New Extremophiles: ocean floor three kilometers down (Introduction)

by David Turell , Friday, April 03, 2020, 00:52 (1483 days ago) @ David Turell

More discoveries:

https://www.sciencedaily.com/releases/2020/04/200402080506.htm

"Newly discovered single-celled creatures living deep beneath the seafloor have provided clues about how to find life on Mars. These bacteria were discovered living in tiny cracks inside volcanic rocks after researchers perfected a new method cutting rocks into ultrathin slices to study under a microscope. Researchers estimate that the rock cracks are home to a community of bacteria as dense as that of the human gut, about 10 billion bacterial cells per cubic centimeter.

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"Undersea volcanoes spew out lava at approximately 1,200 degrees Celsius (2,200 degrees Fahrenheit), which eventually cracks as it cools down and becomes rock. The cracks are narrow, often less than 1 millimeter (0.04 inch) across. Over millions of years, those cracks fill up with clay minerals, the same clay used to make pottery. Somehow, bacteria find their way into those cracks and multiply.

"'These cracks are a very friendly place for life. Clay minerals are like a magic material on Earth; if you can find clay minerals, you can almost always find microbes living in them," explained Suzuki.

The microbes identified in the cracks are aerobic bacteria, meaning they use a process similar to how human cells make energy, relying on oxygen and organic nutrients. (my bold)

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"Then, a drill cut down 125 meters below the seafloor and pulled out core samples, each about 6.2 centimeters across. The first 75 meters beneath the seafloor were mud sediment and then researchers collected another 40 meters of solid rock.

"Depending on the location, the rock samples were estimated to be 13.5 million, 33.5 million and 104 million years old. The collection sites were not near any hydrothermal vents or sub-seafloor water channels, so researchers are confident the bacteria arrived in the cracks independently rather than being forced in by a current. The rock core samples were also sterilized to prevent surface contamination using an artificial seawater wash and a quick burn, a process Suzuki compares to making aburi (flame-seared) sushi.

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"The bacteria appeared as glowing green spheres tightly packed into tunnels that glow orange, surrounded by black rock. That orange glow comes from clay mineral deposits, the "magic material" giving bacteria an attractive place to live.

"Whole genome DNA analysis identified the different species of bacteria that lived in the cracks. Samples from different locations had similar, but not identical, species of bacteria. Rocks at different locations are different ages, which may affect what minerals have had time to accumulate and therefore what bacteria are most common in the cracks.

"Suzuki and his colleagues speculate that the clay mineral-filled cracks concentrate the nutrients that the bacteria use as fuel. This might explain why the density of bacteria in the rock cracks is eight orders of magnitude greater than the density of bacteria living freely in mud sediment where seawater dilutes the nutrients."

Comment: Am article about a study thinking about finding life on Mars. But its point for us is the amazing tenacity of life on Earth. These are aerobic organisms!!! The designer did a great job.