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A rock-dwelling community from cliffs in Beer, UK was exposed to 10 days of LEO as part of the BI... more A rock-dwelling community from cliffs in Beer, UK was exposed to 10 days of LEO as part of the BIOPAN VI mission. An extremophilic cyanobacterium, which was identified as a member of the order Chroococcales was isolated after exposure.
Journal of Geophysical Research Atmospheres
Upcoming Mars Surveyor lander missions will include extensive spectroscopic capabilities designed... more Upcoming Mars Surveyor lander missions will include extensive spectroscopic capabilities designed to improve interpretations of the mineralogy and geology of landing sites on Mars. The 1999 Marsokhod Field Experiment (MFE) was a Mars rover simulation designed in part to investigate the utility of visible/near-infrared and thermal infrared field spectrometers to contribute to the remote geological exploration of a Mars analog field site in the California Mojave Desert. The experiment simultaneously investigated the abilities of an off-site science team to effectively anfilyze and acquire useful imaging and spectroscopic data and to communicate efficiently with rover engineers and an on-site field team to provide meaningful input to rover operations and traverse planning. Experiences gained during the MFE regarding effective communication between different mission operation teams will be useful to upcoming Mars mission teams. Field spectra acquired during the MFE mission exhibited features interpreted at the time as indicative of carbonates (both dolomitic and calcitic), mafic rocks and associated weathering products, and silicic rocks with desert varnish-like coatings. The visible/near-infrared spectra also suggested the presence of organic compounds, including chlorophyll in one rock. Postmission laboratory petrologic and spectral analyses of returned samples confirmed that all rocks identified as carbonates using field measurements alone were calc-silicates and that chlorophyll associated with endolithic organisms was present in the one rock for which it was predicted. Rocks classified from field spectra as silicics and weathered marlcs were recognized in the laboratory as metamorphosed monzonites and diorite schists. This discrepancy was likely due to rock coatings sampled by the field spectrometers compared to fresh rock interiors analyzed petrographically, in addition to somewhat different surfaces analyzed by laboratory thermal spectroscopy compared to field spectra. 7683 7684 JOHNSON ET AL.: REMOTE MINERALOGY-1999 MARSOKHOD FIELD TEST JOHNSON ET AL.: REMOTE MINERALOGY-1999 MARSOKHOD FIELD TEST
As a response to ESA call for mission concepts for its Cosmic Vision 2015?2025 plan, we propose a... more As a response to ESA call for mission concepts for its Cosmic Vision 2015?2025 plan, we propose a mission called ensuremath Darwinensuremath<?iensuremath>. Its primary goal is the study of terrestrial extrasolar planets and the search for life on them. In this paper, we describe different characteristics of the instrument.
Geochmica et Cosmochimica Acta
Microbial activity has been linked to volcanic rock weathering. It is thought that the process is... more Microbial activity has been linked to volcanic rock weathering. It is thought that the process is generally driven by the nutrient requirement of the microbial community and occurs as a result of the sequestration of bioessential elements. Although we know that metabolising bacteria influence rock weathering, the molecular processes invloved are unknown. For the first time, we have used DNA microarray technology to investigate the genes involved in weathering, in particular the sequestering of iron using the heavy metal resistant bacterium, Cupriavidus metallidurans CH34. Extensive studies have characterized the heavy metal resistant and iron uptake mechanisms of this bacterium.Microarray analysis demonstrated that siderophore genes were not differentially expressed when grown in MM284 (iron-limited) with basalt. This was in concurrence with siderophore measurements using the CAS assay. Instead, a large number of porins and membrane transporters in concomitantly with genes associate...
The scientific objectives of the 2018 ExoMars rover mission are to search for traces of past or p... more The scientific objectives of the 2018 ExoMars rover mission are to search for traces of past or present life and to characterise the near-sub surface. Both objectives require study of the rock/regolith materials in terms of structure, textures, mineralogy, and elemental and organic composition. The 2018 ExoMars rover payload consists of a suite of complementary instruments designed to reach these objectives. CLUPI, the high-performance colour close up imager, on board the 2018 ExoMars Rover plays an important role in attaining the mission objectives: it is the equivalent of the hand lens that no geologist is without when undertaking field work. CLUPI is a powerful, highly integrated miniaturized (<700g) low-power robust imaging system, able to operate at very low temperatures (-120°C). CLUPI has a working distance from 10cm to infinite providing outstanding pictures with a color detector of 2652x1768. At 10cm, the resolution is 7 micrometer/pixel in color. The optical-mechanical ...
Little is understood regarding the phylogeny and metabolic capabilities of the earliest colonists... more Little is understood regarding the phylogeny and metabolic capabilities of the earliest colonists of volcanic rocks, yet these data are essential for understanding how life becomes established in, and interacts with the planetary crust, ultimately contributing to critical zone processes and soil formation. Here we report the use of molecular and culture-dependent methods to determine the composition of pioneer microbial communities colonising the basaltic Fimmvörðuháls lava flow at Eyjafjallajökull, Iceland, formed in 2010. Our data show that three to five months post eruption, the lava was colonized by a low-diversity microbial community dominated by Betaproteobacteria, primarily taxa related to nonphototrophic diazotrophs such as Herbaspirillum spp., and chemolithotrophs such as Thiobacillus. Although successfully cultured following enrichment, phototrophs were not abundant members of the Fimmvörðuháls communities, as revealed by molecular analysis, and phototrophy is therefore not likely to be a dominant biogeochemical process in these early successional basalt communities. These results contrast with older Icelandic lava of comparable mineralogy, in which phototrophs comprised a significant fraction of microbial communities and the non-phototrophic community fractions were dominated by Acidobacteria and Actinobacteria.
The existence of ammonia on Titan and Enceladus and potentially other outer Solar System bodies r... more The existence of ammonia on Titan and Enceladus and potentially other outer Solar System bodies raises questions about the habitability of these worlds. Of particular concern for planetary protection is the possibility for Earth microbes inadvertently transported on spacecraft, to survive or even reproduce in these 'hostile' ammonia/ammonia-water environments. Our current understanding of microbial tolerances to ammonia is incomplete and the limits for microbial survival, growth or reproduction have not been established. While some fungi can not only survive but also grow in atmospheres containing 95% N H 3 (1) elsewhere the growth of microorganisms may be inhibited at concentrations of < 1%. The conversion of N H 3 to nitrite by the ubiquitous terrestrial and aquatic ammonia-oxidizing bacteria is a key step in the global nitrogen cycle, and such organisms may potentially possess some of the highest tolerances to ammonia among the bacteria. One of the key factors influencing microbial survival at high ammonia concentrations is pH, determining the ionization of N H 3 to N H + 4 , with N H 3 the more toxic and more abundant form at high pH. Our initial laboratory experiments with Actinobacteria and Proteobacteria strains have demonstrated the lethality of NH3 at concentrations of up to 17.5% at room temperature. However, our findings suggest loss of viability was most likely an effect of high pH rather than a direct N H 3 -specific effect. However, exposure of soil samples (which contain many spore-forming organisms typically found on spacecraft surfaces) showed the survival and subsequent prolific growth of soil bacteria belonging to the Bacillus genus following NH3 exposure over more prolonged periods, also at room temperature at 17.5% N H 3 . The effect of a challenge of low temperature extremes in concert with ammonia is also pertinent to determining the survival and reproductive possibilities in extraterrestrial settings. Soil exposed for six days to concentrations of up to 35% N H 3 at −80 • C resulted in the isolation of viable bacteria at numbers lower than obtained at room temperature exposure. At both temperatures, viable numbers were reduced compared to the 0% NH3 controls at neutral pH and at pH 13.5 (the pH of a 35% N H 3 solution), with viability at −80 • C lower than that at
-Isolates obtained from volcanic rock were dominated by the Actinobacteria phylum, many of which ... more -Isolates obtained from volcanic rock were dominated by the Actinobacteria phylum, many of which could grow on plates containing only washed agar and basalt-palagonite, without nutrient amendment.
Of the 34 meteorites from Mars, none are sedimentary although sediments exist in abundance on the... more Of the 34 meteorites from Mars, none are sedimentary although sediments exist in abundance on the planet. The STONE experiments aim at testing the survivability of different types of analogue martian sediments during entry into the Earth's atmosphere. The rocks are fixed into the heat shield of a FOTON re-entry vehicle around the ablation point and undergo entry speeds of about 7.6 km/s (meteorite entry speeds are slightly higher, at 12-15 km/s). Previous STONE experiments have proven the survivability of dolomite and sandstone through atmospheric passage (STONE 1 and STONE 5). The STONE 6 experiment included an Early Archaean chert (3.446 Ga) from the Pilbara containing cryptic traces of fossil life (microfossils, C isotopes) (N.B. this sample is a good sedimentary Noachian Mars analogue], a Devonian laminite (mudstone) from the Orkneys (Fig 1e), and an Eocene basalt from Austria. A culture of a modern endolithic microorganism, Chroococcidiopsis, was smeared on the back side an...
The STONE 6 experiment demonstrated the survivability of carbonaceous and microfossiliferous mart... more The STONE 6 experiment demonstrated the survivability of carbonaceous and microfossiliferous martian analogue sediments during atmospheric re-entry. Doped endoliths died but their carbonised cells remained.
Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microor... more Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microorganisms reveal that these organisms survive the impact and ejection phase on Mars at shock pressures up to about 50 GPa with exponentially decreasing survival rates.
Icarus
Astronomy & Geophysics, 2015
Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved i... more Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved impact structures. Impact structures can localize water in a number of ways including: 1) circulation of water into hydrothermal systems, 2) ponding of water in the hydrologic depression of the crater. This ponding can occur because of excavation below the water table, filling of the
Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved i... more Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved impact structures. Impact structures can localize water in a number of ways including: 1) circulation of water into hydrothermal systems, 2) ponding of water in the hydrologic depression of the crater. This ponding can occur because of excavation below the water table, filling of the
A rock-dwelling community from cliffs in Beer, UK was exposed to 10 days of LEO as part of the BI... more A rock-dwelling community from cliffs in Beer, UK was exposed to 10 days of LEO as part of the BIOPAN VI mission. An extremophilic cyanobacterium, which was identified as a member of the order Chroococcales was isolated after exposure.
Journal of Geophysical Research Atmospheres
Upcoming Mars Surveyor lander missions will include extensive spectroscopic capabilities designed... more Upcoming Mars Surveyor lander missions will include extensive spectroscopic capabilities designed to improve interpretations of the mineralogy and geology of landing sites on Mars. The 1999 Marsokhod Field Experiment (MFE) was a Mars rover simulation designed in part to investigate the utility of visible/near-infrared and thermal infrared field spectrometers to contribute to the remote geological exploration of a Mars analog field site in the California Mojave Desert. The experiment simultaneously investigated the abilities of an off-site science team to effectively anfilyze and acquire useful imaging and spectroscopic data and to communicate efficiently with rover engineers and an on-site field team to provide meaningful input to rover operations and traverse planning. Experiences gained during the MFE regarding effective communication between different mission operation teams will be useful to upcoming Mars mission teams. Field spectra acquired during the MFE mission exhibited features interpreted at the time as indicative of carbonates (both dolomitic and calcitic), mafic rocks and associated weathering products, and silicic rocks with desert varnish-like coatings. The visible/near-infrared spectra also suggested the presence of organic compounds, including chlorophyll in one rock. Postmission laboratory petrologic and spectral analyses of returned samples confirmed that all rocks identified as carbonates using field measurements alone were calc-silicates and that chlorophyll associated with endolithic organisms was present in the one rock for which it was predicted. Rocks classified from field spectra as silicics and weathered marlcs were recognized in the laboratory as metamorphosed monzonites and diorite schists. This discrepancy was likely due to rock coatings sampled by the field spectrometers compared to fresh rock interiors analyzed petrographically, in addition to somewhat different surfaces analyzed by laboratory thermal spectroscopy compared to field spectra. 7683 7684 JOHNSON ET AL.: REMOTE MINERALOGY-1999 MARSOKHOD FIELD TEST JOHNSON ET AL.: REMOTE MINERALOGY-1999 MARSOKHOD FIELD TEST
As a response to ESA call for mission concepts for its Cosmic Vision 2015?2025 plan, we propose a... more As a response to ESA call for mission concepts for its Cosmic Vision 2015?2025 plan, we propose a mission called ensuremath Darwinensuremath<?iensuremath>. Its primary goal is the study of terrestrial extrasolar planets and the search for life on them. In this paper, we describe different characteristics of the instrument.
Geochmica et Cosmochimica Acta
Microbial activity has been linked to volcanic rock weathering. It is thought that the process is... more Microbial activity has been linked to volcanic rock weathering. It is thought that the process is generally driven by the nutrient requirement of the microbial community and occurs as a result of the sequestration of bioessential elements. Although we know that metabolising bacteria influence rock weathering, the molecular processes invloved are unknown. For the first time, we have used DNA microarray technology to investigate the genes involved in weathering, in particular the sequestering of iron using the heavy metal resistant bacterium, Cupriavidus metallidurans CH34. Extensive studies have characterized the heavy metal resistant and iron uptake mechanisms of this bacterium.Microarray analysis demonstrated that siderophore genes were not differentially expressed when grown in MM284 (iron-limited) with basalt. This was in concurrence with siderophore measurements using the CAS assay. Instead, a large number of porins and membrane transporters in concomitantly with genes associate...
The scientific objectives of the 2018 ExoMars rover mission are to search for traces of past or p... more The scientific objectives of the 2018 ExoMars rover mission are to search for traces of past or present life and to characterise the near-sub surface. Both objectives require study of the rock/regolith materials in terms of structure, textures, mineralogy, and elemental and organic composition. The 2018 ExoMars rover payload consists of a suite of complementary instruments designed to reach these objectives. CLUPI, the high-performance colour close up imager, on board the 2018 ExoMars Rover plays an important role in attaining the mission objectives: it is the equivalent of the hand lens that no geologist is without when undertaking field work. CLUPI is a powerful, highly integrated miniaturized (<700g) low-power robust imaging system, able to operate at very low temperatures (-120°C). CLUPI has a working distance from 10cm to infinite providing outstanding pictures with a color detector of 2652x1768. At 10cm, the resolution is 7 micrometer/pixel in color. The optical-mechanical ...
Little is understood regarding the phylogeny and metabolic capabilities of the earliest colonists... more Little is understood regarding the phylogeny and metabolic capabilities of the earliest colonists of volcanic rocks, yet these data are essential for understanding how life becomes established in, and interacts with the planetary crust, ultimately contributing to critical zone processes and soil formation. Here we report the use of molecular and culture-dependent methods to determine the composition of pioneer microbial communities colonising the basaltic Fimmvörðuháls lava flow at Eyjafjallajökull, Iceland, formed in 2010. Our data show that three to five months post eruption, the lava was colonized by a low-diversity microbial community dominated by Betaproteobacteria, primarily taxa related to nonphototrophic diazotrophs such as Herbaspirillum spp., and chemolithotrophs such as Thiobacillus. Although successfully cultured following enrichment, phototrophs were not abundant members of the Fimmvörðuháls communities, as revealed by molecular analysis, and phototrophy is therefore not likely to be a dominant biogeochemical process in these early successional basalt communities. These results contrast with older Icelandic lava of comparable mineralogy, in which phototrophs comprised a significant fraction of microbial communities and the non-phototrophic community fractions were dominated by Acidobacteria and Actinobacteria.
The existence of ammonia on Titan and Enceladus and potentially other outer Solar System bodies r... more The existence of ammonia on Titan and Enceladus and potentially other outer Solar System bodies raises questions about the habitability of these worlds. Of particular concern for planetary protection is the possibility for Earth microbes inadvertently transported on spacecraft, to survive or even reproduce in these 'hostile' ammonia/ammonia-water environments. Our current understanding of microbial tolerances to ammonia is incomplete and the limits for microbial survival, growth or reproduction have not been established. While some fungi can not only survive but also grow in atmospheres containing 95% N H 3 (1) elsewhere the growth of microorganisms may be inhibited at concentrations of < 1%. The conversion of N H 3 to nitrite by the ubiquitous terrestrial and aquatic ammonia-oxidizing bacteria is a key step in the global nitrogen cycle, and such organisms may potentially possess some of the highest tolerances to ammonia among the bacteria. One of the key factors influencing microbial survival at high ammonia concentrations is pH, determining the ionization of N H 3 to N H + 4 , with N H 3 the more toxic and more abundant form at high pH. Our initial laboratory experiments with Actinobacteria and Proteobacteria strains have demonstrated the lethality of NH3 at concentrations of up to 17.5% at room temperature. However, our findings suggest loss of viability was most likely an effect of high pH rather than a direct N H 3 -specific effect. However, exposure of soil samples (which contain many spore-forming organisms typically found on spacecraft surfaces) showed the survival and subsequent prolific growth of soil bacteria belonging to the Bacillus genus following NH3 exposure over more prolonged periods, also at room temperature at 17.5% N H 3 . The effect of a challenge of low temperature extremes in concert with ammonia is also pertinent to determining the survival and reproductive possibilities in extraterrestrial settings. Soil exposed for six days to concentrations of up to 35% N H 3 at −80 • C resulted in the isolation of viable bacteria at numbers lower than obtained at room temperature exposure. At both temperatures, viable numbers were reduced compared to the 0% NH3 controls at neutral pH and at pH 13.5 (the pH of a 35% N H 3 solution), with viability at −80 • C lower than that at
-Isolates obtained from volcanic rock were dominated by the Actinobacteria phylum, many of which ... more -Isolates obtained from volcanic rock were dominated by the Actinobacteria phylum, many of which could grow on plates containing only washed agar and basalt-palagonite, without nutrient amendment.
Of the 34 meteorites from Mars, none are sedimentary although sediments exist in abundance on the... more Of the 34 meteorites from Mars, none are sedimentary although sediments exist in abundance on the planet. The STONE experiments aim at testing the survivability of different types of analogue martian sediments during entry into the Earth's atmosphere. The rocks are fixed into the heat shield of a FOTON re-entry vehicle around the ablation point and undergo entry speeds of about 7.6 km/s (meteorite entry speeds are slightly higher, at 12-15 km/s). Previous STONE experiments have proven the survivability of dolomite and sandstone through atmospheric passage (STONE 1 and STONE 5). The STONE 6 experiment included an Early Archaean chert (3.446 Ga) from the Pilbara containing cryptic traces of fossil life (microfossils, C isotopes) (N.B. this sample is a good sedimentary Noachian Mars analogue], a Devonian laminite (mudstone) from the Orkneys (Fig 1e), and an Eocene basalt from Austria. A culture of a modern endolithic microorganism, Chroococcidiopsis, was smeared on the back side an...
The STONE 6 experiment demonstrated the survivability of carbonaceous and microfossiliferous mart... more The STONE 6 experiment demonstrated the survivability of carbonaceous and microfossiliferous martian analogue sediments during atmospheric re-entry. Doped endoliths died but their carbonised cells remained.
Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microor... more Shock recovery experiments on a Martian analogue rock (gabbro) loaded with three types of microorganisms reveal that these organisms survive the impact and ejection phase on Mars at shock pressures up to about 50 GPa with exponentially decreasing survival rates.
Icarus
Astronomy & Geophysics, 2015
Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved i... more Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved impact structures. Impact structures can localize water in a number of ways including: 1) circulation of water into hydrothermal systems, 2) ponding of water in the hydrologic depression of the crater. This ponding can occur because of excavation below the water table, filling of the
Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved i... more Because of the lack of recent plate tectonics, the surface of Mars has abundant, well-preserved impact structures. Impact structures can localize water in a number of ways including: 1) circulation of water into hydrothermal systems, 2) ponding of water in the hydrologic depression of the crater. This ponding can occur because of excavation below the water table, filling of the