There is probably hardly a habitat on our planet where microplastics are not yet detectable. The tiny particles have even been found in Antarctic snow. However, little is yet known about the extent to which Antarctic animals are affected. A new study has now taken a close look at emperor penguins (Aptenodytes forsteri) from a remote colony in Dronning Maud Land and found no exposure to microplastic particles. The study was published in the journal Science of The Total Environment.
“No evidence of microplastic ingestion in emperor penguin chicks (…) from the Atka Bay colony (…)” – reads the headline of the article on the study. This is extremely good news, which doesn’t happen often when it comes to microplastics. That’s because microplastic particles have so far been detected almost everywhere it has been looked for, including in other Antarctic penguin species (Adélie, Chinstrap, Gentoo and King penguins). However, the penguin studies were conducted in the region with the highest human activity in Antarctica – around the Antarctic Peninsula – where the animals studied may be more affected by local microplastic pollution.
In contrast, the emperor penguin colony in Atka Bay in Dronning Maud Land examined in the current study is located far from areas of high human activity. With about 9600 animals, the colony is one of the ten largest emperor penguin colonies. According to the research team, which includes lead author Clara Leistenschneider of the University of Basel and scientists from the Alfred Wegener Institute, emperor penguins are particularly well suited as bioindicators of regional marine pollution because, unlike other penguin species, they stay exclusively in the Southern Ocean after their first year of life. During the rearing of their chicks, the parents’ range for foraging trips is only 200 kilometers from the colony. Examining the stomach contents of their chicks is therefore an appropriate method to detect microplastics in the regional water masses and food web.
Among other things, the research team wanted to determine the extent to which microplastics have already penetrated the local food web in the remote Weddell Sea/Dronning Maud Land region. In addition, their goal was to capture the hard, indigestible remains of prey animals that may have ingested microplastics in turn and transferred the particles through the food web.
The team examined the contents of the gizzard of 41 penguin chicks that became separated from the warming colony during storms and died. In their analysis, they focused on “large microplastics,” which are larger than 500 microns. They discovered a total of 85 putative microplastic particles, mostly in the form of fibers, which they analyzed in more detail using infrared spectroscopy to determine the material composition of the particles. However, none of the particles turned out to be microplastics. Most were fibers of natural origin and some were shown to have come from the researchers’ clothing, despite appropriate measures.
According to the team of authors, the results suggest that microplastic concentrations in the local food web of the coastal and marginal sea ice regions of the Weddell Sea and Dronning-Maud Land are currently low enough that particles do not accumulate in emperor penguins through food web transfer.
However, the study is only a snapshot and given the ever-increasing plastic production and thus increasing plastic pollution of the oceans, it may only be a matter of time before the emperor penguins in Atka Bay also come into contact with microplastics. Global warming, which poses several other threats to Antarctic wildlife and ecosystems, is doing its part and could make remote regions still covered by sea ice more accessible, which in turn increases human activity and microplastic inputs.
Julia Hager, PolarJournal
Link to the study: Clara Leistenschneider, Céline Le Bohec, Olaf Eisen, et al. No evidence of microplastic ingestion in emperor penguin chicks (Aptenodytes forsteri) from the Atka Bay colony (Dronning Maud Land, Antarctica), Science of The Total Environment, Volume 851, Part 2, 2022, 158314, https://doi.org/10.1016/j.scitotenv.2022.158314
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