Hydrothermal Chemistry and the Origin of Cellular Life.

Two processes required for life's origin are condensation reactions that produce essential biopolymers by a nonenzymatic reaction, and self-assembly of membranous compartments that encapsulate the polymers into populations of protocells. Because life today thrives not just in the temperate ocean and lakes but also in extreme conditions of temperature, salinity, and pH, there is a general assumption that any form of liquid water would be sufficient to support the origin of life as long as there are sources of chemical energy and simple organic compounds. We argue here that the first forms of life would be physically and chemically fragile and would be strongly affected by ionic solutes and pH. A hypothesis emerges from this statement that hot springs associated with volcanic land masses have an ionic composition more conducive to self-assembly and polymerization than seawater. Here we have compared the ionic solutes of seawater with those of terrestrial hot springs. We then describe preliminary experimental results that show how the hypothesis can be tested in a prebiotic analog environment.