Colorful microbial mats coat terraces of Grand Prismatic Spring in Yellowstone National Park, Midway Geyser Basin, Wyoming, USA.
Colorful microbial mats coat terraces of Grand Prismatic Spring in Midway Geyser Basin, Yellowstone National Park, Wyoming, USA. Grand Prismatic is the largest hot spring in the United States, and the third largest in the world, next to those in New Zealand. Microbial mats of thermophilic (heat-loving) cyano-bacteria and algae thrive here. Yellow, orange, and red pigments are produced by the bacteria as a natural sunscreen. Orange, red, and brown algal mats grow along edges of effluent hot water. Summer mats tend to be orange and red, whereas winter mats become dark green. Yellowstone was the first national park in the world (1872), and UNESCO honored it as a World Heritage site in 1978.Add to Cart Add to Lightbox Download