Natures wonders: Subsea Microorganisms Long Life (Introduction)

by David Turell , Wednesday, May 13, 2020, 18:53 (1653 days ago) @ David Turell

A new article on extremeophiles below the surface of oceans:

https://www.quantamagazine.org/inside-deep-undersea-rocks-life-thrives-without-the-sun-...

"Microbial life, almost unbelievably resilient, abides in boiling hot springs and bone-dry deserts, in pools of acid and polar ice, kilometers up into the sky and kilometers below the ocean floor. And while scientists are eager to uncover microbes in even less familiar territories beyond our solar system, it’s the last Earth-bound frontier on that list — the deep subsurface — where they’re now making exciting progress in their efforts to probe life’s extreme adaptability.

"Lightless, barren of essential nutrients and crushed under inconceivable pressures, the deep subsurface seems unrelentingly inhospitable, yet it is shaping up to be one of Earth’s biggest habitats. Moreover, its strangeness is forcing scientists to reckon with biological systems that operate on completely different energy sources and time scales from those that we surface dwellers are accustomed to.

***

"They’ve dug into sediments as far as 2,500 meters below the seafloor — where they’ve uncovered just a few cells per cubic centimeter, approaching the very limits of their detection ability.

"These cells barely seem alive, at least by our standards. They live very, very slowly, rarely dividing, their energy consumption at times six orders of magnitude lower than that of cells living in surface habitats. “It might take them 100 years or 1,000 years to divide just once,” said Martin Fisk, an ocean ecologist at Oregon State University. “They’re very slowly keeping themselves going.”

***

"Sherwood Lollar, along with Princeton University’s Tullis Onstott and other colleagues, have ventured into those mines to study what they call “the hidden hydro-geosphere,” systems of water isolated deep underground on long geological time scales. In some cases, they’ve found water that hasn’t been exposed to surface environmental factors in millions or even billions of years.

"And in that billion-year-old water, the researchers have found life.

"They’ve also found evidence that those microbes persist by getting energy from an abiotic process called radiolysis, during which radiation released by the rocks reacts with water in the system to release hydrogen, which the cells can then use in various forms as fuel. That’s posed an intriguing question for scientists: Could radiolysis be an alternative process driving much of subsurface life?

"Given that radiolysis occurs everywhere, “it could also be supporting the ocean deep life,” Orsi said. “No one knows.”

***

"...it’s possible that life might have gotten its start on the surface of the Earth, where it found creative ways to survive and spread, including to deeper environments. But it’s also possible that life began underground, at some fortuitous juncture between rock and water — eventually also making its way to the surface and figuring out how to harness the sun’s energy.

***

"A paper published in Nature in March, spearheaded by Edgcomb, detailed the results from one of the most ambitious such pushes to date. They drilled nearly 800 meters below the seafloor at a location where the lower ocean crust bulges up closer to the surface. There, they sampled gabbro rocks, which are formed when magma cools more slowly: They’re typically found beneath basalt and considered a sort of window into the mantle, as well as into what an earlier Earth’s rock environment might have looked like. And in those rocks, the scientists reported trace numbers of cells — which once again seemed to be surviving off nutrients they gleaned from the flow of seawater. Although other researchers, including Orsi, have raised concerns about the possibility that those samples were contaminated, they also expect future analyses to uncover life down there."

Comment: It is obvious. Life is designed to survive anywhere on Earth, but the key is in the design.