Researchers have discovered signs of life in rock samples taken from Earth’s mantle, a discovery that challenges everything we previously knew about life
Yes, your read correctly, researchers have discovered signs of life in rock samples taken from Earth’s mantle, a discovery that challenges everything we previously knew about life and its complexity, and it will surely affect our understanding of life on other planets in the cosmos. It seems that after all, life can exist in the most unimaginable conditions and not just in the ideal environments as we previously thought.
An expedition for the US National Science Foundation which set out in 2000 discovered a field of hydrothermal vents on the Atlantis Massif, featuring a set of never-before-seen ‘limestone chimneys’, which led researchers to name it ‘Lost City’, honoring the mythical lost city of Atlantis described by Plato.
Sixteen years after, in December last year, a team of sciences returned from an International Ocean Discovery Program (IODP) announcing they discovered (as incredible as it sounds) signs of LIFE in the rock samples taken from a number of mantle rocks harvested from the same area. Even though the original goal of the scientific expeditions wasn’t searching for life, but to find out how mantle rock got to the sea floor and its reaction to salt water, finding life in mantle rock is without a doubt, the best thing scientists could have discovered.
This discovery is the ultimate proof that no matter how inhospitable an environment might seem to us, life, as we are yet to understand it, can thrive under the most difficult conditions. This finding raises hopes that researchers will soon discover traces of life forms in our solar system, in places where life might seem impossible for us.
ETH Zurich Professor Gretchen Bernasconi-Green, co-leader of the expeditions said this has to be considered as “a scientific sensation.”
In a statement, Bernasconi-Green explained: “The chimneys are made of calcium, or rather calcium carbonate, which precipitates from the alkaline fluids. This is a natural form of carbon dioxide fixation.”
“We wanted to better understand how much carbon is stored as carbonate in these rocks and the potential of this sequestration, especially in terms of an artificial CO2 sequestration on the sea floor or on land, aided by the serpentinization reaction that led to the formation of alkaline hydrothermal vents.”
There, near the so-called ‘Lost City’, tectonic plates drift apart allowing large active faults to form, carrying mantle materials towards the surface. This is how the group of researchers came across signs of life in the rock which came from the Earth’s mantle.
Now, experts have managed to isolate the cells from a few of the samples and will examine them in detail in a laboratory. Currently, scientists only know that these are microbial cells, but it is too soon to tell whether these are bacteria or archaea.
“Mantle rock contains a mineral called olivine, which turns into serpentine when it comes into contact with water at low temperatures. This produces hydrogen and methane. Both these gases provide a source of energy for microorganisms that have to manage without sunlight,” said Bernasconi-Green suggesting that the cells found were somehow capable of using gasses present within the rock, in order to carry out their metabolic processes, even though the microbes are exposed to more than hostile conditions where alkaline fluids that seep out of the vents make it nearly impossible for life to exist.
This is where it gets interesting. Bernasconi-Green said “The conversion of olivine to serpentine may occur on other planets too – on Mars, for example, where the presence of methane and hydrogen has already been established. Some scientists believe that would be sufficient in itself to allow the emergence of basic life forms.”
Six years ago, microbiologist Dr. Stephen Giovanini said the discovery might also have implications for understanding what life might be like on other planets or moons in the solar system: “The planet that everybody is most interested in is Mars because it’s known that there’s water on Mars. And it’s known that Mars is producing methane. And it’s a bit of a mystery of where that methane comes from. So one possibility is that it’s being produced by abiotic processes like this. And there’s always the possibility that there might be life on Mars. There’s no direct proof of that at this time. Enough is known about Mars to postulate that if there is life there, it’s probably some sort of subterranean life, occurring in rocks very much like the rocks that we were investigating in the North Atlantic.”
It seems that after all, we have to accept that life can thrive in the most unimaginable places on earth, and our solar system. This is why it is very likely that in the near future, we will stumble across alien life on Mars, or on Saturn’s moon Enceladus, where conditions for some sort of life can exist, proving scientists wrong in their theories that in order for life to exist, optimal and ideal conditions must exist.
Source and reference: ETH Zurich’s Institute of Geochemistry and Petrology
Featured image credit: Johan Swanepoel/Shutterstock