Microbes have been found living deep inside this crust at the bottom of the sea. The
crust is several kilometers thick and covers 60 percent of the planet’s surface, making it the largest habitat on Earth
For the first time, scientists have discovered microbes living deep inside Earth’s oceanic crust — the dark volcanic rock at the bottom of the sea. This crust is several kilometers thick and covers 60% of the planet’s surface, making it the largest habitat on Earth.
The microbes inside it seem to survive largely by using hydrogen, formed when water flows through the iron-rich rock, to convert carbon dioxide into organic matter. This process, known as chemosynthesis, is distinct from photosynthesis, which uses sunlight for the same purpose.
Chemosynthesis also fuels life at other deep-sea locations such as hydrothermal vents, but those are restricted to the edges of continental plates. The oceanic crust is much bigger. If similar microbes are found throughout it, the crust “would be the first major ecosystem on Earth to run on chemical energy rather than sunlight”, says Mark Lever, an ecologist at Aarhus University in Denmark, who led the study. The results are published in Science.
“This study is highly significant in that it confirms the existence of a deep-subsurface biosphere that is populated by anaerobic microorganisms,” says Kurt Konhauser, a geomicrobiologist at the University of Alberta in Edmonton, Canada. …
“Given the large volume of sub-sea-floor crust, one can’t help but wonder how the amount of living biomass there compares to that at the Earth’s surface,” says Konhauser. …
Flash back to Dec 2006 and this stunning discovery:
Radioactivity Feeds Microorganisms in Deep Biosphere
It’s like in “Journey to the Center of the Earth” by Jules Vernes.
Earth does not cease to reserve us surprises, in an era when we plan colonies on the Moon….
The researchers found living microorganisms in drilled cores from up to 400 meters below the sea floor; contamination was ruled out….
In the upper layers of sediment, up to 100 million microorganisms/ml were counted; deeper, in the 35 million year old sediments on the Earth’s crust, there were still 1 million microorganisms/ml.
Only the upper layers are in contact with the ocean water, so scientists were puzzled by where the energy to provide life in the depths of the sediment came from.
Taking as a basis the energy sources in the deposits that are available to the cells in the form of organic carbon compounds, it is possible to calculate that the cells could only divide every thousand years, which is not plausible with current understanding of living cells.
They found a model which explains microorganisms’ survival due to the natural radioactivity deep under the sea floor. This provides energy that breaks water apart in hydrogen and oxygen.
Radioactivity is produced by the decomposition of naturally occurring potassium, thorium and uranium isotopes.
This process can deliver sufficient energy for the microorganisms, making these communities independent from the Earth’s surface. …
In my mind this fantastically supports the idea of microbes from outer space surviving a journey of millions of years inside comets where radioactivity (Aluminum, and/or longer lived Potassium, Thorium, Uranium) would provide energy.