'Bolt from deep blue' may have sparked life on Earth

Scientists at the University of Tokyo in Japan, Ryuhei Nakamura and his team, have suggested that hydrothermal vents on the deep ocean floor could have triggered life on planet Earth.

Scientists at the University of Tokyo in Japan have suggested that a bolt from the deep blue seas may have sparked life on Earth.

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Ryuhei Nakamura and his team believe that hydrothermal vents on the deep ocean floor could have triggered life on the planet. They said the vents could generate electric currents, which in turn could have helped generate the complex carbon-based molecules that came together to produce life, as well as provide it with a handy power supply.

Vents bring minerals containing iron, copper and sulphur from deep inside the Earth's crust to the seabed. Nakamura's team wanted to find out if an excess of electrons in these minerals could generate an electric current in the vent, reports New Scientist.

First, the team passed a current through a a type of sulphur-rich chimney wall; then, they simulated the conditions at a hydrothermal vent by pumping hot, sulphur-rich water past one side of a chimney wall, and cold, salty water past the other. This generated a weak but steady electrical current across the chimney wall.

The team thought that the chimney walls catalyse the conversion of sulphides into elemental sulphur as the hot vent fluid travels through them.

The reaction releases electrons which pass through the wall to the salt water outside, where they convert dissolved oxygen into hydrogen peroxide. Nakamura postulates that this electrical current could provide a source of energy for bacteria.

As there was hardly any oxygen around in the primordial ocean to sustain the current, according to Nick Lane, a biochemist who studies hydrothermal vents at University College London, Nakamura suggested that carbon dioxide took the place of oxygen.

If that were correct, then the CO2 would have been converted directly into carbon-based molecules, making complex organic molecules on the early Earth's sea floors - perhaps the chemical precursors of life.

The next step, they say, is to confirm that black smokers generate electricity when they are at the bottom of the ocean, not just in the lab.

The study is published in Angewandte Chemie.