THE ONSET OF LIFE IS A COROLLARY OF CONVECTION ON EARLY EARTH

The Earth agglomerates and heats. Volcanoes evolve carbon oxides and pyrophosphate. Convection cells begin the cooling process. An acidulous Hadean ocean condenses from the carbon oxide sky. The ocean leaks into the crust. High temperature acid springs emit ferrous iron to the ocean. High energy photons oxidise some iron to the ferric state — a dispersed positive electrode. Cooler alkaline waters also rise toward the ocean floor bearing organic molecules reduced from carbon oxides by reaction with residual native iron. Where these waters seep into the ocean, mounds of exhalite, comprising alternating sulfide and hydroxide films and flocculants, arise in the ocean darkness. These returning fluids are frustrated in their attempt to mix with their oceanic source by the precipitation of a barrier of iron sulfide/hydroxide. Pyrophosphate reacts with ammonia. Nucleosides are assembled in greenrust on the flanks of the mound and refluxed.

The mounds are negative electrodes. The Earth is a giant photoelectric cell. The ocean is the electrolyte. The ferric iron is eddy-pumped to the ocean bottom. The iron sulfide/hydroxide bubbles inflate fitfully. Though the hydrothermal solution is trapped, there is some escape of electrons, from hydrogen and methane through the conducting layers of mackinawite (~FeS), drawn to reduce the ferric iron. Now activated, the hydrogen and methane take part in further extempore chemosynthesis. Nucleotides poison the mackinawite but spell the password to a coevolutionary future. The side chains of particular amino acids register to fitting nucleotide triplet clefts. The amino acids are polymerised to form alpha chains by invading protons, making short protopeptides. Some sequester [4Fe-4S] to become protoferredoxins. Peptides, the would-be outer bands of mackinawite, continually spall away from bound RNA (the penultimate layer), driven by the protonmotive force.

This circuitry offers a continuous supply of proticity and electricity at a voltage appropriate for the onset of life. Life may then decouple from the hydrothermal system and individuate. Contention ensues. The chirality war looms. Photosynthesis beckons.