Staging Life in an Early Warm ‘Seltzer’ Ocean

The stage for the origin of life may have been set during a period that was as short as 20 million years within the first 100 million years after the formation of the Moon (at ~4.5 Ga). The atmosphere at that time contained more carbon dioxide than at any other period thereafter. Carbon dioxide sustained greenhouse conditions, accelerated the weathering of a primitive crust, and may have led to conditions conducive to forming the building blocks of life. The conversion of inorganic carbon and nitrogen to the essential building blocks of life may have been facilitated by clays, zeolites, sulfides, and metal alloys that had been formed as the crust reacted with a warm and carbonated (seltzer) ocean. Geochemical modeling constrains the conditions favorable for the formation of these potential mineral catalysts.

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The Transition from Geochemistry to Biogeochemistry

Paradigm-changing discoveries about stellar and planetary evolution, the survival of organic molecules and microorganisms under extreme conditions, and geochemical environments on early Earth and other planets are sparking a synergistic dialogue between geoscientists, chemists, and biologists to understand how life originated. To achieve this goal, we must (i) explain the non enzymatic synthesis of biologically relevant organic molecules under geologically plausible conditions; (ii) overcome the rigid conceptual dichotomy of the “RNA world” versus the “metabolism-first” hypotheses; and (iii) develop high-throughput analytical systems to sample the myriad possible combinations of environmental conditions to find those that could initiate life. This issue of Elements highlight the roles of minerals and geochemical environments in the emergence of protocells, the cell-like entities that might have preceded the Last Universal Common Ancestor.

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