The Arctic is one of the most fragile regions on Earth, and it is one of the regions struggling most not only with climate change, but also with plastic pollution. Both weaken Arctic ecosystems simultaneously, threatening Arctic biodiversity. A new international review study by the Alfred Wegener Institute shows how affected the Arctic and the organisms that live there are by pollution from plastic and microplastics, where the plastic parts come from and the routes by which they enter and are transported within the Arctic. The study appeared in the journal Nature Reviews Earth & Environment.
The review study, which summarises the results of numerous previous studies, makes it clear: plastics and microplastics are detectable virtually everywhere in the Arctic, be it in the atmosphere, in snow, in ice, on surface of the ocean and in the deep sea, on beaches, in rivers and in humans and animals. Although the Arctic is relatively sparsely populated, the level of pollution is similar to that in densely populated regions.
“The Arctic is still assumed to be a largely untouched wilderness,” says AWI expert Dr Melanie Bergmann, the lead author of the study. “In our review, which we jointly conducted with colleagues from Norway, Canada and the Netherlands, we show that this perception no longer reflects the reality. Our northernmost ecosystems are already particularly hard hit by climate change. This is now exacerbated by plastic pollution. And our own research has shown that the pollution continues to worsen.”
Sources and transport routes of plastic in the Arctic
The question of the origin of plastic in the Arctic, as in many other parts of the world, is anything but quickly answered, because there are not the one or two sources from which plastic pollution originates. In the study, the authors distinguish between local and distant sources.
One of the main local sources of plastic waste is communities in the Arctic, where household waste is often collected in open dumps and wastewater is not treated sufficiently — or not treated at all. Shipping is anohter source; fishing in particular contributes enormously to plastic pollution in the Arctic. Nets and lines that are accidentally lost or intentionally discarded in the ocean are especially problematic. In addition, small fragments that are produced when repairing the nets are often simply thrown overboard. The majority of plastic waste in the European Arctic therefore comes from fishing; an earlier AWI study determined that, in some cases, all of the plastic waste washed up on a beach on Spitsbergen came from fishing vessels.
From more distant sources, plastic is transported to the Arctic Ocean via ocean currents from the Atlantic Ocean, the North Sea and, yo a lesser extent, the Pacific Ocean. Rivers, including those running through Siberia, also carry large amounts of plastic from the continent into marine habitats. Microplastics they carry freeze in the sea ice during the winter, and when the ice breaks up in the spring, they are transported with the ice floes via the Transpolar Drift into the Fram Strait between Svalbard and Greenland. In summer, the ice melts and releases the plastic particles into the seawater. Not surprisingly, the seafloor of Fram Strait contains between about 6,600 and 13,300 microplastic particles per kilogram of sediment. Small and light particles such as micro- and nanoplastics from tyre wear or cigarette filters are also carried in the atmosphere to the Far North, where they settle on snow and ice or enter the water directly.
The ecological impact
“Unfortunately, there are very few studies on the effects of the plastic on marine organisms in the Arctic,” Bergmann explains. “But there is evidence that the consequences there are similar to those in better-studied regions: in the Arctic, too, many animals — polar bears, seals, reindeer and seabirds — become entangled in plastic and die. In the Arctic, too, unintentionally ingested microplastic likely leads to reduced growth and reproduction, to physiological stress and inflammations in the tissues of marine animals, and even runs in the blood of humans.”
The best studied are seabirds and it has long been known that they ingest plastic. Birds that forage at the ocean surface, such as northern fulmars (Fulmarus glacialis), ingest particularly large amounts of plastic and microplastics. Both macro- and microplastics have also been found in marine mammals such as sperm whales, belugas, bowhead whales and various seal species.
Not only are the plastic pieces themselves dangerous to the animals, in that they can block or injure their digestive tracts, but also the pollutants that adhere to the plastic and are released into the animals’ bodies. These include additives added to plastics, such as plasticisers, and persistent organic pollutants such as pesticides, solvents, drug residues and other industrial chemicals. Each of these substances in itself has the potential to interfere with hormonal balance and / or early development of animals and / or to cause genetic changes. A cocktail of these pollutants is even more dangerous.
Plastic pollution and climate change
So far, there are hardly any studies on interactions and feedback effects between plastic waste and climate change. Dr Bergmann therefore sees an urgent need for research here, because “initial studies indicate that trapped microplastic changes the characteristics of sea ice and snow.” Many dark particles in the ice, such as from tyre wear, could cause it to absorb more sunlight and thus melt faster. And less ice means that less solar radiation is reflected and more is absorbed by the ocean, which increases global warming (also known as ice-albedo feedback).
In addition, the tiny plastic pieces act as condensation nuclei for cloud formation and rain, thus influencing the weather and, in the long term, the climate. Not to mention the emissions that plastic causes throughout its life cycle, from oil extraction to transportation, refining, manufacturing, and disposal or decomposition in the environment, releasing climate-changing gases. Plastic currently contributes 4.5% to global greenhouse-gas emissions.
“Our review shows that the levels of plastic pollution in the Arctic match those of other regions around the world. This concurs with model simulations that predict an additional accumulation zone in the Arctic,” Dr Bergmann explains. “But the consequences might be even more serious. As climate change progresses, the Arctic is warming three times faster than the rest of the world. Consequently, the plastic flood is hitting ecosystems that are already seriously strained. The resolution for a global plastic treaty, passed at the UN Environment Assembly this February, is an important first step. In the course of the negotiations over the next two years, effective, legally binding measures must be adopted including reduction targets in plastic production. In this regard, the European countries including Germany must cut their plastic output, just as the rich Arctic states have to reduce pollution from local sources and improve the often virtually non-existent waste and wastewater management in their communities. In addition, more regulation and controls are called for with regard to plastic debris from international shipping and fisheries.”
Julia Hager, PolarJournal
Link to the study: Melanie Bergmann, France Collard, Joan Fabres, Geir W. Gabrielsen, Jennifer F. Provencher, Chelsea M. Rochman, Erik van Sebille, Mine B. Tekman: Plastic pollution in the Arctic. Nature Reviews Earth & Environment (2022). DOI: 10.1038/s43017-022-00279-8
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