A print photograph taken in 2018 and published on May 19, 2020 by the University of Cambridge and Matthew Davey shows researcher Andrew Gray geotagging snow algae blooming on Anchorage Island near Davis Station in Antarctica.
Penguins and snow. That's the image that comes to people's minds when they think of Antarctica. Look for photos online and you will get glacial landscapes that are mostly white. But it turns out that the southernmost continent is no longer as monochromatic as we think. It's turning green, and all because of climate change.
In addition to the melting of ice sheets and the death of penguins, global warming is also causing the snow in Antarctica to turn green, according to a new report published in the scientific journal Nature Communications on Wednesday, May 20. In some areas, the green hue is even visible from space. This is the result of algae blooms: As rising temperatures turn solid ice into hail, aquatic organisms like algae thrive on melting snow.
Despite being the driest continent, there is actually some plant life in Antarctica. Mosses and lichens are the two largest types of photosynthetic organisms visible there. They are also the most studied. While previous explorers have observed the presence of algae in Antarctica, they have never been the subject of large-scale research - until now.
Using satellite imagery collected over two years by the European Space Agency's Sentinel-2, as well as observation on the ground, researchers from the University of Cambridge and the British Antarctic Survey observed 1,679 separate blooms of green algae on the Antarctic Peninsula, which is equivalent to a total area of 1.9 square kilometers.
While 1.9 square kilometers of land mass doesn't seem all that significant, Matt Davey, an algae physiologist at the University of Cambridge, told AFP that “in Antarctica, where there is such a small amount of plant life, that amount of biomass is very significant. "
Compared to the rest of the planet, polar regions like Antarctica are experiencing much faster warming. As global temperatures continue to rise, the amount of algal blooms will likely increase as well. This means even more green snow.
The new report suggests that microscopic algae can help reduce carbon dioxide levels in Antarctica (estimating the amount of carbon dioxide absorbed by algae is equivalent to 875,000 average UK gasoline car trips), but experts believe that the effect will not be significant.
Increased algal blooms could also reduce local albedo, a measure of how well a surface reflects radiation from the sun. While white snow can reflect 80 percent of the radiation on its surface, green snow only reflects about 45 percent. Reduced Albedo means more radiation is absorbed, causing the temperature to rise. However, the researchers do not believe that this significantly affects Antarctica's climate.
Photo of the brochure taken in 2018 and published by the University of Cambridge on May 20, 2020, showing snowy green algae near Rothera Research Station, at Rothera Point, Antarctica.
What algae blooms can do is create new habitats or even a new ecosystem, due to its interaction with existing organisms. The team of researchers discovered that algae have already formed close links with some fungal spores and bacteria, and that most algal blooms are found near penguin colonies, where bird droppings serve as fertilizer.
"Studies like ours are really important as they increase our understanding of the complex connections between these species and the more we understand, the more we can protect our planet and these fragile ecosystems that could be lost or changed forever," Davey said in a video from YouTube published by the University of Cambridge.
The researchers plan to carry out similar studies for the red and orange algae in the future to map the flowers across the continent.