Vitriphagy

Natural History, Feb, 2007 by Graciela Flores

Microorganisms can live in the most extreme environments, feed on a host of seemingly inedible materials, and thrive on improbable sources of energy. Can they possibly still surprise us? Try this: they feed on glass inside submarine volcanoes.

Recently Hubert Staudigel, a marine volcanologist at the Scripps Institution of Oceanography in La Jolla, California, and four colleagues published a comprehensive paper augmenting the evidence that distinctive pitting in underwater volcanic glass from around the world is of biological origin. The evidence includes telltale microscopic textures in the glass, such as spiral tunnels and branching tunnels, which are hallmarks of microbia activity. The paper also points to the presence of carbon isotopes characteristic of life, as well as microbial DNA, in the tunnels. The microorganisms apparently dissolve the glass with acid.

The evidence for glass alteration by microorganisms occurs throughout the uppermost thousand feet of oceanic crust, suggesting that the process may be playing an important role in cycling elements between seawater and the seafloor. And because volcanic glass dates to 3.5 billion years ago, the authors argue, it might be just the place to look back in time for the most ancient forms of life. (GSA Today)