Microbes found alive inside a rock after 2 billion years

Deep beneath the Earth’s surface, an extraordinary discovery has been made. Microbes — alive and thriving — have been found sealed within a fracture of 2-billion-year-old rock.

This finding pushes the boundaries of our understanding of life’s resilience and longevity.

Lead researcher Yohey Suzuki, an associate professor from the Graduate School of Science at the University of Tokyo, couldn’t hide his excitement.

“We didn’t know if 2-billion-year-old rocks were habitable,” he said. “Until now, the oldest geological layer in which living microorganisms had been found was a 100-million-year-old deposit beneath the ocean floor, so this is a very exciting discovery.

By studying the DNA and genomes of microbes like these, scientists may be able to understand the evolution of very early life on Earth.

Bushveld Igneous Complex

The rock sample housing these ancient microbes was excavated from the Bushveld Igneous Complex (BIC) in northeastern South Africa.

Covering an area roughly the size of Ireland, the BIC is known for its rich ore deposits, including about 70% of the world’s mined platinum.

Due to its formation from slowly cooled magma and minimal changes over the millennia, the BIC provided a stable environment for microbial life.

The University of Tokyo team, with the support of the International Continental Scientific Drilling Program (ICDP) — a nonprofit organization that funds exploration at geological sites — obtained a 30-centimeter-long core sample from about 50 feet below the ground.

The rock varies in thickness up to 5.5 miles and has remained relatively undisturbed, making it an ideal habitat for organisms to persist over geological timescales.

Closer look at the rock microbes

When the team analyzed thin slices of the rock, they discovered microbial cells densely packed into tiny cracks.

These fractures were sealed off by clay, creating a closed system where the microbes could survive without outside interference. The cells appeared to be living life in slow motion, scarcely evolving over millions of years.

To ensure the microbes were indigenous to the rock and not contaminants, the researchers employed a refined technique involving three types of imaging: infrared spectroscopy, electron microscopy, and fluorescent microscopy.

By staining the DNA of the cells and examining the proteins and surrounding clay, they confirmed the organisms were alive and native to the ancient sample.

Clay-sealed microenvironments

One intriguing aspect of this discovery is the role of clay in preserving these microbes. The clay acted like a natural barrier, sealing off the cracks and preventing anything from entering or leaving.

This created a stable microenvironment where the organisms could survive for unimaginable lengths of time.

Such natural encapsulation raises interesting possibilities. Could similar mechanisms be at play elsewhere, perhaps even on Mars? If so, our chances of finding preserved life forms on other planets might be better than we thought.

Understanding early life on Earth

This discovery opens up new avenues for studying the early evolution of life on Earth. Finding organisms that have persisted in such ancient rocks allows scientists to peer back in time and understand how life may have adapted to extreme environments.

“I am very interested in the existence of subsurface microbes not only on Earth, but also the potential to find them on other planets,” Suzuki shared.

NASA’s Mars Perseverance rover is currently due to bring back rocks that are a similar age to those we used in this study.

“Finding microbial life in samples from Earth from 2 billion years ago and being able to accurately confirm their authenticity makes me excited for what we might be able to now find in samples from Mars,” Suzuki enthused.

Microbes, rocks, and alien life

The techniques perfected in this study could be instrumental in examining rock samples from other planets.

If microbes can survive sealed in rocks for billions of years on Earth, could similar life forms exist elsewhere in our solar system?

It’s a tantalizing question. The methods used to detect and confirm these ancient microbes might help us identify signs of life in Martian rocks. With missions like Perseverance bringing back samples from Mars, the possibilities are expanding.

Living time capsules

The idea that life can endure in such isolation and for such immense periods challenges our perceptions of survival and adaptation. These microbes are like living time capsules, offering a snapshot of life from eons ago.

By studying them, scientists hope to uncover clues about the conditions on early Earth and how life managed to take hold.

This finding also prompts us to reconsider the limits of life on Earth. If microbes can survive in such extreme and isolated conditions, what does that say about life’s ability to adapt?

It suggests that life is incredibly tenacious and can find a way in even the most inhospitable places.

New frontier in microbiology

To sum it all up, this finding doesn’t just push the boundaries of geology and biology — it opens a new frontier. The intersection of deep Earth studies and microbiology could lead to breakthroughs in understanding life’s resilience.

Researchers will continue to explore these ancient habitats, using the perfected techniques to avoid contamination and ensure authenticity. Each new discovery brings us one step closer to unraveling the mysteries of life’s origins.

As we look to the future, the implications of this research are vast. Could studying these ancient microbes help us prepare for discovering life beyond Earth? What adaptations allow these organisms to survive in such extreme conditions?

The answers may lie in continued exploration and cross-disciplinary collaboration. One thing is certain: the Earth’s deep places still have many stories to tell.

The full study was published in the journal Microbial Ecology.

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