Canary Spring is hot, very hot. Its water is boiling. As hot water flows from hot springs such as this, mats of brilliant color appear –yellow, orange, and green. When shadows of trees move over the surface of this water, it can reflect the sky and appear blue. The color is caused by colonies of photosynthetic bacteria and algae. There are 10,000 thermal features in Yellowstone – hot springs, geysers, mud pots and fumaroles. I built this image around three color layers – the bluish green shadowed foreground with the dead trees jutting in to the spring from the left, the steamy orange middleground, and the brown hills in the background.