Blood snow, or watermelon snow, has been recognized since the days of Aristotle, but the problem is that climate change continues to accelerate that process and earth's ice caps are starting to look like a blood bath. The plantlike cells that give the snow its pink pigment is snow algae, and it's drawing heat to the ice caps.
It's a viscous cycle, according to one study by a team of researchers from the University of Leeds and the GFZ German Research Centre for Geosciences.
Using high-throughput sequencing, the team analyzed 40 samples from red snow sites in four regions that are "well-separated and physico-chemically diverse Arctic settings." What they found was a runaway effect, led by the algae and augmented by other impurities like ice caps.
The heat-hungry algae sit atop the ice caps and use their absorptive pigment to draw heat to themselves, and the ice as a result. The more the ice melts, the more favorable conditions are for more algae to do more damage.
The effect can be compared with wearing dark clothes in the sun instead of lighter apparel or T-shirts, according to Stefanie Lutz, a geobiologist at GFZ German Research Centre for Geosciences.
"It is the same for the snow: More heat means more melting," Lutz said.
Snow, seasonal and permanent, covers up to 35 percent of the planet's surface, during most of the year. But during spring and summer, snow algae, the "prolific primary colonizers and producers" that they are, begin to bloom, according to the paper generated from the study.
"Such snow algal blooms can substantially darken the surface of glaciers because of their red pigmentation (secondary carotenoids), which the algae produce as a protection mechanism (for example, from high levels of irradiation)," the paper stated.
The researchers found that red snow can reduce the ice caps' ability to reflect light by up to 20 percent, a process known as "bio-albedo." The subject of bio-albedo and the potential for organic matter to impact light reflect have been a niche topic for years, according to Daniel Remias, biologist at the Fachhochschule Wels, Austria.
"For the first time ever, researchers have investigated the large-scale effect of microorganisms on the melting of snow and ice the Arctic," Remias said, later adding that the study, for the first time, "combines microbiological and genetic analyses of red snow algae with geochemical and mineralogical properties as well as with the albedo of their habitat."