Astrobiology最新文献

{"title":"Potential Habitability of Present-Day Martian Subsurface for Earth-Like Methanogens.","authors":"A Butturini, R Benaiges-Fernandez, O Fors, D García-Castellanos","doi":"10.1089/ast.2024.0100","DOIUrl":"10.1089/ast.2024.0100","url":null,"abstract":"<p><p>The intense debate about the presence of methane in the martian atmosphere has stimulated the study of methanogenic species that are adapted to terrestrial habitats that resemble martian environments. We examined the environmental conditions, energy sources, and ecology of terrestrial methanogens that thrive in deep crystalline fractures, subsea hypersaline lakes, and subglacial water bodies, considered analogs of a hypothetical habitable martian subsurface. We combined this information with recent data on the distribution of buried water/ice and radiogenic elements on Mars, and with models of the subsurface thermal regime of this planet, we identified a 4.3-8.8 km-deep regolith habitat at the midlatitude location of Acidalia Planitia that might fit the requirements for hosting putative martian methanogens analogous to the methanogenic families, Methanosarcinaceae and Methanomicrobiaceae.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"253-268"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143565938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remote Detection of Red Edge Spectral Characteristics in Floating Aquatic Vegetation.","authors":"Aoi Murakami, Yu Komatsu, Kenji Takizawa","doi":"10.1089/ast.2024.0127","DOIUrl":"10.1089/ast.2024.0127","url":null,"abstract":"<p><p>The vegetation red edge of terrestrial plants is a key biosignature for the detection of life on Earth-like habitable exoplanets. Although water is essential for plants, an excess of water can limit the distribution of terrestrial vegetation. On planets with extensive water coverage and limited land, floating vegetation on the water's surface could serve as a crucial indicator of life. This study examined the spectral reflectance of floating plants across various scales, from individual leaves to lake-wide vegetation coverage. Our comparisons between individual leaves revealed that the red edge of floating plants was equivalent to or even more pronounced than that of terrestrial plants. Although water can reduce plant reflectance, the naturally low reflectance of water enhances the detection sensitivity for floating vegetation. Our observations of seasonal changes, such as the proliferation of floating plants in summer and their decline in winter, revealed significant variations in lake reflectance. By analyzing satellite images of lakes and marshes over a 5-year period, we confirmed that these seasonal variations in reflectance reliably indicated the presence of floating vegetation. The seasonal signal showed robustness to the effects of clouds, which pose another challenge on water-rich planets. We propose that floating vegetation be considered alongside, or even in place of, terrestrial vegetation in the search for extraterrestrial life.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"209-224"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recovery of Lipid Biomarkers in Hot Spring Digitate Silica Sinter as Analogs for Potential Biosignatures on Mars: Results from Laboratory and Flight-Like Experiments.","authors":"Maëva Millan, Kathleen A Campbell, Chanenath Sriaporn, Kim M Handley, Bronwyn L Teece, Paul Mahaffy, Sarah S Johnson","doi":"10.1089/ast.2024.0020","DOIUrl":"10.1089/ast.2024.0020","url":null,"abstract":"<p><p>Digitate siliceous sinter deposits are common in geothermal environments. They form via evaporation and precipitation of cooling silica-rich fluids and passive microbial templating. Increasing interest in these \"finger-like\" microstromatolitic sinters is related to their morphological and mineralogical resemblance to opaline silica-rich rocks discovered by NASA's Spirit rover in the Columbia Hills, Gusev crater, Mars. However, these terrestrial deposits remain understudied, specifically in terms of biosignature content and long-term preservation potential. In this study, six digitate, opaline (opal-A) sinter deposits were collected from five Taupō Volcanic Zonegeothermal fields, and their lipid biosignatures were investigated as Mars analogs. Samples were collected in pools and discharge channels of varied temperatures, pH, and water chemistries, with spicular to nodular morphologies. Results revealed the presence of biomarkers from unsilicified and silicified communities populating the hot spring sinters, including lipids from terrigenous plants, algae, and bacteria. Although DNA sequencing suggests that the composition and diversity of microbial communities are correlated with temperature, pH, and water chemistry of the springs, these environmental parameters did not seem to affect lipid recovery. However, the morphology of the sinters did play a role in lipid yield, which was higher in the finest, needle-like spicules in comparison to the broad, knobby sinters. The capability of current Mars flight mission techniques such as pyrolysis-gas chromatography-mass spectrometry to detect lipid biomarkers was also evaluated from a subset of samples in a pilot study under flight conditions. The early preservation of lipids in the studied sinters and their detection using flight-like techniques suggest that martian siliceous deposits are strong candidates for the search for biosignatures on Mars.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"225-252"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143514452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical Evolution of Alanine in Association with the Martian Soil Analog Montmorillonite: Insights Derived from Experiments Conducted on the International Space Station.","authors":"Severin Wipf, Paul Mabey, Riccardo G Urso, Sebastian Wolf, Arthur Stok, Antonio J Ricco, Richard C Quinn, Andrew L Mattioda, Nykola C Jones, Søren V Hoffmann, Hervé Cottin, Didier Chaput, Pascale Ehrenfreund, Andreas Elsaesser","doi":"10.1089/ast.2024.0034","DOIUrl":"10.1089/ast.2024.0034","url":null,"abstract":"<p><p>The <i>Photochemistry on the Space Station</i> (PSS) experiment was part of the European Space Agency's <i>EXPOSE-R2</i> 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.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"97-114"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143045492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Higher Microbial Biomass Accumulation on El Médano 464 Meteorite Compared with Adjacent Soils in the Atacama Desert.","authors":"Gabriel A Pinto, María Ángeles Lezcano, Laura Sanchéz-García, Rodrigo Martínez, Víctor Parro, Daniel Carrizo","doi":"10.1089/ast.2024.0071","DOIUrl":"https://doi.org/10.1089/ast.2024.0071","url":null,"abstract":"<p><p>Chondritic meteorites can be appropriate substrates for the colonization of terrestrial microorganisms. However, determining whether organic compounds are intrinsic to the meteorite or come from external (terrestrial) contamination is still controversial. This research explores the molecular distribution and carbon isotopic composition of three lipid families (hydrocarbons, alkanoic acids, and alcohols) as well as DNA extracted from the interior of a CO carbonaceous chondrite named El Médano 464 (EM 464), discovered in the Atacama Desert in 2019. Three soil samples from the discovery area of EM 464 were collected and used as a background control for the composition and distribution of organic compounds. Our results revealed a higher abundance of the three lipid families in EM 464 compared with the surrounding soil samples. The organic compounds in EM 464 showed a mean δ¹³C value of -27.8 ± 0.5 for hydrocarbons (<i>N</i> = 20), -27.6 ± 1.1 for alkanoic acids (<i>N</i> = 17), and -27.5 ± 2.2‰ for alcohols (<i>N</i> = 18). These δ¹³C-depleted values are compatible with terrestrial biosignatures and are within isotopic values produced as a result of carbon fixation due to the Calvin cycle (δ¹³C of ca. from -19 to -34‰) widely used by photosynthetic terrestrial microorganisms. The DNA analysis (based on the bacterial 16S rRNA gene) showed a dominance of Proteobacteria (now Pseudomonadota) and Actinobacteriota in both meteorite and soils but exhibited different bacterial composition at the family level. This suggests that the microbial material inside the meteorite may have partially come from the adjacent soils, but we cannot rule out other sources, such as windborne microbes from distant locations. In addition, the meteorite showed higher bacterial diversity (H' = 2.4-2.8) compared with the three soil samples (H' = 0.3-1.8). Based on the distribution and δ¹³C value of organic compounds as well as DNA analysis, we suggest that most, if not all, of the organic compounds detected in the studied CO chondrite are of terrestrial origin (<i>i.e.</i>, contamination). The terrestrial contamination of EM 464 by a diverse microbial community indicates that Atacama chondrites can offer distinctive ecological conditions for microorganisms to thrive in the harsh desert environment, which can result in an accumulation of microbial biomass and preservation of molecular fossils over time.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 2","pages":"115-132"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143447824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Correction to:</i> Simplified Meteorite Parent Body Alteration of Amino Acids by Hydrothermal Processes (Doi: 10.1089/Ast.2024.0096).","authors":"","doi":"10.1089/ast.2024.0096.correx","DOIUrl":"https://doi.org/10.1089/ast.2024.0096.correx","url":null,"abstract":"","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 2","pages":"150"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143447777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CO₂ and H₂S in Abiogenic Hydrocarbon Synthesis and the Emergence of Prebiological States.","authors":"Aleksandr Malyshev, Lidiia Malysheva","doi":"10.1089/ast.2024.0042","DOIUrl":"https://doi.org/10.1089/ast.2024.0042","url":null,"abstract":"<p><p>Hydrogen sulfide and carbon dioxide are widespread substances in epithermal endogenous fluids. When the gas of one of these substances is filtered through the condensate of the other, abiogenic hydrocarbon synthesis can result. The direction of such a synthesis is a result of the absorption of the filtering gas by condensate and the formation of hydrocarbons and native sulfur in the condensate. The spatial position of the abiogenic synthesis zones is controlled by isosurfaces of critical temperatures and partial saturation pressures for CO₂ and H₂S. Abiogenic synthesis of hydrocarbons ensures the occurrence of prebiological states. Since the condensation of CO₂ and H₂S is controlled by the physical properties of these substances, it is possible to assess the conditions for the emergence of prebiological states on other planets. Venus demonstrates an example of an \"overheated\" planet on which the occurrence of prebiological states is unlikely in the past and impossible at the present time. Mars shows us a hypothetical example of a possible migration of prebiological states and protolife arising on their basis into the depths of a celestial body. Jupiter demonstrates an example of the localization of hydrocarbon synthesis zones and prebiological states in the gas envelope of the planet.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 2","pages":"133-149"},"PeriodicalIF":3.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143447780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of Organic Precursors via Meteoritic Impacts and Its Implications for Prebiotic Inventory of Early Planetary Surfaces.","authors":"Benjamin Farcy, Ziqin Ni, Ricardo Arevalo, Michael Eller, Veronica T Pinnick, Emile A Schweikert, William B Brinckerhoff","doi":"10.1089/ast.2023.0031","DOIUrl":"https://doi.org/10.1089/ast.2023.0031","url":null,"abstract":"<p><p>Meteoritic impacts on planetary surfaces deliver a significant amount of energy that can produce prebiotic organic compounds such as cyanides, which may be a key step to the formation of biomolecules. To study the chemical processes of impact-induced organic synthesis, we simulated the physicochemical processes of hypervelocity impacts (HVI) in experiments with both high-speed ¹³C₆₀⁺ projectiles and laser ablation. In the first approach, a ¹³C₆₀⁺ beam was accelerated to collide with ammonium nitrate (NH₄NO₃) to reproduce the shock process and plume generation of meteoritic impacts on nitrogen-rich planetary surfaces. In a complementary investigation, a high-power laser was focused on a mixture of calcium carbonate (CaCO₃) and either ammonium chloride (NH₄Cl) or sodium nitrate (NaNO₃) to induce atomization and enable the study of molecular recombination in the postimpact plume. Additionally, isotopically spiked starting material, namely, Ca¹³CO₃, ¹⁵NH₄Cl, Na¹⁵NO₃, and ¹⁵NH₄¹⁵NO₃, was also employed to disambiguate the source of prebiotic molecule production in the resulting recombination plume. Both experiments independently demonstrated the formation of CN^- ions as recombination products, with characteristic mass peak shifts corresponding to the isotopic labeling of the starting material. Yield curves generated from the laser experiments using varying ratios of calcite and NH₄Cl or NaNO₃ indicate that nitrate enables more efficient production of CN^- than ammonium. Thermodynamic software modeling of the laser ablation plume confirmed and further elucidated the experimental yield results, producing good agreement of modeled CN^- yield with observed yield curves. These models indicate that the reduction of atomic N from incomplete NH₄^- atomization during the ablation pulse may have contributed to the lower CN^- yield from the ammonia source relative to the nitrate source. The results of these experiments demonstrated that CN^-, and by proxy, hydrogen cyanide, and other organic precursor molecules could have formed from carbonate deposits, a previously under-appreciated source of organic carbon for impact-induced organic synthesis. These results have implications for the formation of life during meteoritic bombardment on early Earth as well as for other carbonate-bearing planetary bodies such as Mars and Ceres.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 1","pages":"60-71"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond Homochirality: Computer Modeling Hints of Heterochiral Proteins in Early and Extraterrestrial Life.","authors":"Gianluigi Casimo, Gaia Micca Longo, Savino Longo","doi":"10.1089/ast.2024.0072","DOIUrl":"10.1089/ast.2024.0072","url":null,"abstract":"<p><p>Agent-based simulations are set to describe the early biotic selection of oligomers made of monomers of different chirality. The simulations consider the spatial distribution of agents and resources, the balance of biomass of different chirality, and the balance of chemical energy. Following the well-known Wald's hypothesis, a disadvantage is attributed to the change in chirality along the biochemical sequence. A racemic amino acid budget is considered, based on findings in meteorites and the results of Miller's experiments. It is also hypothesized that the very first life forms were heterotrophic. Given these assumptions, our simulations showed that biological sequences were not strictly homochiral and had few chirality changes. These results suggest that the current dominance of homochiral species may have been preceded by a more structurally varied biochemistry. This might be reflected in the few known heterochiral proteins, whose structures are based neither on alpha-helices nor on beta-sheets. Extraterrestrial life forms might be based on such heterochiral proteins.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"22-31"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142943462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Space Radiobiological Exposure Facility on the China Space Station.","authors":"Binquan Zhang, Runtao Zhong, Guohong Shen, Changsheng Tuo, Yongjin Dong, Wei Wang, Meng Zhang, Guanghui Tong, Huanxin Zhang, Bin Yuan, Zida Quan, Bo Su, Qiang Lin, Lei Zhao, Aijun Ma, Jing Wang, Wei Zhang, Weibo Zheng, Fangwu Liu, Ying Sun, Chunqin Wang, Zheng Chang, Lijun Liu, Xianguo Zhang, YueQiang Sun, Tao Zhang, Shenyi Zhang, Yeqing Sun","doi":"10.1089/ast.2024.0027","DOIUrl":"10.1089/ast.2024.0027","url":null,"abstract":"<p><p>The Space Radiobiological Exposure Facility (SREF) is a general experimental facility at the China Space Station for scientific research in the fields of space radiation protection, space radiation biology, biotechnology, and the origin of life. The facility provides an environment with controllable temperatures for experiments with organic molecules and model organisms such as small animals, plant seeds, and microorganisms. The cultivation of small animals can be achieved in the facility with the use of microfluidic chips and images and videos of such experiments can be captured by microscopy. SREF also includes a linear energy transfer (LET) detector, neutron detectors, and a solar ultraviolet (UV) detector to measure the LET spectrum of the charged particles, energy spectrum and dose equivalent of neutrons, and fluence of solar UV radiation, respectively. The facility is reusable, and the model organisms from the first exposure experiment were recovered in orbit and returned to the ground for further study.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"32-41"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142943463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}