A bit of left over snow often remains even after a particularly hot summer. If we examine the snow more closely, the surface appears somewhat red. It’s not, as you might guess, sand from the Sahara desert. Nor is it blood. It is in fact a type of algae (chlamydomonas nivalis) that thrives in snow. If you examine the snow under a microscope, the single algae cells appear dark red or orange and are easy to recognise. The colouring protects the cells from the intense UV radiation present in high-Alpine environments. Their “orange glasses” serve to protect genetic material and ensure survival. The organism is well suited to the cold. The cells prefer temperatures just below 0°C. If we were to take them with us into the valley, they would soon perish.