Abstract:Surface mineral crusts on Earth are highly diverse and usually, contain microbial life. Crusts constitute an attractive target to search for life: they require water for their formation, they efficiently entrap organic matter and are relatively easy to sample and process. They hold a record of life in the form of microbial remains, biomolecules and carbon isotope composition. A miniaturized Raman spectrometer is included in the ExoMars 2020 payload as it is sensitive to a range of photosynthetic pigments. Samp… Show more
“…On Earth, surface mineral crusts exist in different varieties and require water for their formation, entrap organic molecules, and harbor microbial life. Biosignatures of surface mineral crusts can be extracted and assayed similarly to search for evidence of life on Mars (Brolly et al., 2018).…”
Section: Discussionmentioning
confidence: 99%
“…Biosignatures of surface mineral crusts can be extracted and assayed similarly to search for evidence of life on Mars (Brolly et al, 2018).…”
Section: Broader Applications Of Soil Seals To Astrobiology On Marsmentioning
Methane spikes observed in the Martian atmosphere require the abrupt release of large amounts of methane from the Martian subsurface. The mechanism for such release has not been identified. We tested whether gas traps can form under Mars‐like conditions in the shallow Martian regolith due to salt migration in the icy soil. Experiments were performed on various soil samples in a Mars Simulation Chamber comprising different perchlorate salts and water concentrations mixed with JSC Mars‐1A. Inside the chamber, the samples were exposed to a range of temperatures from −20°C to 10°C and maintained CO2 gaseous pressure between 8 and 10 mbars. As a methane analog, Neon was injected periodically underneath the soil sample. It was found that over a wide range of Mars‐like soil parameters, a gas impermeable soil seal can form over a relatively short period (3–13 days) but requires 5%–10% of perchlorate salt content in the soil. It was determined that such a seal could sustain several mbars of neon above the Martian atmospheric pressure in the soil. Based on our experiments, substantial amounts of gaseous methane may accumulate under the soil seal and get released abruptly into the atmosphere upon seal cracking. An abrupt release of methane from the shallow subsurface may help explain methane variability at the Martian surface, as the Mars Science Laboratory detected.
“…On Earth, surface mineral crusts exist in different varieties and require water for their formation, entrap organic molecules, and harbor microbial life. Biosignatures of surface mineral crusts can be extracted and assayed similarly to search for evidence of life on Mars (Brolly et al., 2018).…”
Section: Discussionmentioning
confidence: 99%
“…Biosignatures of surface mineral crusts can be extracted and assayed similarly to search for evidence of life on Mars (Brolly et al, 2018).…”
Section: Broader Applications Of Soil Seals To Astrobiology On Marsmentioning
Methane spikes observed in the Martian atmosphere require the abrupt release of large amounts of methane from the Martian subsurface. The mechanism for such release has not been identified. We tested whether gas traps can form under Mars‐like conditions in the shallow Martian regolith due to salt migration in the icy soil. Experiments were performed on various soil samples in a Mars Simulation Chamber comprising different perchlorate salts and water concentrations mixed with JSC Mars‐1A. Inside the chamber, the samples were exposed to a range of temperatures from −20°C to 10°C and maintained CO2 gaseous pressure between 8 and 10 mbars. As a methane analog, Neon was injected periodically underneath the soil sample. It was found that over a wide range of Mars‐like soil parameters, a gas impermeable soil seal can form over a relatively short period (3–13 days) but requires 5%–10% of perchlorate salt content in the soil. It was determined that such a seal could sustain several mbars of neon above the Martian atmospheric pressure in the soil. Based on our experiments, substantial amounts of gaseous methane may accumulate under the soil seal and get released abruptly into the atmosphere upon seal cracking. An abrupt release of methane from the shallow subsurface may help explain methane variability at the Martian surface, as the Mars Science Laboratory detected.
“…Further astrobiology‐related studies on Mars aimed at detecting liquid water, searching for methane or describing environmental conditions complexly (Diez, 2018; Rummel et al., 2014; Webster et al., 2015), but no further life detection experiments were performed. Ongoing mission of the Perseverance Rover (Landed on Mars in February 2021, mission led by NASA), similarly like upcoming the ExoMars Mission (ESA and Roscosmos, originally scheduled for 2020 but postponed) searches for signs of extinct or, only to some extent, extant life on Mars, which is performed through analyses of organic molecules and also by searching for different physical and chemical biosignatures (Brolly et al., 2019; Goetz et al., 2016; Vago et al., 2017; Voosen, 2021). However, no metabolic experiments related to those conducted during the Viking Mission are planned (Vago et al., 2017).…”
Section: Introductionmentioning
confidence: 99%
“…Thus, an array of experiments is necessary to exclude artefacts or ambiguities during interpretation (Schulze‐Makuch et al., 2015). Preparing such a suite of experiments requires new life detection methods and sites where they can be tested (Brolly et al., 2019). Such sites have to be similar to extraterrestrial ones in terms of environmental conditions and geochemical composition (so‐called analog sites) or simply in terms of low abundances of organisms.…”
The planet Mars is a primary target in the search for extraterrestrial life. Metabolic experiments carried out during the Viking Mission (1976Mission ( -1982 designed to detect respiration and photosynthesis provided inconclusive results, and one type of experiment (Labeled Release) seemed to be positive (Klein, 1977;Levin & Straat, 2016;Schulze-Makuch et al., 2015). Precisely, the Labeled Release experiment demonstrated that addition of radioactively-labeled organic medium to Martian soil resulted in the release of radioactive gas, which suggested that organic compounds were metabolized. Moreover, the breakdown of organic matter was ceased by temperature treatment capable of killing terrestrial microorganisms (Klein, 1977;Levin & Straat, 2016). The positive result of Labeled Release experiment was not confirmed by other experiments carried out during the Viking Mission-the Pyrolytic Release and the Gas Exchange experiments (Klein, 1977). Moreover, during the Viking Mission, no organic matter was found in samples of the Martian soil (Klein, 1977). Results from the Viking Mission have been debated further in the context of geochemical data provided by subsequent missions, especially that of the Phoenix Mars Lander ( 2008) and the Curiosity Rover (since 2012), but the question about the presence of life on Mars remains unanswered (Goetz Abstract The main goal of astrobiological studies is the search for life beyond Earth. Developing life detection methods requires test locations that have similar environmental conditions to extraterrestrial sites or that simply have low organism abundances. In this study, we describe dune sand of a low organic matter content (0.11%) collected from a national park frequented by few people. It is located in temperate zone. We hypothesized that dune sand is characterized by the low abundance of microorganisms and metabolic rates that could be compared to analogs of extraterrestrial environments like the Antarctic McMurdo Dry Valleys or the Atacama Desert. Measurements of CO 2 efflux and ATP concentration demonstrated that hydrating dune sand with sterile distilled water initiated a short period of substantial microbial metabolic activity that lasted from 4 to 5 days. The maximum CO 2 efflux was 100 mgCO 2 m −2 d −1 , which was low compared to values reported for sandy dunes, deserts and poor soils, including McMurdo Dry Valleys. Microscopic observations demonstrated that the abundance of prokaryotic microorganisms in the dune sand was low at roughly one million per cm 3 of sand and was comparable to the abundance reported from the Atacama Desert. The microbial communities in the dune sand were studied based on 16S rRNA gene analyses. The most prominent bacterial genera were Massilia and Bacillus. Study demonstrated that dune sand sampled from a national park area was as useful for testing life detection methods as are other well-established analogs of extraterrestrial environments.Plain Language Summary One of the main goals of contemporary science is the search for life beyond Earth....
“…2). Thus, the interest of using the Micro X-ray fluorescence (μXRF) technique in the meteorite Northwest Africa (NWA) 6963 is to obtain data and to investigate the possible presence of minerals that offer relevant information about Mars for Astrobiology (Brolly et al, 2018; do Nascimento-Dias et al ., 2018; Nascimento-Dias et al ., 2018). Fig.…”
Although we have learned much about the geological characteristics and history of Mars, the gaps in our knowledge certainly exceed what we understand. Martian meteorites, such as Northwest Africa (NWA) 6963, can be excellent materials for understanding the present and past of Mars, as part of the records of the planet's evolution is preserved in these extraterrestrial rocks. Micro X-ray fluorescence provided data, in which it was possible to verify the presence of Ca, P and Y elements, which are call attention because they were detected superimposed in certain regions. The way these elements were detected indicates the formation of minerals composed by the combination of these elements, such as, for example, Calcite (CaCO3), Apatite [Ca5(PO4)3(OH, F, Cl)], Merrilite [Ca9NaMg (PO4)7] and Xenotime (YPO4). These minerals are great indicators of aqueous environments. In general, the formation of these minerals is due to processes involving hydrothermal fluids or sources (>100 °C). Some geological indications suggest that in the past there might have been a large amount of liquid water, which could have accumulated large reservoirs below the Martian surface. Thus, the laboratory study of Martian meteorites and interpretations of minerals present in these samples can contribute in a complementary way to the existing results of telescopic observations and/or missions of space probes as a strategy to indicate reservoirs of liquid water.
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