At this time of year it is summer in Antarctica, which means season of record temperatures (there has been a nine-day heat wave this month) and, sadly, also a time of increased glacial melt as a reminder of our changing weather. However, snow that appears to be spattered with blood has appeared on the Antarctic Peninsula in recent weeks. What is this sinister-looking blood-red snow?
Researchers located at the Vernadsky Research Base of Ukraine (located on Galindez Island, off the coast of the northernmost peninsula of Antarctica) observed that the ice around the base had passed from the pristine white desert to be seen. covered in what scientists know as “watermelon snow.” The Ukrainian Ministry of Education and Science has published several photographs that perfectly illustrate this red and pink snow that seems to cut the edges of glaciers and even areas where reddish puddles appear on the frozen plains.
What causes this watermelon snow?
Although the images shock us, it is a common phenomenon in snow fields around the planet. “Watermelon snow” has a culprit: a toxic microscopic algae called Chlamydomonas nivalis that thrives in freezing temperatures. The germination of this colony of algae is quite fast, so it spreads quickly. The algae produce spores that cope with low temperatures and remain alive in the snow . They love the cold and they are the equivalent of algae that we can find in rivers but with a different hue.
But why does it look pink or red? Because in addition to the chlorophyll that we all know for its characteristic green color, they have a reddish pigment (red carotene, astaxanthin) in their gelatinous envelope that serves as a shield against ultraviolet radiation and thus preserve them from genetic mutations. Microscopic organisms have been found in snow all over the planet for thousands of years; in fact, Aristotle himself wrote it down in the 3rd century BC. C. These algae remain dormant in the snow during the winter, but when the weather warms up, as is the case right now in the Antarctic summer (between October and February), the spores are exposed to sunlight and begin to grow as if from flowers will try to produce this phenomenon worthy of a horror movie. This is the reason why the snow turns a reddish-pink color.
” This snow contributes to climate change, because the raspberry-red snow reflects less sunlight and melts faster,” explains the biologist of the Ministry of Education and Science of Ukraine Andriy Zotov. “As a result, more and more shiny algae form in the snow.” The more ice that melts, the faster the algae can spread. That, in turn, leads to more warming, more melting, and more algal blooms.
Physics doctor Mar Gómez explained on Twitter the consequences of this event:
When the cold temperatures return with winter, the algae go dormant and the red tint disappears. This phenomenon can be observed in the Arctic, the Alps and other high mountain ecosystems .
Although we have seen this snow in red and also pink, single-celled organisms can also appear in different colors, including green and, less frequently, orange. And everything seems to indicate that, probably, we will see more events like this as the weather changes.
