1 - Life under extreme conditions: the role of liquid water at interfaces

Physical mechanisms extending the domain of liquid water at interfaces into the solid and vapor regions of the bulk phase diagram are crucial for the survival of life under extreme conditions such as cold and dry climates. These conditions are encountered locally in polar and desert regions on Earth and globally on other planets like Mars.

We discuss three classes of phenomena:

• (i) the premelting of ice, which allows for films and veins of liquid water at temperatures well below freezing,
• (ii) the adsorption of water on solid mineral surfaces, and
• (iii) the wetting of hygroscopic salts with the persistence of briny films even for thermodynamic conditions remote from those of bulk liquid water.

We describe how these mechanisms are used by a variety of organisms on Earth ranging from bacteria in permafrost to anti-freeze protein expressing arctic fishes and assess their significance for putative microbial life on Mars.

Public Lecture with two Presentations on Extraterrestrial Life

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