A Montana State University doctoral student is seeking to glimpse the biological processes of the early Earth by studying how microorganisms live in the harsh environment of the Samail Ophiolite, a unique geologic formation on the Arabian Peninsula.
Libby Fones visited Oman this past spring, prior to the pandemic travel restrictions, to gather water samples from an ophiolite, a chunk of the Earth’s crust and underlying mantle that was once under the ocean but was forced to the surface by millions of years of tectonic activity. Oman and the United Arab Emirates are home to the Samail Ophiolite, one of the largest such formations in the world, measuring more than 350 miles long and nearly 100 miles wide.
Having brought the samples safely home, Fones, a Ph.D. candidate in the Department of Microbiology and Immunology in MSU’s College of Agriculture, is now ready to continue exploring the microorganisms that live in and on the Samail Ophiolite’s rocks. Fones and her adviser Eric Boyd recently published an article in Nature’s ISME Journal describing samples analyzed in previous years, and now, with a grant from the U.S. Department of Energy’s Joint Genome Institute awarded last month, Fones, Boyd and postdoctoral researcher Rachel Spietz of the Boyd Lab will seek to uncover how the organisms live in this chemically unique environment and gain a glimpse into the biological processes of early Earth.
“The research experiences that Dr. Boyd provides for his graduate students and postdoctoral fellows are truly unique and available to only a handful of investigators in the world,” said Jovanka Voyich, head of the Department of Microbiology and Immunology. “This project underscores his international reputation as being one of the foremost scientific leaders working to define the processes that support life in early Earth analog environments.”
The unique geochemistry and tectonic activity of the Samail Ophiolite provide such an analog environment, said Fones, who is originally from Minnesota and is in her fourth year of doctoral studies. The area offers a uniquely accessible look at rock types normally found on the ocean floor.
“The Samail Ophiolite is fascinating because this is likely similar to the composition of most rock that was exposed on the surface of early Earth,” Fones said. “It allows us to study what microbes might have been doing in an early Earth system.”
In particular, Fones and Spietz will study the biological impacts of a process called serpentinization, which occurs when iron-rich rocks such as those found in the Samail Ophiolite react with water. Serpentinization creates hydrogen, said Fones, which the microbes they are studying can use as a source of energy.
“Looking at these microbial communities gives us an insight into what life was like before organisms evolved to be able to use sunlight,” said Spietz. “This life was present on early Earth when the process of serpentinization was likely rampant. It is perhaps not surprising that most evidence suggests this type of early life was dependent on hydrogen for fuel.”
“World class facilities and researchers continue to attract amazing graduate students and postdoctoral scholars to MSU to conduct their studies,” said Boyd. “Libby and Rachel are two extraordinary examples of what can happen when we attract the right scientists and get them working together collaboratively. I look forward to seeing these two women carry out this project and further their academic careers.”
Over the next three years, Fones and Spietz will partner with the Joint Genome Institute, a program of the Department of Energy focused on using genomic science to advance knowledge in clean energy production and the environmental sciences, to sort and sequence the genomes of the 1,386 microbial cells collected from those samples. They’ll examine exactly how the organisms use the chemical products of serpentinization to survive and how the byproducts of their activities could affect humans.
As serpentinization progresses, it generates fluids that react with carbon dioxide in the surrounding air, converting it into solid carbonate minerals. Some scientists believe this process could be a promising way to sequester carbon dioxide, which is a greenhouse gas. Fones and Spietz will seek to understand whether the microorganisms they’ve found in that environment could cause a re-release of that carbon dioxide or generate methane, which has even more potent environmental impacts.
“The idea is that if you react carbon dioxide with the ions produced through serpentinization and generate a solid mineral, that it could be a stable way to store carbon so that it’s not in the atmosphere,” Fones said. “The question then is, how stable is that carbon in its sequestered mineral form?”
Digging further into the dynamics of the Samail Ophiolite could offer insight into similar processes that were widespread on the early Earth, and which could also have implications much closer to home.
“Thinking about what’s going on underground in this system in Oman is very relevant here in Montana because we have rock formations that have undergone similar transformations through water-rock reactions,” Spietz said. Other research in Boyd’s lab studying the doings below the surface of nearby Yellowstone National Park, where reactions between hydrothermal water and rock happen constantly.
“It’s not unrealistic to think that the same processes could be fueling microbial life right here under our feet,” she said.
Fones said the possible discoveries are endless beneath the surface of Earth, where the extent of biodiversity is virtually unknown.
“We are still on the pioneering front of subsurface microbiology, but recent estimates have suggested that about a fifth of total life could be underground,” she said. “Starting to understand what that life is doing and how it’s contributing to nutrient cycling processes is relevant regardless of what system you’re interested in.”