Hydrothermal vents were not the cradle of life: Calgary geochemist refutes long-standing hypothesis

Benjamin Tutolo, a leading geochemist at the University of Calgary, has published a study in the prestigious scientific journal PNAS that calls into question one of the most enduring theories in the biology of the origin of life. For several decades, the scientific community has adhered to the view that the first living organisms emerged near deep-sea hydrothermal vents — underwater "chimneys" that release heat, hydrogen, and alkaline solutions. The discovery in 2000 of the "Lost City" hydrothermal field in the Atlantic Ocean, with its tall carbonate chimneys, only reinforced this paradigm. However, according to Tutolo, the entire concept rests on outdated and, as it turns out, false assumptions about the chemical conditions that prevailed on Earth nearly four billion years ago.

The sulfur that was not there, and the gradients that could not have existed

The key error, as pointed out by the geochemist, concerns the role of sulfide minerals. For many years, scientists considered them the main catalysts of primary metabolism in hydrothermal systems. Nevertheless, as a re-examination of the data shows, the alkaline vents, the surrounding rocks, and the ancient ocean itself contained essentially no sulfur in quantities sufficient to drive the chemical reactions necessary for the emergence of life. Moreover, the powerful proton gradients — the difference in hydrogen ion concentration between the alkaline fluid of the vents and the acidic ocean — which, according to earlier models, were supposed to provide the energy for primary metabolism, simply could not have existed under real conditions.

A measurement error: alkalinity "inflated" by cooling

A special place in Tutolo's argumentation is occupied by a methodological error made in interpreting data on the alkalinity of hydrothermal fluids. High alkalinity readings were recorded only when the liquid samples were brought to the surface and cooled. Under the enormous pressure and extreme temperatures on the ocean floor, these same solutions had a significantly lower alkalinity than had been assumed. Thus, the fundamental parameter on which the entire "alkaline vents as the cradle of life" model was built turned out to be overestimated due to a sampling artifact.

Evaporative lakes as the new cradle

Rather than deep-sea vents, Tutolo suggests redirecting attention to surface water systems. According to his analysis, it is precisely in evaporative basins and lakes — temporary water bodies subject to cycles of evaporation and concentration of dissolved substances — that the combination of chemical conditions necessary for the synthesis of key components of living cells arises: ribonucleic acid (RNA), proteins, and lipids. These conditions include periodic changes in salt concentration, fluctuations in pH, and the availability of organic molecules, which makes evaporative lakes a far more likely environment for the emergence of the first biochemical systems than stable underwater vents.

Impact on the search for extraterrestrial life

Revising the place where life originated on Earth has direct practical consequences for astronomy and planetary science. In Tutolo's own words, the targeted search for traces of biological activity at hydrothermal vents on Mars or on the icy moons of Jupiter and Saturn — Europa, Enceladus, Titan — may prove futile if life on these bodies (should it exist) arose through a different scenario. At the same time, the chances of detecting extraterrestrial life do not disappear: evaporative lakes could theoretically form on the surfaces of other planets and moons, opening a new direction for future missions and observations.

Context: parallel research on the origin of life

Tutolo's work is not the only one in recent years to have revised established views on the origin of life. In particular, in March 2025, a group of researchers, the results of which were reported by Gazeta.ru, demonstrated that calcium ions may have played a significant role in stabilizing early biomolecules and influencing the conditions for the emergence of life. These parallel lines of research indicate that the scientific community is undergoing a large-scale revision of abiogenesis models, and none of them is yet definitive.