Heat-loving or thermophilic bacteria (pictured here in orange and yellow) thrive in the extreme environment of hot springs such as this one in Yellowstone National Park. The microbes, which include photosynthetic cyanobacteria, form extensive multispecies communities called microbial mats that can be seen with the naked eye. Over time, the microbial mats interact with minerals in the water, forming hardened structures called microbialites—part rock, part microbe (pictured here as white pearl-shaped structures). This is an ancient process—the oldest fossil microbial mats, called stromatolites, are estimated to be around 3.5 billion years old.
For more on the amazing worlds of microbes watch “I Contain Multitudes”
This photograph was captured along the edge of a thermal stream flowing out from Octopus Spring, a hot spring in Yellowstone National Park, Wyoming, U.S.A.
Scott Chimileski, PhD and Roberto Kolter, PhD, Harvard Medical School, Boston, MA.
As seen in Life at the Edge of Sight: A Photographic Exploration of the Microbial World, Harvard University Press, 2017.