Extreme extremophiles: from deep sea cores (Introduction)

by David Turell , Wednesday, August 12, 2020, 19:35 (1345 days ago) @ David Turell

Another reported story of these strange barely alive bacteria:

https://www.quantamagazine.org/zombie-microbes-redefine-lifes-energy-limits-20200812/

"Energy drives the planet; it’s the currency that all living things use to grow, develop and function. But just how little energy do cells need to get by? Sediment-dwelling microbes below the seafloor — which may outnumber the microbial cells found in the oceans themselves — are providing some surprising answers. The organisms not only challenge what scientists thought they knew about life’s energy needs, but hint at new ways of defining what life is and where we might find it.

"Last week in Science Advances, researchers presented the most complete picture to date of the strange, hidden biosphere beneath the seafloor. Ocean drilling expeditions have repeatedly probed those lightless depths and uncovered cells that survive almost in suspended animation, consuming orders of magnitude less energy than their neighbors at the surface. But the model presented in the new study shows that this zombielike state probably applies to the vast majority of microbes in ocean sediments — and that they typically subsist on energy budgets approaching a theoretical minimum for life.

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"They found that the cells buried in ocean sediments operate at incredibly low power levels. In total, microbes in those sediments, which in some places might extend kilometers below the seafloor, collectively use a mere tenth of a percent of the power consumed in the upper 200 meters of the ocean. Each cell, on average, survives its sediment burial at a power level significantly lower than that of “some of the most energy-starved things in the world,” as Lloyd puts it — and orders of magnitude lower than that of any organism ever measured in lab settings.

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"The implication of the study’s estimates is that this underground biome has almost no cell division: Some individual cells down there might be 100 million years old. It also means that in all that time, those cells might not have evolved or changed much at all. It’s a biosphere characterized by stasis. “Really, most of the cells are barely hanging on,” Amend said. “Our concept of how cells evolve goes out the window for this incredibly large biosphere.”

"And yet, because of their numbers and the eons over which they have survived, these almost- but-not-quite-dead cells play an important role in the production of methane, the degradation of the planet’s largest pool of organic carbon, and other processes. “They are such extraordinarily low-power beings, but they actually have an outsize effect on the Earth,” Lloyd said.

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"The model in Bradley’s new paper hints at a possible explanation: When the 100-million-year-old sediment first formed, the trapped microbes might have actually had more energy or power. According to Morono, perhaps that initial condition, followed by a more immediate drop in energy levels, somehow made long-term survival likelier as the cells got buried deeper.

"He is hopeful that researchers will continue to integrate information from more studies into models to gain these kinds of insights. But already, modeling seems to have helped confirm something that many scientists have suspected. “What are the margins of life? What do you need for it to be life?” Lloyd said. “It turns out, not very much.'”

Comment: It is obvious life is determined to survive here. Yet it is very difficult for us to figure out how it started naturally. That is why I still support God as the agent. The design requirement is so strong.