Astrobiology最新文献

{"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":"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":"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":"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":"<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":"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":"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":"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":"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}

{"title":"Amplicon Sequencing Reveals Diversity in Spatially Separated Microbial Communities in the Icelandic Mars Analog Environment Mælifellssandur.","authors":"George Tan, Chloe N LeCates, Anna Simpson, Samuel Holtzen, D Joshua Parris, Frank J Stewart, Amanda Stockton","doi":"10.1089/ast.2023.0124","DOIUrl":"10.1089/ast.2023.0124","url":null,"abstract":"<p><p>Exploration missions to Mars rely on landers or rovers to perform multiple analyses over geographically small sampling regions, while landing site selection is done using large-scale but low-resolution remote-sensing data. Utilizing Earth analog environments to estimate small-scale spatial and temporal variation in key geochemical signatures and biosignatures will help mission designers ensure future sampling strategies meet mission science goals. Icelandic lava fields can serve as Mars analog sites due to conditions that include low nutrient availability, temperature extremes, desiccation, and isolation from anthropogenic contamination. This work reports analysis of samples collected using methods analogous to those of planetary missions to characterize microbial communities at different spatial scales in Mælifellssandur, Iceland, an environment with homogeneity at \"remote imaging\" resolution (overall temperature, apparent moisture content, and regolith grain size). Although microbial richness did not vary significantly among samples, the phylogenetic composition of the sediment microbiome differed significantly among sites separated by 100 m, which suggests distinct microbial signatures despite apparent homogeneity from remote observations. This work highlights the importance of considering microenvironments in future life-detection missions to extraterrestrial planetary bodies.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"72-81"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962136","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":"Informing Planetary Protection Policies for the Future Exploration of Ceres: State of Understanding after the Dawn Mission.","authors":"Julie Castillo-Rogez, Lynnae C Quick, Marc Neveu, Jennifer Scully, Tom A Nordheim, Brian Clement, Laura Newlin, Nico Schmedemann, Amanda Hendrix, Carol Raymond, Marc Rayman","doi":"10.1089/ast.2024.0066","DOIUrl":"10.1089/ast.2024.0066","url":null,"abstract":"<p><p>We review the current state of understanding of Ceres as it relates to planetary protection policy for future landed missions, including for sample return, to the dwarf planet. The Dawn mission found Ceres to be an intriguing target for a mission, with evidence for the presence of regional, possibly extensive liquid at depth, and local expressions of recent and potentially ongoing activity. The Dawn mission also found a high abundance of carbon in the regolith, interpreted as a mix of carbonates and amorphous carbon, as well as locally high concentrations of organic matter. Key findings from this review are as follows: (1) outside of the region of Occator crater, Ceres shows no geological evidence for conduits from the surface to the interior; and (2) considering the biological potential of Ceres' deep interior, a surface sample return mission should be considered Category V restricted, unless it can be demonstrated that evaporites sourced from Ceres' deep brine region, and recently exposed in Occator crater, have not been scattered to the rest of Ceres' surface; in that case, the probability of returning an unsterilized particle to an acceptably low value is to be determined by a future study.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 1","pages":"82-95"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027923","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":"A One-Dimensional Energy Balance Model Parameterization for the Formation of CO₂ Ice on the Surfaces of Eccentric Extrasolar Planets.","authors":"Vidya Venkatesan, Aomawa L Shields, Russell Deitrick, Eric T Wolf, Andrew Rushby","doi":"10.1089/ast.2023.0103","DOIUrl":"10.1089/ast.2023.0103","url":null,"abstract":"<p><p>Eccentric planets may spend a significant portion of their orbits at large distances from their host stars, where low temperatures can cause atmospheric CO₂ to condense out onto the surface, similar to the polar ice caps on Mars. The radiative effects on the climates of these planets throughout their orbits would depend on the wavelength-dependent albedo of surface CO₂ ice that may accumulate at or near apoastron and vary according to the spectral energy distribution of the host star. To explore these possible effects, we incorporated a CO₂ ice-albedo parameterization into a one-dimensional energy balance climate model. With the inclusion of this parameterization, our simulations demonstrated that F-dwarf planets require 29% more orbit-averaged flux to thaw out of global water ice cover compared with simulations that solely use a traditional pure water ice-albedo parameterization. When no eccentricity is assumed, and host stars are varied, F-dwarf planets with higher bond albedos relative to their M-dwarf planet counterparts require 30% more orbit-averaged flux to exit a water snowball state. Additionally, the intense heat experienced at periastron aids eccentric planets in exiting a snowball state with a smaller increase in instellation compared with planets on circular orbits; this enables eccentric planets to exhibit warmer conditions along a broad range of instellation. This study emphasizes the significance of incorporating an albedo parameterization for the formation of CO₂ ice into climate models to accurately assess the habitability of eccentric planets, as we show that, even at moderate eccentricities, planets with Earth-like atmospheres can reach surface temperatures cold enough for the condensation of CO₂ onto their surfaces, as can planets receiving low amounts of instellation on circular orbits.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"42-59"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142977352","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":"Waste Heat and Habitability: Constraints from Technological Energy Consumption.","authors":"Amedeo Balbi, Manasvi Lingam","doi":"10.1089/ast.2024.0082","DOIUrl":"10.1089/ast.2024.0082","url":null,"abstract":"<p><p>Waste heat production represents an inevitable consequence of energy conversion as per the laws of thermodynamics. Based on this fact, by using simple theoretical models, we analyze constraints on the habitability of Earth-like terrestrial planets hosting putative technological species and technospheres characterized by persistent exponential growth of energy consumption and waste heat generation. In particular, we quantify the deleterious effects of rising surface temperature on biospheric processes and the eventual loss of liquid water. Irrespective of whether these sources of energy are ultimately stellar or planetary (e.g., nuclear, fossil fuels) in nature, we demonstrate that the loss of habitable conditions on such terrestrial planets may be expected to occur on timescales of ≲1000 years, as measured from the start of the exponential phase, provided that the annual growth rate of energy consumption is of order 1%. We conclude with a discussion of the types of evolutionary trajectories that might be feasible for industrialized technological species, and we sketch the ensuing implications for technosignature searches.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"25 1","pages":"1-21"},"PeriodicalIF":3.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027927","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}