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The Feeding Mars study was devised as a small, pilot proof of concept study to research the potential for using aquaponic effluents as an additive to regoliths which on Mars and the Moon are devoid of organic material and thus lacking microbes which assist in the delivery of water and nutrients to the plants via their roots. This research investigates aquaponics as a way to potentially produce fish and vegetal products in regoliths on Mars and the Moon as well as in extreme environments on Earth. In order to settle on Mars, settlers will have to grow their own food in systems that are self-perpetuating, with little or no inputs being brought from Earth once these systems have been established. This means that nutrients from the fish water can be used to grow plants in the hydroponic parts of the aquaponic system but also potentially in the Martian regoliths which are treated with effluents taken from aquaponic systems. Once production is established additional nutrients can be sourced from the arisings and waste, both from the fish (that are processed and eaten) and the plants, which can be used as compost to turn the regoliths into soil. In order to have fish in space, there is also the need for the systems to be self-sustaining in the production of fish feed. The key outcomes of the project were that all the species grown (potatoes, tomatoes, dwarf beans, carrots, lettuce, spring onions, chives and basil) indicate the potential to be grown in regoliths with the addition of aquaponic effluents. A significant result was that on the whole the plants that were grown with the addition of aquaponic effluents were greener than those grown in the horticultural soil, indicating that the nutrient supply was adequate. However, a key lesson learned is that germination and thus development of the plants grown in the Mars simulant and analogue was slower than those grown in the horticultural soil. Thus, developing nutrients in the soil before planting is necessary as it is with agriculture and horticulture practices on Earth, where manuring/fertilization occurs before planting. The consequence of this research, and the envisaged research to follow is not only for extra-terrestrial environments. The Earth has its own hostile environments, characterised with regoliths and other unproductive soils, and aquaponic water and aquaponic wastes can readily be envisaged as providing solutions to growing nutritious food in areas where agriculture is not currently viable. The research was undertaken in an exhibition gallery setting at the University of Greenwich in order to encourage public interest and dialogue, which it did. [ABSTRACT FROM AUTHOR]

Rock varnish, a dark-coloured natural feature rich in manganese (Mn), iron (Fe), and clay minerals that forms on rock surfaces and subsurface rock fractures in extremely dry and cold environments, is believed to provide nutritional support to microbiota. Because varnish supports an extensive microbial community, this rock coating is considered a substrate for potential microbial life to thrive in extreme environments on Earth. Although research in the past decades have advanced understanding of the varnish microbiome, little is known about this microbial community in settings that are high altitude (lower oxygen), dry, and cold. We present here new morphological, chemical, and rock magnetic results of rock varnish from this environmental setting, the Ladakh, a potential analogue site for life in extreme environments. Our results include the presence of putative magnetofossils-in the form of nanochains present in the rock varnish layer. Further, the higher concentrations of oxidised Mn4+ and carboxylic acid functionality on the varnish surface revealed organic signatures. These collective results point towards the enriched concentration of magnetic minerals on the varnish layer that are possibly sourced through biotic forms. Consequently, the rock varnish can serve as an archive of ancient environmental records, as well as a potential geomaterial for astrobiological studies from the Martian analogue field location of Ladakh, which needs to be explored further for extensive biogeochemical studies. • Ladakh's rock varnish as a potential geomaterial for Mars analogue studies in extreme settings. • Presence of putative magnetofossil-like entities in the varnish layer reported for the first time. • Higher levels of oxidized Mn4+ and carboxylic acids on the varnish surface revealed organic signatures through XPS analysis. • Comprehensive magnetic characterisation of rock varnish unveils magnetite as the dominant magnetic mineral. [ABSTRACT FROM AUTHOR]

Meteorites that fall to Earth quickly become contaminated with terrestrial microorganisms. These meteorites are out of chemical equilibrium in the environments where they fall, and equilibration promotes formation of low-temperature alteration minerals that can entomb contaminant microorganisms and thus preserve them as microfossils. Given the well-understood chemistry of meteorites and their recent discovery on Mars by rovers, a similarly weathered meteorite on Mars could preserve organic and fossil evidence of a putative past biosphere at the martian surface. Here, we used several techniques to assess the potential of alteration minerals to preserve microfossils and biogenic organics in terrestrially weathered ordinary chondrites from the Nullarbor Plain, Australia. We used acid etching of ordinary chondrites to reveal entombed fungal hyphae, modern biofilms, and diatoms within alteration minerals. We employed synchrotron X-ray fluorescence microscopy of alteration mineral veins to map the distribution of redox-sensitive elements of relevance to chemolithotrophic organisms, such as Mn-cycling bacteria. We assessed the biogenicity of fungal hyphae within alteration veins using a combination of Fourier-transform infrared spectroscopy and pyrolysis gas chromatography-mass spectrometry, which showed that alteration minerals sequester and preserve organic molecules at various levels of decomposition. Our combined analyses results show that fossil microorganisms and the organic molecules they produce are preserved within calcite–gypsum admixtures in meteorites. Furthermore, the distributions of redox-sensitive elements (e.g., Mn) within alteration minerals are localized, which qualitatively suggests that climatically or microbially facilitated element mobilization occurred during the meteorite's residency on Earth. If returned as part of a sample suite from the martian surface, ordinary chondrites could preserve similar, recognizable evidence of putative past life and/or environmental change. [ABSTRACT FROM AUTHOR]

We report 3 years of data from one meteorological and three smaller stations in University Valley, a high-elevation (1677 m) site in the Dry Valleys of Antarctica with extensive dry permafrost. Mean air temperature was -23.4°C. Summer air temperatures were virtually always < 0°C and were consistent with the altitude lapse rate and empirical relationships between summer temperature, distance from the coast and elevation. The measured frost point (-22.5°C) at the 42 cm deep ice table is equal to the surface frost point and above the atmospheric frost point (-29.6°C), providing direct evidence that surface conditions control ground ice depth. Observed peak surface soil temperatures reach 6°C for ice-cemented ground > 15 cm deep but stay < 0°C when it is shallower. We develop an energy balance model tuned to this rocky and dry environment. We find that differences in peak soil surface temperatures are primarily due to the higher thermal diffusivity of ice-cemented ground compared to dry soil. Sensitivity studies show that expected natural variability is insufficient for melt to form and significant excursions from current conditions are required. The site's ice table meets the criteria for a Special Region on Mars, with 30% of the year > -18°C and water activity > 0.6. [ABSTRACT FROM AUTHOR]

Aperiodic discharge of brine at Blood Falls forms a red-tinged fan at the terminus of Taylor Glacier, Antarctica. Samples from this discharge provide an opportunity for mineralogical study at a Martian analogue study site. Environmental samples were collected in the field and analyzed in the laboratory using Fourier transform infrared, Raman, visible to near-infrared, and Mössbauer spectroscopies. Samples were further characterized using microprobe and inductively coupled plasma optical emission spectroscopy for chemistry, and x-ray diffraction, scanning electron microscopy, and transmission electron microscopy for mineralogy, crystallography, and chemistry. The mineralogy of these samples is dominated by the carbonate minerals calcite and aragonite, accompanied by quartz, feldspar, halide, and clay minerals. There is no strong evidence for crystalline iron oxide/hydroxide phases, but compositionally and morphologically diverse iron- and chlorine-rich amorphous nanospheres are found in many of the samples. These results showcase the strengths and weaknesses of different analytical methods and underscore the need for multiple complementary techniques to inform the complicated mineralogy at this locale. These analyses suggest that the red color at Blood Falls arises from oxidation of dissolved Fe2+ in the subglacial fluid that transforms upon exposure to air to form nanospheres of amorphous hydroxylated mixed-valent iron-containing material, with color also influenced by other ions in those structures. Finally, the results provide a comprehensive mineralogical analysis previously missing from the literature for an analogue site with a well-studied sub-ice microbial community. Thus, this mineral assemblage could indicate a habitable environment if found elsewhere in the Solar System.

Martian dust simulant (i.e., a terrestrial substitute for Martian dust) is the basis for experimentally investigating the properties of Martian dust and its effects on Mars exploration activities. In this study, we reported a new Martian dust simulant (Jining Martian Dust Simulant, called JMDS‐1), which was prepared based on terrestrial Jining basalt (90 wt%) and other mineral phases (i.e., 2 wt% magnetite, 2 wt% hematite, 2 wt% anhydrite, 2 wt% calcite, and 2 wt% kaolin). Measurements of JMDS‐1 dust simulant show that JMDS‐1 has a bulk composition, mineralogy, reflectance spectra, and particle characteristics similar to the Martian dust detected by Mars rovers. In addition, we measured the thermal conductivity of dust simulant, soil simulant, and dust‐soil simulant mixtures under simulated Martian conditions (i.e., −30°C; 500–1,000 Pa). The results reveal that the micro‐sized dust simulant has a thermal conductivity of ∼0.015 W/mK, which is two times lower than the thermal conductivity of sub‐millimeter sized soil simulant (i.e., ∼0.035 W/mK). This implies that the dust layer on Mars seems to play a significant role to change the thermal properties of surface materials. Key Points: A new Martian dust simulant JMDS‐1 was developed and characterizedJMDS‐1 dust simulant has similar mineralogy, bulk chemistry, and physical properties to the dust on MarsThermal conductivity of dust simulant was measured under Martian conditions [ABSTRACT FROM AUTHOR]

The Mars Desert Research Station (MDRS) is a Mars-simulation campus set in a Martian planetary analogue in southern Utah. Despite a long history of astrobiology research, collections-based taxonomic inventories of the macro-level biodiversity around the station are relatively new. This study serves to add to the initial vascular plant list published for the station in 2016, where 39 species were recorded for MDRS. Here we report 40 new species, two new taxa recorded only to genus and two species re-identified from our 2016 fieldwork, bringing the total number of taxa in the "Martian" flora to 79 species and two taxa recorded to genus.

Abstract Martian dust simulant (i.e., a terrestrial substitute for Martian dust) is the basis for experimentally investigating the properties of Martian dust and its effects on Mars exploration activities. In this study, we reported a new Martian dust simulant (Jining Martian Dust Simulant, called JMDS‐1), which was prepared based on terrestrial Jining basalt (90 wt%) and other mineral phases (i.e., 2 wt% magnetite, 2 wt% hematite, 2 wt% anhydrite, 2 wt% calcite, and 2 wt% kaolin). Measurements of JMDS‐1 dust simulant show that JMDS‐1 has a bulk composition, mineralogy, reflectance spectra, and particle characteristics similar to the Martian dust detected by Mars rovers. In addition, we measured the thermal conductivity of dust simulant, soil simulant, and dust‐soil simulant mixtures under simulated Martian conditions (i.e., −30°C; 500–1,000 Pa). The results reveal that the micro‐sized dust simulant has a thermal conductivity of ∼0.015 W/mK, which is two times lower than the thermal conductivity of sub‐millimeter sized soil simulant (i.e., ∼0.035 W/mK). This implies that the dust layer on Mars seems to play a significant role to change the thermal properties of surface materials.

Martian lava tube caves resulting from a time when the planet was still volcanically active are proposed to contain deposits of water ice, a feature that may increase microbial habitability. In this study, we taxonomically characterized and directly measured metabolic activity of the microbial communities that inhabit lava tube ice from Lava Beds National Monument, an analogue environment to martian lava tubes. We investigated whether this environment was habitable to microorganisms by determining their taxonomic diversity, metabolic activity, and viability using both culture-dependent and culture-independent techniques. With 16S rRNA gene sequencing, we recovered 27 distinct phyla from both ice and ice–rock interface samples, primarily consisting of Actinobacteria, Proteobacteria, Bacteroidetes, Firmicutes, and Chloroflexi. Radiorespiration and Biolog EcoPlate assays found these microbial communities to be metabolically active at both 5°C and −5°C and able to metabolize diverse sets of heterotrophic carbon substrates at each temperature. Viable cells were predominantly cold adapted and capable of growth at 5°C (1.3 × 104 to 2.9 × 107 cells/mL), and 24 of 38 cultured isolates were capable of growth at −5°C. Furthermore, 14 of these cultured isolates, and 16 of the 20 most numerous amplicon sequences we recovered were most closely related to isolates and sequences obtained from other cryophilic environments. Given these results, lava tube ice appears to be a habitable environment, and considering the protections martian lava tubes offer to microbial communities from harsh surface conditions, similar martian caves containing ice may be capable of supporting extant, active microbial communities. [ABSTRACT FROM AUTHOR]

The Mars Desert Research Station (MDRS) is a Mars-simulation campus set in a Martian planetary analogue in southern Utah. Despite a long history of astrobiology research, collections-based taxonomic inventories of the macro-level biodiversity around the station are relatively new. This study serves to add to the initial vascular plant list published for the station in 2016, where 39 species were recorded for MDRS. Here we report 40 new species, two new taxa recorded only to genus and two species re-identified from our 2016 fieldwork, bringing the total number of taxa in the "Martian" flora to 79 species and two taxa recorded to genus. [ABSTRACT FROM AUTHOR]

Mars-analogous and relevant terrestrial- and orbit-based remote sensing datasets were gathered and used for both an in and out of simulation geological assessment of a pre-selected "landing site" for the CanMars, Mars Sample Return Analogue Deployment (MSRAD), and Mars Utah Rover Field Investigation (MURFI) analogue missions. The analogue mission site is situated in the Henry Mountains Basin just outside of Hanksville, Utah. The results of a comprehensive multispectral analysis based on Landsat 8 and ASTER of the landing site, landing ellipse area, and surrounding region, were synthesized with other datasets providing information on the morphology and basic physical properties of the spectrally-defined surface units. The synthesis yielded insights into the geologic materials present, the sampling opportunities for the analogue rover available at the site and the geologic history of the site. The datasets provided to the in-simulation science team were determined to be sufficient to generally identify ∼88% of the geologic units previous mapped in the field. The area was determined to be dominated by clastic sedimentary rocks (a high-silica/quartz- and Fe-oxide-bearing geologic materials), but also include a variety of aqueous alteration phases consistent with a complex climate, environmental, and water-rock history. Positive identification of additional phases from orbit include: Al-smectite clay-, gypsum- and carbonate-bearing rocks or deposits. An association between these components with fine-scale layered bedrock exposures and sinuous ridges, consistent with inverted channels, provide evidence of a viably Mars-analogous "landing site", which yeilds diverse samples for in-situ analysis and sampling by the CanMars and MURFI analogue missions. • Mars-relevant terrestrial remote sensing datasets used to characterize the geology of a site just outside of Hanksville, UT. • Site hosts three mission analogue activities, two past and one ongoing (i.e., Mars Desert Research Station – MDRS). • Site comprised of gypsum/anhydrite, high-silica, carbonate and clay bearing materials for exploration/sampling. • The majority of field-based mapped units are identifiable from orbit. [ABSTRACT FROM AUTHOR]

Abstract Sediments collected from Lake Towuti, an ultramafic-hosted lake in Indonesia, preserve a visible alternating pattern of red and green sediments due to variations in clay mineral and Fe-oxide composition and abundance consistent with changes in iron oxidation state through time. Spectral, mineralogical, and chemical analyses on soils, river, and sediment samples from across the lake and its catchment were carried out to better understand the starting composition of these sediments and the processes that affected them before and after deposition. Despite high Fe abundances in all samples and abundant Fe oxides in lateritic source regions, mineralogical analyses (X-ray diffraction (XRD) and Mössbauer spectroscopy) of the modern lake sediment show almost no well-crystalline iron oxides. In addition, sequential Fe extractions suggest an increasing proportion of easily extractable, poorly crystalline (X-ray amorphous) material with burial depth. XRD, bulk chemistry, and visible-near infrared (VNIR) spectral reflectance measurements demonstrate that clay mineralogy and bulk chemistry can be inferred from VNIR data. These results provide evidence for variations in Fe mineralogy and crystallinity based on location in this source to sink system. Understanding how the mineralogy and chemistry of sediments within a ferruginous lake basin are affected by transport, chemical alteration, physical alteration, and deposition from source to sink on Earth, and the degree to which these trends and underlying processes can be inferred from chemical and spectral properties, may provide useful direction in assessing paleoenvironmental conditions in other terrestrial lakes as well as ancient lacustrine environments preserved in the stratigraphic record of Mars. [ABSTRACT FROM AUTHOR]

Abstract: Abundant polygonal surface structure (PSS) landforms within the Qaidam Basin, Tibetan Plateau, northwestern China, are considered to be excellent analogues for the PSSs on Mars. In this study, we have carried out fieldwork in the Dalangtan Playa, a large dried salt lake in the northwestern Qaidam Basin, complemented with laboratory analyses of collected samples. Our study shows that (1) the playa PSSs can be divided into three groups: small (<10 m), medium (10–100 m), and large (>100 m) according to their sizes; (2) the samples collected from the PSSs are dominated by halite (mostly >50 wt %), followed by feldspar (mostly ~20 wt %), quartz, and minor clays; (3) illite‐ and chlorite‐dominated clay minerals are detected in nearly all medium‐ to large‐sized PSS regions; the average halite content of small‐sized PSSs is higher than that of larger PSSs; (4) most small‐sized PSSs are distributed on the flat playa floors, while larger PSSs tend to occur at the edge of the Dalangtan Playa with higher elevations. The topography within the Dalangtan Playa controls different mineralogical precipitation primarily due to evaporation processes. Thus, correlations of the size‐dependent PSS occurrences and elevations seem to indicate that the PSS formation is strongly influenced by the mineralogy. The geomorphological similarity of these PSSs and their counterparts on Mars indicates that the Martian PSSs likely formed as a result of environmental change from wet to dryer condition, and it also suggests that there are similar controlling factors responsible for the PSS formation on Mars. [ABSTRACT FROM AUTHOR]

Perennial springs at the Gypsum Hill site on Axel Heiberg Island in the Canadian Arctic (79°24′N, 90°44′W) represent a high-fidelity analogue to hydrothermal systems that might exist on Mars. The springs were surveyed using an electromagnetic induction sounder (EMIS) and ground penetrating radar (GPR). Both instruments probed the subsurface to a depth of approximately 3 m. Lateral EMIS soundings were performed every metre along a 400 m long reconnaissance line roughly oriented SW-NE and extending through 23 active springs and 1 dry outlet to measure electrical conductivity. Two distinct zones were identified within the survey area on the basis of these data: in the southwest portion, sharp conductivity peaks correspond to isolated springs with well-defined outlets, flowing over dry rocky soil; in the northeast portion, the springs are fed by a pervasive network of saline fluids, resulting in high background readings and muddy surface conditions. These observations are consistent with vertical EMIS sounding data which showed that the brine body feeding the saline springs can be found closer to the ground surface towards the northeast portion of the survey site. In areas of high electrical conductivity, the GPR data exhibits strong scattering. The noisy areas are sharply defined and interpreted to correspond to narrow vertical conduits feeding individual spring outlets. The EMIS is a rugged instrument that could be included as payload in future rover-based Mars exploration missions aiming at probing the shallow subsurface for the presence of brine pockets. [ABSTRACT FROM AUTHOR]

Hypersaline lakes are characteristic for Western Australia and display a rare combination of geochemical and mineralogical properties that make these lakes potential analogues for past conditions on Mars. In our study, we focused on the geochemistry and mineralogy of Lake Orr and Lake Whurr. While both lakes are poor in organic carbon (<1%), the sediments' pH values differ and range from 3.8 to 4.8 in Lake Orr and from 5.4 to 6.3 in Lake Whurr sediments. Lake Whurr sediments were dominated by orange and red sediment zones in which the main Fe minerals were identified as hematite, goethite, and tentatively jarosite and pyrite. Lake Orr was dominated by brownish and blackish sediments where the main Fe minerals were goethite and another paramagnetic Fe(III)- phase that could not be identified. Furthermore, a likely secondary Fe(II)-phase was observed in Lake Orr sediments. The mineralogy of these two salt lakes in the sampling area is strongly influenced by events such as flooding, evaporation, and desiccation, processes that explain at least to some extent the observed differences between Lake Orr and Lake Whurr. The iron mineralogy of Lake Whurr sediments and the high salinity make this lake a suitable analogue for Meridiani Planum on Mars, and in particular the tentative identification of pyrite in Lake Whurr sediments has implications for the interpretation of the Fe mineralogy of Meridiani Planum sediments. [ABSTRACT FROM AUTHOR]

This paper exposes the unique set of attributes explaining why precious opal has formed in such abundance in central Australia, and almost nowhere else on Earth. The Early Cretaceous history of the Great Artesian Basin is that of a high-latitude flexural foreland basin associated with a Cordillera Orogen built along the Pacific margin of Gondwana. The basin, flooded by the Eromanga Sea, acted as a sink for volcaniclastic sediments eroded from the Cordillera's volcanic arc. The Eromanga Sea was shallow, cold, poorly connected to the open ocean, muddy and stagnant, which explains the absence of significant carbonates. Iron-rich and organic matter-rich sediments contributed to the development of an anoxic sub-seafloor in which anaerobic, pyrite-producing bacteria thrived. Rich in pyrite, ferrous iron, feldspar, volcanic fragments and volcanic ash, Lower Cretaceous lithologies have an exceptionally large acidification potential and pH neutralisation capacity. This makes Lower Cretaceous lithologies particularly reactive to oxidative weathering. From 97 to 60 Ma, Australia remained at high latitude, and a protracted period of uplift, erosion, denudation and crustal cooling unfolded. It is possibly during this period that the bulk of precious opal was formed via acidic oxidative weathering. When uplift stopped atca60 Ma, the opalised redox front was preserved by the widespread deposition of a veneer of Cenozoic sediments. On Earth, regional acidic weathering is rare. Interestingly, acidic oxidative weathering has been documented at the surface of Mars, which shares an intriguing set of attributes with the Great Artesian Basin including: (i) volcaniclastic lithologies; (ii) absence of significant carbonate; (iii) similar secondary assemblages including opaline silica; (iv) similar acidic oxidative weathering driven by very similar surface drying out; and, not surprisingly, (v) the same colour. This suggests that the Australian red centre could well be the best regional terrestrial analogue for the surface of the red planet. [ABSTRACT FROM AUTHOR]

Knowing the risks, costs, and complexities associated with human missions to Mars, analogue research can be a great (low-risk) tool for exploring the challenges associated with the preparation for living, operating, and undertaking research in interplanetary missions. Short-duration analogue studies, such as those being accomplished at the Mars Desert Research Station (MDRS), offer the chance to study mission operations and human factors in a simulated environment, and therefore contribute to exploration of the Moon and Mars in planned future missions. This article is based upon previously published articles, abstracts, and presentations by a series of independent authors, human factor studies performed on mars analogue station by Crew 100B. The MDRS Crew 100B performed studies over 15 days providing a unique insight into human factor issues in simulated short-duration Mars mission. In this study, 15 human factors were evaluated and analyzed by subjective and objective means, and from the summary of results it was concluded that optimum health of an individual and the crew as a whole is a necessity in order to encourage and maintain high performance and the satisfaction of project goals. [ABSTRACT FROM AUTHOR]

Abstract: The soil carbon content and its relation to site characteristics are important in evaluating current local, regional, and global soil C storage and projecting future variations in response to climate change. In this study we analyzed the concentration of organic and inorganic carbon and their relationship with in situ climatic and geological characteristics in 485 samples of surface soil and 17 pits from the hyper-arid area and 51 samples with 2 pits from the arid–semiarid region from the Atacama Desert located in Peru and Chile. The soil organic carbon (SOC) in hyperarid soils ranged from 1.8 to 50.9μgC per g of soil for the 0–0.1m profile and from 1.8 to 125.2μgC per g of soil for the 0–1m profile. The analysis of climatic (temperature and precipitation), elevation, and some geologic characteristics (landforms) associated with hyper-arid soils explained partially the SOC variability. On the other hand, soil inorganic carbon (SIC) contents, in the form of carbonates, ranged from 200 to 1500μgC per g of soil for the 0–0.1m profile and from 200 to 3000μgC per g of soil for the 0–1.0m profile in the driest area. The largest accumulations of organic and inorganic carbon were found near to arid–semiarid areas. In addition, the elemental carbon concentrations show that the presence of other forms of inorganic carbon (e.g. graphite, etc.) was negligible in these hyperarid soils. Overall, the top 1m soil layer of hyperarid lands contains ∼11.6Tg of organic carbon and 344.6Tg of carbonate carbon. The total stored carbon was 30.8-fold the organic carbon alone. To our knowledge, this is the first study evaluating the total budget carbon on the surface and shallow subsurface on ∼160,000km2 of hyperarid soils. [Copyright &y& Elsevier]

The adsorption of nucleic acids to mineral matrixes can result in low extraction yields and negatively influences molecular microbial ecology studies, in particular for low-biomass environments on Earth and Mars. We determined the recovery of nucleic acids from a range of minerals relevant to Earth and Mars. Clay minerals, but also other silicates and nonsilicates, showed very low recovery (< 1%). Consequently, optimization of DNA extraction was directed towards clays. The high temperatures and acidic conditions used in some methods to dissolve mineral matrices proved to destruct DNA. The most efficient method comprised a high phosphate solution ( P/ EtOH; 1 M phosphate, 15% ethanol buffer at pH 8) introduced at the cell-lysing step in DNA extraction, to promote chemical competition with DNA for adsorption sites. This solution increased DNA yield from clay samples spiked with known quantities of cells up to nearly 100-fold. DNA recovery was also enhanced from several mineral samples retrieved from an aquifer, while maintaining reproducible DGGE profiles. DGGE profiles were obtained for a clay sample for which no profile could be generated with the standard DNA isolation protocol. Mineralogy influenced microbial community composition. The method also proved suitable for the recovery of low molecular weight DNA (< 1.5 kb). [ABSTRACT FROM AUTHOR]

We collected and analysed soil cores from four geologic units surrounding Mars Desert Research Station (MDRS) Utah, USA, including Mancos Shale, Dakota Sandstone, Morrison formation (Brushy Basin member) and Summerville formation. The area is an important geochemical and morphological analogue to terrains on Mars. Soils were analysed for mineralogy by a Terra X-ray diffractometer (XRD), a field version of the CheMin instrument on the Mars Science Laboratory (MSL) mission (2012 landing). Soluble ion chemistry, total organic content and identity and distribution of microbial populations were also determined. The Terra data reveal that Mancos and Morrison soils are rich in phyllosilicates similar to those observed on Mars from orbital measurements (montmorillonite, nontronite and illite). Evaporite minerals observed include gypsum, thenardite, polyhalite and calcite. Soil chemical analysis shows sulfate the dominant anion in all soils and SO4>>CO3, as on Mars. The cation pattern Na>Ca>Mg is seen in all soils except for the Summerville where Ca>Na. In all soils, SO4 correlates with Na, suggesting sodium sulfates are the dominant phase. Oxidizable organics are low in all soils and range from a high of 0.7% in the Mancos samples to undetectable at a detection limit of 0.1% in the Morrison soils. Minerals rich in chromium and vanadium were identified in Morrison soils that result from diagenetic replacement of organic compounds. Depositional environment, geologic history and mineralogy all affect the ability to preserve and detect organic compounds. Subsurface biosphere populations were revealed to contain organisms from all three domains (Archaea, Bacteria and Eukarya) with cell density between 3.0×106 and 1.8×107 cells ml−1 at the deepest depth. These measurements are analogous to data that could be obtained on future robotic or human Mars missions and results are relevant to the MSL mission that will investigate phyllosilicates on Mars. [ABSTRACT FROM AUTHOR]

Humankind's innate curiosity makes us wonder whether life is or was present on other planetary bodies such as Mars. The EuroGeoMars 2009 campaign was organized at the Mars Desert Research Station (MDRS) to perform multidisciplinary astrobiology research. MDRS in southeast Utah is situated in a cold arid desert with mineralogy and erosion processes comparable to those on Mars. Insight into the microbial community composition of this terrestrial Mars analogue provides essential information for the search for life on Mars: including sampling and life detection methodology optimization and what kind of organisms to expect. Soil samples were collected from different locations. Culture-independent molecular analyses directed at ribosomal RNA genes revealed the presence of all three domains of life (Archaea, Bacteria and Eukarya), but these were not detected in all samples. Spiking experiments revealed that this appears to relate to low DNA recovery, due to adsorption or degradation. Bacteria were most frequently detected and showed high alpha- and beta-diversity. Members of the Actinobacteria, Proteobacteria, Bacteroidetes and Gemmatimonadetes phyla were found in the majority of samples. Archaea alpha- and beta-diversity was very low. For Eukarya, a diverse range of organisms was identified, such as fungi, green algae and several phyla of Protozoa. Phylogenetic analysis revealed an extraordinary variety of putative extremophiles, mainly Bacteria but also Archaea and Eukarya. These comprised radioresistant, endolithic, chasmolithic, xerophilic, hypolithic, thermophilic, thermoacidophilic, psychrophilic, halophilic, haloalkaliphilic and alkaliphilic micro-organisms. Overall, our data revealed large difference in occurrence and diversity over short distances, indicating the need for high-sampling frequency at similar sites. DNA extraction methods need to be optimized to improve extraction efficiencies. [ABSTRACT FROM AUTHOR]

Abstract: The possibility of dating basalt using luminescence was tested on four samples with independent age control from Cima volcanic field, California, with the ultimate aim of assessing whether the technique could be used to date sediments on the surface of Mars. Previous analysis of these samples had demonstrated that the infrared stimulated luminescence (IRSL) signal is most suitable for dating as it showed the lowest fading rate among various luminescence signals. In this study, changes in equivalent dose as a function of preheat are described. The ages for the two youngest Cima samples agree with the independent ages based on cosmogenic nuclide measurements (12.0 ± 0.8 ka). In the two older samples (dated to 320 and 580 ka by K–Ar), the luminescence behaviour is more complex and the form of the IRSL decay curve is seen to vary with dose. Mathematical fitting is used to isolate two components and their intensities are used to produce dose response curves. The slower component yields a larger equivalent dose. However, even using this component and after correction for fading, the ages obtained for the older samples are younger than the K–Ar ages. [ABSTRACT FROM AUTHOR]

Characteristic geological features and hydrated minerals recently found on the surface of Mars by the NASA planetary rovers Spirit and Opportunity suggest that a possible biosphere could have once existed there. Analytical instrumentation protocols for the unequivocal detection of biomarkers in suitable geological matrices are critical for future unmanned explorations, including the forthcoming ESA-ExoMars mission scheduled for 2018. Raman spectroscopy is currently a part of the Pasteur instrumentation suite of the ExoMars mission scheduled for 2018 for the remote detection of extant or extinct life signatures in the Martian surface and subsurface. Terrestrial analogues of Martian sites have been identified, and the biogeological modifications incurred as a result of extremophilic survival activity have been studied. Polyaromatic hydrocarbons (PAHs) are recognised as a class of degradation product that occur from biological processes terrestrially. In this work, various concentrations of polyaromatic hydrocarbons in matrices of gypsum, calcite and quartz have been investigated by Raman microspectrometry to determine the lowest detectable organic levels. The studies are conceived in simulation of their potential PAHs identification in geobiological conditions in Martian scenarios. Two laser source wavelengths, namely, 785 and 633 nm, were adopted to excite Raman spectra from the PAHs, which represent degraded carbons and therefore potentially provide a key bimolecular marker of ancient life. [ABSTRACT FROM AUTHOR]

Abstract: A key question in understanding life on Mars under dry(ing) conditions is how arid soils respond to small levels of liquid water. We have conducted a series of simulated rain experiments in the hyperarid core region of the Atacama Desert. Rain amounts from 0.24 to 3.55mm were applied in the early evening to the soil. We conclude that rain events of less than 1mm do not saturate the surface, and the soil humidity at the surface remains below 100%. Rain events of 2mm or more generate free water in the pore space of the soil surface, which may be necessary to support biological activity in the soil. The crust on the surface of the soil is a strong barrier to the diffusion of subsurface moisture and subsequent evaporation. Our results show that once the relative humidity in hyperarid soils begins to fall below 100% the rate of decrease is quite rapid. Thus, the precise value assumed for the limits of life or water activity, do not appreciably change the time of water availability resulting from small desert rains. The Atacama Desert results may be applied to models of (H2O) wetting in the upper soils of Mars due to light rains, melting snow and heavy precipitating fog. [Copyright &y& Elsevier]

Abstract: GPR provides high resolution images of aeolian strata in frozen sand in the McMurdo Dry Valleys of Antarctica. The results have positive implications for potential GPR surveys of aeolian strata on Mars. Within the Lower Victoria Valley, seasonal changes in climate and a topographically-constrained wind regime result in significant wind reversals. As a consequence, dunes show reversing crest-lines and flattened dune crests. Ground-penetrating radar (GPR) surveys of the dunes reveal sets of cross-strata and low-angle bounding surfaces produced by reversing winds. Summer sand transport appears to be dominant and this is attributed to the seasonal increase in solar radiation. Solar radiation which heats the valley floor melts ice cements making sand available for transport. At the same time, solar heating of the valley floor generates easterly winds that transport the sand, contributing to the resultant westward dune migration. The location of the dune field along the northern edge of the Lower Victoria Valley provides some shelter from the powerful föehn and katabatic winds that sweep down the valley. Topographic steering of the winds along the valley and drag against the valley wall has probably aided the formation, migration and preservation of the dune field. Optically-stimulated luminescence (OSL) ages from dune deposits range from 0 to 1.3kyr showing that the dune field has been present for at least 1000yr. The OSL ages are used to calculate end-point migration rates of 0.05 to 1.3m/yr, which are lower than migration rates reported from recent surveys of the Packard dunes and lower than similar-sized dunes in low-latitude deserts. The relatively low rates of migration are attributed to a combination of dune crest reversal under a bimodal wind regime and ice cement that reduces dune deflation and restricts sand entrainment. [Copyright &y& Elsevier]

Abstract: Gossan samples collected during a reconnaissance expedition to High Lake in Nunavut, Canada, were analyzed to determine their mineral components and to define parameters for the geochemical environment in which they formed. The gossan represents a natural acid drainage site in an arctic environment that serves as an analogue to the conditions under which sulfate and Fe-oxide possibly formed on Mars. Rock and soil samples were taken from three different outcrops and analyzed using XRD, SEM/EDS and Mössbauer. Two main mineral assemblages were observed. The first assemblage, which was found primarily in samples from the first outcrop, contained chlorite, Fe-phosphates, Fe-oxide and quartz. The second assemblage, which was found at the second and third outcrops, was primarily quartz, mica and jarosite. One sample (G41), containing Fe-oxide, jarosite and gypsum, appears to be transitional between a Fe-oxide dominant assemblage to a jarosite dominant assemblage. Thermodynamic equilibria predicts that the gossan pore water should range from mildly acidic, relatively sulfate-poor (pH 3–6; SO4 <1000mgl−1) to highly acidic and relatively sulfate-rich (pH 0.5–3; SO4 >3000mgl−1) for the first and second mineral assemblages, respectively. Kinetic reaction models indicate that the second assemblage replaces the first during evaporation or freezing of water. Compared to acid mine drainage (AMD) sites located in temperate regions, the arctic High Lake gossan lacks diversity in sulfate species and has smaller diagenetic crystal sizes. The smaller crystal size may reflect the slower reaction rates at colder temperatures and the seasonal water saturation. These initial results indicate that the High Lake gossan deposit does record mechanisms for which minerals like hematite, goethite, gypsum and jarosite, which are found on Mars, can form in an environment that involves seasonal water occurrence in a cold climate. [Copyright &y& Elsevier]

Abstract: The Rio Tinto site is recognised as a terrestrial Mars analogue because of the presence of jarosite and related sulfates which have recently been identified by the NASA Mars Exploration Rover “Opportunity” in the El Capitan region of Meridiani Planum on Mars. It has long been known that acidophilic microbial action is responsible for the deep blood-red colour of the water in Rio Tinto, where the pH varies from about 1.5 to 3.0 and the water is rich in iron and sulfur. Following recent Raman spectroscopic characterisation of the mineral phases of the Rio Tinto system, we report here a study of the biological components found in several specimens of deposited minerals and near the waterside that were collected during a GeoRaman VI Conference organized field trip in 2006. Key biosignatures were found for carotenoids, scytonemin and mycosporine-like amino acids, which are indicative of the biological colonisation of exposed mineral substrates; information from this study will be useful for targeting Martian sites using a miniaturized Raman instrument where the biosignatures of relict or extant life could remain in the geological record. [Copyright &y& Elsevier]

The geologic histories of planetary surfaces reveal that Earth and Mars have been pummeled by cataclysmic impact events. The surface of Mars has been perused to have an impact origin for its hemispheric dichotomy. The spallation during impact events causes the interplanetary transfer of material from Mars to Earth or Mars to Phobos/Deimos. Assessing the survival of micro-organisms in impact conditions is critical for the development of planetary protection strategies for future missions. Shock waves are generated during such major impact events. The objective of the present investigation was to explore the microbial diversity of the hypersaline sulphated Laguna de Peña Hueca, Spain and to study the effect of shock waves on extremophilic bacteria isolated from the lake. Peña Hueca is a hypersaline sulphated lagoon rich in Mg–Na–SO 4 –Cl, epsomite and hexahydrate and it potentially serves as Planetary field analogue site for Martian chloride deposits and salt-rich subsurface brines of Ocean worlds like Enceladus and Europa. The microbial community structure of the lagoon was studied by 16S rRNA metagenomic sequencing. The phylogenetic studies indicated the presence of phyla Euryarchaeota , Proteobacteri a, and Bacteroides in the hypersaline brines of the lagoon. The anoxic sediments of Peña Hueca showed the presence of Haloanaerobiaeta and Hadesarchaeota including the anoxic genus of Haloanaerobium , Desulfosalsimonas and Desulfovermiculum. The effect of impact shock on the halophilic bacterium Halomonas gomseomensis EP-3 isolated from Laguna de Peña Hueca was studied in a Reddy shock tube. The halophilic bacterium was exposed to shock waves at a peak shock pressure of 300 ​kPa and a temperature of 400 ​K. The results of shock recovery experiments of halophilic bacteria reveal 97% killing at 300 ​kPa and Mach number of 1.47 in comparison with Bacillus sp. This study indicates that gram-positive spore-forming Bacillus sp. are better adapted to survival in impact shock waves in comparison to non-sporulating halophiles. In the current study, we present the first report on response of halophiles in impact shock. Furthermore, we demonstrate a novel application of the simple handheld Reddy shock tube in astrobiology. The survival studies of halophiles isolated from terrestrial analogue sites in impact shock can provide valuable insights in astrobiology and microbial physiology in impact shock stress. • First report on effect of shock on halophilic bacteria isolated from Planetary Field analogue site. • Microbial Diversity of hypersaline Laguna de Peña Hueca, a terrestrial analogue ofMars and Ocean worlds reported. • Novel application of Reddy shock tube in astrobiology to study impact events or fate of micro-organisms in impact [ABSTRACT FROM AUTHOR]

The Puna Plateau of northwestern Argentina is a promising region for analogue investigations of Martian aeolian processes owing to its high altitude, low atmospheric pressure, aridity, geology, and widespread granular and bedrock aeolian landforms. Despite a growing body of research about the region's enigmatic aeolian landforms, little is known about the contemporary aeolian environment, processes, and landscape dynamics. To address this gap, we used a combination of modelled weather data, satellite imagery, and field measurements to characterize the wind regime, aeolian sediment transport, and allied surface changes. The study focused on the Campo de Piedra Pómez (CPP) – a volcanic landscape with a variety of Mars analogue landforms: gravel-mantled megaripples, yardangs, ventifacts, periodic bedrock ridges, and aeolian rat-tails. Modelled weather data from the European Center for Medium-Range Forecasting's ERA-Interim reanalysis dataset confirm the contemporary dominance of northwesterly winds in this region, consistent with the primary orientation of yardangs. These data also indicate the presence of less frequent southeasterly winds, which may explain why re-entrant profiles are observed on the southeast flanks of a small portion of the yardang population, and why some aeolian rat-tails point to the northwest. Observations from multi-temporal satellite imagery indicate that deposition and displacement of small sediment patches overlying ignimbrite bedrock is relatively common across the region. Samples retrieved from sediment traps deployed over one year in the region suggest a broad range of particle densities are mobilized by wind, which implies a wide range of wind speed for fluid entrainment. Conventional aeolian transport models do not consider the effects of particle density variations on transport processes. However, in areas with multiple density sediment present, our results point towards a need for aeolian models to consider density when quantifying and qualifying sediment transport. • Remote sensing, in situ data, and climate reanalyses are used to characterize the aeolian regime at a Mars analogue site; • Change detection attests to widespread sediment transport despite low modelled wind speeds; • Thermally-driven winds caused by albedo may be responsible for sediment transport from non-dominant directions; • Documented transport of particles with a wide range of sizes and densities; • In multimodal density particle areas careful consideration of sediment transport equations are needed. [ABSTRACT FROM AUTHOR]

This work details the laboratory analysis of a suite of 10 samples collected from an inverted fluvial channel near Hanksville, Utah, USA as a part of the CanMars Mars Sample Return Analogue Deployment (MSRAD). The samples were acquired along the rover traverse for detailed off-site analysis to evaluate the TOC and astrobiological significance of the samples selected based on site observations, and to address one of the science goals of the CanMars mission: to evaluate the ability of different analytical techniques being employed by the Mars2020 mission to detect and characterize any present biosignatures. Analytical techniques analogous to those on the ExoMars, MSL and the MER rovers were also applied to the samples. The total organic carbon content of the samples was <0.02% for all but 4 samples, and organic biosignatures were detected in multiple samples by UV–Vis–NIR reflectance spectroscopy and Raman spectroscopy (532 nm, time-resolved, and UV), which was the most effective of the techniques. The total carbon content of the samples is < 0.3 wt% for all but one calcite rich sample, and organic C was not detectable by FTIR. Carotene and chlorophyll were detected in two samples which also contained gypsum and mineral phases of astrobiological importance for paleoenvironment/habitability and biomarker preservation (clays, gypsum, calcite) were detected and characterized by multiple techniques, of which passive reflectance was most effective. The sample selected in the field (S2) as having the highest potential for TOC did not have the highest TOC values, however, when considering the sample mineralogy in conjunction with the detection of organic carbon, it is the most astrobiologically relevant. These results highlight importance of applying multiple techniques for sample characterization and provide insights into their strengths and limitations. • Detection and characterization of organic carbon and biomolecules by multiple rover-equivalent instruments. • Detection and characterization of astrobiologically relevant mineral phases. • Application of lab-based techniques analogues to instrumentation from multiple rover missions. [ABSTRACT FROM AUTHOR]