Wednesday, March 22, 2017


In snowy places across the globe, “watermelon snow” forms as the summer sun heats up and melts winter’s leftovers. The colorful snow is made up of communities of algae that thrive in freezing temperatures and liquid water, resulting in algal blooms. When these typically green organisms get a lot of sun, they produce a natural type of sunscreen that paints the slopes pink and red. The addition of color to the surface darkens the snow, allowing it to heat up faster, and melt more quickly.

By far, the most common species of snow alga is Chlamydomonas nivalis, which colors snow red or pink. With their pair of front-mounted flagella, they ply the films of water found in melting snow drifts. Midsummer is the best time of the year to see them, if you live in a high-altitude or Arctic clime with snowbanks that stubbornly refuse to yield to the sun.

Yet surprsingly, active C. nivalis cells are not pink when you look at them under the microscope. Here's a closeup alongside a slinky green alga called Euglena. The homely, roundish cells are Chlamydomonas, and you can see both their paired flagella and the cells' various organelles.

Image & info via NYT

Gif source & info:

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