The Color of Heat

25” by 23”

by Vicki Conley

The intense blue color at the center of Grand Prismatic Spring in Yellowstone National Park is a result of water temperatures as high as 189 degrees. Not much can live at temperatures this extreme, so it is very clear. As the water cools near the edges of the spring, conditions become just right for single-celled thermophiles, including cyanobacteria, that can generate energy through photosynthesis. Cooler temperatures increase bacterial diversity dramatically creating the orange and ultimately the reddish brown areas. It is amazing to me how the cellular processes in these microorganisms paint the landscape in such vibrant colors.