Editing Thermophile (section)

==Classification==
Thermophiles can be classified in various ways.  One classification sorts these organisms according to their optimal growth temperatures:<ref>{{cite journal|author=Stetter, K.|title=History of discovery of the first hyperthermophiles|journal=Extremophiles|year=2006|volume=10|issue=5|pages=357–362|doi=10.1007/s00792-006-0012-7|pmid=16941067|s2cid=36345694}}</ref>
# Simple thermophiles: {{convert|50–64|C|F}}
# Extreme thermophiles {{convert|65–79|C|F}}
# Hyperthermophiles {{convert|80|C|F}} and beyond, but not below {{convert|50|C|F}}

In a related classification, thermophiles are sorted as follows:
# Facultative thermophiles (also called moderate thermophiles) can thrive at high temperatures, but also at lower temperatures (below {{convert|50|C}}), whereas
# Obligate thermophiles (also called extreme thermophiles) require such high temperatures for growth.
# [[Hyperthermophile]]s are particularly extreme thermophiles for which the optimal temperatures are above {{convert|80|C}}.

[[File:Thermophilic bacteria.jpg|thumb|A colony of thermophiles in the outflow of [[Mickey Hot Springs]], [[Oregon]],  the water temperature is approximately
{{convert|60|C}}.]]

Many hyperthermophilic [[Archaea]] require elemental [[sulfur]] for growth. Some are [[anaerobe]]s that use the sulfur instead of [[oxygen]] as an [[electron acceptor]] during [[anaerobic respiration|anaerobic cellular respiration]]. Some are [[lithotroph]]s that oxidize sulphur to create [[sulfuric acid]] as an energy source, thus requiring the microorganism to be adapted to very low [[pH]] (i.e., it is an [[acidophile (organisms)|acidophile]] as well as thermophile). These organisms are inhabitants of hot, sulfur-rich environments usually associated with [[volcanism]], such as [[hot springs]], [[geysers]], and [[fumaroles]].  In these places, especially in Yellowstone National Park, [[wikt:zonation|zonation]] of microorganisms according to their temperature optima occurs. These organisms are often colored, due to the presence of [[photosynthetic]] pigments.{{cn|date=February 2023}}