Scientists discovered bacteria living in ancient rock samples buried beneath sediment at the bottom of the Pacific Ocean. Photo by Caitlin Devor/The University of Tokyo/CC

April 2 (UPI) -- If bacteria can survive inside the cracks of ancient rocks buried beneath the ocean floor, surely they can live on Mars. That's the logic of Yohey Suzuki, a researcher at the University of Tokyo.

Suzuki's latest findings suggest bacteria can survive without much help from photosynthesis. The Japanese researcher found a dense community of bacteria living in tiny cracks in volcanic rock formed millions of years ago.


When underwater volcanoes spew molten magma across the sea bed, the lava quickly hardens into basalt. Tiny cracks form as the rock cools. Over time, these cracks become filled with clay minerals.

According to the latest study, published Thursday in the journal Communications Biology, bacteria also work their way into these cracks. The deep sea rock cracks are more inviting than one might imagine.

"It is difficult to believe but ancient basalt rocks are very comfortable for life," Suzuki told UPI in an email. "Clay is known to concentrate organic matter from the surrounding dilute solution."

The bacteria found in the cracks are aerobic bacteria. Like humans, they need oxygen and organic matter to survive. Without organic matter from photosynthesis, the bacteria must find alternative sources of energy. The new findings suggest clay minerals provide the bacteria with a consistent source of organic matter.

The research bodes well for the search for life on Mars, as the deep sea rock cracks are similar to rock environs found on the Red Planet.

"Organic matter provided from photosynthesis is extremely low," Suzuki said. "The same rock type (basalt) and clay that is abundant in Martian basalt is the same type as that found in this study. Clay is very diverse and sensitive to conditions under which it forms. The same clay means that the environment is very similar (temp, salinity, pH)."

Suzuki and his colleagues collected the ancient rock samples during an expedition to the South Pacific in 2010, part of the Integrated Ocean Drilling Program. Researchers also collected seafloor mud samples.

Surprisingly, the ancient rock cracks hosted higher densities of bacteria than the mud samples.

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Suzuki developed a careful sanitizing technique to prevent the ancient basalt rock samples from getting contaminated prior to analysis.

"I just sterilized the outside of the rock sample," Suzuki said. "After the rock surface sterilization, I opened the cracks to avoid contamination from the surface without harming."

Scientists hope their bacteria hunting techniques will help planetary scientists better prepare for the future Mars missions and the ongoing hunt for life on the Red Planet.

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"We are targeting deeper and older rocks from the oceanic crust," Suzuki said. "We are also targeting clay-filled faults that may cause large earthquake near future."