Some like it hotter

From Washington, D.C., at a meeting of the American Society for Microbiology

A microbe found where volcanic activity has cracked the floor of the Pacific Ocean has set a new record for the upper temperature limit for life. This organism grows readily at 121C in the laboratory and can even survive a few hours at 130C, Kazem Kashefi of the University of Massachusetts in Amherst and his colleagues report. The previous record was held by a microbe that could grow at a temperature of 113C.

The new record holder, known as strain 121, was isolated during a submersible dive to a hydrothermal vent, a rift in the ocean floor where water can be as hot as 300C. A variety of odd animals and microbes thrives on the heat and chemicals released at these vents.

A genetic analysis of strain 121 indicates that the microbe is an archaea, a life form that resembles bacteria but that may be more closely related to plants and animals (SN: 8/24/96, p. 116:

Scientists typically sterilize lab dishes and instruments with water heated to 121C because that temperature kills all previously described microbes, notes Kashefi. Determining the upper temperature limit for life, he adds, may provide clues to how and where life originated on this planet and to where life could exist elsewhere.


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