Extreme extremophiles: from deep sea cores (Introduction)

by David Turell , Wednesday, July 29, 2020, 15:36 (1579 days ago) @ David Turell

Thought to be up to a 100 million years old:

https://www.sciencemag.org/news/2020/07/scientists-pull-living-microbes-100-million-yea...

"Microbes buried beneath the sea floor for more than 100 million years are still alive, a new study reveals. When brought back to the lab and fed, they started to multiply. The microbes are oxygen-loving species that somehow exist on what little of the gas diffuses from the ocean surface deep into the seabed.

"The discovery raises the “insane” possibility, as one of the scientists put it, that the microbes have been sitting in the sediment dormant, or at least slowly growing without dividing, for eons.

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"To find out, Morono and his colleagues mounted a drilling expedition in the South Pacific Gyre, a site of intersecting ocean currents east of Australia that is considered the deadest part of the world’s oceans, almost completely lacking the nutrients needed for survival. When they extracted cores of clay and other sediments from as deep as 5700 meters below sea level, they confirmed the samples did indeed contain some oxygen, a sign that there was very little organic material for bacteria to eat.

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"...in these samples, there were no more than 1000 bacteria in the same amount of sediment. So, the biologists had to develop specialized techniques such as using chemical tracers to detect whether any contaminating seawater got into the samples and developing a way to analyze very small amounts of cells and isotopes. “The preparation and care needed to do this work was really impressive,” says Kenneth Nealson, an environmental microbiologist retired from the University of Southern California.

"The added nutrients woke up a variety of oxygen-using bacteria. In samples from the 101.5-million-year-old layer, the microbes increased by four orders of magnitude to more than 1 million cells per cubic centimeter after 65 days, the team reports today in Nature Communications.

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"Genetic analysis of the microbes revealed they belonged to more than eight known bacterial groups, many of which are commonly found elsewhere in saltwater where they play important roles in breaking down organic matter. “It suggests that learning to survive under conditions of extreme energy limitation is a widespread ability,” Nealson says, one that may have evolved early, when there was not much for microbes to feed on. “It may have been a very handy survival trick.”

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"...the bottom line, says Bo Barker Jørgensen, a marine microbiologist at Aarhus University who was not involved with the work, is “low food and energy seem not to set the ultimate limit for life on Earth.”

Comment: studies like this have been presented here but with 'younger' forms. Life can be any where and can certainly survive.