Microbes Found In Yellowstone’s Hot Springs Are Showing Us How Prehistoric Life Survived With No Oxygen
After more than two decades of analysis, researchers from Montana State University have finally revealed how three microbes from two different hot springs in Yellowstone National Park evolved from living in a prehistoric low-oxygen environment to the one that exists today.
They hope it can shed some light on the evolution of life before the Great Oxidation Event occurred 2.4 million years ago when the Earth’s atmosphere only contained about two percent oxygen. Afterward, it jumped to 20 percent.
According to the study authors, Conch Spring and Octopus Spring were chosen for microbe extraction because they shared geochemical similarities.
Conch Spring has higher amounts of sulfide and oxygen than Octopus Spring. The difference allowed the researchers to compare the three microbes at both high and low oxygen levels.
The microbes were thermophilic, meaning they thrived in heat. Each spring was about 190 degrees Fahrenheit.
“When oxygen started to increase in the environment, these thermophiles were likely important in the origin of microbial life,” said Bill Inskeep, a professor in the Department of Land Resources and Environmental Sciences at Montana State.
“There was an evolution of organisms that utilized oxygen. Octopus has more oxygen, and sure enough, there’s more aerobic organisms there. These environments have different casts of characters.”
The research team analyzed the microbes aquificota, Pyropristinus, and Thermoproteota. They were all found on “streamers,” green, stringy algae that attaches to rocks and other objects in the rapid water currents in which they live.
The team looked at respiratory genes in each microbe and compared them. They found that the genes of the low-oxygen microbes from Conch Spring were more active.
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Meanwhile, the genes of the microbes from the higher-oxygen Octopus Spring showed greater diversity. This shows how they were able to adapt to higher oxygen levels. Depending on their environmental conditions, the organisms could switch between different metabolic strategies.
The research represents over 20 years of scientific investigation in Yellowstone National Park. By assessing the genes these microbes express in different environments, the researchers have been able to determine how early life may have adapted as the Earth’s atmosphere shifted.
“It would be very difficult to reproduce this kind of an experiment in the laboratory; imagine trying to [create] hot-water streams with just the right amounts of oxygen and sulfide,” said Inskeep.
“And that’s what’s so nice about studying these environments. We can make these observations in the exact geochemical conditions that these organisms need to thrive.”
Modern hot springs cannot replicate the ancient conditions of Earth with complete accuracy, but they still demonstrate the remarkable ability of microbial life to adapt and survive based on available resources.
The details of the full study were published in the journal Nature Communications.
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