Snow algae

Snow algae are a group of freshwater micro-algae that grow in the alpine and polar regions of the Earth.

[2] Snow algae are pigmented by chlorophyll and carotenoids and can be a variety of colors depending on the individual species, life stage, and topography/geography.

Primary carotenoids, such as the yellow xanthophyll, are typically used in low concentrations for photosynthesis while still offering some UV protection.

The alga Chlamydomonas nivalis is a very abundant component of red blooms due to its high concentrations of astaxanthin and its derivatives.

[15] Later in the summer, the bloom may switch to orange or red due high production of astaxanthin during low nutrient periods and the snow algae’s more stable cyst stage that they use to over-winter.

These microbial and algal communities cycle globally significant amounts of carbon, nitrogen, iron, and sulfur.