Life on Earth may have originated in deep-sea vents

Electrical energy produced naturally inside the warm, gentle springs on the sea floor might have given rise to life on Earth, a new study suggests.
Researchers at NASA's Jet Propulsion Laboratory in Pasadena, California and colleagues, found that life may have begun inside warm, gentle springs on the sea floor, at a time long ago when Earth's oceans churned across the entire planet.
This idea of hydrothermal vents as possible places for life's origins was first proposed in 1980 by other researchers, who found them on the sea floor near Cabo San Lucas, Mexico.
Called "black smokers," those vents bubble with scalding hot, acidic fluids.

In contrast, the vents in the new study are gentler, cooler and percolate with alkaline fluids.
"Life takes advantage of unbalanced states on the planet, which may have been the case billions of years ago at the alkaline hydrothermal vents," said Michael Russell of JPL.

"Life is the process that resolves these disequilibria." said Russell, the lead author of the new study.
This "water world" theory says that the warm, alkaline hydrothermal vents maintained an unbalanced state with respect to the surrounding ancient, acidic ocean - one that could have provided so-called free energy to drive the emergence of life.

In fact, the vents could have created two chemical imbalances. The first was a proton gradient, where protons - which are hydrogen ions - were concentrated more on the outside of the vent's chimneys, also called mineral membranes.
The proton gradient could have been tapped for energy - something our own bodies do all the time in cellular structures called mitochondria.
The second imbalance could have involved an electrical gradient between the hydrothermal fluids and the ocean.
Billions of years ago, when Earth was young, its oceans were rich with carbon dioxide.
When the carbon dioxide from the ocean and fuels from the vent - hydrogen and methane - met across the chimney wall, electrons may have been transferred.

These reactions could have produced more complex carbon-containing, or organic compounds - essential ingredients of life as we know it.
Like proton gradients, electron transfer processes occur regularly in mitochondria.
"Life lives off proton gradients and the transfer of electrons," said Laurie Barge, second author of the study.
The study was published in the journal Astrobiology.