by Juliana Kenny
Summer snow in the Arctic, dubbed “watermelon snow” because of its pink hue, has become so prevalent that scientists are hailing it as an important factor in understanding how the planet is warming.
The pink snow gets its color from blooming algae that is normally green, but turns pink as the summer sun grows more powerful to protect itself in the way sunscreen typically does for humans. A study published in Nature Communications says that blooms of snow algae can lead to an albedo decrease of 13% over the course of an Arctic melt season. (Albedo is how much light, or radiation, a surface reflects. So, snow’s albedo is the proportion of radiation the snow’s surface reflects back into the atmosphere.)
The report states:
Here we show that red snow, a common algal habitat blooming after the onset of melting, plays a crucial role in decreasing albedo. Our data reveal that red pigmented snow algae are cosmopolitan as well as independent of location-specific geochemical and mineralogical factors. The patterns for snow algal diversity, pigmentation and, consequently albedo, are ubiquitous across the Arctic and the reduction in albedo accelerates snow melt and increases the time and area of exposed bare ice.
Because albedo change directly affects glacial melt, watermelon snow can give clues as to how climate shifts, and what effect global warming is having on the Arctic. In laymen’s terms: dark snow absorbs more light. Pink snow means that snow is melting more quickly.
Stefanie Lutz, a geobiologist at GFZ German Research Center for Geosciences told the New York Times that she is worried that a “runaway effect” could occur “whereby melting snow would cause algae to bloom, which would darken the snow, causing more to melt, creating more water, which also darkens the snow and feeds the algae, and so on, in a circular pattern of cotton candy-colored surfaces melting,” writes the NYT.
The findings are set to improve our understanding of glacial climate and the crucial rising of sea levels.