Alkaline hydrothermal vents are widely regarded as promising environments for the emergence of early chemolithoautotrophic metabolisms. However, their bulk physicochemical conditions—including elevated temperatures, alkaline pH, abundant metal ions, and rapid fluid flow—are generally unfavorable for the long-term persistence of RNA, amphiphiles, and other fragile prebiotic structures. Here, we propose the hypothesis that dynamically generated gas–liquid interfaces associated with microbubbles may have provided overlooked microscale niches within hydrothermal mixing zones. Such interfaces may concentrate organic molecules through interfacial adsorption, promote amphiphile assembly, and create localized gradients in temperature and pH. Rather than conferring complete molecular stabilization, these environments may have increased the persistence of prebiotic molecules relative to the surrounding bulk fluids, thereby extending opportunities for molecular interaction and selection. We further suggest that repeated cycles of interfacial concentration, film formation, and bubble collapse could facilitate vesicle formation and compartmentalization, providing a potential pathway from transient molecular assemblies to protocell-like structures. This framework generates experimentally testable predictions and highlights gas–liquid interfaces as a potentially important but underexplored component of alkaline hydrothermal origin-of-life scenarios.
S. Kato (Thu,) studied this question.