A tiny organism has been found doing something that seemed almost impossible: remaining alive inside rock that is about 2 billion years old. The discovery in South Africa pushes the known limits of life deep into the planet’s crust and sets a new record for the oldest living microorganism ever found in ancient rock.
The microbe was recovered from samples taken in the Bushveld Igneous Complex, a vast geological formation created when magma cooled beneath the Earth’s surface roughly 2 billion years ago. The area spans about 66,000 square kilometers and is also known as one of the world’s major mineral stores, holding around 70% of global platinum reserves.
What makes the finding especially striking is not only the age of the host rock, but the likely stability of the environment around it. Scientists believe the rock’s long-term isolation helped preserve narrow fractures where the microorganism survived with little disturbance from outside conditions.
How scientists ruled out contamination
Studying life this old always carries a serious risk of contamination from drilling tools, air, or modern biological material. To avoid that problem, the research team used several methods to confirm that the microorganism truly came from inside the rock.
They applied infrared spectroscopy to examine the chemical composition around the microbe. The team also used electron and fluorescence microscopy to inspect cell structures and to tag microbial DNA, helping verify that the organism was alive.
Clay analysis added another layer of confidence. Natural clay layers indicated that the rock fractures had remained sealed for a very long time, making it extremely unlikely that outside organisms could have entered later.
Yohey Suzuki of the Graduate School of Science at the University of Tokyo said the team previously did not know whether 2-billion-year-old rock could still serve as a habitat for life. That uncertainty highlights how much of the subsurface world on Earth remains unexplored.
A record that exceeds previous discoveries
The South African finding goes far beyond the former record for the oldest known living microbe in rock. Before this, the oldest living microorganism had been found in 100-million-year-old deep-sea sediment.
That gap in age is enormous, and it changes how scientists think about the persistence of life in extreme environments. It suggests that life can survive in far older and more isolated places than researchers had previously assumed.
The microbes living beneath the surface are also thought to run on extremely slow metabolism. Because of that, their evolutionary changes are believed to happen much more slowly than in organisms living at the surface.
Why the discovery matters beyond Earth
The microorganism was found about 15 meters below the ground, inside rock that is estimated to be about 2 billion years old. That combination of depth, age, and geological isolation makes the discovery one of the strongest signs yet that life can endure deep within Earth’s crust.
The finding also matters for the study of early life. By examining the genome of such a microbe, scientists may be able to treat it as a kind of time capsule that preserves traces of very ancient biology.
The methods used in the study may also help astrobiology research. The contamination-avoidance techniques and rock analysis could guide future investigations of Martian samples that are brought back to Earth.
Mars has ancient rocky environments that are considered similar in some respects to those studied in South Africa. For that reason, the discovery may help scientists design better ways to search for signs of life without being misled by outside contamination.
Source: mediaindonesia.com
