Scientists have found prokaryotes believed to have been alive when trapped in salt crystals 34,000 years ago, according to a study published this month in The Geological Society of America’s open-access journal GSA Today.
“Microbes are known to exist in subsurface habitats, such as sub-seafloor sediments and continental and oceanic crust, to depths of up to 3 km,” the paper reads.
“Prokaryotes (single-celled organisms lacking a nucleus and other membrane-bound specialized structures) in these subsurface environments live in water within sediment pores and rock fractures.”
Organisms have also been found in glaciers up to 8 million years old, according to the paper.
“Collectively, these discoveries have extended the realm of the biosphere into Earth’s crust and have given hope for finding life beneath the surface of other planets, moons, asteroids, and comets of our solar system where present surface conditions are inhospitable,” the paper reads.
The researchers, Drs. Tim Lowenstein and Michael Timofeeff of the State University of New York at Binghamton, and Dr. Brian Schubert of the University of Hawaii at Manoa (Ph.D. student at the State University of New York at Binghamton at the time of the study), found organisms trapped in fluid inclusions—microscopic areas of droplets of water—within salt crystals, and were able to grow them in a laboratory setting.
“The organisms are called archaea, one of the two prokaryote domains (the other is bacteria),” Lowenstein told The Epoch Times.
“We were the first group to look inside the salts before we tried to culture microbes from them,” Timofeeff added.
“They are trapped alongside a type of algae called Dunaliella, which just so happens to produce the food the archaea need to survive—the sugar alcohol glycerol,” Lowenstein said, explaining how the organisms could survive for so long.
However, light cannot enter the crystals, so the algae didn’t survive, and the archaea were left only with whatever glycerol the algae had the moment they were trapped. As the archaea were in an isolated system, reproduction would be hard, leading the researchers to believe that the organisms they found alive are the same ones trapped in the crystals 34,000 years ago and not their descendents.
“They can reproduce, but at some point they will use up their available resources and conditions for life will become unfavorable,” Timofeeff said.
Compared with their modern counterparts, these ancient organisms are rounder and smaller.
“We believe this is evidence that the cells have moved into a starvation survival mode and miniaturized,” Timofeeff said. “When conditions for life become unfavorable, some microbes are able to move into a starvation survival mode and miniaturize.”
Salt crystals that are 63,000 years old containing microbes were found along with the 34,000-year-old ones, but the researchers weren’t sure if the organisms in them were alive.
“The only way we can be 100 percent sure that any microbe we observe inside of a fluid inclusion is alive is to give it conditions favorable for growth and see if it does,” Timofeeff said.
“There are a number of reasons why a microbe trapped inside an inclusion might not grow. The factors for survivability are not well known. We do know they should have enough glycerol to make it.”
The researchers also noted that an earlier study has claimed the finding of a bacterium trapped in a crystal formed in the Permian period (299 million to 251 million years ago), but the study is controversial as some believe that the bacterium is a contaminant from the laboratory.
“Although we are beginning to understand the community of microorganisms inside modern and ancient fluid inclusions, much more needs to be learned about how they survive,” the researchers said in conclusion of their paper.
“Such knowledge will be vital as studies further explore deep life on Earth and elsewhere in the solar system, where materials that potentially harbor microorganisms are millions and even billions of years old.”
To read the research paper, please visit http://bit.ly/eqWOCp
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