When it comes to understanding the origins of life, scientists have already determined that biochemical building blocks—amino acids, nucleobases, and sugars—can form under early-Earth-like conditions. But figuring out how those simple species combined in a dilute solution to form complex macromolecules has been harder. A new study suggests a key role for fluid dynamics in microscale pore networks within mineral structures at hydrothermal vents (Proc. Natl. Acad. Sci. USA 2017, DOI: 10.1073/pnas.1612924114). A team led by Victor M. Ugaz at Texas A&M University studied a model system of pore-mimicking cylindrical cells using computational and experimental methods. They found that thermal gradients characteristic of alkaline hydrothermal vent systems result in chaotic fluid flow. That fluid flow transports organic molecules from the bulk fluid to catalytically active pore surfaces, where the species may adsorb and react. Simultaneously, the chaotic flow also provides bulk mixing that prevents localized depletion of chemical species, thereby ensuring a continuous supply of building blocks.