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How does microbial life manage to survive in subglacial environments over millions of years? New research from the University of Bristol has found that the grinding of bedrock by glaciers and ice sheets produces a continual supply of hydrogen gas, a ready source of energy ('food') for many microbes. This hydrogen is most likely formed when the highly reactive surfaces of freshly fractured silicate minerals react with and split water.
Lead author, Dr Jon Telling of Bristol's School of Geographical Sciences said: "A wide diversity of microbes inhabit vast 'wetland' areas beneath ice sheets and many glaciers but life certainly isn't easy for them. They have to contend with cold temperatures, high pressures from overlying ice, dwindling food supplies as washed-in soils and vegetation are consumed, and constant crushing as rocks embedded in glacier beds are ground against bedrock or sediment."
However, when Dr Telling and colleagues investigated whether hydrogen produced during this grinding of rock could provide a continual source of energy to support subglacial life, they found that living in a 'rock crusher' has an unexpected advantage.
The researchers collected a range of silicate rocks representative of subglacial environments in Greenland, Canada, Norway and Antarctica and crushed them with a sledgehammer and ball mill to varying surface areas. Then, under an inert atmosphere in the laboratory, they added water and measured the production of hydrogen over time.
(Score: 4, Insightful) by Covalent on Monday November 02 2015, @03:15AM
There has been much speculation about whether or not life could survive on Mars, Europa, Enceladus, etc. It's clear now from the extreme environments on Earth, all of which harbor life, that the answer is almost certainly yes. Thus the conclusion is that if life can get started in most places, then there should be life on several worlds in our solar system alone.
But it's that "getting started" bit that's the tricky part. We have no idea where and how life originated on this planet. Since all life has DNA, and that DNA is remarkably similar, scientists have concluded that all living things share a common ancestor. This means that almost all living things share a common ancestor that lived in a very different environment - the common ancestor could not have arisen under a glacier, in a thermal vent, and under the soil all at the same time.
This simple fact may allow the presence (or absence) of life on other worlds to help pin down what happened on the early Earth. If there is life on Europa, for example, then that life almost certainly started out near a hydrothermal vent. There would be few other places on Europa that could conceivably have been the origin. That would lend a bit of evidence toward that also being the starting point on Earth. But if Mars also has life, then the picture gets more complicated. Mars may have had hydrothermal vents at one point, but perhaps not. Finally, if Europa, Mars, Enceladus are all sterile, then perhaps there was some unusual environment on early Earth that allowed for the starting point of life that those other bodies never had.
All in all, though, this is just grist for the imagination mill. I would be surprised if the rest of the solar system were sterile. I sure hope it's not!
You can't rationally argue somebody out of a position they didn't rationally get into.
(Score: 0) by Anonymous Coward on Monday November 02 2015, @05:43AM
Does this imagination mill also produce hydrogen?