These red algae colored snow

The immense glaciers of our mountains, composed of snow which turns into ice over the centuries, offer a white surface which sometimes dangerously dazzles the mountaineers who walk them.

But this whiteness is very relative: the dust and the sediments carried away by the glacier often come to dirty the snow. And what about these reddish sandy dust from time to time from the Sahara, which cover the surface with an amazing ocher color?

Cold -resistant microscopic algae

But even more astonishing is a natural flowering that manifests itself in spring, in the form of blood red spots. This flowering betrays the presence of unexpected hosts: microscopic algae, very resistant to cold, and which develop thanks to seasonal snow deposited on the glacier. After a long period of ice melting, Sanguina nivaloideS- This is his name – takes advantage of a snowy mantle full of liquid water to develop quickly.

Like their large marine cousins, these algae implement a very active photosynthesis in the spring: dedicated collecting pigments use light energy to produce essential chemical compounds. The rest of the time, especially in contact with the frozen soil, they freeze in the form of cysts, packaged in a protective shackles. Until the next spring bleeding.