When you walk through the hot springs of Yellowstone National Park, you may find extreme environments. However, they could also be a host to a wild diversity of microbes that might give some insight into the evolution of life on Earth as well as in the far-off planets.
Extremely high temperatures of hot springs cannot be tolerated by photosynthetic life. However, chemosynthetic microorganisms that are dependent only on chemicals, not the sun, for energy still survive in such environments. These amazing microbes might survive and are thought to be the nearest modern relatives to the planet's early life.
"Chemosynthetic microorganisms provide useful models for understanding how life might persist in extraterrestrial systems, like the subsurface of Europa, for instance, where light energy will not be available but abundant sources of chemical energy might be," said Daniel Colman, a geomicrobiologist at Montana State University in Bozeman.
It was in 2014 that Colman and his colleagues gathered samples from chemosynthetic microbial groups in 15 hot springs at Yellowstone National Park. These are complex environments with a wide availability of nutrients within the hot spring. The team examined how the variations could affect chemosynthetic groups without oxygen at a particular area, according to Phys.org.
Colman and his team's study was titled "Ecological differentiation in planktonic and sediment-associated chemotrophic microbial populations in Yellowstone hot springs," in the journal FEMS Microbiology Ecology. The team examined microorganisms that were planktonic, or free-swimming, or those who lived in sediment. The scientists then looked at the chemistry of the water as well as the sediments' mineralogy. Yellowstone bacteria are microaerophiles. They require oxygen but at low concentrations compared to those in the Earth's atmosphere. On the other hand, sediment communities in Yellowstone show a predominance of chemosynthetic microbes relying on inorganic substances for oxidants, such as elemental sulfur or oxidized iron.
Researchers surmise that during early evolution, early life was limited by the availability of oxidants. They had to survive only with whatever was available. This could be similar to extra-terrestrial settings on places like Europa.
"These environments are understudied in astrobiology research, but hold tremendous promise as accessible analogs for extraterrestrial habitable environments that might be present on Enceladus, Mars, or Europa," Colman said.
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