bacteria which have the capacity to grow and reproduce under conditions of atmospheric pressure and under pressures of several hundred atmospheres. Pressure-tolerant bacteria exist predominantly in an aqueous stratum in the muds of oceans and seas, but they are found also in the surface layers of soils. Some species of pressure-tolerant bacteria multiply better at high pressures than at atmospheric pressure and are called barophilic bacteria. Some investigators confirm the existence of bacteria which develop only at high pressure (obligatory barophilic bacteria). Most pressure-tolerant bacteria lose the capacity to reproduce at pressures above 400–600 atmospheres (the pressure at the lowest depths of the ocean, 4,000–6,000 m). Some, however, reproduce at pressures of 900–1,000 atmospheres (the pressure in the deep depressions in the ocean). During cultivation at high hydrostatic pressures, some biochemical processes of pressure-tolerant bacteria are amplified and others are suppressed.
REFERENCEKriss, A. E. “Biologicheskoe deistvie vysokikh davlenii.” In the collection Uspekhi mikrobiologii, vol. 6. Moscow, 1969.
A. E. KRISS