Snow algae are a group of green algae (Chlorophyta) that look red because they make pigments that are bright colors. These pigments protect snow algae from damaging their photosynthetic machinery in the intense light of their alpine environments. Some snow algae produce pigments that are orange or green, so if you see pink, red, orange, or green snow, it’s likely algae growing.
Snow algae are complex cells (eukaryotes, cells with a nucleus) and are just one part of a snow microbiome. Although you can’t see it, there is also a thriving community of microbes present including bacteria, fungi, and single-cell predators that eat algae and bacteria.
Don’t be fooled by Wikipedia and other sources that say all pink snow is the species Chlamydomonas nivalis. There are many different snow algae species described by researchers around the world, and many algae once called Chlamydomonas nivalis have been renamed into other groups. One goal of our work at the Living Snow Project is to help describe snow algae species and their distribution across space and time.
To learn more about the basics of snow algae and why we study it, see this short talk by LSP founder and director, Dr. Robin Kodner, for the Northwest Avalanche Center annual snow science meeting in 2017.