Deep within the ocean’s black smokers, the swirling hydrothermal vents that have intrigued scientists for years, lies a potential glimpse into Earth’s earliest life forms. An international team of researchers may have uncovered the fossilized evidence of ancient microbial activity, a discovery with profound implications not only for our planet’s history but also for the possibility of life elsewhere in the cosmos.
At the heart of this groundbreaking study are iron-sulfur minerals, specifically pyrite, commonly known as “fool’s gold.” The team, which includes Eric Runge, Professor Jan-Peter Duda, Professor Andreas Kappler, and Dr. Muammar Mansor, has focused on these minerals’ unique shapes, which could be indicative of bacterial processes occurring in deep-sea hydrothermal vents billions of years ago. Published in Communications Earth & Environment, their research provides compelling insights into the origin of life.
Hot springs on our planet have been around for at least 3.77 billion years, presenting dynamic environments rich in organic substances that could have catalyzed the emergence of life. These environments are not limited to Earth.
“However, research into biosignatures is not relevant solely for deciphering the history of life on Earth,” says Jan-Peter Duda. “Hot springs, similar to those on the ocean floor, could occur for example on Saturn’s moon Enceladus. If there is life there, it is most likely to be microorganisms. Studies like ours provide the basis for recognizing the traces of such organisms.”
“In order to understand how life originated, we are following the evolution of microorganisms back billions of years. To do this, we are looking for traces of life, which we call biosignatures, in the oldest rocks on earth,” explains Eric Runge explains Eric Runge. Distinguishing between minerals shaped by living organisms or by non-biological processes is a delicate task, and the team is refining their methods to spot these life indicators.
“In our analyses, pyrite in its characteristic spherical form proved to be particularly interesting, with a structure similar to that of a raspberry,” reports Andreas Kappler. “It only formed in this shape when the starting material—magnetite—was formed by iron-reducing bacteria.”
Both types of magnetite dissolved rapidly, yet the resultant crystal forms diverged significantly over the course of weeks. “While pyrite crystals—branched and shaped like fir trees—formed in the experiments with non-biological magnetite, the pyrite in the experiments with biological magnetite was more spherical,” Runge notes.
Relevant articles:
– Iron-sulfur minerals may bear witness to first microbes on Earth that lived billions of years ago, Phys.org