Editing Hot spring (section)

==Ecosystems==
{{See also|Thermophile}}
[[File:Algal mats on hot pool, Orakei Korako 1.jpg|thumb|right|[[Algal mat]]s growing in the ''Map of Africa'' hot pool, [[Orakei Korako]], New Zealand]]
Hot springs often host communities of microorganisms adapted to life in hot, mineral-laden water. These include [[thermophile]]s, which are a type of [[extremophile]] that thrives at high temperatures, between {{convert|45|and|80|°C|°F|abbr=on}}.<ref>{{cite book |title=Brock Biology of Microorganisms | year=2006|vauthors=Madigan MT, Martino JM | edition=11th |pages=136 |publisher=Pearson |isbn=978-0-13-196893-6}}</ref> Further from the vent, where the water has had time to cool and precipitate part of its mineral load, conditions favor organisms adapted to less extreme conditions. This produces a succession of microbial communities as one moves away from the vent, which in some respects resembles the successive stages in the evolution of early life.{{sfn|Farmer|2000}}

For example, in a bicarbonate hot spring, the community of organisms immediately around the vent is dominated by filamentous thermophilic [[bacteria]], such as ''[[Aquifex]]'' and other [[Aquificales]], that oxidize sulfide and hydrogen to obtain energy for their life processes. Further from the vent, where water temperatures have dropped below {{convert|60|°C||}}, the surface is covered with microbial mats {{convert|1|cm||}} thick that are dominated by [[cyanobacteria]], such as ''[[Spirulina (genus)|Spirulina]]'', ''[[Oscillatoria]]'', and ''[[Synechococcus]]'',<ref>{{cite journal |last1=Pentecost |first1=Allan |title=Cyanobacteria associated with hot spring travertines |journal=Canadian Journal of Earth Sciences |date=2003-11-01 |volume=40 |issue=11 |pages=1447–1457 |doi=10.1139/e03-075|bibcode=2003CaJES..40.1447P }}</ref> and [[green sulfur bacteria]] such as ''[[Chloroflexus]]''. These organisms are all capable of [[photosynthesis]], though green sulfur bacteria produce [[sulfur]] rather than [[oxygen]] during photosynthesis. Still further from the vent, where temperatures drop below {{convert|45|°C||}}, conditions are favorable for a complex community of microorganisms that includes ''Spirulina'', ''[[Calothrix]]'', [[diatoms]] and other single-celled [[eukaryotes]], and grazing insects and protozoans. As temperatures drop close to those of the surroundings, higher plants appear.{{sfn|Farmer|2000}}

Alkali chloride hot springs show a similar succession of communities of organisms, with various thermophilic bacteria and [[archaea]] in the hottest parts of the vent. Acid sulfate hot springs show a somewhat different succession of microorganisms, dominated by acid-tolerant algae (such as members of [[Cyanidiophyceae]]), [[fungi]], and diatoms.{{sfn|Drake|Campbell|Rowland|Guido|2014}} Iron-rich hot springs contain communities of photosynthetic organisms that oxidize reduced ([[ferrous]]) iron to oxidized ([[ferric]]) iron.{{sfn|Parenteau |Cady|2010}}

Hot springs are a dependable source of water that provides a rich chemical environment. This includes [[Oxidation|reduced]] chemical species that microorganisms can oxidize as a source of energy.