Red snow algae blooms are triggered by alpine shrubs acting as secret nutrient hubs for the water.

Snow algae can turn entire mountain ranges pink and cause them to melt much faster by absorbing more sunlight. These massive blooms do not just grow in place, they are fueled by meltwater flowing from the roots of nearby bushes. The shrubs concentrate nitrogen and phosphorus that allow the algae to explode across the snowpack. This creates a feedback loop where warmer weather grows more shrubs, which feeds more algae, which melts more snow. Understanding this hydrological connection is the only way to predict how fast mountain glaciers will disappear.