Thermophiles in Time and Space

Mars' Burns Cliff view of rock layers.
Yellowstone environments show how mineralization preserves biosignatures of thermophilic communities, which could help scientists recognize similar signatures elsewhere. These layers of rock on Mars have minerals and features developed by interactions between liquid water and rocks over time. This evidence does not prove life developed on Mars, but it brings the possibility one step closer to reality.

Photo and caption adapted from, image by NASA/JPL


To Mars—and Beyond?

The hydrothermal features of Yellowstone and their associated thermophilic communities are studied by scientists searching for evidence of life on other planets. The connection is extreme environments. If life began in the extreme conditions thought to have been widespread on ancient Earth, it may well have developed on other planets—and might still exist today.

The chemosynthetic microbes that thrive in some of Yellowstone’s hot springs do so by metabolizing inorganic chemicals, a source of energy that does not require sunlight. Such chemical energy sources provide the most likely habitable niches for life on Mars or on the moons of Jupiter—Ganymede, Europa, and Callisto—where uninhabitable surface conditions preclude photosynthesis. Chemical energy sources, along with extensive groundwater systems (such as on Mars) or oceans beneath icy crusts (such as on Jupiter’s moons) could provide habitats for life.


Similar Signatures

Thermophile communities leave behind evidence of their shapes as biological “signatures.” For example, at Mammoth Hot Springs, rapidly depositing minerals entomb thermophile communities. Scientists compare these modern signatures to those of ancient deposits elsewhere, such as sinter deposits in Australia that are 3.5 billion years old. These comparisons help scientists better understand the environment that supported life on early Earth, and give
them an idea of what to look for on other planets.

Yellowstone National Park will continue to be an important site for studies at the physical and chemical limits of survival. These studies will give scientists a better understanding of the conditions that give rise to and support life, and of how to recognize signatures of life in ancient rocks and on distant planets.

Timeline showing the dominant forms of life during earth's history
Yellowstone’s hydrothermal features contain modern examples of earth’s earliest life forms, both chemo- and photosynthetic, and thus provide a window into earth’s ancient past. Based on life on earth, the search for life on other planets seems more likely to encounter evidence of microorganisms than of more complex life. Yellowstone hydrothermal communities reveal the extremes life can endure, providing clues to environments that might harbor life on other worlds.



Source: Data Store Collection 7681. To search for additional information, visit the Data Store.

Archaea are found in place like the mudpots of Mud Volcano.
Thermophilic Archaea

Archaea are the most extreme of all extremophiles.

Traverine terraces of Mammoth Hot Springs host thermophilic bacteria.
Thermophilic Bacteria

Almost all hot springs and geysers host thermophilic bacteria.

Green colors line a thermal runoff pool.
Thermophilic Eukarya

Microscopic plants and animals live in the extreme environments of Yellowstone's hydrothermal features.

Blue waters of Congress Pool are host to thermophilic viruses.
Thermophilic Viruses

Viruses, a logical part of thermophilic ecosystems, have been found in some pools in Yellowstone.

Orange-colered bacterial column growing in geyser runoff water.
Thermophilic Communities

Thermophilic communities are very diverse, depending on the microbes living there, the pH, and the water temperature.

A dark blue hot spring with a white crested edge rimmed by orange water.
Life in Extreme Heat

Hydrothermal features are habitats for microscopic organisms called thermophiles: "thermo" for heat, "phile" for lover.

Last updated: August 14, 2023

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