Researchers Measure Record Levels of Microplastic in Arctic Sea Ice

Ice Drift and the Chemical Fingerprint Offer Clues to Origin of Pollutants

The particle density and composition varied significantly from sample to sample. At the same time, the researchers determined that the plastic particles were not uniformly distributed throughout the ice core. “We traced back the journey of the ice floes we sampled and can now safely say that both the region in which the sea ice is initially formed and the water masses in which the floes drift through the Arctic while growing, have an enormous influence on the composition and layering of the encased plastic particles,” relates Ilka Peeken.

The team of researchers also learned e.g. that ice floes, which are driven in the pacific water masses of the Canadian Basin, contain particularly high concentrations of polyethylene particles. Polyethylene is above all used in packaging material. As the experts write in their study, “Accordingly, we assume that these fragments represent remains of the so-called Great Pacific Garbage Patch and are pushed along the Bering Strait and into the Arctic Ocean by the Pacific inflow.”

In contrast, the scientists predominantly found paint particles from ship’s paint and nylon waste from fishing nets in ice from the shallow marginal seas of Siberia. These findings suggest that both the expanding shipping and fishing activities in the Arctic are leaving their mark. The high microplastic concentrations in the sea ice can thus not only be attributed to sources outside the Arctic Ocean. Instead, they also point to local pollution in the Arctic.

Six Predominant Types of Pollutants

The researchers found a total of 17 different types of plastic in the sea ice, including packaging materials like polyethylene and polypropylene, but also paints, nylon, polyester, and cellulose acetate, the latter is primarily used in the manufacture of cigarette filters. Taken together, these six materials accounted for roughly half of all the microplastic particles detected.

According to Ilka Peeken, the sea ice binds all this plastic litter for two to a maximum of eleven years — the time it takes for ice floes from the marginal seas of Siberia or the North American Arctic to reach the Fram Strait, where they melt. But conversely, this also means that sea ice transports large quantities of microplastic to the waters off the northeast coast of Greenland.

Cellulose Particles Instead of Plastic

Environmentally Friendly Microplastic Alternatives in Cosmetics

The researchers can’t yet say whether the released plastic particles subsequently remain in the Arctic or are transported farther south; in fact, it seems likely that the plastic litter begins sinking into deeper waters relatively quickly. Free-floating microplastic particles are often colonised by bacteria and algae, which makes them heavier and heavier. Sometimes they clump together with algae, which makes them drift down to the seafloor much faster, explains AWI biologist and co-author Dr Melanie Bergmann.

The observations made by researchers at the AWI’s deep-sea network Hausgarten in the Fram Strait lend additional weight to this thesis. As Melanie Bergmann relates, “We recently recorded microplastic concentrations of up to 6,500 plastic particles per kilogram of seafloor; those are extremely high values.”

The study was published in the online portal of the journal Nature Communications under the original title below: Ilka Peeken, Sebastian Primpke, Birte Beyer, Julia Guetermann, Christian Katlein, Thomas Krumpen, Melanie Bergmann, Laura Hehemann, Gunnar Gerdts: Arctic sea ice is an important temporal sink and means of transport for microplastic, Nature Communications, DOI: 10.1038/s41467-018-03825-5

(ID:45271826)