Life Below Earths Ocean Floor Give Scientists Hope for Finding Life on Mars

Ten years ago, scientists from the University of Tokyo, Japan, led an expedition to drill into rock 400 feet below the ocean floor. They have been studying the various rock samples, ranging in age from thirteen million years to 104 million years, ever since. Theses ocean rocks formed when undersea volcanoes spewed out lava which cooled into fractured rock and became buried under ocean sediment. The cracks filled with clays from the ocean floor.

The scientists knew that rocks beneath the surface of dry land were home to bacteria, and they looked for bacteria living in the ocean rocks. After intense study, with some missteps along the way, they finally found dense bacterial colonies, numbering more than 100 billion bacterial cells per cubic inch, living in the clay-filled cracks. This density of bacteria is similar to that found in the human gut. That compares to a paltry 1000 bacteria per cubic inch living in the muddy layers above the rock on the ocean floor.

"I thought it was a dream, seeing such rich microbial life in rocks," said Associate Professor Yohey Suzuki from the University of Tokyo, one of the leaders of the expedition. "Honestly, it was a very unexpected discovery. I was very lucky because I almost gave up."

This finding excites astrobiologists who search for signs of past, or present, life on Mars. Much of Mars was once covered by lakes and oceans, with similar clay minerals. Just as in the Earth study, Martian ocean sediments were eventually covered and compressed into rock at the bottom of those bodies of water.

"Minerals are like a fingerprint for what conditions were present when the clay formed. Neutral to slightly alkaline levels, low temperature, moderate salinity, iron-rich environment, basalt rock -- all of these conditions are shared between the deep ocean and the surface of Mars," said Suzuki.

Mars 2020 Rover Perseverance. Credit NASA

NASA will launch the next Martian rover, Perseverance, in late July or early August. Among other scientific instruments, Perseverance posses a biological testing lab that will search for similar bacterial colonies, living or fossilized, in similar Martian rock that was once the bottom of a Martian sea. The findings of Dr. Suzuki’s team gave NASA scientists the road map for searching for ancient, Martian bacterial colonies that may, perhaps, tell us that Mars was once, possibly still is, a home for life.

 Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

This is reprinted by permission from the Oklahoman and www.newsok.com.