Scientists Discover Nearly 1 Billion-Year-Old Organisms, Possibly Alive

The microorganisms are 830 million years old, and may still be kicking. The find has implications for the search for life on Mars, researchers say.
Scientists Discover Nearly 1 Billion Year Old Organisms, Possibly Alive
Image: Schreder-Gomes et. al. 
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A team of researchers have located 830 million–year–old microorganisms in a piece of Australian rock salt, and they may even be alive.

According to the researchers, the finding may also have implications for the search for alien life in future samples returned to Earth from Mars. 

As detailed in a paper published in the peer-reviewed journal Geology, a team out of West Virginia University located the microorganisms in a piece of ancient halite, the mineral form of sodium chlorine that develops within saltwater and salty lake water. They found it in a fluid inclusion—a bubble of water or gas trapped in rock—in a well-dated fragment of sediment in the Browne sediment formation in central Australia, and, upon inspection with a microscope, spotted the tiny critters.


“Even after such a significant amount of time, these microorganisms are still detectable,” Sara Schreder-Gomes, first author on the paper and former Master’s Candidate in Geology at West Virginia University, said in an email to Motherboard. “We might find biosignatures in similar minerals (halite and gypsum) on Mars that are returned to Earth.” 

Those organisms were likely either blown into halite by water, or they were extremophiles—microbes that live in extreme temperature or acidity conditions—the authors posit. They showed up blue fluorescent under an ultraviolet-visible light, a color that’s “consistent with that of modern microorganisms,” the authors note, indicating that the organic material has not been altered. 

The microorganisms may even still be alive after almost one billion years, a question that the researchers leave open-ended but lay out a few reasons why they could still be kicking. 

“We know that modern halophilic (salt-loving) organisms, including bacteria, archaea, algae, and fungi, have ‘survival mechanisms’ that allow them to survive adverse conditions,” Schreder-Gomes said.

The researchers note that some other microorganisms that live in halite slow their biological activity when their environment becomes too saline, and may be revived. Past studies have located other living prokaryotes in ancient halite formations, the oldest known instance of which  is 250 million years old, the paper notes. “Therefore, it is plausible that microorganisms from the Neoproterozoic Browne Formation are extant,” the authors write.

The researchers say that the survival of microorganisms over such long periods of time is not fully understood.  It’s been proposed that radiation would have killed organisms over such a long period of time, but previously discovered organisms in halite were protected. Trapped microorganisms can also feed off the nutrients of nearby dead cells or organic compounds also trapped in the fluid inclusion, the authors write. 

“Fluids inside primary inclusions serve as microhabitats for trapped microorganisms, allowing exceptional preservation of organic matter over long periods of geological time,” the authors write in the paper. 

The rocks in the Browne Formation, the fragment of sediment from which the halite was located, contain a similar “suite of minerals” to Martian rocks, and thus point to the possibility that similar structures have been preserved over long periods of time on Mars, the paper notes. The red planet has also in the past contained saline lakes that precipitated halite, and, as the mineral has served as a long-term home for micro-organisms on earth, could do the same there. Indeed, earlier work presented at a conference by the same team said that “it may serve as an analog for martian chemical sediments,” and “the methods used here may prove useful for examination of samples returned to Earth from Mars in the future.” 

“Ancient chemical sediments, both of terrestrial and extraterrestrial origin, should be considered potential hosts for ancient microorganisms and organic compounds,” the new paper reads.