Who says you need air and sunlight to live?

Scientists find life thriving in the hostile oceanic layers of the Earth’s crust

by Daisy Dunne

Scientists studying the activity of the “dark biosphere”, the portion of the Earth shrouded in both darkness and mystery, have revealed how tiny organisms called microbes can obtain the energy required for life directly from their rocky surroundings of the oceanic crust - the layer of rock found covering the Earth directly beneath the sea. Life found deep within the oceanic crust of the Earth has the potential to make up the biggest ecosystem, a functioning unit considering all living organisms as well as their physical environment, the world has ever seen. This is due to the fact that 60% of the Earth’s surface is covered by oceanic crust. This new discovery poses a great challenge to pre-existing views concerning the normal conditions of life, which are based on the theory that energy is fixed by plants from sunlight and passed from organism to organism through a food chain. In contrast, scientists have shown how an astounding number of organisms can exploit energy from the natural reaction of infiltrating sea water with the inorganic (non-living) substances found in the rocky crust.

Why is this new revelation so important? Finding a thriving community of organisms living independently of sunlight and oxygen strengthens the idea that there may indeed be life on other planets. Similar life forms to such microorganisms could potentially exist be deriving energy in the absence of appropriate light from rocky deposits found in their own planet’s constitution. One of the microbiologists behind the paper, Dr Mark Lever, hopes his findings will contribute to our understanding of extra-terrestrial life. He suggests, "I think it's quite likely there is similar life on other planets. On Mars, even though we don't have oxygen, we have rocks there that are iron-rich. It's feasible that similar reactions could be occurring on other planets and perhaps in the deep subsurface of these planets." This research opens a whole new door to the possibilities of life in hostile but mineral-rich environments, both on Earth and on other planets, that were previously disregarded as unsuitable to sustaining life.    

Scientific paper: http://www.sciencemag.org/content/339/6125/1305