Diversity of thermophilic prokaryotes

The term ”thermophilic prokaryotes” covers an immense taxonomic and functional diversity of bacteria and archaea, spanning the length and breadth of the prokaryotic Tree of Life. Indeed, thermophiles are found within most major prokaryotic lineages and their functional diversity runs the gamut of biochemical and physiological adaptations. Thus, examples can be found of thermophilic lithoautotrophs as well as chemoheterotrophs, obligate anaerobes and aerophiles, extreme halophiles, acidophiles and alkaliphiles, and more. Their ecology is likewise diverse, with thermophiles found in a variety of habitats ranging from hydrothermal vents to desert soil to industrial settings and wastewater treatment facilities. It goes without saying that such immense diversity cannot be reviewed comprehensively in a relatively short book chapter. We thus aim to present examples pulled from diverse taxa within the vast menagerie of prokaryotic thermophiles in order to give insights into the metabolic, taxonomic, and ecological diversity of thermophilic prokaryotes rather than attempting an exhaustive review.