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Growth of the acidophilic iron–sulfur bacterium Acidithiobacillus ferrooxidans under Mars-like geochemical conditions

Bauermeister, Anja und Rettberg, Petra und Flemming, Hans-Curt (2013) Growth of the acidophilic iron–sulfur bacterium Acidithiobacillus ferrooxidans under Mars-like geochemical conditions. Planetary and Space Science, Epub ahead of print (in Press). Elsevier. doi: 10.1016/j.pss.2013.09.009. ISSN 0032-0633.

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Kurzfassung

The question of life on Mars has been in focus of astrobiological research for several decades, and recent missions in orbit or on the surface of the planet are constantly expanding our knowledge on Martian geochemistry. For example, massive stratified deposits have been identified on Mars containing sulfate minerals and iron oxides, which suggest the existence of acidic aqueous conditions in the past, similar to acidic iron- and sulfur-rich environments on Earth. Acidophilic organisms thriving in such habitats could have been an integral part of a possibly widely extinct Martian ecosystem, but remains might possibly even exist today in protected subsurface niches. The chemolithoautotrophic strain Acidithiobacillus ferrooxidans was selected as a model organism to study the metabolic capacities of acidophilic iron–sulfur bacteria, especially regarding their ability to grow with in situ resources that could be expected on Mars. The experiments were not designed to accurately simulate Martian physical conditions (except when certain single parameters such as oxygen partial pressure were considered), but rather the geochemical environment that can be found on Mars. A. ferrooxidans could grow solely on the minerals contained in synthetic Mars regolith mixtures with no added nutrients, using either O₂as an external electron acceptor for iron oxidation, or H₂as an external electron donor for iron reduction, and thus might play important roles in the redox cycling of iron on Mars. Though the oxygen partial pressure of the Martian atmosphere at the surface was not sufficient for detectable iron oxidation and growth of A. ferrooxidans during short-term incubation (7 days), alternative chemical O₂-generating processes in the subsurface might yield microhabitats enriched in oxygen, which principally are possible under such conditions. The bacteria might also contribute to the reductive dissolution of Fe³⁺-containing minerals like goethite and hematite, which are characterized by a high thermodynamic stability. Even in a desiccated environment, A. ferrooxidans survived for one week under simulated Martian shallow subsurface conditions (6 hPa, −20 °C, 0.13% O₂) in the form of dried biofilms without loss of viability. Low temperature and low oxygen pressure were favorable to survival. Thus, the acidophilic iron–sulfur bacterium A. ferrooxidans may be considered a plausible candidate of a potential Martian food web based on its metabolic capacities. As an autotroph it would be located at the base of such a food web, providing organic carbon.

elib-URL des Eintrags:https://elib.dlr.de/84862/
Dokumentart:Zeitschriftenbeitrag
Titel:Growth of the acidophilic iron–sulfur bacterium Acidithiobacillus ferrooxidans under Mars-like geochemical conditions
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Bauermeister, Anja German Aerospace Center DLR e.V., Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln (Cologne), GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Rettberg, PetraGerman Aerospace Center DLR e.V., Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, D-51147 Köln (Cologne), GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Flemming, Hans-CurtUniversity of Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Universitätsstr.5, D-45141 Essen, GermanyNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:2013
Erschienen in:Planetary and Space Science
Referierte Publikation:Ja
Open Access:Nein
Gold Open Access:Nein
In SCOPUS:Ja
In ISI Web of Science:Ja
Band:Epub ahead of print (in Press)
DOI:10.1016/j.pss.2013.09.009
Verlag:Elsevier
ISSN:0032-0633
Status:veröffentlicht
Stichwörter:Acidophilic iron–sulfur bacteria, Mars, Minerals, Microbial food web
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Raumfahrt
HGF - Programmthema:Forschung unter Weltraumbedingungen
DLR - Schwerpunkt:Raumfahrt
DLR - Forschungsgebiet:R FR - Forschung unter Weltraumbedingungen
DLR - Teilgebiet (Projekt, Vorhaben):R - Vorhaben Strahlenbiologie (alt)
Standort: Köln-Porz
Institute & Einrichtungen:Institut für Luft- und Raumfahrtmedizin > Strahlenbiologie
Hinterlegt von: Kopp, Kerstin
Hinterlegt am:25 Okt 2013 11:46
Letzte Änderung:07 Nov 2023 12:42

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