Extremophiles

Microbes have populated Planet Earth for some 3.8 billion years. During this time, they have evolved an unimaginable diversity of structural adaptations and metabolic functions that enable them collectively to pursue an amazing diversity of lifestyles and occupy an incredibly diverse spectrum of environments. Many of these environments are considered by us humans to be highly extreme and totally hostile to life as we know it. But for the microbes that live in such places, they are just home, even if they are too extreme for most life forms. Because we and most other organisms on the planet cannot live in such environments, it is the parts of Planet Earth that microbes occupy which define the biosphere – the part of the planet in which active life exists (see Topic Framework: Microbes define the biosphere, by Vieto et al, in Section Adventures and Discovery). Microbes living at the boundaries (limits) of the biosphere, where its most extreme conditions occur, are special: they are the extremophiles. Let’s get to know these exceptional bugs that define our biosphere and that have unique properties and lifestyles! (NB: these are the most resilient microbial heroes we know now; but there are certainly others, just awaiting discovery by intrepid microbiologists, that will be tolerant of even more extreme conditions.) And let us learn where they live, because some of these places are extraordinary, exciting, magical and mysterious, locations of new explorations and discovery!