MORGANTOWN, W.Va. (WBOY) — New WVU research has found evidence of suspected microorganisms held intact after 830 million years, suggesting new possibilities for the survival of other microorganisms contained in rock as they travel through space or on other planets.
The suspect microbes were found in a core sample called Empress 1A, extracted from a depth of more than 1,500 meters in central Australia. The core was made up of halite, but you probably know it better as plain old table salt. As salt crystals form, they trap tiny pockets of liquid called “fluid inclusions” that can act as mini habitats for microorganisms, and these pockets can remain intact for extremely long periods of time.
Dr. Kathleen C. Benison, Sara Schreder-Gomes and Jeremiah A. Bernau were the three researchers from WVU who published the report, which can be read here. The researchers used a combination of microscopes and ultraviolet-visible light to detect the microbes inside the 830 million-year-old crystal.
“The UV light causes fluorescence in anything with carbon-carbon or carbon-hydrogen bonds, and there are different colors that fluoresce for bacteria and algae and organic compounds. So that’s one way to tell that this was organic material,” Benison said.
However, Benison said they do not know if these organisms are still alive or not.
“One of the things that we do know is that if you go to a modern salt lake environment, there are microorganisms that have the ability to go dormant,” Benison said.
For example, if a salt lake starts to evaporate, the lake will get saltier and begin to form salt crystals. As these crystals form, tiny pockets of liquid can become trapped in the crystals, where the organisms living in the fluid begin to shrink and go into a dormant state.
However, there are challenges to finding out if these microorganisms are still alive. If researchers dissolved the sample to see if the microorganisms could be cultured from the resulting salt water, there would be cross-contamination of many other generations of fluid inclusions.
“We would be mixing any original salt organisms with any alteration that’s happened through time. So maybe that rock formed 830 million years ago, but maybe 100 million years ago some fluid came through and added some more salt or altered some salt,” Benison said.
Benison said that salt beds on Mars could have similar inclusions, and samples gathered from the Perseverance rover can be analyzed to find out if there are organisms trapped inside.
“We know there are salt minerals on Mars, so there’s the possibility of having biosignatures,” Benison said.