The Red Snow Mystery

In summertime, perpetual snow fields on high mountains are sometimes tinged with a color that is a mixture of red and pink. This incredible phenomenon is caused by snow algae, which are unicellular members of green algae that change color by producing carotenoids for protection against the high UV radiation and therefore appear red. Snow algae are able to survive the extreme conditions of alpine and polar snow fields. They even have the unique ability to actively live at a temperature of approximately 0 °C with very low nutrient levels. Conversely, most other plants in these conditions either reduce their metabolic activities or are simply unable to survive.