Microbes Have Huge Ecosystem Beneath Ocean Floors And Could Live On Other Planets Too

A vast underground world of microbe is buried hundreds of meters beneath the ocean floor inside of the oceanic crust, which in turn is covered by several kilometers of water, according to a new study that analyzed samples from such a location. It could turn out to be one of the largest ecosystems on the planet, that possibly influences global elemental cycles and may also help guide future searches for new life forms in space.

Mark Lever, a microbiologist at Aarhus University in Denmark and lead author of the study, extracted borehole cores with the rocks and their microbes in 2004, during an international research expedition to the eastern flank of the Juan de Fuca Ridge off the Washington coast. The water there is 2.6 kilometers deep and an 260 meters blanket of mud buries the crust. Detailed studies by other groups show seawater circulates through the crust here. Scientists collected samples of basalt that had formed about 3.5 million years ago, and discovered DNA from microbes that could "metabolize sulphur compounds" and even a few that produced methane, according to Nature.com.

"Our evidence suggests that this is an ecosystem that is based on chemosynthesis and not on photosynthesis, which would make it the first major ecosystem on Earth that is based on chemosynthesis," explained Lever.

While researchers have known about bacteria and other such microbes hiding under oceanic crust for some time, the recent study was the first to recognize the range of their existence within the crust. Under careful handling to prevent contamination, Lever also raised the bacteria in a lab at the University of North Carolina, Chapel Hill, for five years. The microorganisms released puffs of methane, adding proof of an active crustal community. In the future, they could also help explain the possibility of life on other planets, said scientists.

"I think it's quite likely there is similar life on other planets," Lever said. "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."

Earlier in the week, NASA said it had learned the chemical makeup for life in rocks on Mars, building blocks that include sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. According to researchers, the recent study indicates Mars could have supported microbial life at some point.

"As long as there's space for microbes, and biochemistry, life persists," said Andreas Teske, a microbial ecologist at the University of North Carolina, and co-author of the study.

"Deep subsurfaces could be the best hiding place for life on other planets, where surface conditions are too harsh but the right chemical conditions are available below."