Evolution: more deep Earth life found (Evolution)

by David Turell , Monday, August 26, 2019, 17:58 (1697 days ago) @ David Turell

Over three kilometers deep in a mine, using sulfates in their metabolism:

https://email.labxmediagroup.com/e2t/c/*N5LN8FBnm5FNW7_KrL92C9NMW0/*W3S-c0R1XLDBFV_2yBZ...

"Researchers have uncovered the first direct evidence of resident microbes in Kidd Creek Mine, a 3-kilometer-deep copper and zinc mine in Ontario. The findings, published last month (July 18) in Geomicrobiology Journal, confirm previous work indicating that ancient, sulfate-rich water in the region could support what researchers call “deep microbial life,” and add to growing evidence that there’s a vast biosphere thriving in the Earth’s crust that has little or no interaction with the surface.

“'This paper is groundbreaking, so to speak,” says John Spear, a microbial ecologist at the Colorado School of Mines who was not involved in the work. “They were able to get an idea of the amount of native microbial biomass . . . and they were able to confirm that the waters that the microbes are living in are host waters—they’re not contaminated or impacted by water coming from the surface.”

"Studies of deep mines and boreholes over the last decade have documented signs of microbes in several areas of the Earth’s continental crust—a hot and dark environment traditionally thought to be inhospitable to life.

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"Compared to service water—water supplied to the mine from a nearby lake on the surface—the density of microbial organisms in the fracture water was low, the team found: approximately 1,000 to 10,000 cells/ml, as opposed to the 100,000 cells/ml in the water coming from above ground.

"The researchers also analyzed the metabolic activity of microbes in the sample, by incubating cells with various food sources and then recording whether or not that food was metabolized. This type of analysis can’t directly provide taxonomic information or detect microbes that aren’t active. But it did show, as Sherwood Lollar and her colleagues had predicted, that the active microbial community consisted almost entirely of sulfate reducers.

“'Sulfate reducers are using sulfate and some reduced carbon compound . . . to fix carbon in the subsurface,” notes Spear, “meaning that these sulfate reducers could be primary producers in the subsurface of the Kidd Creek Mine. And if it’s true there, over a mile deep, you wonder if this is true all around the Earth.”

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“'The more we continue to show that life shows up in all of these different places, the more we understand that these are generalizable to the planet,” she says. “What it means, I would expect, is [that] we are likely to find these organisms almost anywhere we go look in these kinds of settings around the world.'”

Comment: The Earth is the perfect planet to support life everywhere. And it shows how diverse are the metabolic systems used.