The odd reddish hue found in mountain snow is caused by green algae. Algae is one of the most diverse and ubiquitous forms of life on Earth, so it’s not particularly surprising that it has managed to find its way to some of the highest peaks in the world. However, the climate crisis is accelerating snowmelt and glacial retreat in these habitats, a trend that may upend many algal colonies and the larger ecosystems that rely on them.
That’s why European scientists have banded together to form ALPALGA, a collaboration that aims to better understand these alpine algae, which can act as primary producers, pioneer species, and “potential markers of climate change,” according to a study published on Monday in Frontiers in Plant Science. “I’ve seen, in my lifetime, the disappearance of ecosystems on a scale not of 100 years, but decades,” said study author Eric Maréchal, director of the Cell and Plant Physiology Laboratory, a joint unit of CNRS, CEA, INRA and University Grenoble Alpes, in a call. “This ecosystem is super fragile.”
In a way, the fragility of these systems is counter-intuitive, because the algal blooms that produce these alpine stains of red, purple, and orange are actually a sign of flourishing life. The eerie biological dye goes by many names—watermelon snow or red snow, for instance—and it is common on mountain tops and glaciers around the world, from the Sierra Nevada, to the Himalayas, to Greenland’s ice sheets, sparking speculation among mountaineers, naturalists, and polar explorers for centuries.
Scientists now know the effect is a microalgal adaptation strategy to the onset of summer, which brings with it snowmelt and intense sunshine and UV radiation. Green algae are green, as the name implies, but warmer weather triggers them to produce a red carotenoid pigment as a kind of sunscreen.
Jesus: Hey, Dad? God: Yes, Son? Jesus: Western civilization followed me home. Can I keep it? God: Certainly not! And put it down this minute--you don't know where it's been! Tom Robbins in Another Roadside Attraction