Extreme extremophiles: more novel forms in the very deep sea (Introduction)

by David Turell , Tuesday, January 25, 2022, 19:39 (1034 days ago) @ David Turell

At extreme temperatures of 120 degrees C:

https://www.newscientist.com/article/2305667-microbes-survive-deep-below-the-seafloor-a...

"Living microbes have been found in sediments 1.2 kilometres below the seafloor, where the temperature reaches 120°C. The discovery shows that life in seafloor sediments can survive higher temperatures than previously thought and is therefore present at greater depths than we realised.

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"Although these experiments couldn’t be done at temperatures above 95°C on the ship, the fact that some of these microbes came from sediments naturally heated to 120°C shows that they do survive at this temperature, says Treude.

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"At 120°C, the heat is doing a lot of damage to cells, so microbes may need high metabolisms to generate enough energy to repair this damage. It is a race to stay alive, says Treude.

"It isn’t clear what these heat-loving, or thermophilic, microbes are, as the team was unable to sequence their DNA. Nor is it clear how they came to be in the sediments, given that this would have been a very cold environment for a long time after the sediments that the samples came from were first deposited.

"However, a few thermophilic microbes would have been present when the sediments were deposited, and they may have somehow clung on until temperatures began to rise due to being buried under more material, says team member Felix Beulig at Aarhus University in Denmark.

“'We always find a fraction of thermophiles in sediments, even Arctic sediments,” says Beulig.

"As the temperatures rose, all the microbes that weren’t tolerant of heat would gradually have died off, says team member Florian Schubert at the German Research Centre for Geosciences in Potsdam. “The microbes that cannot adapt, they just die,” he says.

"Patrick Forterre at the Pasteur Institute in Paris says that while there are reliable results showing microbe growth at 106°C, nobody has been able to replicate the two lab studies claiming growth at 122°C. “It’s very difficult to determine the upper temperature limit,” he says.

"He is therefore sceptical of the idea of microbes living normally at 120°C, but he does think it is possible that they could somehow survive and became active again at lower temperatures."

Comment: The ability to be alive anywhere is amazing.