The Secret of Survival of Organisms in the Earth's Depths Revealed

Chinese researchers have discovered how microorganisms in the Earth's interior obtain energy without sunlight. It turns out that living organisms in deep rocks use chemical reactions caused by tectonic faults as an energy source - thereby disproving the well-known principle that "all life depends on the Sun." The work is published in the journal Science Advances (SciAdvances).

The study was conducted by Professor He Hongping and Professor Zhu Jianxi from the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences. They modeled the processes occurring during crustal faults and found that at the moment of crack formation in rocks, free radicals are released that can split water. This results in the formation of hydrogen and hydrogen peroxide - substances that create a strong redox gradient in fracture zones.

This gradient triggers reactions with iron in water and rocks: depending on the conditions, iron can transition from divalent form (Fe²⁺) to trivalent form (Fe³⁺) and back. Such processes support the biochemical cycles of carbon, nitrogen, and sulfur, providing microbes with the necessary substances for life.

Scientists note that during earthquakes and other tectonic fault processes, the amount of hydrogen released can be 100,000 times higher than in other known mechanisms, such as serpentinization or water radiolysis. This makes faults one of the most efficient energy sources for underground life.

The results of the work provide a new understanding of how the biosphere is structured in the deep layers of the Earth, where there is neither sunlight nor organic matter. Moreover, according to the authors, similar conditions may exist on other Earth-like planets, which expands the prospects in the search for extraterrestrial life.