Extremophile

File:Diversity of extreme environments on Earth.jpg Material was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].}}]]

In the 1980s and 1990s, biologists found that microbial life can survive in extreme environments—niches that are acidic, extraordinarily hot, or with irregular air pressure for example—that would be inhospitable to complex organisms. Some scientists even concluded that life may have begun on Earth in hydrothermal vents far beneath the ocean's surface.{{Cite web |date=June 2003 |title=Mars Exploration Rover Launches – Press kit |url=https://mars.jpl.nasa.gov/mer/newsroom/merlaunch.pdf |access-date=14 July 2009 |publisher=NASA}}

According to astrophysicist Steinn Sigurdsson, "There are viable bacterial spores that have been found that are 40 million years old on Earth—and we know they're very hardened to radiation."{{Cite web |last=BBC Staff |date=23 August 2011 |title=Impacts 'more likely' to have spread life from Earth |url=https://www.bbc.co.uk/news/science-environment-14637109 |access-date=24 August 2011 |publisher=BBC}} Some bacteria were found living in the cold and dark in a lake buried a half-mile deep under the ice in Antarctica,{{Cite web |last=Gorman |first=James |name-list-style=vanc |date=6 February 2013 |title=Bacteria Found Deep Under Antarctic Ice, Scientists Say |url=https://www.nytimes.com/2013/02/07/science/living-bacteria-found-deep-under-antarctic-ice-scientists-say.html |url-access=limited |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2013/02/07/science/living-bacteria-found-deep-under-antarctic-ice-scientists-say.html |archive-date=2022-01-01 |access-date=6 February 2013 |website=The New York Times}}{{cbignore}} and in the Marianas Trench, the deepest place in Earth's oceans.{{Cite web |last=Choi |first=Charles Q. |name-list-style=vanc |date=17 March 2013 |title=Microbes Thrive in Deepest Spot on Earth |url=http://www.livescience.com/27954-microbes-mariana-trench.html |access-date=17 March 2013 |publisher=LiveScience}}{{Cite journal |vauthors=Glud RN, Wenzhöfer F, Middelboe M, Oguri K, Turnewitsch R, Canfield DE, Kitazato H |date=17 March 2013 |title=High rates of microbial carbon turnover in sediments in the deepest oceanic trench on Earth |journal=Nature Geoscience |volume=6 |issue=4 |pages=284–88 |bibcode=2013NatGe...6..284G |doi=10.1038/ngeo1773}} Expeditions of the International Ocean Discovery Program found microorganisms in {{Cvt|120|C}} sediment that is {{Cvt|1.2|km}} below seafloor in the Nankai Trough subduction zone.{{Cite journal |last1=Heuer |first1=Verena B. |last2=Inagaki |first2=Fumio |last3=Morono |first3=Yuki |last4=Kubo |first4=Yusuke |last5=Spivack |first5=Arthur J. |last6=Viehweger |first6=Bernhard |last7=Treude |first7=Tina |last8=Beulig |first8=Felix |last9=Schubotz |first9=Florence |last10=Tonai |first10=Satoshi |last11=Bowden |first11=Stephen A. |date=2020-12-04 |title=Temperature limits to deep subseafloor life in the Nankai Trough subduction zone |url=https://www.science.org/doi/10.1126/science.abd7934 |journal=Science |language=en |volume=370 |issue=6521 |pages=1230–34 |bibcode=2020Sci...370.1230H |doi=10.1126/science.abd7934 |issn=0036-8075 |pmid=33273103 |hdl-access=free |hdl=2164/15700 |s2cid=227257205}}{{Cite web |title=T-Limit of the Deep Biosphere off Muroto |url=https://www.jamstec.go.jp/chikyu/e/exp370/ |access-date=2021-03-08 |website=www.jamstec.go.jp}} Some microorganisms have been found thriving inside rocks up to {{convert|1900|ft}} below the sea floor under {{convert|8500|ft}} of ocean off the coast of the northwestern United States.{{Cite web |last=Oskin |first=Becky |name-list-style=vanc |date=14 March 2013 |title=Intraterrestrials: Life Thrives in Ocean Floor |url=http://www.livescience.com/27899-ocean-subsurface-ecosystem-found.html |access-date=17 March 2013 |publisher=LiveScience}} According to one of the researchers, "You can find microbes everywhere—they're extremely adaptable to conditions, and survive wherever they are." A key to extremophile adaptation is their amino acid composition, affecting their protein folding ability under particular conditions.{{Cite journal |vauthors=Reed CJ, Lewis H, Trejo E, Winston V, Evilia C |date=2013 |title=Protein adaptations in archaeal extremophiles |journal=Archaea |volume=2013 |pages=373275 |doi=10.1155/2013/373275 |pmc=3787623 |pmid=24151449 |doi-access=free}} Studying extreme environments on Earth can help researchers understand the limits of habitability on other worlds.{{Cite web |year=2015 |title=NASA Astrobiology Strategy |url=https://nai.nasa.gov/media/medialibrary/2015/10/NASA_Astrobiology_Strategy_2015_151008.pdf |url-status=dead |archive-url=https://web.archive.org/web/20161222190306/https://nai.nasa.gov/media/medialibrary/2015/10/NASA_Astrobiology_Strategy_2015_151008.pdf |archive-date=22 December 2016 |access-date=12 October 2017 |website=NASA |pages=59}}

Tom Gheysens from Ghent University in Belgium and colleagues showed that endospores from a species of Bacillus bacteria were viable after being heated to temperatures of {{convert|420|C}}.{{Cite web|url=https://www.smithsonianmag.com/air-space-magazine/turn-heat-bacterial-spores-can-take-temperatures-hundreds-degrees-180970425/|title=Turn Up the Heat: Bacterial Spores Can Take Temperatures in the Hundreds of Degrees|first1=Smithsonian|last1=Magazine|first2=Dirk|last2=Schulze-Makuch|website=Smithsonian Magazine}}

File:Microorganisms from the hypersaline Lake Tyrrell.jpg (salinity> 20% w/v), in which the eukaryotic chlorophyte, Dunaliella salina, can be tentatively identified. Dunaliella salina is grown commercially for the carotenoid, β-carotene, which is widely used as a natural food colorant as well as a precursor to vitamin A. Alongside is the haloarchaeon, Haloquadratum walsbyi, which has flat square-shaped cells with gas vesicles that allow flotation to the surface, most likely to acquire oxygen.]]

• Acidophile: an organism with optimal growth at pH levels of 3.0 or below.

• Alkaliphile: an organism with optimal growth at pH levels of 9.0 or above.

• Capnophile: an organism with optimal growth conditions in high concentrations of carbon dioxide. An example would be Mannheimia succiniciproducens, a bacterium that inhabits a ruminant animal's digestive system.{{Cite journal |last1=Hong |first1=Soon Ho |last2=Kim |first2=Jin Sik |last3=Lee |first3=Sang Yup |last4=In |first4=Yong Ho |last5=Choi |first5=Sun Shim |last6=Rih |first6=Jeong-Keun |last7=Kim |first7=Chang Hoon |last8=Jeong |first8=Haeyoung |last9=Hur |first9=Cheol Goo |last10=Kim |first10=Jae Jong |date=2004-09-19 |title=The genome sequence of the capnophilic rumen bacterium Mannheimia succiniciproducens |journal=Nature Biotechnology |volume=22 |issue=10 |pages=1275–81 |doi=10.1038/nbt1010 |issn=1087-0156 |pmid=15378067 |doi-access=free |s2cid=35247112}}

• Halophile: an organism with optimal growth at a concentration of dissolved salts of 50 g/L (= 5% m/v) or above (for comparison, the ocean salinity is about 35 g/L (= 3.5% m/v)).

• Hyperpiezophile: an organism with optimal growth at hydrostatic pressures above 50 MPa (= 493 atm = 7,252 psi).

• Hyperthermophile: an organism with optimal growth at temperatures above {{Convert|80|C||abbr=on}}.

• Metallotolerant: an organism capable of tolerating high levels of dissolved heavy metals in solution, such as copper, cadmium, arsenic, and zinc. Examples include Ferroplasma sp., Cupriavidus metallidurans and GFAJ-1.{{Cite news |date=9 July 2012 |title=Studies refute arsenic bug claim |work=BBC News |url=https://www.bbc.co.uk/news/science-environment-18770964 |access-date=10 July 2012}}{{Cite journal |author-link5=Julia Vorholt |vauthors=Erb TJ, Kiefer P, Hattendorf B, Günther D, Vorholt JA |date=July 2012 |title=GFAJ-1 is an arsenate-resistant, phosphate-dependent organism |journal=Science |volume=337 |issue=6093 |pages=467–70 |bibcode=2012Sci...337..467E |doi=10.1126/science.1218455 |pmid=22773139 |s2cid=20229329|doi-access=free }}{{Cite journal |vauthors=Reaves ML, Sinha S, Rabinowitz JD, Kruglyak L, Redfield RJ |date=July 2012 |title=Absence of detectable arsenate in DNA from arsenate-grown GFAJ-1 cells |journal=Science |volume=337 |issue=6093 |pages=470–73 |arxiv=1201.6643 |bibcode=2012Sci...337..470R |doi=10.1126/science.1219861 |pmc=3845625 |pmid=22773140}}

• Oligotroph: an organism with optimal growth in nutritionally limited environments.

• Osmophile: an organism with optimal growth in environments with a high sugar concentration.

• Piezophile or barophile: an organism with optimal growth in hydrostatic pressures above 10 MPa (= 99 atm = 1,450 psi).

• Polyextremophile (mixed Latin/Greek compound for affection for many extremes): not a well-defined category itself – an organism that qualifies as an extremophile under more than one category.

• Psychrophile or cryophile: an organism with optimal growth at temperatures of {{Convert|15|C||abbr=}} or lower.

• Radioresistant: organisms resistant to high levels of ionizing radiation, most commonly ultraviolet radiation. This category also includes organisms capable of resisting nuclear radiation, notably gamma rays.

• Sulphophile: an organism with optimal growth conditions in high concentrations of sulfur. An example would be Sulfurovum epsilonproteobacteria, a sulfur-oxidizing bacteria that inhabits deep-water sulfur vents.{{Cite journal |last1=Meier |first1=Dimitri V |last2=Pjevac |first2=Petra |last3=Bach |first3=Wolfgang |last4=Hourdez |first4=Stephane |author5-link=Peter Girguis|last5=Girguis |first5=Peter R |last6=Vidoudez |first6=Charles |last7=Amann |first7=Rudolf |last8=Meyerdierks |first8=Anke |date=2017-04-04 |title=Niche partitioning of diverse sulfur-oxidizing bacteria at hydrothermal vents |journal=The ISME Journal |volume=11 |issue=7 |pages=1545–58 |doi=10.1038/ismej.2017.37 |issn=1751-7362 |pmc=5520155 |pmid=28375213|bibcode=2017ISMEJ..11.1545M }}

• Thermophile: an organism with optimal growth at temperatures above {{Convert|45|C||abbr=on}}.

• Xerophile: an organism with optimal growth at water activity below 0.8.

There are many classes of extremophiles that range all around the globe; each corresponding to the way its environmental niche differs from mesophilic conditions. These classifications are not exclusive. Many extremophiles fall under multiple categories and are classified as polyextremophiles. For example, organisms living inside hot rocks deep under Earth's surface are thermophilic and piezophilic such as Thermococcus barophilus.{{Cite journal |vauthors=Marteinsson VT, Birrien JL, Reysenbach AL, Vernet M, Marie D, Gambacorta A, Messner P, Sleytr UB, Prieur D |date=April 1999 |title=Thermococcus barophilus sp. nov., a new barophilic and hyperthermophilic archaeon isolated under high hydrostatic pressure from a deep-sea hydrothermal vent |journal=International Journal of Systematic Bacteriology |volume=49 Pt 2 |issue=2 |pages=351–59 |doi=10.1099/00207713-49-2-351 |pmid=10319455 |doi-access=free}} A polyextremophile living at the summit of a mountain in the Atacama Desert might be a radioresistant xerophile, a psychrophile, and an oligotroph. Polyextremophiles are well known for their ability to tolerate both high and low pH levels.{{Cite journal |display-authors=6 |vauthors=Yadav AN, Verma P, Kumar M, Pal KK, Dey R, Gupta A, Padaria JC, Gujar GT, Kumar S, Suman A, Prasanna R |date=2014-05-31 |title=Diversity and phylogenetic profiling of niche-specific Bacilli from extreme environments of India |journal=Annals of Microbiology |volume=65 |issue=2 |pages=611–29 |doi=10.1007/s13213-014-0897-9 |s2cid=2369215|doi-access=free }} Note that "tolerant" or "resistant" organisms are not necessarily extremophiles: tolerant or resistant organisms may survive despite harsh conditions instead of thriving in harsh conditions. For example, the tardigrade (Tardigrada spp.), despite being highly resistant to many stresses, is not an extremophile properly speaking.{{cite web |url=https://frontlinegenomics.com/everything-you-need-and-want-to-know-about-tardigrades/|title=Everything you need (and want) to know about tardigrades|publisher=Front Line Genomics|access-date=17 May 2025|vauthors = Robertson L |date=October 2022}}

Astrobiology is the multidisciplinary field that investigates how life arises, distributes, and evolves in the universe. Astrobiology makes use of physics, chemistry, astronomy, solar physics, biology, molecular biology, ecology, planetary science, geography, and geology to investigate the possibility of life on other worlds and recognize biospheres that might be different from that on Earth.{{Cite book |title=The life and death of planet Earth |vauthors=Ward PD, Brownlee D |date=2004 |publisher=Owl Books |isbn=978-0805075120 |location=New York}}{{page needed|date=June 2021}} Astrobiologists are interested in extremophiles, as it allows them to map what is known about the limits of life on Earth to potential extraterrestrial environments For example, analogous deserts of Antarctica are exposed to harmful UV radiation, low temperature, high salt concentration and low mineral concentration. These conditions are similar to those on Mars. Therefore, finding viable microbes in the subsurface of Antarctica suggests that there may be microbes surviving in endolithic communities and living under the Martian surface. Research indicates it is unlikely that Martian microbes exist on the surface or at shallow depths, but may be found at subsurface depths of around 100 meters.{{Cite journal|title=The role of habitat structure for biomolecule integrity and microbial survival under extreme environmental stress in Antarctica (and Mars?): ecology and technology|vauthors=Wynn-Williams DA, Newton EM, Edwards HG |date=2001 |journal=Exo-/Astro-biology: Proceedings of the First European Workshop, 21–23 May 2001, ESRIN, Fracscati, Italy |isbn=978-92-9092-806-5 |volume=496 |page=226 |bibcode=2001ESASP.496..225W}}

Recent research carried out on extremophiles in Japan involved a variety of bacteria including Escherichia coli and Paracoccus denitrificans being subject to conditions of extreme gravity. The bacteria were cultivated while being rotated in an ultracentrifuge at high speeds corresponding to 403,627 g (i.e. 403,627 times the gravity experienced on Earth). P. denitrificans was one of the bacteria which displayed not only survival but also robust cellular growth under these conditions of hyperacceleration which are usually found only in cosmic environments, such as on very massive stars or in the shock waves of supernovas. Analysis showed that the small size of prokaryotic cells is essential for successful growth under hypergravity. The research has implications on the feasibility of panspermia.{{Cite web |last=Than, Ker |date=25 April 2011 |title=Bacteria Grow Under 400,000 Times Earth's Gravity |url=http://news.nationalgeographic.com/news/2011/04/110425-gravity-extreme-bacteria-e-coli-alien-life-space-science/ |archive-url=https://web.archive.org/web/20110427083206/http://news.nationalgeographic.com/news/2011/04/110425-gravity-extreme-bacteria-e-coli-alien-life-space-science/ |url-status=dead |archive-date=27 April 2011 |access-date=28 April 2011 |website=National Geographic – Daily News |publisher=National Geographic Society}}{{Cite journal |vauthors=Deguchi S, Shimoshige H, Tsudome M, Mukai SA, Corkery RW, Ito S, Horikoshi K |date=May 2011 |title=Microbial growth at hyperaccelerations up to 403,627 x g |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=108 |issue=19 |pages=7997–8002 |bibcode=2011PNAS..108.7997D |doi=10.1073/pnas.1018027108 |pmc=3093466 |pmid=21518884 |doi-access=free}}{{Cite web |last=Reuell |first=Peter |date=2019-07-08 |title=Harvard study suggests asteroids might play key role in spreading life |url=https://news.harvard.edu/gazette/story/2019/07/harvard-study-suggests-asteroids-might-play-key-role-in-spreading-life/ |access-date=2019-10-06 |website=Harvard Gazette}}

On 26 April 2012, scientists reported that lichen survived and showed remarkable results on the adaptation capacity of photosynthetic activity within the simulation time of 34 days under some conditions similar to those on Mars in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Center (DLR).{{Cite web |last=Baldwin |first=Emily |name-list-style=vanc |date=26 April 2012 |title=Lichen survives harsh Mars environment |url=https://www.skymania.com/wp/lichen-survives-harsh-martian-setting/ |access-date=27 April 2012 |publisher=Skymania News |archive-date=12 November 2020 |archive-url=https://web.archive.org/web/20201112042544/https://www.skymania.com/wp/lichen-survives-harsh-martian-setting/ |url-status=dead }}{{Cite journal |vauthors=De Vera JP, Kohler U |date=26 April 2012 |title=The adaptation potential of extremophiles to Martian surface conditions and its implication for the habitability of Mars |url=http://meetingorganizer.copernicus.org/EGU2012/EGU2012-2113.pdf |journal=EGU General Assembly Conference Abstracts |volume=14 |pages=2113 |bibcode=2012EGUGA..14.2113D |access-date=27 April 2012}}

On 29 April 2013, scientists at Rensselaer Polytechnic Institute, funded by NASA, reported that, during spaceflight on the International Space Station, microbes seem to adapt to the space environment in ways "not observed on Earth" and in ways that "can lead to increases in growth and virulence".{{Cite journal |display-authors=6 |vauthors=Kim W, Tengra FK, Young Z, Shong J, Marchand N, Chan HK, Pangule RC, Parra M, Dordick JS, Plawsky JL, Collins CH |date=29 April 2013 |title=Spaceflight promotes biofilm formation by Pseudomonas aeruginosa |journal=PLOS ONE |volume=8 |issue=4 |pages=e62437 |bibcode=2013PLoSO...862437K |doi=10.1371/journal.pone.0062437 |pmc=3639165 |pmid=23658630 |doi-access=free}}

On 19 May 2014, scientists announced that some microbes, like Tersicoccus phoenicis, may be resistant to methods usually used in spacecraft assembly clean rooms, giving rise to speculation that such microbes could have withstood space travel and are present on the Curiosity rover now on the planet Mars.{{Cite journal |last=Madhusoodanan |first=Jyoti |name-list-style=vanc |date=19 May 2014 |title=Microbial stowaways to Mars identified |url=https://www.nature.com/news/microbial-stowaways-to-mars-identified-1.15249 |journal=Nature |doi=10.1038/nature.2014.15249 |access-date=23 May 2014 |s2cid=87409424|url-access=subscription }}

On 20 August 2014, scientists confirmed the existence of microorganisms living half a mile below the ice of Antarctica.{{Cite journal |vauthors=Fox D |date=August 2014 |title=Lakes under the ice: Antarctica's secret garden |journal=Nature |volume=512 |issue=7514 |pages=244–46 |bibcode=2014Natur.512..244F |doi=10.1038/512244a |pmid=25143097 |doi-access=free}}{{Cite web |last=Mack |first=Eric |name-list-style=vanc |date=20 August 2014 |title=Life Confirmed Under Antarctic Ice; Is Space Next? |url=https://www.forbes.com/sites/ericmack/2014/08/20/life-confirmed-under-antarctic-ice-is-space-next/ |access-date=21 August 2014 |website=Forbes}}

In September 2015, scientists from [https://www.cnr.it/en CNR-National Research Council] of Italy reported that S. soflataricus survived under Martian radiation at a wavelength that was considered lethal to most bacteria. This discovery is significant because it indicates that not only bacterial spores, but also growing cells can resist to strong UV radiation.{{Cite journal |vauthors=Mastascusa V, Romano I, Di Donato P, Poli A, Della Corte V, Rotundi A, Bussoletti E, Quarto M, Pugliese M, Nicolaus B |date=September 2014 |title=Extremophiles survival to simulated space conditions: an astrobiology model study |journal=Origins of Life and Evolution of the Biosphere |volume=44 |issue=3 |pages=231–37 |bibcode=2014OLEB...44..231M |doi=10.1007/s11084-014-9397-y |pmc=4669584 |pmid=25573749}}

In June 2016, scientists from Brigham Young University reported that endospores of Bacillus subtilis were able to survive high speed impacts up to 299±28 m/s, extreme shock, and extreme deceleration. They pointed out that this feature might allow endospores to survive and to be transferred between planets by traveling within meteorites or by experiencing atmosphere disruption. Moreover, they suggested that the landing of spacecraft may also result in interplanetary spore transfer, given that spores can survive high-velocity impact while ejected from the spacecraft onto the planet surface. This is the first study which reported that bacteria can survive in such high-velocity impact. However, the lethal impact speed is unknown, and further experiments should be done by introducing higher-velocity impact to bacterial endospores.{{Cite journal |vauthors=Barney BL, Pratt SN, Austin DE |date=June 2016 |title=Survivability of bare, individual Bacillus subtilis spores to high-velocity surface impact: Implications for microbial transfer through space |journal=Planetary and Space Science |volume=125 |pages=20–26 |bibcode=2016P&SS..125...20B |doi=10.1016/j.pss.2016.02.010}}

In August 2020 scientists reported that bacteria that feed on air discovered 2017 in Antarctica are likely not limited to Antarctica after discovering the two genes previously linked to their "atmospheric chemosynthesis" in soil of two other similar cold desert sites, which provides further information on this carbon sink and further strengthens the extremophile evidence that supports the potential existence of microbial life on alien planets.{{Cite news |title=Microbes living on air a global phenomenon |language=en |work=phys.org |url=https://phys.org/news/2020-08-microbes-air-global-phenomenon.html |access-date=8 September 2020}}{{Cite news |date=19 August 2020 |title=Bacteria that "eat" only air found in cold deserts around the world |work=New Atlas |url=https://newatlas.com/biology/air-eating-bacteria-antarctica-artic/ |access-date=8 September 2020}}{{Cite journal |last1=Ray |first1=Angelique E. |last2=Zhang |first2=Eden |last3=Terauds |first3=Aleks |last4=Ji |first4=Mukan |last5=Kong |first5=Weidong |last6=Ferrari |first6=Belinda C. |date=2020 |title=Soil Microbiomes With the Genetic Capacity for Atmospheric Chemosynthesis Are Widespread Across the Poles and Are Associated With Moisture, Carbon, and Nitrogen Limitation |journal=Frontiers in Microbiology |language=en |volume=11 |page=1936 |doi=10.3389/fmicb.2020.01936 |issn=1664-302X |pmc=7437527 |pmid=32903524 |doi-access=free |s2cid=221105556}} 50px Text and images are available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].

The same month, scientists reported that bacteria from Earth, particularly Deinococcus radiodurans, were found to survive for three years in outer space, based on studies on the International Space Station. These findings support the notion of panspermia.{{Cite news |last=Strickland |first=Ashley |date=26 August 2020 |title=Bacteria from Earth can survive in space and could endure the trip to Mars, according to new study |work=CNN News |url=https://www.cnn.com/2020/08/26/world/earth-mars-bacteria-space-scn/index.html |access-date=26 August 2020}}{{Cite journal |last=Kawaguchi, Yuko |display-authors=et al. |date=26 August 2020 |title=DNA Damage and Survival Time Course of Deinococcal Cell Pellets During 3 Years of Exposure to Outer Space |journal=Frontiers in Microbiology |volume=11 |page=2050 |doi=10.3389/fmicb.2020.02050 |pmc=7479814 |pmid=32983036 |doi-access=free |s2cid=221300151}} 50px Text and images are available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].

Extremophiles can also be useful players in the bioremediation of contaminated sites as some species are capable of biodegradation under conditions too extreme for classic bioremediation candidate species. Anthropogenic activity causes the release of pollutants that may potentially settle in extreme environments as is the case with tailings and sediment released from deep-sea mining activity.{{Cite journal |last1=Frid |first1=Christopher L. J. |last2=Caswell |first2=Bryony A. |date=2017-11-23 |title=Marine Pollution |journal=Oxford Scholarship Online |volume=1 |doi=10.1093/oso/9780198726289.001.0001 |isbn=9780198726289}} While most bacteria would be crushed by the pressure in these environments, piezophiles can tolerate these depths and can metabolize pollutants of concern if they possess bioremediation potential.{{citation needed|date=May 2023}}

There are multiple potential destinations for hydrocarbons after an oil spill has settled and currents routinely deposit them in extreme environments. Methane bubbles resulting from the Deepwater Horizon oil spill were found 1.1 kilometers below water surface level and at concentrations as high as 183 μmol per kilogram.{{Cite journal |last1=Reddy |first1=C. M. |last2=Arey |first2=J. S. |last3=Seewald |first3=J. S. |last4=Sylva |first4=S. P. |last5=Lemkau |first5=K. L. |last6=Nelson |first6=R. K. |last7=Carmichael |first7=C. A. |last8=McIntyre |first8=C. P. |last9=Fenwick |first9=J. |last10=Ventura |first10=G. T. |last11=Van Mooy |first11=B. A. S. |author-link11=Benjamin Van Mooy |date=2011-07-18 |title=Composition and fate of gas and oil released to the water column during the Deepwater Horizon oil spill |journal=Proceedings of the National Academy of Sciences |volume=109 |issue=50 |pages=20229–34 |doi=10.1073/pnas.1101242108 |issn=0027-8424 |pmc=3528605 |pmid=21768331 |doi-access=free}} The combination of low temperatures and high pressures in this environment result in low microbial activity. However, bacteria that are present including species of Pseudomonas, Aeromonas and Vibrio were found to be capable of bioremediation, albeit at a tenth of the speed they would perform at sea level pressure.{{Cite journal |last1=Margesin |first1=R. |last2=Schinner |first2=F. |date=2001-09-01 |title=Biodegradation and bioremediation of hydrocarbons in extreme environments |journal=Applied Microbiology and Biotechnology |volume=56 |issue=5–6 |pages=650–63 |doi=10.1007/s002530100701 |issn=0175-7598 |pmid=11601610 |s2cid=13436065}} Polycyclic aromatic hydrocarbons increase in solubility and bioavailability with increasing temperature.{{citation needed|date=April 2021}} Thermophilic Thermus and Bacillus species have demonstrated higher gene expression for the alkane mono-oxygenase alkB at temperatures exceeding {{Cvt|60|C}}.{{citation needed|date=April 2021}} The expression of this gene is a crucial precursor to the bioremediation process. Fungi that have been genetically modified with cold-adapted enzymes to tolerate differing pH levels and temperatures have been shown to be effective at remediating hydrocarbon contamination in freezing conditions in the Antarctic.{{Cite journal |last1=Duarte |first1=Alysson Wagner Fernandes |last2=dos Santos |first2=Juliana Aparecida |last3=Vianna |first3=Marina Vitti |last4=Vieira |first4=Juliana Maíra Freitas |last5=Mallagutti |first5=Vitor Hugo |last6=Inforsato |first6=Fabio José |last7=Wentzel |first7=Lia Costa Pinto |last8=Lario |first8=Luciana Daniela |last9=Rodrigues |first9=Andre |last10=Pagnocca |first10=Fernando Carlos |last11=Pessoa Junior |first11=Adalberto |date=2017-12-11 |title=Cold-adapted enzymes produced by fungi from terrestrial and marine Antarctic environments |journal=Critical Reviews in Biotechnology |volume=38 |issue=4 |pages=600–19 |doi=10.1080/07388551.2017.1379468 |issn=0738-8551 |pmid=29228814 |hdl-access=free |hdl=11449/175619 |s2cid=4201439}}

Acidithiubacillus ferroxidans has been shown to be effective in remediating mercury in acidic soil due to its merA gene making it mercury resistant.{{Cite journal |last1=Takeuchi |first1=Fumiaki |last2=Iwahori |first2=Kenji |last3=Kamimura |first3=Kazuo |last4=Negishi |first4=Atsunori |last5=Maeda |first5=Terunobu |last6=Sugio |first6=Tsuyoshi |date=January 2001 |title=Volatilization of Mercury under Acidic Conditions from Mercury-polluted Soil by a Mercury-resistant Acidithiobacillus ferrooxidans SUG 2-2 |journal=Bioscience, Biotechnology, and Biochemistry |volume=65 |issue=9 |pages=1981–86 |doi=10.1271/bbb.65.1981 |issn=0916-8451 |pmid=11676009 |s2cid=2158906|doi-access=free }} Industrial effluent contain high levels of metals that can be detrimental to both human and ecosystem health.{{Cite journal |last=Nagajyoti |first=P.C. |date=2008 |title=Heavy metal toxicity: Industrial Effluent Effect on Groundnut (Arachis hypogaea L.) Seedlings |journal=Journal of Applied Sciences Research |volume=4 |issue=1 |pages=110–21}}{{Cite journal |last=Fakayode |first=S.O. |date=2005 |title=Impact assessment of industrial effluent on water quality of the receiving Alaro River in Ibadan, Nigeria. |journal=African Journal of Environmental Assessment and Management |volume=10 |pages=1–13}} In extreme heat environments the extremophile Geobacillus thermodenitrificans has been shown to effectively manage the concentration of these metals within twelve hours of introduction.{{Cite journal |last1=Chatterjee |first1=S.K. |last2=Bhattacharjee |first2=I. |last3=Chandra |first3=G. |date=March 2010 |title=Biosorption of heavy metals from industrial waste water by Geobacillus thermodenitrificans |journal=Journal of Hazardous Materials |volume=175 |issue=1–3 |pages=117–25 |doi=10.1016/j.jhazmat.2009.09.136 |issn=0304-3894 |pmid=19864059}} Some acidophilic microorganisms are effective at metal remediation in acidic environments due to proteins found in their periplasm, not present in any mesophilic organisms, allowing them to protect themselves from high proton concentrations.{{Cite journal |last=Chi |first=A. |date=2007 |title=Periplasmic proteins of the extremophile Acidithiobacillus ferrooxidans: a high throughput proteomics analysis |journal=Molecular & Cellular Proteomics |volume=6 |issue=12 |pages=2239–51 |doi=10.1074/mcp.M700042-MCP200 |doi-access=free |pmc=4631397 |pmid=17911085}} Rice paddies are highly oxidative environments that can produce high levels of lead or cadmium. Deinococcus radiodurans are resistant to the harsh conditions of the environment and are therefore candidate species for limiting the extent of contamination of these metals.{{Cite journal |last1=Dai |first1=Shang |last2=Chen |first2=Qi |last3=Jiang |first3=Meng |last4=Wang |first4=Binqiang |last5=Xie |first5=Zhenming |last6=Yu |first6=Ning |last7=Zhou |first7=Yulong |last8=Li |first8=Shan |last9=Wang |first9=Liangyan |last10=Hua |first10=Yuejin |last11=Tian |first11=Bing |date=September 2021 |title=Colonized extremophile Deinococcus radiodurans alleviates toxicity of cadmium and lead by suppressing heavy metal accumulation and improving antioxidant system in rice |journal=Environmental Pollution |volume=284 |pages=117127 |doi=10.1016/j.envpol.2021.117127 |issn=0269-7491 |pmid=33892465|bibcode=2021EPoll.28417127D }}

Some bacteria are known to also use rare earth elements on their biological processes. For example, Methylacidiphilum fumariolicum, Methylorubrum extorquens, and Methylobacterium radiotolerans are known to be able to use lanthanides as cofactors to increase their methanol dehydrogenase activity.{{Cite journal |last1=Phi |first1=Manh Tri |last2=Singer |first2=Helena |last3=Zäh |first3=Felix |last4=Haisch |first4=Christoph |last5=Schneider |first5=Sabine |last6=Op den Camp |first6=Huub J. M. |last7=Daumann |first7=Lena J. |date=2024-03-01 |title=Assessing Lanthanide-Dependent Methanol Dehydrogenase Activity: The Assay Matters |url=https://pubmed.ncbi.nlm.nih.gov/38269599/ |journal=ChemBioChem |volume=25 |issue=5 |pages=e202300811 |doi=10.1002/cbic.202300811 |issn=1439-7633 |pmid=38269599}}{{Citation |last1=Good |first1=Nathan M. |date=2021-01-01 |volume=650 |pages=97–118 |editor-last=Cotruvo |editor-first=Joseph A. |url=https://www.sciencedirect.com/science/article/pii/S0076687921000719 |access-date=2024-04-10 |publisher=Academic Press |last2=Martinez-Gomez |first2=N. Cecilia|title=Rare-Earth Element Biochemistry: Methanol Dehydrogenases and Lanthanide Biology |chapter=Expression, purification and testing of lanthanide-dependent enzymes in Methylorubrum extorquens AM1 |series=Methods in Enzymology |doi=10.1016/bs.mie.2021.02.001 |pmid=33867027 |isbn=978-0-12-823856-1 |url-access=subscription }}{{citation needed|date=May 2023}}

File:Acid mine drainage comparison.jpg{{Cite web |last=US EPA |first=REG 03 |date=2016-09-09 |title=Actions Eliminate Long-Time, Major Acid Mine Discharge |url=https://www.epa.gov/pa/actions-eliminate-long-time-major-acid-mine-discharge |access-date=2024-04-13 |website=www.epa.gov |language=en}}]]

Acid mine drainage is a major environmental concern associated with many metal mines. This is due to the fact that this highly acidic water can mix with groundwater, streams, and lakes. The drainage turns the pH in these water sources from a more neutral pH to a pH lower than 4. This is close to the acidity levels of battery acid or stomach acid. Exposure to the polluted water can greatly affect the health of plants, humans, and animals. However, a productive method of remediation is to introduce the extremophile, Thiobacillus ferrooxidans. This extremophile is useful for its bioleaching property. It helps to break down minerals in the waste water created by the mine. By breaking down the minerals Thiobacillus ferrooxidans start to help neutralize the acidity of the waste water. This is a way to reduce the environmental impact and help remediate the damage caused by the acid mine drainage leaks.{{Cite web |last=US EPA |first=OW |date=2015-09-15 |title=Abandoned Mine Drainage |url=https://www.epa.gov/nps/abandoned-mine-drainage |access-date=2024-04-13 |website=www.epa.gov |language=en}}{{Cite web |title=Acid Mine Drainage |url=https://earthworks.org/issues/acid-mine-drainage/ |access-date=2024-04-13 |website=Earthworks |language=en-US}}{{Cite journal |last1=Valdés |first1=Jorge |last2=Pedroso |first2=Inti |last3=Quatrini |first3=Raquel |last4=Dodson |first4=Robert J |last5=Tettelin |first5=Herve |last6=Blake |first6=Robert |last7=Eisen |first7=Jonathan A |last8=Holmes |first8=David S |date=December 2008 |title=Acidithiobacillus ferrooxidans metabolism: from genome sequence to industrial applications |journal=BMC Genomics |language=en |volume=9 |issue=1 |page=597 |doi=10.1186/1471-2164-9-597 |doi-access=free |issn=1471-2164 |pmc=2621215 |pmid=19077236}}

Psychrophilic microbes metabolize hydrocarbons which assists in the remediation of hazardous, oil-based pollutants in the Arctic and Antarctic regions. These specific microbes are used in this region due to their ability to perform their functions at extremely cold temperatures.{{Cite journal |last1=Chaudhary |first1=Dhiraj Kumar |last2=Kim |first2=Dong-Uk |last3=Kim |first3=Dockyu |last4=Kim |first4=Jaisoo |date=2019-03-11 |title=Flavobacterium petrolei sp. nov., a novel psychrophilic, diesel-degrading bacterium isolated from oil-contaminated Arctic soil|journal=Scientific Reports |language=en |volume=9 |issue=1 |pages=4134 |doi=10.1038/s41598-019-40667-7 |pmid=30858439 |bibcode=2019NatSR...9.4134C |issn=2045-2322|pmc=6411956 }}{{Cite journal |last=Wackett |first=Lawrence P. |date=May 2012 |title=Bioremediation of oil spills: An annotated selection of World Wide Web sites relevant to the topics in Microbial Biotechnology |journal=Microbial Biotechnology |language=en |volume=5 |issue=3 |pages=450–451 |doi=10.1111/j.1751-7915.2011.00330.x |issn=1751-7915 |pmc=3821688}}

{{see also|Uranium#Biotic and abiotic}}

Any bacteria capable of inhabiting radioactive mediums can be classified as an extremophile. Radioresistant organisms are therefore critical in the bioremediation of radionuclides. Uranium is particularly challenging to contain when released into an environment and very harmful to both human and ecosystem health.{{Citation |title=Toxicological Profile for Uranium |date=2002-01-12 |work=ATSDR's Toxicological Profiles |publisher=CRC Press |doi=10.1201/9781420061888_ch157 |doi-broken-date=11 November 2024 |isbn=978-1-4200-6188-8 |hdl=2027/mdp.39015032949136 |hdl-access=free}}{{Cite journal |last=Heising-Goodman |first=Carolyn |date=March 1981 |title=Nuclear Power and Its Environmental Effects |journal=Nuclear Technology |volume=52 |issue=3 |pages=445 |doi=10.13182/nt81-a32724 |bibcode=1981NucTe..52..445H |issn=0029-5450}} The NANOBINDERS project is equipping bacteria that can survive in uranium rich environments with gene sequences that enable proteins to bind to uranium in mining effluent, making it more convenient to collect and dispose of.{{Cite journal |last=Marques |first=Catarina R. |date=2018-06-01 |title=Extremophilic Microfactories: Applications in Metal and Radionuclide Bioremediation |journal=Frontiers in Microbiology |volume=9 |page=1191 |doi=10.3389/fmicb.2018.01191 |issn=1664-302X |pmc=5992296 |pmid=29910794 |doi-access=free}} Some examples are Shewanella putrefaciens, Geobacter metallireducens and some strains of Burkholderia fungorum.{{citation needed|date=May 2023}}

Radiotrophic fungi, which use radiation as an energy source, have been found inside and around the Chernobyl Nuclear Power Plant.{{Cite magazine |url=http://www.sciencenews.org/articles/20070526/fob5.asp |archiveurl=https://web.archive.org/web/20080424001002/http://www.sciencenews.org/articles/20070526/fob5.asp |archivedate=2008-04-24 |magazine=Science News |title=Dark Power: Pigment seems to put radiation to good use |date=May 26, 2007 |volume=171 |number=21 |page=325 |first=Davide |last=Castelvecchi}}

Radioresistance has also been observed in certain species of macroscopic lifeforms. The lethal dose required to kill up to 50% of a tortoise population is 40,000 roentgens, compared to only 800 roentgens needed to kill 50% of a human population.{{Cite web|url=https://www.upi.com/Science_News/2002/05/06/Tortoise-blood-fights-radiation-sickness/36041020716491/|title=Tortoise blood fights radiation sickness - UPI.com|website=UPI}} In experiments exposing lepidopteran insects to gamma radiation, significant DNA damage was detected only at 20 Gy and higher doses, in contrast with human cells that showed similar damage at only 2 Gy.{{Cite journal |last1=Chandna |first1=S. |last2=Dwarakanath |first2=B. S. |last3=Seth |first3=R. K. |last4=Khaitan |first4=D. |last5=Adhikari |first5=J. S. |last6=Jain |first6=V. |year=2004 |title=Radiation responses of Sf9, a highly radioresistant lepidopteran insect cell line |url=https://pubmed.ncbi.nlm.nih.gov/15204707/ |journal=International Journal of Radiation Biology |volume=80 |issue=4 |pages=301–315 |doi=10.1080/09553000410001679794 |pmid=15204707 |s2cid=24978637}}

New sub-types of extremophiles are identified frequently and the sub-category list for extremophiles is always growing. For example, microbial life lives in the liquid asphalt lake, Pitch Lake. Research indicates that extremophiles inhabit the asphalt lake in populations ranging between 10⁶ and 10⁷ cells/gram.[https://www.technologyreview.com/2010/04/15/91763/microbial-life-found-in-hydrocarbon-lake/ Microbial Life Found in Hydrocarbon Lake.] the physics arXiv blog 15 April 2010.{{Cite journal |last1=Schulze-Makuch |first1=Dirk |last2=Haque |first2=Shirin |last3=De Sousa Antonio |first3=Marina Resendes |last4=Ali |first4=Denzil |last5=Hosein |first5=Riad |last6=Song |first6=Young C. |last7=Yang |first7=Jinshu |last8=Zaikova |first8=Elena |last9=Beckles |first9=Denise M. |last10=Guinan |first10=Edward |last11=Lehto |first11=Harry J. |last12=Hallam |first12=Steven J. |year=2011 |title=Microbial Life in a Liquid Asphalt Desert |journal=Astrobiology |volume=11 |issue=3 |pages=241–58 |arxiv=1004.2047 |bibcode=2011AsBio..11..241S |doi=10.1089/ast.2010.0488 |pmid=21480792 |s2cid=22078593}} Likewise, until recently, boron tolerance was unknown, but a strong borophile was discovered in bacteria. With the recent isolation of Bacillus boroniphilus, borophiles came into discussion.{{Cite journal |vauthors=Ahmed I, Yokota A, Fujiwara T |date=March 2007 |title=A novel highly boron tolerant bacterium, Bacillus boroniphilus sp. nov., isolated from soil, that requires boron for its growth |journal=Extremophiles |volume=11 |issue=2 |pages=217–24 |doi=10.1007/s00792-006-0027-0 |pmid=17072687 |s2cid=2965138}} Studying these borophiles may help illuminate the mechanisms of both boron toxicity and boron deficiency.

In July 2019, a scientific study of Kidd Mine in Canada discovered sulfur-breathing organisms which live {{Convert|7900|ft}} below the surface, and which breathe sulfur in order to survive. These organisms are also remarkable due to eating rocks such as pyrite as their regular food source.{{Cite journal |last1=Lollar |first1=Garnet S. |last2=Warr |first2=Oliver |last3=Telling |first3=Jon |last4=Osburn |first4=Magdalena R. |last5=Lollar |first5=Barbara Sherwood |year=2019 |title='Follow the Water': Hydrogeochemical Constraints on Microbial Investigations 2.4 km Below Surface at the Kidd Creek Deep Fluid and Deep Life Observatory |journal=Geomicrobiology Journal |volume=36 |issue=10 |pages=859–72 |doi=10.1080/01490451.2019.1641770 |bibcode=2019GmbJ...36..859L |s2cid=199636268}}[https://deepcarbon.net/worlds-oldest-groundwater-supports-life-through-water-rock-chemistry World’s Oldest Groundwater Supports Life Through Water-Rock Chemistry] {{Webarchive|url=https://web.archive.org/web/20190910013319/https://deepcarbon.net/worlds-oldest-groundwater-supports-life-through-water-rock-chemistry |date=10 September 2019 }}, 29 July 2019, deepcarbon.net.[https://www.nbcnews.com/mach/science/strange-life-forms-found-deep-mine-point-vast-underground-galapagos-ncna1050906 Strange life-forms found deep in a mine point to vast 'underground Galapagos'], By Corey S. Powell, 7 Sept. 2019, nbcnews.com.

{{Main|Extremophiles in biotechnology}}

The thermoalkaliphilic catalase, which initiates the breakdown of hydrogen peroxide into oxygen and water, was isolated from an organism, Thermus brockianus, found in Yellowstone National Park by Idaho National Laboratory researchers. The catalase operates over a temperature range from 30 °C to over 94 °C and a pH range from 6–10. This catalase is extremely stable compared to other catalases at high temperatures and pH. In a comparative study, the T. brockianus catalase exhibited a half life of 15 days at 80 °C and pH 10 while a catalase derived from Aspergillus niger had a half life of 15 seconds under the same conditions. The catalase will have applications for removal of hydrogen peroxide in industrial processes such as pulp and paper bleaching, textile bleaching, food pasteurization, and surface decontamination of food packaging.{{Cite web |title=Bioenergy and Industrial Microbiology |url=https://inlportal.inl.gov/portal/server.pt/community/idaho_national_laboratory_biological_systems/352/bioenergy_and_industrial_microbiology/2660 |url-status=dead |archive-url=https://web.archive.org/web/20141018040930/https://inlportal.inl.gov/portal/server.pt/community/idaho_national_laboratory_biological_systems/352/bioenergy_and_industrial_microbiology/2660 |archive-date=18 October 2014 |access-date=3 February 2014 |website=Idaho National Laboratory |publisher=U.S. Department of Energy}}

DNA modifying enzymes such as Taq DNA polymerase and some Bacillus enzymes used in clinical diagnostics and starch liquefaction are produced commercially by several biotechnology companies.{{Cite book |title=Extremophiles: Microbiology and Biotechnology |publisher=Caister Academic Press |year=2012 |isbn=978-1-904455-98-1 |veditors=Anitori RP}}

Over 65 prokaryotic species are known to be naturally competent for genetic transformation, the ability to transfer DNA from one cell to another cell followed by integration of the donor DNA into the recipient cell's chromosome.{{Cite journal |vauthors=Johnsborg O, Eldholm V, Håvarstein LS |date=December 2007 |title=Natural genetic transformation: prevalence, mechanisms and function |journal=Research in Microbiology |volume=158 |issue=10 |pages=767–78 |doi=10.1016/j.resmic.2007.09.004 |pmid=17997281|doi-access=free }} Several extremophiles are able to carry out species-specific DNA transfer, as described below. However, it is not yet clear how common such a capability is among extremophiles.{{citation needed|date=May 2023}}

The bacterium Deinococcus radiodurans is one of the most radioresistant organisms known. This bacterium can also survive cold, dehydration, vacuum and acid and is thus known as a polyextremophile. D. radiodurans is competent to perform genetic transformation.{{Cite journal |vauthors=Moseley BE, Setlow JK |date=September 1968 |title=Transformation in Micrococcus radiodurans and the ultraviolet sensitivity of its transforming DNA |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=61 |issue=1 |pages=176–83 |bibcode=1968PNAS...61..176M |doi=10.1073/pnas.61.1.176 |pmc=285920 |pmid=5303325 |doi-access=free}} Recipient cells are able to repair DNA damage in donor transforming DNA that had been UV irradiated as efficiently as they repair cellular DNA when the cells themselves are irradiated. The extreme thermophilic bacterium Thermus thermophilus and other related Thermus species are also capable of genetic transformation.{{Cite journal |vauthors=Koyama Y, Hoshino T, Tomizuka N, Furukawa K |date=April 1986 |title=Genetic transformation of the extreme thermophile Thermus thermophilus and of other Thermus spp |journal=Journal of Bacteriology |volume=166 |issue=1 |pages=338–40 |doi=10.1128/jb.166.1.338-340.1986 |pmc=214599 |pmid=3957870}}

Halobacterium volcanii, an extreme halophilic (saline tolerant) archaeon, is capable of natural genetic transformation. Cytoplasmic bridges are formed between cells that appear to be used for DNA transfer from one cell to another in either direction.{{Cite journal |vauthors=Rosenshine I, Tchelet R, Mevarech M |date=September 1989 |title=The mechanism of DNA transfer in the mating system of an archaebacterium |journal=Science |volume=245 |issue=4924 |pages=1387–89 |bibcode=1989Sci...245.1387R |doi=10.1126/science.2818746 |pmid=2818746}}

Sulfolobus solfataricus and Sulfolobus acidocaldarius are hyperthermophilic archaea. Exposure of these organisms to the DNA damaging agents UV irradiation, bleomycin or mitomycin C induces species-specific cellular aggregation.{{Cite journal |display-authors=etal |vauthors=Fröls S, Ajon M, Wagner M, Teichmann D, Zolghadr B, Folea M, Boekema EJ, Driessen AJ, Schleper C, Albers SV |date=November 2008 |title=UV-inducible cellular aggregation of the hyperthermophilic archaeon Sulfolobus solfataricus is mediated by pili formation |url=https://www.rug.nl/research/portal/en/publications/uvinducible-cellular-aggregation-of-the-hyperthermophilic-archaeon-sulfolobus-solfataricus-is-mediated-by-pili-formation(0dd2a8eb-0f4b-4382-805d-158a870be95e).html |journal=Molecular Microbiology |volume=70 |issue=4 |pages=938–52 |doi=10.1111/j.1365-2958.2008.06459.x |pmid=18990182 |doi-access=free}}{{Cite journal |display-authors=etal |vauthors=Ajon M, Fröls S, van Wolferen M, Stoecker K, Teichmann D, Driessen AJ, Grogan DW, Albers SV, Schleper C |date=November 2011 |title=UV-inducible DNA exchange in hyperthermophilic archaea mediated by type IV pili |url=https://pure.rug.nl/ws/files/6771142/2011MolMicrobiolAjon.pdf |journal=Molecular Microbiology |volume=82 |issue=4 |pages=807–17 |doi=10.1111/j.1365-2958.2011.07861.x |pmid=21999488 |doi-access=free |s2cid=42880145}} UV-induced cellular aggregation of S. acidocaldarius mediates chromosomal marker exchange with high frequency. Recombination rates exceed those of uninduced cultures by up to three orders of magnitude. Frols et al. and Ajon et al. hypothesized that cellular aggregation enhances species-specific DNA transfer between Sulfolobus cells in order to repair damaged DNA by means of homologous recombination. Van Wolferen et al.{{Cite journal |vauthors=van Wolferen M, Ajon M, Driessen AJ, Albers SV |date=July 2013 |title=How hyperthermophiles adapt to change their lives: DNA exchange in extreme conditions |journal=Extremophiles |volume=17 |issue=4 |pages=545–63 |doi=10.1007/s00792-013-0552-6 |pmid=23712907 |s2cid=5572901}} noted that this DNA exchange process may be crucial under DNA damaging conditions such as high temperatures. It has also been suggested that DNA transfer in Sulfolobus may be an early form of sexual interaction similar to the more well-studied bacterial transformation systems that involve species-specific DNA transfer leading to homologous recombinational repair of DNA damage (and see Transformation (genetics)).{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}}

Extracellular membrane vesicles (MVs) might be involved in DNA transfer between different hyperthermophilic archaeal species.{{Cite journal |vauthors=Gaudin M, Krupovic M, Marguet E, Gauliard E, Cvirkaite-Krupovic V, Le Cam E, Oberto J, Forterre P |date=April 2014 |title=Extracellular membrane vesicles harbouring viral genomes |journal=Environmental Microbiology |volume=16 |issue=4 |pages=1167–75 |doi=10.1111/1462-2920.12235 |pmid=24034793|bibcode=2014EnvMi..16.1167G }} It has been shown that both plasmids{{Cite journal |vauthors=Gaudin M, Gauliard E, Schouten S, Houel-Renault L, Lenormand P, Marguet E, Forterre P |date=February 2013 |title=Hyperthermophilic archaea produce membrane vesicles that can transfer DNA |journal=Environmental Microbiology Reports |volume=5 |issue=1 |pages=109–16 |doi=10.1111/j.1758-2229.2012.00348.x |pmid=23757139|bibcode=2013EnvMR...5..109G }} and viral genomes can be transferred via MVs. Notably, a horizontal plasmid transfer has been documented between hyperthermophilic Thermococcus and Methanocaldococcus species, respectively belonging to the orders Thermococcales and Methanococcales.{{Cite journal |vauthors=Krupovic M, Gonnet M, Hania WB, Forterre P, Erauso G |year=2013 |title=Insights into dynamics of mobile genetic elements in hyperthermophilic environments from five new Thermococcus plasmids |journal=PLOS ONE |volume=8 |issue=1 |pages=e49044 |bibcode=2013PLoSO...849044K |doi=10.1371/journal.pone.0049044 |pmc=3543421 |pmid=23326305 |doi-access=free}}

• Earliest known life forms
• Dissimilatory metal-reducing microorganisms
• Extremotroph
• List of microorganisms tested in outer space
• Mesophile, an organism that grows best in moderate temperatures
• Neutrophile, an organism that grows best in a neutral pH level
• RISE project
• Tardigrade

{{reflist}}

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• {{Cite journal |vauthors=Wilson ZE, Brimble MA |date=January 2009 |title=Molecules derived from the extremes of life |journal=Natural Product Reports |volume=26 |issue=1 |pages=44–71 |doi=10.1039/b800164m |pmid=19374122 |ref=none}}
• {{Cite journal |vauthors=Rossi M, Ciaramella M, Cannio R, Pisani FM, Moracci M, Bartolucci S |date=July 2003 |title=Extremophiles 2002 |journal=Journal of Bacteriology |volume=185 |issue=13 |pages=3683–3689 |doi=10.1128/JB.185.13.3683-3689.2003 |pmc=161588 |pmid=12813059 |ref=none}}
• {{Cite journal |last=C.Michael Hogan |year=2010 |title=Extremophile |url=http://www.eoearth.org/article/Extremophile?topic=49540 |journal=Encyclopedia of Earth, National Council of Science & the Environment, Eds. E. Monosson & C. Cleveland |ref=none}}
• {{Cite book |title=Polyextremophiles: life under multiple forms of stress |date=2013 |publisher=Springer |isbn=978-94-007-6488-0 |veditors=Seckbach J, Oren A, Stan-Lotter H |location=Dordrecht |ref=none}}

{{refend}}

• [https://serc.carleton.edu/microbelife/extreme/environments.html Extreme Environments - Science Education Resource Center]
• [https://inlportal.inl.gov/portal/server.pt?open=514&objID=2660&parentname=CommunityPage&parentid=0&mode=2&in_hi_userid=200&cached=true Extremophile Research] {{Webarchive|url=https://web.archive.org/web/20141018040848/https://inlportal.inl.gov/portal/server.pt?open=514&objID=2660&parentname=CommunityPage&parentid=0&mode=2&in_hi_userid=200&cached=true |date=18 October 2014 }}
• [http://www.nhm.ac.uk/zoology/extreme.html Eukaryotes in extreme environments]
• [http://www.extremophiles.ir The Research Center of Extremophiles] {{Webarchive|url=https://web.archive.org/web/20160111023711/http://www.extremophiles.ir/ |date=11 January 2016 }}
• [https://www.daviddarling.info/encyclopedia/E/extremophile.html DaveDarling's Encyclopedia of Astrobiology, Astronomy, and Spaceflight]
• [https://extremophiles.org/ The International Society for Extremophiles]
• [https://inlportal.inl.gov/portal/server.pt/community/idaho_national_laboratory_biological_systems/352/bioenergy_and_industrial_microbiology/2660 Idaho National Laboratory] {{Webarchive|url=https://web.archive.org/web/20141018040930/https://inlportal.inl.gov/portal/server.pt/community/idaho_national_laboratory_biological_systems/352/bioenergy_and_industrial_microbiology/2660 |date=18 October 2014 }}
• [https://web.archive.org/web/20140510021244/http://www.daviddarling.info/encyclopedia/P/polyextremophile.html Polyextremophile on David Darling's Encyclopedia of Astrobiology, Astronomy, and Spaceflight]
• [https://deepcarbon.net/feature/how-hot-is-too-hot#.V9Fp-4WASfE/ T-Limit Expedition]

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Category:Environmental microbiology

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Category:Bacteria

Category:Ecology

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