Microorganisms can be found in deep subsurfaces that reach into the Earth, where they live in large veins and pores of bedrock. Microbes belowground, also known as microorganisms or microbes, make up half of the world’s living material and are essential for the survival of all forms of life up the food chain. They are crucial for creating an environmentally sustainable future. They can alter the chemical makeup of minerals and break down pollutants.
Although it is obvious that bacteria and archaea have important roles, evidence of their presence in the subsurface can only be found in trace amounts of biological material, which seeps through cave streams, mine walls and drill holes that tap into the aquifers.
Many scientists believe that the subsurface microbial community composition is affected by local environmental factors such as temperature, acidity and oxygen concentration. Environmental selection can take many years or millennia for significant community-level changes to slow-growing communities such as the subsurface.
With data from nearly 5,000 feet belowground Stanford University researchers have now shown that deep-subsurface microbial communities can shift in just days. These shifts can also be caused by geological activity, not only environmental pressures. The results were published in last month. Proceedings of the National Academy of Sciences (PNAS).
“In the subsurface, it is difficult to understand how environmental selection can be the dominant driver in community dynamics. It could be just a changing flow or movement of groundwater through cracks and crevices that’s driving our observations,” Yuran Zhu, PhD ’20, the lead study author, who did the research as a PhD student.
Filling in the gaps
Reading a random page from a 1000-word biography of someone is like reading a glimpse into their lives. Previous studies on deep subsurface microbes only provided glimpses. Stanford researchers collected water samples weekly from multiple geothermal wells over a period of 10 months. They showed that these populations can change over time, which is the first evidence for geological activity being a driver for microbial community evolution.
Anne Dekas is a geomicrobiologist, senior author, and assistant professor in Earth system science. “To have a time sequence over 10 months, especially at weekly resolution, was a really unique perspective that allowed us different questions about how these communities change with the passage of time.
Dekas explained that, while geological activity might be suspected by microbial ecologists, she was surprised at the extent to which community shifts occurred following a change in flow network.
Boreholes and test tubes
The study used samples taken from a flow test at the Sanford Underground Research Facility, formerly known as the Homestake Gold Mine in South Dakota. Zhang described the transition from a borehole setting to a lab-filled with a PCR machine at campus as “like connecting two completely different worlds.” This refers to the way this work unites the distinct fields in microbial ecology, geothermal engineering.
The researchers discovered microbial DNA fingerprints by analysing the water samples. Each of the 132 samples contained tens to thousands of unique sequencing IDs. These data were used to demonstrate that geological activity can quickly mix diverse biological communities, and from places that were not previously connected.
Roland Horne, senior author of this microbiology study and the Thomas Davies Barrow Professor in Earth Sciences, stated that one of the additional pieces from the study was that microbe populations have moved from place to place. But, it is also a result of the network. “This is important from the reservoir perspective because it reveals something which isn’t revealed using normal geothermal analytical techniques.”
Biology meets geology
Current geothermal technologies only provide a limited amount of data. This is similar to having access to roads that are blocked from side roads that lead you home. Horne stated that the investigation of microorganisms allows for more detailed mapping of the subsurface’s complex intricacies.
You may be able to use biology in your research. This could also help you understand the deep subsurface, which is a frontier for geological storage. Combining biology and geology requires a fundamental understanding of both subjects.
Zhang was co-advised and advised by Horne, Dekas, and said, “On the geoothermal underground project I realized that reservoir engineers, geologists, or geophysicists often aren’t as familiar with microbiology.” “There is a lot of common knowledge in geochemistry but not as much in geomicrobiology.”
This work may even have a wider meaning than Earth-based sciences. If some of Earth’s oldest life forms can change and diversify as a result of geological activity then we might be able to expect similar outcomes for life on other planets.
Zhang stated, “What we observe could possibly link to the early story life’s development.” “If early life formation or diversification is driven by geological activity, then we might look for extraterrestrial existence on planets that show geological activity.”
The U.S. Department of Energy funded the study in part.