On Feb. 3, 2025, scientists from Montana State University reported new knowledge of how ancient microorganisms adapted from a low-oxygen prehistoric environment to the one that exists today. The work builds on more than two decades of scientific research in Yellowstone National Park by MSU professor Bill Inskeep.

The study compared the heat-loving organisms in two Yellowstone thermal features, Conch Spring and Octopus Spring, located in the park’s Lower Geyser Basin. These locations were selected because they are geochemically similar, with one notable exception: Conch Spring is higher in sulfide and oxygen compared to Octopus Spring. For that reason, they were able to focus on two contrasting thermal environments with both low and high levels of oxygen.

Three types of thermophilic microbes – organisms that thrive in high-temperature environments – were found in both springs, whose temperatures hover around 190 degrees Fahrenheit. The paper states that microbes’ lifestyles in their respective environments can shed light on how life evolved prior to and through the Great Oxidation Event, the period roughly 2.4 billion years ago when Earth’s atmosphere transitioned from having almost no oxygen to the nearly 20% oxygen content it has today.

While visually similar, the streamers in Conch and Octopus springs hosted very different collections of microbes. Although three species of microbes were common to both springs, the higher-oxygen Octopus Spring had much greater diversity. That offers insight into how they evolved to thrive in a higher-oxygen world, the scientists said. The study was published in the journal Nature Communications.