Reference Work Entry

The Prokaryotes

pp 210-262

Life at Low Temperatures

  • Siegfried Scherer
  • , Klaus Neuhaus


Most habitats on our planet are permanently cold. By volume, 90% of the world’s oceans have a temperature of 5°C or less, supporting both psychrophilic and psychrotolerant microorganisms. When terrestrial habitats are included, over 80% of the earth’s biosphere is permanently cold (Russell, 1990a). Archaea contribute significantly to biomass in cold environments, although few have been isolated (Goodchild et al., 2004).

Microorganisms that are able to grow at low temperatures are termed “psychrophilic” (sometimes also “obligate psychrophiles”) and “psychrotolerant” (or “facultative psychrophiles” or “psychrotrophs”) or even “psychroactive” (Nozhevnikova et al., 2001b). We recommend here the use of only the designations “psychrophilic” and “psychrotolerant.” (Morita, 1975) has defined psychrophiles “as organisms having an optimal temperature for growth at about 15°C or lower, a maximal temperature for growth at about 20°C, and a minimal temperature for growth at about 0°C or ...

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