Astrobiology最新文献

{"title":"From Polymerization-Enabled Folding and Assembly to Chemical Evolution: Key Processes for Emergence of Functional Polymers in the Origin of Life.","authors":"Rotem Edri, Manesh Prakash Joshi, Moran Frenkel-Pinter, Nicholas V Hud, Christine D Keating, Luke J Leman","doi":"10.1177/15311074251365943","DOIUrl":"10.1177/15311074251365943","url":null,"abstract":"<p><p>Chemical and geological processes on prebiotic Earth are believed to have resulted in the emergence of life through the increasing organization and functionality of organic molecules. This primer provides an overview of some key abiotic chemical and physical processes that could have contributed to life's building blocks (amino acids, nucleotides, fatty acids, and monosaccharides) becoming more ordered during the early stages in the origin of life. The processes considered include polymerization, intramolecular folding, multimolecular assembly, and chemical evolution through various selective mechanisms. Our goal is to provide an accessible, high-level synopsis of these key general concepts for a diverse audience.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"15311074251365943"},"PeriodicalIF":2.6,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144940289","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 Existing Frameworks of Delivery of Major Volatiles and the Feasibility of Mars-Mass Planetary Embryos as the Major Volatile Contributors to Bulk Silicate Earth.","authors":"Debjeet Pathak, Rajdeep Dasgupta","doi":"10.1177/15311074251365197","DOIUrl":"10.1177/15311074251365197","url":null,"abstract":"<p><p>The presence of major volatile elements-carbon, hydrogen, nitrogen, and sulfur-on Earth is critical for establishing life. The origin of these life-essential volatile elements (LEVEs) on Earth has been studied for many years. Here, we present a brief compilation of the prevailing ideas regarding volatile delivery to Earth and evaluate their origins, strengths, and weaknesses. Motivated by the fact that one model of LEVE delivery is via a giant impactor to Earth, we subsequently present a geochemical model aimed at understanding the possible volatile inventory and fractionation between the core, the silicate magma ocean (MO), and the atmosphere of a Mars-mass embryo. We looked at various end-member accretion scenarios of the embryo and their influence on the embryo's LEVE budget and the LEVE ratios. We varied various chemical (initial concentration of volatiles in the undifferentiated bodies and the oxygen fugacity [<i>f</i>O₂] of geochemical fractionation) and physical parameters (silicate-mass fraction of the accreting bodies, MO depth) to observe their effects on the absolute and relative LEVE budgets of the embryo. Our results show that an oxidizing condition (log<i>f</i> O₂ ≥ IW-1 [Iron-Wüstite]) is critical in establishing the relative LEVE budget of the embryo's MO, closer to that of present-day bulk silicate Earth. Furthermore, the accretion of larger bodies to form the Mars-mass embryo results in the closest match of the LEVE ratios to that of the present-day bulk silicate Earth (BSE). However, the absolute LEVE budget of the MO of Mars-mass embryo is depleted by at least 1-2 orders of magnitude compared with the BSE under all model calculation scenarios. In contrast, the CI-chondrite-normalized LEVE budget of the embryos's core, in many of the scenarios, especially from the reduced (<i>e.g.,</i> IW-2) bodies, overlaps or exceeds the present-day BSE estimate. We argue that for a Mars-mass, differentiated embryo, the cores provide a better prospect for LEVE delivery to proto-Earth, through core breakups and subsequent mixing in the MO or solid mantle. Future studies need to better assess whether the fractional retention of core materials in the silicate reservoir can match the present-day BSE LEVE budgets and how such a process compares with the LEVE delivery via less-processed primitive asteroids.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"15311074251365197"},"PeriodicalIF":2.6,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144871177","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":"Biosignature Detection and Preservation in Lake Salda Microbialites Under Simulated Martian Conditions.","authors":"Connor J Ballard, Louisa J Preston, Lewis R Dartnell, Eva Mateo-Marti, Catherine Regan, Andrew Coates","doi":"10.1177/15311074261417883","DOIUrl":"10.1177/15311074261417883","url":null,"abstract":"<p><p>The alteration of martian deposits under extreme surface conditions remains a key challenge for their mineral-organic interpretation and paleoenvironmental reconstruction. This study investigates the spectral detection and alteration of mineral-organic signatures in Lake Salda hydromagnesite microbialites under martian sublimation and radiation (UV) conditions. Samples were analyzed using visible near-infrared and Fourier transform infrared (FTIR) spectroscopy, then sublimated via lyophilization and exposed to UV radiation in the Planetary Atmospheres and Surfaces Simulation Chamber. Sublimation reduced the intensity of water and carbonate vibrations and enhanced CH₂ ν₃ and PO₂^- ν₃ organic features; this demonstrated that interstitial water sublimation may reduce O-H spectral noise, improve organic visibility, and reveal volatile sublimation patterns for future Mars rovers, such as Rosalind Franklin. In a three-sol (74 h) simulation of martian UV radiation (200-400 nm) under 7 mbar of CO₂, FTIR spectral intensity was reduced, and organic CH₂ ν₃ and PO₂^- features were significantly degraded. These findings reveal spectral alterations under martian surface conditions and highlight organic biosignature vulnerability at equatorial latitudes, informing preservation protocols for future missions.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"114-131"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146140981","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":"Cold-Water CO₂ Geysers as Ocean World Plume Analogs: Investigation of Habitability Indicators in Crystal and Champagne Geysers Pre- and Posteruption.","authors":"Morgan L Cable, Elizabeth J Kirby, Isabella A Musto, Christopher R Glein, D Alex Patthoff, Sally L Potter-McIntyre, Kathleen L Craft","doi":"10.1177/15311074261416868","DOIUrl":"10.1177/15311074261416868","url":null,"abstract":"<p><p>Ocean world plumes at Enceladus, Triton, and possibly Europa are astrobiologically significant. These active processes may transport fresh material from potentially habitable subsurface environments to the surface and atmosphere/exosphere, where they can be accessed by spacecraft and telescopic observations. However, it is currently unclear if chemical fractionation or other modification processes might occur during subsurface transport and eruption and potentially lead to changes in concentrations of habitability indicators relative to the source reservoir. To explore this phenomenon in a natural setting, we investigated the cold CO₂ geysers in Green River, Utah, which have eruptions driven by volatile exsolution. We collected samples from two geysers with different vent diameters and discharge volumes and compared the chemical composition of the erupted effluent and mineralogy of evaporite deposits with their respective pre-erupted waters; we also performed geochemical modeling to reconstruct the original chemical speciation of the source waters. Observed increases in electrical conductivity for both the erupted effluents may be due to an influx of warm fluids enriched in CO₂-charged brine entering the aquifer and initiating eruption via CO₂ exsolution and buoyant acceleration. Modeling results indicate source waters extremely rich in dissolved CO₂ with pH values significantly lower than those of erupted waters. The outgassing of CO₂ and significant levels of sulfate, Na/K ratio, and acidic pH suggest that the effluent from this geysering system may serve as a natural analog for putative plume deposits on Europa. The larger geyser (Crystal) had evaporites that were carbonate-rich, while the smaller geyser (Champagne) produced evaporites dominated by sulfate minerals. Furthermore, in a sample of erupted Champagne waters cooled rapidly in vacuum to replicate a frozen plume deposit, vitreous MgSO₄ was the primary constituent; this was not the main component in solution or identified in the evaporite or surrounding tufa. Overall, our observations suggest that geyser discharge volume, eruptive energy, and/or proximity to the host reservoir may all play a role in the composition of plume ejecta and surface deposits, and care should be taken in integrating both <i>in situ</i> and remote sensing observations to fully characterize plume deposits and make robust inferences of ocean composition. Key Words: Enceladus-Europa-Reflectance spectroscopy-Raman spectroscopy-Habitability indicator-Plume. Astrobiology 26, 79-98.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"79-98"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146112118","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":"Does the Measured Abundance Suggest a Biological Origin for the Ancient Alkanes Preserved in a Martian Mudstone?","authors":"Alexander A Pavlov, Caroline Freissinet, Daniel P Glavin, Christopher H House, Jennifer C Stern, Amy C McAdam, Anais Roussel, Jason P Dworkin, Luoth Chou, Andrew Steele, Paul R Mahaffy, Denise Buckner, Felipe Gomez","doi":"10.1177/15311074261417879","DOIUrl":"10.1177/15311074261417879","url":null,"abstract":"<p><p>The measured abundance (30-50 ppb) of long-chain (C₁₀-C₁₂) alkanes and their possible carboxylic acid precursors found in the ancient Cumberland mudstone in Gale crater would have been substantially higher before the onset of exposure to ionizing radiation approximately 80 million years ago. Based on recent radiolysis experiments, we estimate conservatively that the Cumberland mudstone would have contained 120-7700 ppm of long-chain alkanes and/or fatty acids before ionizing radiation exposure. Such a high concentration of large organic molecules in martian sedimentary rocks cannot be readily explained by the accretion of organics from carbon-rich interplanetary dust particles and meteorites, nor by the deposition of hypothetical haze-derived organics from an ancient martian atmosphere. We discuss the feasibility of two additional mechanisms--one abiotic and one biological--that could have been capable of depositing this level of long-straight-chain organic molecules in the ancient martian mudstones: allochthonous transport of hydrothermally synthesized organics and autochthonous accumulation of organics from a hypothetical ancient Mars biosphere. To advance and test these and any additional working hypotheses put forth to explain such high concentrations of primary organics on Mars requires an understanding of the radiolytic degradation products expected for organics preserved in mineralogically comparable mudstones.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"154-161"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146112114","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":"Solar UV Irradiance for Biological Exposure Experiments on the China Space Station.","authors":"Binquan Zhang, Guohong Shen, Changsheng Tuo, Huanxin Zhang, Ying Sun, Yongjin Dong, Shenyi Zhang, Lijun Liu, Xianguo Zhang","doi":"10.1177/15311074261417889","DOIUrl":"10.1177/15311074261417889","url":null,"abstract":"<p><p>Exposure experiments that involve biological samples subjected to solar ultraviolet (UV) radiation (UVA, UVB, and UVC wavelengths) have advanced an understanding of biological responses in the harsh environment of space. These experiments provide insights about the role of such materials with regard to the origin and evolution of life and the development of protective strategies for long-term space habitation. A solar UV detector was developed to measure solar UV irradiance during exposure experiments as part of the Space Radiobiological Exposure Facility (SREF) on the China Space Station (CSS). This detector, which utilizes three SiC photodiodes, measures solar UV irradiance across three wavelength bands to determine UV doses received by exposed samples. Detector calibration is based on spectral solar irradiance data. From June 2023 to September 2024, the SREF completed three exposure missions that spanned a total duration of 465 days. Throughout these missions, the solar UV detector monitored the solar UV irradiance, which revealed periodic variations in the measured data that corresponded to changes in the solar beta angle and the CSS orbit. The cumulative radiation dose for the missions was 391 MJ m^-2 for UVA, 78.6 MJ m^-2 for UVB, and 30.1 MJ m^-2 for UVC.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"108-113"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146083982","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":"Impact of Various Inactivation Approaches on Surrogate Proteinaceous Particles for Sample Return Missions.","authors":"Aspen L Hirsch, Emily P Seto, Wayne W Schubert, Julia C Lin, Kacy Paul, Danil Dobrynin, Eric D Ross, Yury O Chernoff","doi":"10.1177/15311074261417878","DOIUrl":"10.1177/15311074261417878","url":null,"abstract":"<p><p>Return of Mars samples is a high priority in the planetary science community and has remained an enduring goal of planetary exploration programs. Development of sterilization techniques to prevent potential contamination of Earth's biosphere with unknown life-forms that could exist on planetary bodies requires the use of the most robust biological indicators. We argue that self-seeding proteinaceous particles (prions) represent the most robust biological agents found on Earth. To evaluate the impact of various sterilization techniques on prion activity, we used derivatives of yeast prion proteins Sup35 and Ure2, which are not harmful to humans. Our study demonstrated that effective antimicrobial modalities, which include prolonged dry heat (up to 200°C), vapor hydrogen peroxide, gamma irradiation (up to 100 kGy), and ambient air or wet He/water plasma (deposited energy density of up to 6.3 kJ/cm²), did not eliminate the biological activity of yeast prions. However, ultraviolet C (UVC) irradiation at a wavelength of 260-270 nm for 16-24 days eliminated Ure2 prion detection and biological activity, and prolonged UVC irradiation eliminated detection of Sup35 prions and reduced, although did not eliminate, their biological activity. These data suggest that UVC could be an essential component of in-flight sterilization techniques for all future planetary missions.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"132-147"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146123761","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":"Ribose Accumulation in Borate-Rich Prebiotic Environments.","authors":"Yuna Takahashi, Hyo-Joong Kim, Steven A Benner, Takeshi Kakegawa, Yoshihiro Furukawa","doi":"10.1177/15311074261417882","DOIUrl":"10.1177/15311074261417882","url":null,"abstract":"<p><p>Under the RNA first hypothesis for the origin of life, RNA that emerges from prebiotic chemistry performed both catalytic and informational roles. Ribose is the only sugar in RNA; thus, many have sought to understand how ribose might have emerged on a prebiotic Earth. Ribose can be formed from formaldehyde with small amounts of glycolaldehyde by formose-like processes. However, under the strongly alkaline conditions of the reaction, ribose is consumed as it is formed. Here, we show that borate significantly decreases the consumption of the ribose formed in the formose reaction, which results in higher amounts of ribose that remained as the reaction progressed. Given a longer timescale of prebiotic chemical reactions governed by geological processes, borate-rich environments could have contributed to accumulating ribose on prebiotic Earth. Borate could be available on proto-continents and is known to contribute to ribonucleoside synthesis, ribose 5-phosphate synthesis, and nucleoside phosphorylation. Therefore, such environments might have promoted chemical reactions to RNA.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"99-107"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146200091","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":"Viking Mars, Now 50 Years Old, Still Needs a Scientific Analysis.","authors":"Steven A Benner, Dirk Schulze-Makuch, Jan Spacek, Clay Abraham","doi":"10.1177/15311074251404929","DOIUrl":"10.1177/15311074251404929","url":null,"abstract":"<p><p>Gas chromatography-mass spectrometry data from the Viking Mars mission were misinterpreted in 1976 as showing that martian soils contain no organic molecules, and therefore no life, even though the three life detection experiments delivered by Viking all reported life-positive data under the terms of their experimental design. This mistake has been propagated for a half century, including in textbooks and National Aeronautics and Space Administration-endorsed documents, even though it has been known since 2009 that the martian soils contained perchlorate, perchlorate destroys organic materials in ways that might generate the GC-MS results, and Curiosity in 2013 observed such processes in Gale crater on Mars, as have other rovers since. Anomalies in the propagated misinterpretation, including a contradiction between the \"strong martian soil oxidant\" hypothesis and quantitative results in the carbon assimilation experiment, were \"explained away\" in 1976, in some cases by invoking results of experiments that had not yet been done. Today, a scientific back-and-forth is long overdue to develop an understanding of what Viking revealed about the possibility of life on the near surface of Mars. Starting this back-and-forth here, we note how the Viking results are compatible with a soil that contains bacterial autotrophs that respire with stored oxygen on Mars (BARSOOM), a lifestyle adapted to its environment, including sparse resources that drive dormancy, scarce atmospheric oxygen, and a cold and briny fluid only intermittently available, perhaps, when the water-ice fogs seen by Viking indicate that the relative humidity exceeds 100%.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"148-153"},"PeriodicalIF":2.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145861929","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":"Biotic and Abiotic Signatures in Sulfate- and Carbonate-Rich Hypersaline Lakes as Analogs for Mars.","authors":"Hemani Kalucha, Benjamin W Johnson, Miquela Ingalls, Paul D Asimow, Hanna C Leapaldt, Ellen Olsen, James Mullahoo, Woodward W Fischer","doi":"10.1177/15311074251413234","DOIUrl":"https://doi.org/10.1177/15311074251413234","url":null,"abstract":"<p><p>Lacustrine sulfate- and carbonate-rich deposits have been detected at Jezero and Gale craters on Mars. The preservation of potential biosignatures in these sites may depend on the nature of precipitated salts and the early diagenetic history of <i>in situ</i> minerals. In this study, we explore a collection of Mars analog hypersaline depositional environments in British Columbia. Magnesium salts and other sulfate and carbonate salts precipitate from the variable water chemistry of Atlin Playa and a suite of lakes on the Cariboo Plateau. Authigenic and detrital grains were distinguished on the basis of their microscale morphology revealed by scanning electron microscopy. Authigenic minerals display distinct textures such as globular or prismatic clumps or delicately preserved cement that envelops angular, detrital grains. However, microscale authigenic textures become rare below the sediment-water interface due to early diagenetic dissolution and reprecipitation of salts during wet-dry cycles in the lakes. Such early diagenetic overprinting of salts could pose problems for identifying primary environments and any potential biosignatures they might have preserved in 3-4 billion-year-old rocks on Mars. The δ¹³C of organic matter and δ³⁴S of sulfate salts are reflective of source materials instead of diagenesis. Total organic carbon content is a function of the abundance of salt minerals, with a well-defined maximum in organic carbon content at an optimum salt content. Our findings demonstrate hypersaline lakes as key preservers of organic carbon and salts as a high-priority mineral target for finding organic carbon on Mars.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":"26 1","pages":"48-65"},"PeriodicalIF":2.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146028240","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}