A new ecosystem has been discovered deep in the oceanic crust.
The oceanic crust is huge, covering 60 percent of the surface of our planet, making this new ecosystem the largest on Earth.
“We’re providing the first direct evidence of life in the deeply buried oceanic crust. Our findings suggest that this spatially vast ecosystem is largely supported by chemosynthesis,” Dr. Mark Lever, a microbiologist at the Center for Geomicrobiology of Aarhus University in Denmark, said.
Life on the surface has given us a biased view of life’s energy sources. Above water, plants harness energy from the sun in photosynthesis. Herbivores gain this energy when they eat the plants. Carnivores get this energy when they eat the herbivores and this happens all the way up the food chain. But deep within the oceanic crust, where sunlight can’t penetrate 2.5 kilometers of water, and certainly not the hundreds of meters of the mud that sits at bottom, highly specialized organisms harvest energy from a different initial source.
“There are small veins in the basaltic oceanic crust and water runs through them. The water probably reacts with reduced iron compounds, such as olivine, in the basalt and releases hydrogen. Microorganisms use the hydrogen as a source of energy to convert carbon dioxide into organic material,” Lever told Phys Org.
Scientists have known that life can exist that far down, but had not seen direct proof of the organisms existence.
“So far, evidence for life deep within oceanic crust was based on chemical and textural signatures in rocks, but direct proof was lacking,” said Dr. Olivier Rouxel of the French IFREMER institute.
This discovery could mean big things for studying where life can exist. If organisms can live in pitch darkness, buried in mud and living off reduced iron for sustenance, could other species living off chemosynthesis exist on other planets?
"Life in the deeply buried oceanic crust is supported by energy-sources that are fundamentally different from the ones that support life in both the mud layers in the sea bed and the oceanic water column. It is possible that life based on chemosynthesis is found on other planets, where the chemical environment permits,” said Dr. Lever. “Our continued studies will hopefully reveal whether this is the case, and also what role life in the oceanic crust plays in the overall carbon cycle on our own planet.”
