More than 10 miles into the backcountry of Yellowstone National Park, on the edge of the Caldera, lives a high-altitude community so diverse that scientists at Montana State University call it "incredible, unique and truly strange" .
The community of microorganisms lives in a sapphire blue hot spring at 8,600 feet above sea level on the watershed. It's a basin where volcanic gases rise to mix with snowmelt and rainwater, a phenomenon that allows for exceptionally high levels of diversity, said Dan Colman, assistant research professor. Department of Microbiology and Immunology, College of Agriculture and College of Letters. Science.
Colman found in a miniature size sample more microbial biodiversity than it did if there was a combination of all the plant and animal biodiversity of Yellowstone. Some were Archaea bacteria and others, two of the three areas of life, and less than half of them had previously been detected in hydrothermal systems. Some may even be modern parents of ancient microbes, potentially offering lessons on life on the primitive Earth and the potential for life on other planets.
"We think this work has quite broad implications that span multiple disciplines," said Colman, lead author of a science article that explained MSU's findings in the hot spring known as Smoke Jumper 3 or SJ3. .
The document was published on February 8 in the online journal Nature Communications. Co-authors were associate professor Eric Boyd and PhD student Melody Lindsay, both of the Department of Microbiology and Immunology.
Boyd stated that the document is unique in that it does not only describe the diversity found in a hot spring; it also explains the conditions that allowed this diversity to develop and maintain itself.
"Many people are interested in discovering diversity – it's the ultimate goal – it's admirable," Boyd said. "What Dan wanted to know is why, why do we have so much diversity and why are some sources more diverse than others?"
Colman attributes this diversity to the unique geochemistry of the Smoke Jumper geyser basin, particularly SJ3. He stated that SJ3 is the ideal place to begin to understand how geological processes lead to an increase in volcanic gases in hydrothermal systems and how, in return, microbial life depends on chemical sources of energy rather than light.
"We show that this is due to its geographical position and, not to mention, that it is at the top of one of the largest active volcanoes in the world," he said. "SJ3 is located at high elevation on the continental watershed, which prevents deep hydrothermal aquifers from reaching this area."
Colman said that SJ3 and other similar sources are fueled by large amounts of volcanic gases generated by the boiling of the hydrothermal waters when they rise to the surface. These gases can mix with near-surface waters, such as recent rains or slush.
He noted that the volcanic gas that leads into SJ3 is very different from the gases present in our atmosphere in that it lacks oxygen. On the contrary, the volcanic gas is enriched in hydrogen, methane and carbon monoxide, while the water it infiltrates is highly oxidized or rich in oxygen. Mixing these different types of fluids is likely to improve conditions conducive to microbial life, leading to greater diversity and providing new opportunities to take advantage of their "gaseous" environment.
Comparing the SJ3 to a buffet, Colman said, "A more diverse food source is attracting more and more people, just like a hot spring that offers a variety of chemical conditions."
So why did the MSU researchers focus on this particular hot spring while Yellowstone had 14,000 hot springs they could have studied?
Interested for a long time in the role of hydrogen in supporting microbes that derive their energy from chemicals rather than light, Mr. Boyd explained that the hot springs of Smoke Jumper and those of the park had been studied in the 1920s and early 1930s by scientists at the Carnegie Institute in Washington. They published their findings in 1935, and subsequent work by the US Geological Survey found particularly high volumes of volcanic gas in the Smoke Jumper geyser basin. Knowing this, Boyd and four other people spent a day in Yellowstone in July 2014 collecting samples of SJ3 and three nearby hot springs.
"Just looking at a hot spring does not necessarily tell you how biodiverse it is," Boyd said. "But as soon as we measured the pH of the spring and taken other measurements, we knew we were sampling a single spring."
Colman said it had taken about three more years to run the genetic sequencing tests and analyze the results revealing the diversity of the microbial community. Most hot springs contain two types of microbial organisms. It brought together representatives of nearly half of all known groups of microorganisms living on Earth, including dozens and dozens of archaeal and bacterial non-cultured lines.
"In addition, many lines that we have detected in SJ3 have recently attracted particular attention because of their potential for information on the evolution of methanogenesis (the biological creation of methane), in addition to previously unknown types of methanogens. and deep-branched microbial lineages associated with subterranean environments and many other enigmatic lineages, "said Colman. "It is likely that further studies on such systems and their intriguing organisms will bring important additional information on microbial ecology and shed new light on their role in the evolution of biogeochemical processes."