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The detection of organic molecules associated with life on Mars is one of the main goals of future life-searching missions such as the ESA-Roscosmos ExoMars and NASA 2020 mission. In this work we studied the preservation of 25 amino acids that were spiked onto the Mars-relevant minerals augite, enstatite, goethite, gypsum, hematite, jarosite, labra...
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... silica window (to ensure good UV transmission) providing direct illu- mination of the sample area with a UV spectrum similar to that encountered on the surface of Mars (e.g. Patel et al., 2002 ). The lamp output, along with a typical modeled UV irradiance expected at the surface of Mars at local noon (taken from Patel et al., 2002 ) is shown in Fig. 3 . After setting the samples in the chamber and previous to the experiments, the pressure was reduced to a vac- uum ( < 1 mbar) for > 10 min and at room temperature. This en- sures that there is no air and no water vapor in the atmosphere. Then, the chamber was pressurized at 6 mbar with a mixture of 95% CO 2 and 5% N 2 , mimicking the ...Context 2
... Mars, the diurnal profile of UV irradiance encountered at the surface exhibits a bell-shaped profile (such as demonstrated in Patel et al., 2002 ), therefore the local noon irradiance represents a peak irradiance and the UV lev- els throughout the rest of the day are significantly lower. Given the higher irradiance level of the lamp as shown in Fig. 3 , coupled with the effect of a diurnal light curve profile, the lab irradiance of 28 h is calculated to correspond to a martian equivalent UV dose of approximately 6.5 days. Upon completion, the chamber was re- stored to ambient conditions before removal of the samples from the ...Citations
... Clay's pertinence extends to Mars due to its abundance on the martian surface (Chyba and Sagan, 1992;Murchie et al., 2009); indeed, montmorillonite is frequently employed as a mineral clay surrogate for Mars in simulation experiments (Böttger et al., 2012;Primm et al., 2018). Paradoxically, alongside their potential to shield amino acids such as alanine from UV radiation, clays might hasten or amplify photodegradative effects due to their ability to catalyze polymerization via their large inner surfaces and charge-carrier transport capabilities (dos Santos et al., 2016). Our array of sample specimens helped us scrutinize how montmorillonite layers might protect alanine molecules from solar UV radiation. ...
... The UV absorption of montmorillonite is primarily attributed to the d-orbital electrons of iron (II) in the mineral (Gauger et al., 2015). Furthermore, the iron can also catalyze reactions that lead to increased decay rates of amino acids (dos Santos et al., 2016;Liu and Kounaves, 2021;Martin, 1980). We observed this effect in the unshielded alanine thin 108 WIPF ET AL. ...
... Thanks to the favorable ratio of large surface area to small pore dimensions, montmorillonite can provide effective bulk protection against UV radiation. Previous experiments conducted with alanine concentrations in the mM range have also shown that the preservative effect increases significantly with a higher concentration of intercalated alanine (dos Santos et al., 2016). In our experiments, we used an alanine-saturated organoclay, suggesting that we investigated an organoclay with the highest possible preservation effect in the given configuration. ...
The Photochemistry on the Space Station (PSS) experiment was part of the European Space Agency's EXPOSE-R2 mission and was conducted on the International Space Station from 2014 to 2016. The PSS experiment investigated the properties of montmorillonite clay as a protective shield against degradation of organic compounds that were exposed to elevated levels of ultraviolet (UV) radiation in space. Additionally, we examined the potential for montmorillonite to catalyze UV-induced breakdown of the amino acid alanine and its potential to trap the resulting photochemical byproducts within its interlayers. We tested pure alanine thin films, alanine thin films protected from direct UV exposure by a thin cover layer of montmorillonite, and an intimate combination of the two substances forming an organoclay. The samples were exposed to space conditions for 15.5 months and then returned to Earth for detailed analysis. Concurrent ground-control experiments subjected identical samples to simulated solar light irradiation. Fourier-transform infrared (FTIR) spectroscopy quantified molecular changes by comparing spectra obtained before and after exposure for both the space and ground-control samples. To more deeply understand the photochemical processes influencing the stability of irradiated alanine molecules, we performed an additional experiment using time-resolved FTIR spectroscopy for a second set of ground samples exposed to simulated solar light. Our collective experiments reveal that montmorillonite clay exhibits a dual, configuration-dependent effect on the stability of alanine: while a thin cover layer of the clay provides UV shielding that slows degradation, an intimate mixture of clay and amino acid hastens the photochemical decomposition of alanine by promoting certain chemical reactions. This observation is important to understand the preservation of amino acids in specific extraterrestrial environments, such as Mars: cover mineral layer depths of several millimeters are required to effectively shield organics from the harmful effects of UV radiation. We also explored the role of carbon dioxide (CO2), a byproduct of alanine photolysis, as a tracer of the amino acid. CO2 can be trapped within clay interlayers, particularly in clays with small interlayer ions such as sodium. Our studies emphasize the multifaceted interactions between montmorillonite clay and alanine under nonterrestrial conditions; thus, they contribute valuable insights to broader astrobiological research questions.
... n this plot are based on the center of the band around 3.95 μm and the presence of the 2.7 μm phyllosilicate absorption centered at 2.7 μm. The role of phyllosilicates and their intimate mixture conditions are relevant, as they may protect organics from the effects of space weathering by efficiently absorbing organic molecules (O. Poch et al. 2015;R. dos Santos et al. 2016). The fact that these identified bright spots plot in a similar region to spectra from Ernutet and Urvara of Figure 13 indicates that they might share similar mineralogical characteristics. Since mineral assemblages are indicative of formation and alteration processes, they may have undergone similar geological processes to what created ...
We explore the spatial distribution of organics on Ceres using the visible and near-infrared data collected by the Dawn mission. We employ a spectral mixture analysis (SMA) approach to map organic materials within the Ernutet crater at the highest available spatial resolution, thereby revealing a discontinuous, granular distribution and a possible association with an ancient crater on which Ernutet has been superimposed. The SMA technique also helps us identify 11 new areas as potential sites for organics. These regions are predominantly located within craters or along their walls, resembling the distribution pattern observed in Ernutet, which implies a possible geological link with materials exposed from beneath the surface. In one of these candidate regions situated in the Yalode quadrangle, we detected the characteristic 3.4 μ m absorption band in the infrared spectrum, indicative of organics and carbonates. By combining the spatial resolution of the Framing Camera data with the spectral resolution of the Visual and Infrared Imaging Spectrometer using SMA, we investigated the distribution of the 3.4 μ m band in this quadrangle. The absorption pattern correlates with the Yalode/Urvara smooth material unit, which formed after significant impacts on Ceres. The association of organic-rich materials with complex and multiple large-impact events supports an endogenous origin for the organics on Ceres.
... This is probably due to the large errors caused by the clay, whose origin is natural. Natural materials are not homogeneous due to irregularities in mineral surfaces, which can cause variations in the adsorption of L-alanine (dos Santos et al., 2016;Galvez-Martinez et al., 2019;Cruz-Hernández et al., 2022). After saturation, the amount sorbed is independent of the concentration, and this is the maximum amount of sorption. ...
Amino acids have been detected in some meteorites and are readily synthesized in prebiotic experiments. These molecules may have been precursors of oligomers and polymers in the early Earth. These reactions were likely to happen in the protected confined spaces on the porous surface of olivine and in the interlayer nanospace of montmorillonite. This study describes experimental and theoretical research on the sorption of l -alanine onto surfaces of silicate minerals, olivine and montmorillonite. Kinetics of the sorption of this amino acid at different pH media was performed. This sorption has been also studied at atomic scale by means of quantum mechanical calculations finding that this sorption is energetically favourable. These results strongly support the premise that minerals could have actively participated in prebiotic reactions.
... These metabolites could be preserved in minerals that precipitated at the time of deposition even if cellular material was not directly preserved, making detection via GC-MS within the first centimeters of Martian regolith (or meters with the MOMA instrument onboard Exo-Mars) possible (Alwmark et al., 2023). Alone these metabolites would not resist to oxidations and radiations, but within silica or mineral matrix it might be preserved for millions of years (Kminek and Bada, 2006;Pavlov et al., 2012;Aubrey et al., 2006;Buch et al., 2022;dos Santos et al., 2016). The combination of elemental and molecular analysis will help strengthen the hypothesis on organic matter preservation conditions and past life traces detection. ...
From Viking landers to Perseverance rover, Mars has been explored by several in situ missions capable of analyzing organic compounds. Results from the SAM and SHERLOC on Curiosity and Perseverance, respectively, support the detection of lean organic matter (at ppb-ppm levels) in the top surface samples, although the source (s) and preservation mechanisms are still ambiguous. Perseverance is currently exploring a fluvio-lacustrine system at Jezero crater and may explore an ancient volcanic terrain after exiting the crater. As Perseverance would collect samples for potential return to Earth, preparation is needed for sample return efforts through various means including i) the detection of trace organic compounds in various matrices, ii) validation of compounds identified by Martian rovers, and iii) better understanding of mechanisms of their production on Mars. On these returned samples, the community may be able to resolve the timing of organic matter formation and refine hypotheses regarding organic preservation in Martian soils despite the presence of numerous oxidants, salts, and pH-temperature intra and inter-site variations that are less conductive to long-term preservation of organic matter. For instance, acidic conditions promote clay catalyzed isomerization, but seem to benefit for the fatty acid preservation producing organic-salts or favoring salt dissolution in the matrix to protect organic compounds from radiations and water alteration. With a similar aim, we selected samples from Yellowstone National Park hot springs and silica sinters as analogs to locations visited by Curiosity and Perseverance or-in the future-Rosalind Franklin rover. The hot springs in this study developed over hundreds to thousands of years, providing optimal conditions (i.e., matrix composition, temperature, pH) of preservation for organic molecules, extremophilic and mesophilic cells. In our study, the most well preserved organic matter and biosignatures were detected in acidic silica sinters with a surface (water) temperature below 50 • C and a minor crystalline phase. The gas chromatography-mass spectrometry molecular analysis revealed a variety of organic compounds we classified as bioindicators (such as amino acids, nucleobases, and sugars), and biosignatures (such as long-chain branched and/or (poly)unsaturated lipids, secondary metabolites involved in the quorum sensing or communication between individuals). We validated with a SAM/MOMA-like benchtop extracting oven the organic matter extraction protocols performed with the SAM experiment. We identified using the different SAM and MOMA extraction protocols (pyrolysis and wet-chemistry derivatizations) eight microbial classes through a unique untargeted environmental metabolomics' method embracing space flight technology constraints. Additionally , we identified one (and likely two) agnostic biosignature(s): i) the concomitance of some elements and organic compounds in the analogs (correlation of organic matter elements: C, N, S, P and organic molecules co-located with essential biological elements: Fe, Mg, V, Mn and non-essential biological elements concentrated by
... 28,29 Whether to discover the emergence of proto-biomolecules or to identify biosignatures from earliest lifeforms, it is essential to understand when minerals would be supporting and enabling the development of the complexity necessary for life's origin and when they may be hindering the reactions and preserving the molecular evidence of the event. 30,31 ...
Conspectus
The origin of life remains one of the most profound mysteries in science. Over millennia, theories have evolved, yet the question persists: How did life emerge from inanimate matter? At its core, the study of life’s origin offers insights into our place in the universe and the nature of life itself. By delving into the chemical and geological processes that led to life’s emergence, scientists gain a deeper understanding of the fundamental principles that govern living systems. This knowledge not only expands our scientific understanding but also has profound implications for fields ranging from astrobiology to synthetic biology.
This research employs a multidisciplinary approach, combining a diverse array of techniques, from space missions to wet laboratory experiments to theoretical modeling. Investigations into the formation of the first proto-biomolecules are tailored to explore both the complex molecular processes that underpin life and the geological contexts in which these processes may have occurred. While laboratory experiments are aimed at mimicking the processes of early planets, not every process and sample is attainable. To this end, we demonstrate the use of molecular modeling techniques to complement experimental efforts and extraterrestrial missions. The simulations enable researchers to test hypotheses and explore scenarios that are difficult or impossible to replicate in the laboratory, bridging gaps in our understanding of prebiotic processes across vast time and space scales.
Minerals, particularly layered structures like clays and hydrotalcites, play diverse and pivotal roles in the origin of life. They concentrate organic species, catalyze polymerization reactions (such as peptide formation), and provide protective environments for the molecules. Minerals have also been suggested to have acted as primitive genetic materials. Nevertheless, they may lack the ability for long-term information replication. Instead, we suggest that minerals may act as transcribers of information encoded in environmental cyclic phenomena, such as tidal or seasonal changes. We argue that extensive protection of the produced polymer will immobilize it, making it inactive for any further function. Therefore, in order to generate a functional polymer, it is essential that it remains mobile and chemically active. Furthermore, we suggest a route to the identification of pseudobiosignatures, a polymer that was polymerized on the same mineral surface and consequently retained through overprotection.
This Account presents a comprehensive evaluation of the current understanding of the role of layered mineral surfaces on life’s origin and biosignature preservation. It highlights the complexity of mineral-organic interactions and proposes pathways for proto-biomolecule emergence and methods for identifying and interpreting potential biosignatures. Ultimately, the quest to uncover the origin of life continues to drive scientific exploration and innovation, offering profound insights into the fundamental nature of existence and our place in the universe.
... The extremely slow rates of SO 4 2− reduction would favor the preservation of trapped organics from the harsh Mars surface environmental conditions over extended geological periods 24,26 . Moreover, dos Santos et al. 27 have shown that sulfates protect amino acids against UV photodamage likely due to their opacity to UV radiation.All these studies suggest that sulfate-rich Martian sediments and rocks can be potential targets for the detection of organic compounds 22 . ...
The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard the Mars 2020 Perseverance rover detected so far some of the most intense fluorescence signals in association with sulfates analyzing abraded patches of rocks at Jezero crater, Mars. To assess the plausibility of an organic origin of these signals, it is key to understand if organics can survive exposure to ambient Martian UV after exposure by the Perseverance abrasion tool and prior to analysis by SHERLOC. In this work, we investigated the stability of organo-sulfate assemblages under Martian-like UV irradiation and we observed that the spectroscopic features of phthalic and mellitic acid embedded into hydrated magnesium sulfate do not change for UV exposures corresponding to at least 48 Martian sols and, thus, should still be detectable in fluorescence when the SHERLOC analysis takes place, thanks to the photoprotective properties of magnesium sulfate. In addition, different photoproduct bands diagnostic of the parent carboxylic acid molecules could be observed. The photoprotective behavior of hydrated magnesium sulfate corroborates the hypothesis that sulfates might have played a key role in the preservation of organics on Mars, and that the fluorescence signals detected by SHERLOC in association with sulfates could potentially arise from organic compounds.
... Several studies showed that a mineral matrix has a protective effect under gamma radiation compared with irradiating biomolecules by themselves (Baqué et al., 2018;Ertem et al., 2021). More research has been conducted under UV radiation and has shown the clear preservation effect of clay-and sulfate-rich mineralogies (Poch et al., 2015;Dos Santos et al., 2016;Fornaro et al., 2018). Here, we investigated for the first time the impact of mineralogy on the preservation of hopanes and steranes in natural samples exposed to gamma radiation. ...
Mars has been exposed to ionizing radiation for several billion years, and as part of the search for life on the Red Planet, it is crucial to understand the impact of radiation on biosignature preservation. Several NASA and ESA missions are looking for evidence of ancient life in samples collected at depths shallow enough that they have been impacted by galactic cosmic rays (GCRs). In this study, we exposed a diverse set of Mars analog samples to 0.9 Megagray (MGy) of gamma radiation to mimic 15 million years of exposure on the Martian surface. We measured no significant impact of GCRs on the total organic carbon (TOC) and bulk stable C isotopes in samples with initial TOC concentration > 0.1 wt. %; however, diagnostic molecular biosignatures presented a wide range of degradation that didn't correlate to factors like mineralogy, TOC, water content, and surface area. Exposure dating suggests that the surface of Gale crater has been irradiated at more than five times our dose, yet using this relatively low dose and "best-case scenario" geologically recalcitrant biomarkers, large and variable losses were nevertheless evident. Our results empasize the importance of selecting sampling sites at depth or recently exposed at the Martian surface.
... The differences shown in this plot are based on the center of the band around 3.95 μm, and the presence of the 2.7 µm phyllosilicates absorption centered at 2.7 μm. The role of phyllosilicates and their intimate mixture conditions are relevant as they may protect organics from the effects of space weathering by efficiently absorbing organic molecules (Poch et al., 2015;Dos Santos et al., 2016). The fact that bright spots we identified plot in a similar region of Fig. 13 as spectra from Ernutet indicates that whatever mineral assemblage exists at Ernutet is also manifested at the bright spots, which may imply a common origin or petrogenesis for the materials in both places. ...
We explore the spatial distribution of organics on Ceres using the visible and near-infrared data collected by the Dawn mission. We employ a spectral mixture analysis (SMA) approach to map organic materials within the Ernutet crater at the highest available spatial resolution revealing a discontinuous, granular distribution and a possible correlation with an ancient crater on which Ernutet has been superimposed. The SMA technique also helps us identify 11 new areas as potential sites for organics. These regions are predominantly located within craters or along their walls, resembling the distribution pattern observed in Ernutet, which implies a possible geological link with materials exposed from beneath the surface. In one of these candidate regions situated in the Yalode quadrangle, we detected the characteristic 3.4-micron absorption band in the infrared spectrum, indicative of organics and carbonates. By combining the spatial resolution of the Framing Camera data with the spectral resolution of the Visual and Infrared Imaging Spectrometer using SMA, we investigated the distribution of the 3.4-micron band in this quadrangle. The absorption pattern correlates with the Yalode/Urvara smooth material unit, which formed after significant impacts on Ceres. The association of organic-rich materials with complex and multiple large-impact events supports for an endogenous origin for the organics on Ceres.
... The extremely slow rates of SO4 2reduction would favor the preservation of trapped organics from the harsh Mars surface environmental conditions over extended geological periods 21,23 . Moreover, dos Santos et al. 24 have shown that sulfates protect amino acids against UV photodamage likely due to their opacity to UV radiation.All these studies suggest that sulfaterich Martian sediments and rocks can be potential targets for the detection of organic compounds 19 . ...
The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard the Mars 2020 Perseverance rover detected so far some of the most intense fluorescence signals in association with sulfates analyzing abraded patches of rocks at Jezero crater, Mars. To assess the plausibility of an organic origin of these signals, it is key to understand if organics can survive exposure to ambient Martian UV after exposure by the Perseverance abrasion tool and prior to analysis by SHERLOC. In this work, we investigated the stability of organo-sulfate assemblages under Martian-like UV irradiation and we observed that the spectroscopic features of phthalic and mellitic acid embedded into hydrated magnesium sulfate do not change for UV exposures corresponding to at least 48 Martian sols and, thus, should still be detectable in fluorescence when the SHERLOC analysis takes place, thanks to the photoprotective properties of magnesium sulfate. In addition, different photoproduct bands diagnostic of the parent carboxylic acid molecules could be observed. The photoprotective behavior of hydrated magnesium sulfate corroborates the hypothesis that sulfates might have played a key role in the preservation of organics on Mars, and that the fluorescence signals detected by SHERLOC in association with sulfates could potentially arise from organic compounds.
... Jarosite has drawn scientific interest because of its presence on Mars. NASA's Opportunity rover discovered jarosite deposits on the surface of Mars [2], suggesting the past presence of water and possible acidic conditions in certain regions of the planet. ...
Jarosite is a hazardous waste material produced during hydrometallurgy operations in the extraction of zinc ore. This hazardous Jarosite is harmful to humans as well as aquatic life. It is not disposed of directly due to guidelines of the government of India which is why 2% lime and 10% cement by weight of Jarosite are mixed with Jarosite for making a non-hazardous material Jarofix. The waste marble slurry (WMS) is generated during the cutting of marble blocks in factories. This fine WMS creates environmental problems in nearby areas of factories. In this study, cement was replaced with Jarosite, and fine aggregates (river sand) were replaced with WMS in rigid pavement concrete. One control and four replacement mixes were cast in the laboratory. In the replacement mixes, cement was partially substituted by Jarosite at a 10% constant rate, and fine aggregates were partially substituted by waste marble slurry in varying percent of 0 to 30 at an interval of 10%. A water to binder ratio (w/b) of 0.35 is opted for mix design. All five mixes were tested for fresh and mechanical properties of rigid pavement concrete and results were analysed with a control mix. The laboratory experiment reveals that both Jarosite and WMS reduced concrete workability. The study does show, however, that mixing 10% Jarosite with conventional Portland cement and replacing 20% of Fine Aggregates with WMS improves the mechanical properties of rigid pavement concrete. These results indicate that jarosite and WMS can be substituted for cement and Fine Aggregates at precise percentage levels.
