Monday, July 26, 2021

Microbes Thrive on Pulverized Rock Under a Half-Mile of Antarctic Ice

This is not particularly surprising.  in fact an absence would be surprising.  Yet it reminds us that the rock contact of a mile thick glacier is crushed rock.  That is actually a huge environment for single cellular life in particular and possibly even bigger critters.

Water flow will also dissolve a lot of that rock away as well to increase porosity and permiability.

We are waking up to just how rich the habitat happens to be.  It may well be possible to drive horizontal tunnels deep into such a glacier using a block liner with keystone to handle the compressive stress.

Microbes Thrive on Pulverized Rock Under a Half-Mile of Antarctic Ice

The research offers clues about what to look for when searching for life on other planetsAn image from another drilling project at Lake Mercer in Antarctica called SALSA. Shown here is the UV collar, borehole and hot water drill. (Billy Collins via University of Bristol)


Beneath 2,500 feet of ice at the South Pole, a 23-square-mile unfrozen lake flows in complete darkness under that immense mass of ice and snow. What’s in that buried lake is even more surprising: life. Microbes thrive in this unbelievably inhospitable environment, feeding on chemical compounds released from crushed rock caused by erosion.

New research by the University of Bristol details how different kinds of microscopic organisms survive on a previously unknown source of nutrients from ancient sediments. Their results were published this month in the journal Nature Communications Earth & Environment.

The discovery of how these microbes exist in such extreme conditions may provide clues for scientists searching for life on other planets. Study author Beatriz Gill Olivas, a glaciologist at the University of Bristol, says this research could offer clues about where to look when exploring other worlds.

“Lakes in Antarctica can be a proxy for extreme environments in other planetary systems,” she tells Harry Baker of Live Science. “They offer a great insight into how microbial life might survive in other environments.”

Olivas heads an international team of scientists studying microbial life in Antarctica’s Lake Whillans, which was discovered from space in 2007. They used sediment samples taken from the body of water and replicated the environment in the lab, measuring the various compounds released from the pulverized rock, including methane, ammonium, nitrogen, sulfur and iron.

The team showed that single-celled organisms in Lake Whillans, namely bacteria and archaea, had abundant nutrients to not only survive, but to thrive, reports Isaac Schultz of Gizmodo. Scientists found the body of water has 54 times the amount of carbon necessary to sustain life. Olivas points out that microbes could be living throughout the large subglacial lake because of the high levels of life-sustaining compounds.

“Subglacial Lake Whillans is part of a large interconnected hydrological system, so erosion taking place upstream could represent a potential source of biologically important compounds to this and other lakes within the system that might harbor thriving communities of microbial life,” she tells Schultz.

This study was the first to use sediment samples from the lake. Olivas says the compounds produced in her lab were sufficient to sustain both methanotrophs, microbes that depend on methane for carbon and energy, and methanogens, microbes that produce methane.

“Only two previous studies have looked at the potential influence of erosion on subglacial energy and nutrient sources, which involved crushing largely unweathered rock samples,” she says in a University of Bristol press release. “This is the first study to use highly weathered, ancient marine sediments, yet concentrations of gases measured largely agreed with previous results.”

While this research helps explain how these microbes survive in Antarctica, it also provides an understanding of how life might exist elsewhere in the solar system—and beyond. Since many planets are icebound or experience extreme temperatures, digging down into frozen areas might enable scientists to eventually find extraterrestrial life.

“We obviously can’t say that these processes will be definitely sustaining exoplanetary microbes,” Olivas tells Baker. “However, it definitely offers some insights into how microbes in icy planets and moons may survive.”

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