They should have died billions of years – but they are still alive in Japan

Researchers studying five hot -rich hot sources in Japan have identified microbial communities that resemble those who have existed during one of the most important environmental transitions of the earth. These ecosystems help researchers understand how life has worked in the low oxygen and predominance of iron and conditions that marked the Earth’s oceans about 2.3 billion years ago.

This era, known as the major oxygenation event, saw atmospheric oxygen levels increase considerably, forcing early forms of life to adapt or disappear. Although many microorganisms cannot survive the change, a small group has found ways to persist – and hot sources in Japan can hold the key to understanding how they did.

Hot -rich hot springs as analogues of early earth

Hot sources, located across Japan, provide a rare combination of geochemical conditions: high levels of ferrous iron, low oxygen concentrations and almost neutral ph values. These factors reflect what scientists believe they are dominant characteristics of the ancient oceans at the start of oxygenation. According to research published in the journal Microbes and environmentSprings act as natural laboratories to rebuild microbial life at the end of Archaean proterozoic eras at the first.

“”These hot -rich hot sources provide a unique natural laboratory to study microbial metabolism in earth -type conditions“Said Shawn McGlynn, one of the study authors. His team, based in Earth-Life Science Institute and the Institute of Tokyo Sciences, analyzed microbial genomes and metabolic functions found in the springs.

Out of five springs studied, four have proven to host dominant populations of bacteria oxidizing iron – microbes that use ferrous iron as a primary energy source. These organisms flourish in low oxygen content and can reflect how an early microbial life avoided extinction during the rise of the oxygen from the earth.

Dominance of iron oxidators and microbial diversity

The research team has recovered and analyzed more than 200 high quality microbial genomes from spring ecosystems. The data showed a coherent scheme: microaerophilic iron oxidants were dominant, coexisting with smaller populations of cyanobacteria producing oxygen and anaerobic microbes. These communities have proven to support almost complete biogeochemical cycles involving transformations of carbon, nitrogen and sulfur.

“”Despite the differences in geochemistry and microbial composition on the sites“Noted the co-author of the Fatima li-hau study,”Our results show that in the presence of ferrous iron and limited oxygen, communities of microaerophilic iron oxidant, oxygenic photommers and anaerobicity coexist and constantly maintain remarkably similar and complete biogeochemical cycles. “”

Interestingly, only one of the five hot sources has shown different microbial makeup. At this location, metabolisms not based on iron were dominant – a divergence that researchers plan to examine more closely in future work. But the general consistency of iron -based systems in the other four springs suggests a widespread survival strategy dating billions of years.

Implications for planetary science and the first ecosystems

The results could reshape the way scientists think of the early biosphere of the earth. Rather than being entirely swept away by the increase in oxygen, some microbial ecosystems may have sculpted ecological niches, using iron as a source of energy while coexisting with newly emerging oxygen photos. The springs closely offer the structure and function of these old systems.

This detailed image of early microbial ecology does not only concern the understanding of the past of the earth. This could also influence the current research in life beyond our planet. The environmental conditions preserved in these Japanese springs – launch oxygen, rich iron and neutral pH content – can also exist elsewhere in the solar system or on exoplanets.

Research, emphasizing how life can adapt to drastic planetary changes, throws a base to explore organic resilience in unknown environments. As Li-Hau said, “This article expands our understanding of the function of microbial ecosystems during a crucial period in the history of the earth, the transition of an anoxic ocean rich in iron to an oxygenated biosphere. “”