Did life arise near deep sea vents?

William Martin, from the Institut für Botanik III Heinrich-Heine-Universität, Düsseldorf, Germany and colleagues from the University of London, have a new theory about the origin of life. Rather than having arisen out of a ‘primordial soup’ a theory first published by J.B.S. Haldane in 1929, they believe life arose from gases around deep-sea hydrothermal vents.

The idea that life evolved at the base of hydrothermal vents was proposed by Michael J. Russell of the Jet Propulsion Laboratory, Caltech. Tiny crevasses in the deep sea vents enclose micro-environments containing mixes of H₂, CO₂, N₂, and H₂S which could have recombined into organic molecules.

Geochemical gradients across the tiny pores in these microscopic caverns could have driven energy production. This ‘proton-motive force’, also known as chemiosmosis, may have allowed the earliest cells to generate adenosine triphosphate (ATP) or an equivalent energy currency. Martin and his team suggest that the external protein gradient of the vent pores was replicated within the earliest cells.

There are two reasons to suspect that Martin and his team are on to something. For one thing, there are creatures alive today that rely on hydrothermal energy rather than on the sun. So, clearly it’s possible for organisms to make their living in this way. For another, most extant organisms use a similar internal ion gradient to synthesize ATP.

Martin argues that the reason living organisms employ chemiosmosis is that their earliest ancestors did as well.