Yellowstone National Park is teeming with life.
Elk herds numbering in the thousands wander in and out of its borders each year. Families of bison wander meadows and eagles soar above. Bears, wolves and mountain lions eke out an existence in the forests and valleys.
That’s the life we can see with our naked eye. It’s part of the reason Yellowstone was the first area to become a national park.
But then there’s the hot springs, the brightly colored pools and the pots of boiling, stinking mud. Those environments seem too inhospitable to host any kind of life. What could possibly live in acidic water measuring over 160 degrees Fahrenheit?
Plenty, according to researchers.
How that life forms, how long it takes to move from hundreds of meters below the Earth’s crust until it is exploded into the air and what it feeds off of might just be a missing piece in the puzzle of the origins of life as we see it.
“It’s a stretch to say we’re studying life’s origins. We’re studying a system to learn how life might have originated on Earth,” said Eric Boyd, an associate professor at Montana State University.
“The reason they’re interesting to study is I think if you ask a lot people what the major unanswered questions are on Earth, and they say it seems to be where did we come from, where are we going and are we alone?”
Before we start exploring the formations of life, let’s back up a bit.
Boyd is a microbiologist who recently partnered with University of Wyoming geologists Brad Carr, who focuses on geophysics, and Ken Sims, a world-renown geochemist famous for studying some of the planet’s most inhospitable places.
The three of them are an unlikely trio in the scientific world, but together, Sims calls their collaboration “geohydrobiology, or the study of how earth, water and life connect.”
Both Boyd and Sims have been working in Yellowstone for years.
Sims has been studying what Yellowstone looks like underneath the surface.
Boyd has been looking at life in hot springs that live off of minerals.
Carr has been working with Sims on that same underground geology.
Sims spent years working with the National Park Service to gain permits to study the plumbing underneath Old Faithful.
“When you go into Yellowstone and look at the Old Faithful Visitor Center, there will be cartoons in there that some sort of creative scientist combined with a graphic artist to make, almost like a legend that gets passed down, but it’s all cartoons,” Sims said.
“They don’t know what it looks like under there. What is the piping look like under the system? Let’s stop drawing cartoons when we don’t know anything and draw real pictures.”
It was as part of that project that Sims, Boyd and Carr decided to also study the microorganisms in the world’s most famous geyser. Their work was ultimately paid for by UW’s Roy Shlemon Quaternary Center, the National Science Foundation and NASA.
“One of the most compelling reasons people have for going to Yellowstone National Park is it has the highest number of geysers in the world, Old Faithful being one of them,” Boyd said. “And as microbiologists, we have never in a single study in Yellowstone looked at how variation in a hot spring over time, a geyser, affects microbial processes.”
What this means, and how it relates to how life originally formed, is, well, complicated.
To understand life, the researchers first needed to look at the water.
During the last Ice Age, Yellowstone was covered by the Pinedale Glaciation. When it melted and retreated, much of the water likely rushed out to sea, but it also seeped into the ground, Sims said.
Sims is using isotopes – essentially tiny clocks in rocks – to understand how much of the water under Old Faithful is recharge from modern-day snow and rain and how much is left over from hundreds of thousands of years ago.
“What is causing this thing? It’s the iconic geyser, why is it so regular? Is it going to stop going off one day?”
He can tell by studying how the water interacts with rocks.
And with time scales – understanding how fast water comes up from underneath, where it is being stored and how it interacts with the rock on its way up – Boyd can begin to understand the processes that support life that is teeming deep under the surface.
Because even though temperatures are well above boiling, and it won’t see the light of day until it breaches the surface, there is plenty of life.
“I will go so far as to say nearly everything you see with your naked eye is supported by light energy from the sun in the form of plants,” he said. “There’s a whole different form of life out there you don’t see with your naked eye … There’s a sizeable biosphere under our feet, communities entirely supported by chemosynthesis, and they’re using the minerals in rocks. It’s the same process of photosynthesis, you’re extracting electrons out of water and the product is oxygen.”
And that process, because it’s so far underground and unexposed to any light, is tough to study.
It’s also all that was likely on Earth until about 2.8 billion to 3 billion years ago.
Which is why being able to study microorganisms in a place like Old Faithful, in a place like Yellowstone, could help scientists understand what was on the planet prior to the life we know today. It could also help inform about the potential for life on other planets where there are or were geysers or hot springs, Boyd said.
“If life can originate on Earth,” he said, “and originate in a place like a hot spring or geyser or the like, and you see evidence for these geothermal features on other planets, you think ‘why couldn’t it originate there?’”
The team has enough data to begin writing papers. Sims is finishing a paper on timescales between two pools that are 15 meters apart with different chemistry but came from the same source. They also hope to go back in April for more samples.
As for microorganisms and what they could tell us about how life originally formed, Boyd is still analyzing the material.
“We know there are cells in those waters from Old Faithful,” he said. “We know that the life there is very diverse, and it will be a couple months before we know precisely what that life is doing.”