Geologists from West Virginia University have discovered living cells in halite (rock salt). From the analysis conducted it is estimated that the cells are 830 million years old, although there is a possibility that they could be older than a billion years.
The team made the discovery around 5000 feet below the surface where minerals of salt have been created millions of years ago. Halite, what scientists refer to as rock salt is actually sodium chloride and the living cells are trapped inside of these salt particles.
For this type of living cell or organism, sodium chloride is a perfect environment for preservation, which allowed the cells to live for so many millions of years.
Leader of the study Schroeder-Gomes described that during the formation of rock salt, water containing living cells could be trapped inside. Most of the cells would die, but there are some cells that find the environment perfect to sustain themself.
The team is not sure if these cells are still alive and they won’t know until they find a way to decompose the minerals without harming the cells. Despite this, the team has high hopes as other scientists have found that microorganisms are able to live in recent and modern environments where halite forms.
One of the main problems, in this case, is the natural doses of radiation that over such a long period of time would destroy organic matter. At the same time, the geologists have argued in their research paper that previous studies where ancient microorganisms have been studied were found to have survived, despite natural radiation:
“It has been suggested that radiation would destroy organic matter over long time periods, yet Nicastro et al. (2002) found that buried 250 million-year-old halite was exposed to only negligible amounts of radiation. Additionally, microorganisms may survive in fluid inclusions by metabolic changes, including starvation survival and cyst stages, and coexistence with organic compounds or dead cells that could serve as nutrient sources.” (Quote by Sara I. Schreder-Gomes; Kathleen C. Benison; Jeremiah A. Bernau)
In order to actually see these organisms, the research team used ultraviolet petrography and transmitted light. They first identified the halite crystals under a normal microscope and then used a high-performance microscope that is able to magnify 2,000x to study the fluid inside of the mineral crystals and discover the microorganisms.
This has opened a new path for geologists as they now can search other minerals for signs of ancient life.