Opening details

The organisms found in the rock are special because they have been separated from the Earth for billions of years, much longer than any other living thing we’ve ever seen. Scientists in the journal Microbial Ecology say the record so far has been microbes evolving alone over 100 million years.

Microbes in isolated underground pockets like this tends to develop more slowlyBecause they are isolated from many factors and influences that drive evolution in more crowded and vibrant habitats. This means that the newly discovered community of microbes is genetically much closer to their ancient ancestors than their surface relatives. This colony could tell us something we didn’t know before about the evolution of microbes on Earth.

It is also suggested that Mars may have had underground microbial communities that penetrated deep into the rock long before water disappeared from the planet’s surface. By the way, theories about this have been around for a long time.

We didn’t know if 2 billion year old rocks were habitable. By studying the DNA and genomes of such microbes, we can understand the very early evolution of life on Earth.
– say scientists.

The 30-centimeter sample was retrieved from a depth of 15 meters with the help of the International Continental Scientific Drilling Programme. The Bushveld Igneous Complex in northeastern South Africa, where the rock is cored, is a massive formation covering 66,000 square kilometers. Its age is estimated to be approximately 2 billion years. It was formed from molten magma that cooled below the Earth’s surface.

A sample of the rock obtained by scientists / Photo: Yohei Suzuki

Geomicrobiologist Yohei Suzuki from the University of Tokyo and his colleagues have done a tremendous study on this subject. Making sure the microbes they find are indigenous and not the result of contamination from the mining process. They used a technique developed several years ago that involved sterilizing the outside of the sample before dissecting it and examining its contents.

They then used cyanine dye to paint the sections. This dye is special because it binds to the DNA of living organisms. Before, If there is DNA in the sample it should burnLike a Christmas tree. That’s exactly what happened.

The scientists say the sample was permeated with clay, which filled veins near pockets in the rock near microbial colonies. The result of this clay packaging was multifaceted: it provided microbes with a resource for life, organic and inorganic materials that they could metabolize. It also effectively insulated the rock, preventing both microbes from escaping and anything else from getting in, including drilling fluid.

Microbes on the rock are illuminated in green / Photo: Yohei Suzuki

What’s next?

Scientists will now analyze the microbes’ DNA to determine how they have changed in the 2 billion years since their ancestors were isolated from the rest of life on Earth.

The team will extract more samples from the Bushveld Igneous Complex to help characterize the microbes found there and fit them into Earth’s evolutionary history.

And of course this will have implications for what we want and can find beyond Earth.

I am very interested in the existence of subterranean microbes not only on Earth, but also in the possibility of their existence on other planets.
– Suzuki says.

NASA’s Perseverance rover collected several samples on Mars and scattered them across the planet’s surface. If the institution can find the funding to bring these samples to Earth, we may find the same in these samples. Although the ages of these rocks are almost the same, it is worth noting that the Mars samples were obtained from the surface, not from a depth of 15 meters. Given the aggressive radiation on the Red Planet, the chances of anything alive existing there are almost zero. But we might find something fossilized.