Deep-sea microbes that barely breathe

Until now.

We normally cannot see what rate they are working at, Hans Roy,a geomicrobiologist at Aarhus University in Denmark,said of the microbes. It is so slow for us,it looked like suspended animation.

But for a study in the current issue of the journal Science,Roy and his colleagues measured the oxygen concentration in layers of sediment gathered from the sea bottom in the North Pacific Gyre,off Hawaii,100 feet below the surface. The researchers calculated how much oxygen should have diffused into each layer of the sediment.

Any missing oxygen was likely to have been consumed by the microbes,Roy said. The deepest microbes that the researchers observed used just 0.001 femtomoles of oxygen per day; to put it another way,it would take 10 years for a microbe to consume the amount that a human inhales in a

single breath.

They are surviving on a minimum energy limit, Roy said. The whole community seems to be hovering right at the hunger limit.

The deep-sea microbes still largely remain a mystery to scientists,he added. And because the microbes are so slow-moving,they are difficult to study.

We dont know much about these actual microbes yet, Roy said,but we know they are there.