The role of silica in the dawn of life on our planet

Informations projet

PROTOS

N° de convention de subvention: 101118811

DOI

10.3030/101118811

Date de signature de la CE 24 Juin 2024

Date de début 1 Juillet 2024

Date de fin 30 Juin 2030

Financé au titre de

• European Research Council (ERC)

Coût total

€ 9 996 000,00

Contribution de l’UE

€ 9 996 000,00

Coordonné par

FUNDACION DONOSTIA INTERNATIONAL PHYSICS CENTER
Spain

Periodic Reporting for period 1 - PROTOS (The role of silica in the dawn of life on our planet)

Période du rapport: 2024-07-01 au 2025-12-31

Résumé du contexte et des objectifs généraux du projet

All information humankind has of the ancient past of our planet comes from analyzing the geological record encoded in rocks. There is, however, no rock record of the first 600 million years of Earth’s history. Unlocking the secrets of this earliest period –the Hadean– is a fundamental task for science, as it is key to understanding how the planet became habitable, when the first forms of metabolism and self-replication developed, and life appeared. The lack of a geological record has led scientists to use computational modeling to make inferences about the conditions in Early Earth’s environments. Less common are laboratory experiments specifically targeted to simulating Hadean conditions. Based on ubiquitous carbonaceous chert deposits in the oldest rock record, it is widely accepted that many early Archean aquatic settings were reducing and rich in silica and some basic carbon-based molecules. We reason that such aquatic conditions were already established during the early Hadean, and inevitably led to the existence of a large-scale factory of simple and complex organic compounds, many of them relevant to prebiotic chemistry and to the route to biomimetic hybrid microstructures able to self-organize and catalyze prebiotic reactions relevant to the origin of life. Our project is aimed at understanding the crucial role of silica in directing the geochemical and protobiological processes, creating habitats for early life, and preserving early biomass on Earth’s surface during the first billion years of its history. PROTOS will use an array of laboratory experiments to systematically study ab-initio reactions of water and gases with the earliest rock types in order to determine compositions of aquatic habitats and subsequent silica precipitation mechanisms, organic synthesis processes on silica/iron surfaces, and the preservation of the first remnants of life. PROTOS will change our view of the infancy of the planet.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

High-temperature water–rock interaction experiments show that Fe-solution react with calcite and magnesite to produce magnetite and release H2. At ambient temperatures, H2 is produced by a previously unrecognized mineral self-organization mechanism capable of generating sustained redox gradients. Time-resolved analyses show that membrane-forming mineral structures create localized chemically reactive microenvironments even when the surrounding system is not strongly reducing. A quantitative reactive transport model reproduces mineral growth, diffusion and redox evolution, linking experimental observations with theoretical predictions. The broader implications of this mineral-driven energy generation mechanism are currently being evaluated internally to assess its technological scope and applicability, while dedicated scientific publications are in preparation. Together, these results provide experimental evidence that mineral-mediated processes could have supplied both energy and compartmentalization relevant to early chemical evolution. At the same time, systematic investigations of silica solubility and nucleation across a wide pH range have revealed deviations from classical alkaline solubility models, refining current understanding of silica speciation. Advanced analytical approaches will allow exploring the role of early-stage silica clusters and polymerization dynamics, including biomorph formation with carbonates and Fe(II). Newly developed microfluidic reactors enable controlled diffusion-driven mineral growth and real-time observation of biomorph formation and silica–metal membrane development. These experiments demonstrate that purely physicochemical processes can generate complex tubular and vesicle-like morphologies, highlighting the importance of robust abiotic reference frameworks when interpreting potential biosignatures. Prebiotic chemistry experiments further expand this integrated approach. A time-resolved Miller-type reactor has been developed to continuously monitor gas-phase chemistry during spark-discharge simulations. The results show that prebiotic synthesis unfolds as a dynamic reaction network rather than a simple linear pathway, characterized by rapid methane consumption, accumulation of reduced species, transient hydrocarbon intermediates and sustained formation of oxidized carbon compounds. Solid organic films produced under these conditions have been characterized spectroscopically, and ongoing research explores mineral catalytic effects and isotopic signatures.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

By combining hydrothermal geochemistry, silica physical chemistry, prebiotic reaction networks and isotope geochemistry, PROTOS moves beyond isolated experimental approaches toward an integrated reconstruction of silica-rich Hadean environments. A major advance lies in the identification of a silica-mediated mineral self-organization process capable of generating sustained redox gradients within compartmentalized systems. Rather than relying solely on bulk water–rock reactions, the project demonstrates that self-organized mineral architectures can maintain localized reactive microenvironments. Coupled experimental and modelling results provide quantitative evidence that such systems could have supplied both chemical energy and spatial organization for early chemical evolution. The broader technological implications of this mechanism are currently under internal evaluation. The project also refines silica and iron(II) chemistry under alkaline conditions by resolving speciation and nucleation dynamics beyond traditional models. Integrating silicon isotope data from laboratory systems and natural cherts creates a direct bridge between controlled experiments and the geological record, improving frameworks for biosignature discrimination. Time-resolved monitoring of Miller-type experiments redefines prebiotic chemistry as a dynamic, evolving network of reactions, enabling direct coupling between mineral self-organization and organic synthesis. In parallel, artificial silicification and alteration experiments provide quantitative constraints on biosignature preservation pathways, strengthening interpretation of Archean rocks and informing planetary exploration of silica-rich hydrothermal deposits. Together, these advances establish a coherent and mechanistic framework for understanding how silica-rich systems may have influenced early chemical evolution and the preservation of life’s earliest traces.

Protocells hanging on the SOF. By Jenewein et al., 2024.

Artist’s vision of Hadean era, the geochemical scenario of the origin of life that PROTOS will study