Scientists find alarming levels of toxic microplastics in Arctic

By Mark Waghorn via SWNS

Algae floating in the Arctic is packed with tiny bits of plastic that are toxic to humans, according to new research.

Levels are ten times higher as the surrounding seawater. Krill consume the simple aquatic plants that move up the food chain - onto our dinner plates.

Microplastics, under five millimeters long, are eaten by filter feeders and passed to fish, seabirds and polar bears.

Marine animals may be more exposed than previously feared. They depend on krill to survive the harsh climate.

The findings are based on an analysis of algae Melosira arctica, the most common species that grow under sea ice.

This concentration at the base of the food web poses a threat to creatures that feed on algae at the surface.

Clumps of dead algae also transport the plastic with its pollutants particularly quickly into the deep sea.

Lead author Dr. Melanie Bergmann, a biologist at the Alfred Wegener Institute in Bremerhaven, Germany, said: "We have finally found a plausible explanation for why we always measure the largest amounts of microplastics in the area of the ice edge, even in deep-sea sediment.

"The speed at which the Alga descends means that it falls almost in a straight line below the edge of the ice.

"Marine snow, on the other hand, is slower and gets pushed sideways by currents so sinks further away.

"With the Melosira taking microplastics directly to the bottom, it helps explain why we measure higher microplastic numbers under the ice edge."

Melosira arctica grows at a rapid pace during spring and summer - forming meter-long cell chains there.

The cells stick to the underside of the ice. When they die and it melts, clumps can sink several thousand meters to the bottom of the deep sea within a single day.

There they form an important food source for bottom-dwelling animals and bacteria. But as well as food, they transport dangerous cargo - microplastics.

An international team collected samples during an expedition on the research vessel Polarstern in the summer of 2021.

Surprisingly, the clumps of algae contained an average of 25,000 microplastic particles per cubic meter - about ten times more than the surrounding water.

Co-author Dr. Deonie Allen, of the University of Canterbury, said: "The filamentous algae have a slimy, sticky texture, so it potentially collects microplastic from the atmospheric deposition on the sea, the seawater itself, from the surrounding ice and any other source that it passes.

"Once entrapped in the algal slime they travel as if in an elevator to the seafloor, or are eaten by marine animals."

It sheds fresh light on widespread microplastics identified in zooplankton that inhabit the ice.

The organisms are eaten by cod which are eaten by seabirds and seals - and these in turn by polar bears.

The detailed analysis showed a variety of different plastics are found in the Arctic, including polyethylene, polyester, polypropylene, nylon, acrylic and many more.

In addition to various chemicals and dyes, this creates a mix of substances whose impact on the environment and living creatures is difficult to assess.

Dr. Bergmann said: "People in the Arctic are particularly dependent on the marine food web for their protein supply, for example through hunting or fishing.

"This means they are also exposed to the microplastics and chemicals contained in it.

"Microplastics have already been detected in human intestines, blood, veins, lungs, placenta and breast milk and can cause inflammatory reactions, but the overall consequences have hardly been researched so far."

Microplastics are released directly into the ocean by the gradual breakdown of larger pieces.

They also enter the sea from health and beauty products, washing synthetic textiles and abrasion of car tires.

They can be carried on currents from the huge garbage patch in the Pacific or arise locally due to pollution from shipping and fishing.

Co-author Dr. Steve Allen, of Dalhousie University in Canada, said: "Micro and nano plastics have basically been detected in every place scientists have looked in the human body and within a plethora of other species.

"It is known to change behaviors, growth, fecundity and mortality rates in organisms and many plastic chemicals are known toxins to humans."

Moreover, the Arctic ecosystem is already threatened by the profound environmental upheavals caused by the climate crisis.

If the organisms are now additionally exposed to microplastics and the chemicals they contain, it can weaken them further.

Dr Bergmann added: "So, we have a combination of planetary crises that we urgently need to address effectively.

"Scientific calculations have shown that the most effective way to reduce plastic pollution is to reduce the production of new plastic.

"This should therefore definitely be prioritized in the global plastics agreement that is currently being negotiated."

The study was published in the journal Environmental Science and Technology.