Glacier Blood? Watermelon Snow? Whatever It’s Called, Snow Shouldn’t Be So Red.

Researchers are starting to investigate the species that drive alpine algal blooms to better understand their causes and effects.

Winter through spring, the French Alps are wrapped in austere white snow. But as spring turns to summer, the stoic slopes start to blush. Parts of the snow take on bright colors: deep red, rusty orange, lemonade pink. Locals call this “sang de glacier,” or “glacier blood.” Visitors sometimes go with “watermelon snow.” In reality, these blushes come from an embarrassment of algae. In recent years, alpine habitats all over the world have experienced an uptick in snow algae blooms — dramatic, strangely hued aggregations of these normally invisible creatures. While snow algae blooms are poorly understood, that they are happening is probably not a good sign. Researchers have begun surveying the algae of the Alps to better grasp what species live there, how they survive and what might be pushing them over the bleeding edge. Some of their initial findings were published this week in Frontiers in Plant Science.