots" in the future.
The study, conducted by scientists at the universities of Manchester, Durham University and University of Utrecht in the Holland, looked at the effects of sediment transport on the seabed and described it as the largest current on earth.
For this purpose, the team conducted experiments to mix quartz sand with microplastic fragments and fibers in a flume designed to simulate the sediment flow of the seabed. Then, scientists analyzed how these flows move sediment around and distribute plastic material across the seafloor.
The team's analysis shows that avalanches distribute different types of microplastics in different ways. Microplastic fragments tend to accumulate in the lower part, while the distribution of microplastic fibers is more uniform and the settling time is longer. Scientists believe that this is due to the large surface area of the fibers, which also means that they are more likely to sink into sand particles and eventually deposit in the deep sea floor. "This is in contrast to what we see in the river, where floods wash away the microplastics. Dr Ian Kane said: "as the sediment settles out of the current, the high sediment load in these deep currents causes the fibers to be trapped on the seafloor."
In general, the team believes that it is clear how these sediment streams can transfer large amounts of plastic waste from the near shore to the deep sea. Understanding this distribution can help scientists understand why different animals eat different types and sizes of plastics, learn more about the consequences, and explain how toxins accumulate on the surface of the ocean.
The study was published in the journal Environmental Science and technology.
