May 16, 2022 08:50 AM
(This post was last modified: May 16, 2022 06:25 PM by C C.)
https://www.sciencealert.com/830-million...alian-rock
EXCERPTS: An incredible discovery has just revealed a potential new source for understanding life on ancient Earth. A team of geologists has just discovered tiny remnants of prokaryotic and algal life – trapped inside crystals of halite dating back to 830 million years ago.
Halite is sodium chloride, also known as rock salt, and the discovery suggests that this natural mineral could be a previously untapped resource for studying ancient saltwater environments. Moreover, the organisms trapped therein may still be alive.
The extraordinary study also has implications for the search for ancient life, not just on Earth, but in extraterrestrial environments, such as Mars, where large salt deposits have been identified as evidence of ancient, large-scale liquid water reservoirs.
The organisms don't look like you might be expecting. Previous ancient microfossils have been found pressed into rock formations, such as shale, dating back billions of years. Salt is not able to preserve organic material in the same way.
[...] Inside, they found organic solids and liquids, consistent with prokaryotic and eukaryotic cells, based on their size, shape and ultraviolet fluorescence.
The range of fluorescence was interesting, too. Some of the samples showed colors consistent with organic decay, while others demonstrated the same fluorescence of modern organisms, suggestive, the researchers said, of unaltered organic material.
It's even possible that some of the organisms are still alive, the researchers noted. The fluid inclusions could serve as microhabitats where tiny colonies thrive. And living prokaryotes have been extracted from halite dating back 250 million years; why not 830 million?
"Possible survival of microorganisms over geologic time scales is not fully understood," the researchers wrote.
"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."
This absolutely has implications for Mars, where deposits can be found that have similar compositions to the Browne Formation, the researchers said... (MORE - missing details)
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RELATED:
(2006) Extremely halophilic archaea and the issue of long-term microbial survival
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188376/
ABSTRACT: Halophilic archaebacteria (haloarchaea) thrive in environments with salt concentrations approaching saturation, such as natural brines, the Dead Sea, alkaline salt lakes and marine solar salterns; they have also been isolated from rock salt of great geological age (195–250 million years). An overview of their taxonomy, including novel isolates from rock salt, is presented here; in addition, some of their unique characteristics and physiological adaptations to environments of low water activity are reviewed. The issue of extreme long-term microbial survival is considered and its implications for the search for extraterrestrial life. The development of detection methods for subterranean haloarchaea, which might also be applicable to samples from future missions to space, is presented... (MORE - details)
EXCERPTS: An incredible discovery has just revealed a potential new source for understanding life on ancient Earth. A team of geologists has just discovered tiny remnants of prokaryotic and algal life – trapped inside crystals of halite dating back to 830 million years ago.
Halite is sodium chloride, also known as rock salt, and the discovery suggests that this natural mineral could be a previously untapped resource for studying ancient saltwater environments. Moreover, the organisms trapped therein may still be alive.
The extraordinary study also has implications for the search for ancient life, not just on Earth, but in extraterrestrial environments, such as Mars, where large salt deposits have been identified as evidence of ancient, large-scale liquid water reservoirs.
The organisms don't look like you might be expecting. Previous ancient microfossils have been found pressed into rock formations, such as shale, dating back billions of years. Salt is not able to preserve organic material in the same way.
[...] Inside, they found organic solids and liquids, consistent with prokaryotic and eukaryotic cells, based on their size, shape and ultraviolet fluorescence.
The range of fluorescence was interesting, too. Some of the samples showed colors consistent with organic decay, while others demonstrated the same fluorescence of modern organisms, suggestive, the researchers said, of unaltered organic material.
It's even possible that some of the organisms are still alive, the researchers noted. The fluid inclusions could serve as microhabitats where tiny colonies thrive. And living prokaryotes have been extracted from halite dating back 250 million years; why not 830 million?
"Possible survival of microorganisms over geologic time scales is not fully understood," the researchers wrote.
"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."
This absolutely has implications for Mars, where deposits can be found that have similar compositions to the Browne Formation, the researchers said... (MORE - missing details)
- - - - - -
RELATED:
(2006) Extremely halophilic archaea and the issue of long-term microbial survival
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188376/
ABSTRACT: Halophilic archaebacteria (haloarchaea) thrive in environments with salt concentrations approaching saturation, such as natural brines, the Dead Sea, alkaline salt lakes and marine solar salterns; they have also been isolated from rock salt of great geological age (195–250 million years). An overview of their taxonomy, including novel isolates from rock salt, is presented here; in addition, some of their unique characteristics and physiological adaptations to environments of low water activity are reviewed. The issue of extreme long-term microbial survival is considered and its implications for the search for extraterrestrial life. The development of detection methods for subterranean haloarchaea, which might also be applicable to samples from future missions to space, is presented... (MORE - details)
