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The authors wish to thank N. Gerardin, A. Dernier and R. Marchand for their skilful technical assistance and the French Institute for Polar Research (IPEV – Institut Polaire Francais) for generously accommodating our research fellows at the French Antarctic station J.S. Dumont d’Urville in Terre Adelie. The generous support of the ‘Region Wallonne’ (contract FIRST EUROPE R0202/215266), the European Union (network contract CT970131) and the ‘Fonds National de la Recherche Scientifique’ is gratefully acknowledged. S D’Amico is a FNRS postdoctoral researcher. Frederic Roulling and Florence Piette are holders of a FRIA fellowship.

Chemical reaction rates often show a strong temperature dependency and a decrease of 10°C from room temperature typically divides the rate by a factor oscillating between 1.5 and 4. The decrease of the rate constant k indeed obeys an equation proposed by Svante Arrhenius as early as in 1889: $$K = A{e^{ - Ea/RT}}$$ (1) in which E a is the activation energy, R the gas constant (8.31 kJ mol−1) and T the temperature in Kelvin.

Although the average temperature on earth is probably of the order of 15 °C, the environments with extreme temperature in which life can be considered possible are very common on the surface of the planet.