17. Life and extreme environments

To our present knowledge, the Earth seems to be the single habitable and inhabited planet within the solar system. The concept of habitability is often defined in terms of the requirements for human existence. However, that part of the Earth’s biosphere permanently inhabited by human beings is rather small and most of the planet, its deep core or mantle, will clearly never see a living organism. In between these two zones (inhabited and uninhabited), a variety of environments exist where human beings cannot live permanently, or physically access, although other forms of life exist within them.

Coping with these latter environments, microbes, plants and animals have demonstrated the ability to adapt and metabolise under high environmental stress. Relying on specific and complicated mechanisms, some organisms even require such conditions to live and evolve.

From the bottom of the seas to the highest mountains, from the hottest regions to the cold Antarctic plateau, environments labelled as ‘extreme’ are numerous on Earth and they present a wide variety of features and characteristics. The life processes occurring within these environments are equally diverse, not only depending on stress factors but also on the type organisms, ranging from microbes to higher species.

18. Extreme environments

Extreme environments have features that are challenging for any research activity and their associated technological development. At the forefront of the technological challenges induced by extreme environments are issues of automation of sampling, monitoring and analysing equipment, miniaturization of sensors and robotics. Industries and research institutions involved in generating such capabilities are developing competencies and know-how applicable to a whole range of such activities.

It is important to foster and catalyse research activities on life processes in extreme environments, not only because they are applicable to some of the main scientific questions such as understanding the basics of life processes, the origin of life or the potential existence of extraterrestrial life, but also because the economic potential behind these activities is important. For all these reasons, ‘investigating life in extreme environments’ represents a major challenge for Earth’s inhabitants at the beginning of the 21^st century.

The study of humans evolving in extreme environments also provides new keys to the understanding of psychological, physiological, social and societal functioning of individuals and groups