Abstract

The Earth contains a plethora of environments that, from an anthropocentric perspective, might be classified as extreme. Relative to the typical standard conditions of temperature, pressure, humidity, air quality, light, nutrient supply, shelter, lack of predation, etc. that many humans encounter in everyday life, almost all other forms of life live under more constrained conditions. From this per-spective, the world is clearly full of extremes – tempera-ture, salinity and pH being the abiotic factors that first to spring to mind. Even environments that represent large portions of the biosphere, such as cold environments (e.g.> 80 % of the Earth’s biosphere is permanently below 5°C), are considered extreme – clearly not because they are extreme to the large number of organisms that can survive there, but because the extreme cold greatly restricts human colonization (e.g. the cold deep ocean).