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Airdate: Jul 20, 2010
Scientist: Prof. Derek Lovley

Geobacter - Discovery

Geobacter - Discovery
Iron-breathing creatures on the banks of the Potomac? Stay tuned!

ambience: water, birds

Sometimes it's possible to make a profound scientific discovery with something as mundane as mud. I'm Jim Metzner and this is the Pulse of the Planet.

Derek Lovley is a professor of microbiology at the University of Massachusetts in Amherst. Back in 1987, he was studying microorganisms that depended upon metals like iron for their survival.

"We recovered some of the bottom sediments from the Potomac River, brought them back in the laboratory and placed them into a medium that contained some iron and just selected for organisms that might be able to grow using iron instead of oxygen the way that most life forms grow."

Dr. Lovley's team realized they were seeing a new phenomenon when the bacteria began to do something completely unexpected.

"We were seeing the iron get converted into a magnetic mineral, which is magnetite. This was one of geobacter's first unique properties that we understood was that it could convert basically rust to this magnetic mineral. No one had ever found an organism like this before, so it was quite an exciting moment."

The newly discovered organism was named geobacter and they're not just found in the Potomac River.

"They can be recovered from any mud, anywhere where there's a lack of oxygen and abundance of ferric iron minerals which is in many soils. They thrive and they are actually the predominate organisms in those environments. Nobody had just ever looked for them before."

So instead of breathing oxygen, geobacter lives off of iron.

"Geobacter survives much in the way that we do, in that we get our energy from converting organic material - basically our food - to carbon dioxide. We use oxygen to carry out that conversion. Geobacter lives in environments where there is no oxygen. It has found a strategy to use iron to replace the oxygen."

The discovery of geobacter has led scientists to some amazing results - including a low cost way of cleaning up toxic waste. We'll hear more in future programs.

Pulse of the Planet is presented by the National Science Foundation. I'm Jim Metzner.