| At depths of about 2,600 m along the East Pacific Rise, sulfide chimneys or "black smokers" are emitting superheated fluids at about 350 degree C into cold seawater. Dissolved in these fluids are a suite of gases, including CH sub(4), H sub(2), CO, and N sub(2)O Baross and colleagues reported the production and utilization of some of these gases at 100 degree C and atmospheric pressure by bacterial communities cultured from black-smoker fluids collected at 21 degree N. Subsequently, evidence was obtained for the growth of these bacteria at 265 atm pressure and at least 250 degree C, and for their possible production of CH sub(4) at 300 degree C. In this paper, the evidence for (and against) bacterial growth at high temperature and pressure is reviewed and... |
