The vivid colors in the spring are the result of pigmented archaea in the microbial mats that grow around the edges of the mineral-rich water. The archaea produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids and on the temperature of the water which favors one archaea over another. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green.[8] The center of the pool is sterile due to extreme heat.

[jvandem]

Nice shot