…Live bacteria … have even been recovered from rock salt crystals that had been buried for 250 million years …
This is from Physiology and Biochemistry of Extremophiles edited by Charles Gerday and Nicolas Glansdorff (2007):
… When salt concentrations increase, the biological diversity decreases, and at concentrations about 150 to 200 g/liter, macroorganisms no longer survive. On the other hand, highly salt-tolerant and often even highly salt-requiring microorganisms can be found up to the highest salt concentrations: NaCl-saturated brines that contain salt concentrations of over 300 g/liter.
… Maybe the most surprising environment in which halophilic microorganisms have been found is the rock salt deposits found in many places worldwide. Live bacteria (endospore-forming organisms of the genus Bacillus) have even been recovered from rock salt crystals that had been buried for 250 million years, while viable Archaea of the family Halobacteriaceae or their 16S ribosomal RNA genes were recovered from ancient salt deposits as well.
[line break added] These microorganisms appear to survive within small liquid inclusions within the solid rock salt. Although the claim that these organisms indeed had survived within the crystals for millions of years is not uncontested, it is now well established that indeed halophilic Bacteria and Archaea can retain their viability for long times in such brine inclusions within salt crystals.
My most recent previous post from this book is here.
-Julie
Coloring 