A new study released by England's Bristol University sheds light on how life survived during the Ice Age, when the earth was entirely covered in ice for millions of years.
The study's chief researcher John Tilling says the findings are the result of research and study of modern day glaciers and ice sheets which are "home to a surprisingly abundant source of life" .
"Sections of liquid water beneath and inside the ice provide a habitat for a genetically diverse variety of microbes. And studying these organisms gives us some clue what life may have looked like if there were indeed periods of the planet’s history when the land was entirely covered in ice for millions of years," he says.
Tilling says he and colleagues at Bristol University discovered a mechanism that could have allowed creatures to free energy in the form of hydrogen from the water itself.
"Our research suggests that reactions at the surface of rocks underneath the ice sheets can provide a novel source of energy that is enough to support subglacial microbes. These reactions are similar to those that happen when flint is struck against another flint or steel to produce sparks for lighting fires.
"Glaciers and ice sheets are also effective at grinding rocks together, eroding huge volumes of rock and changing the physical landscape over thousands of years. To replicate this process in the lab, we crushed a variety of different rocks in a ball mill to similar grain sizes of glacier sediment, and then added cold water. We found that mixing ground silicate with water at 0°C always produces hydrogen gas. The finer the rock is ground, the more hydrogen is produced"
Tilling says hydrogen is a ready source of energy – effectively food – for many subglacial microbes. He says this "lightening" reaction sustains life and biodiversity today in some of the most harsh environments on earth, so there is no real reason why that would not have applied during historic Ice Ages.
"The exciting prospect this raises is that life might be found in the seemingly inhospitable surroundings of other icy planets and moons throughout the galaxy," says Tilling.