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dc.contributor.authorStevens, Adam H.
dc.contributor.authorChilders, Delma
dc.contributor.authorFox-Powell, Mark
dc.contributor.authorNicholson, Natasha
dc.contributor.authorJhoti, Elisha
dc.contributor.authorCockell, Charles S.
dc.identifier.citationStevens , A H , Childers , D , Fox-Powell , M , Nicholson , N , Jhoti , E & Cockell , C S 2019 , ' Growth, viability, and death of planktonic and biofilm Sphingomonas desiccabilis in simulated martian brines ' , Astrobiology , vol. 19 , no. 1 , pp. 87-98 .
dc.identifier.otherPURE: 257990254
dc.identifier.otherPURE UUID: 734b52ff-42b2-492c-b5e7-8def7bdf1815
dc.identifier.otherScopus: 85059394268
dc.identifier.otherPubMed: 30048150
dc.identifier.otherWOS: 000440140700001
dc.descriptionThis research was supported by the UK Science Technology and Facilities Council under Grant ST/M001261/1.en
dc.description.abstractAqueous solutions on Mars are theorized to contain very different ion compositions than those on Earth. To determine the effect of such solutions on typical environmental micro-organisms, which could be released from robotic spacecraft or human exploration activity, we investigated the resistance of Sphingomonas desiccabilis to brines that simulate the composition of martian aqueous environments. S. desiccabilis is a desiccation-resistant, biofilm-forming microbe found in desert crusts. The viability of cells in both planktonic and biofilm forms was measured after exposure to simulated martian brines. Planktonic cells showed a loss of viability over the course of several hours in almost all of the seven brines tested. Biofilms conferred greater resistance to all the brines, including those with low water activity and pH, but even cells in biofilms showed a complete loss of viability in <6 h in the harsher brines and in <2 days in the less harsh brines. One brine, however, allowed the microbes to maintain viability over several days, despite having a water activity and pH lower and ionic strength higher than brines that reduced viability over the same timescales, suggesting important ion-specific effects. These data show that biofilm-forming cells have a greater capacity to resist martian aqueous extremes, but that evaporative or deliquescent brines are likely to be destructive to many organisms over relatively short timescales, with implications for the habitability of Mars and for micro-organisms dispersed by robotic or human explorers.
dc.rightsCopyright © Adam H. Stevens et al., 2018; Published by Mary Ann Liebert, Inc. This Open Access article is distributed under the terms of the Creative Commons License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.en
dc.subjectGE Environmental Sciencesen
dc.subjectQH301 Biologyen
dc.subjectAgricultural and Biological Sciences (miscellaneous)en
dc.subjectSpace and Planetary Scienceen
dc.titleGrowth, viability, and death of planktonic and biofilm Sphingomonas desiccabilis in simulated martian brinesen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Earth & Environmental Sciencesen
dc.contributor.institutionUniversity of St Andrews. St Andrews Centre for Exoplanet Scienceen
dc.description.statusPeer revieweden

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