AstrobiologyPub Date : 2025-03-28DOI: 10.1089/ast.2024.0131
Francisco Calapez, Rodrigo Dias, Rute Cesário, Bruno Pedras, João Canário, Zita Martins
{"title":"Spectroscopic Protocol for Biosignature Detection: Arctic Ice Samples as Analogs for Icy Moons.","authors":"Francisco Calapez, Rodrigo Dias, Rute Cesário, Bruno Pedras, João Canário, Zita Martins","doi":"10.1089/ast.2024.0131","DOIUrl":"https://doi.org/10.1089/ast.2024.0131","url":null,"abstract":"<p><p>The moons of Jupiter and Saturn, such as Europa and Enceladus, are strong candidates for the search for life outside of Earth. Together with the use of direct observational methods, physical and chemical processes that take place on icy moons may be studied on planetary field analogs, that is, on similar reachable locations on Earth. Fieldwork performed on planetary field analogs can test protocols and technology that may be applied on future space missions to extraterrestrial environments. The Arctic is a strong candidate for such studies. This study assesses a spectroscopic protocol for biosignature detection in the Arctic, as a proxy to icy moons. Samples of ice and the water underneath were collected by our team in different locations at and nearby Hudson Bay, Canada, and spectroscopic analysis detected the presence of humic acid in all the samples. On the contrary, biosignatures such as amino acids and β-carotene may have been present in concentrations below the limit of detection of the equipment used. With proper optimization, it will be possible to implement this simple protocol that relies on lightweight equipment in future space missions to icy moons.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727635","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}
AstrobiologyPub Date : 2025-03-28DOI: 10.1089/ast.2024.0148
Michael T Mellon, Aldin F Aksay, Hanna G Sizemore, Christopher P McKay
{"title":"Humidity Enhancement in Dry Permafrost: The Effects of Temperature Cycles on Habitability.","authors":"Michael T Mellon, Aldin F Aksay, Hanna G Sizemore, Christopher P McKay","doi":"10.1089/ast.2024.0148","DOIUrl":"https://doi.org/10.1089/ast.2024.0148","url":null,"abstract":"<p><p>The search for life in the solar system often focuses on water and on environments where habitable conditions exist, persistently or occasionally. In this search, dry permafrost (ice-free frozen soil) has received minimal attention. It was previously proposed that within martian dry permafrost the water activity (<math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math>, an essential property for habitability) could be enhanced by diurnal thermal cycles and water desorption from soil grains, but the details remain unexplored. We examined <math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math> in dry soil (which contained only vapor and adsorbed water) through experiments and numerical simulations and contrasted the results with a habitability threshold for terrestrial organisms (<math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow><mo> </mo><mo> </mo><mo>></mo><mo> </mo><mo> </mo><mn>0.6</mn></math>). We found that heating cycles in a soil raised <math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math>. As water vapor desorbs from warming soil grains, it diffuses toward cooler adjacent soil, where a fraction of this incoming vapor enhances the local <math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math>. In laboratory tests with loess and clay soils, we observed <math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math> to increase by 0.06-0.12. Extrapolating from laboratory to permafrost conditions by using numerical simulations, we found that some Antarctic soils can be boosted periodically into a habitable range. In contrast, the current martian climate is too dry or cold for this <math><mrow><msub><mrow><mi>a</mi></mrow><mrow><mi>w</mi></mrow></msub></mrow></math>-enhancement process to impact habitability. However, high-obliquity periods on Mars are analogous to the Antarctic case.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727631","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}
AstrobiologyPub Date : 2025-03-26DOI: 10.1089/ast.2024.0124
Daniel Duzdevich, Collin Nisler, Janusz J Petkowski, William Bains, Caroline K Kaminsky, Jack W Szostak, Sara Seager
{"title":"Simple Lipids Form Stable Higher-Order Structures in Concentrated Sulfuric Acid.","authors":"Daniel Duzdevich, Collin Nisler, Janusz J Petkowski, William Bains, Caroline K Kaminsky, Jack W Szostak, Sara Seager","doi":"10.1089/ast.2024.0124","DOIUrl":"https://doi.org/10.1089/ast.2024.0124","url":null,"abstract":"<p><p>Venus has become a target of astrobiological interest because it is physically accessible to direct exploration, unlike exoplanets. So far this interest has been motivated not by the explicit expectation of finding life but rather by a desire to understand the limits of biology. The venusian surface is sterilizing, but the cloud deck includes regions with temperatures and pressures conventionally considered compatible with life. However, the venusian clouds are thought to consist of concentrated sulfuric acid. To determine if any fundamental features of life as we understand them here on Earth could in principle exist in these extreme solvent conditions, we tested several simple lipids for resistance to solvolysis and their ability to form structures in concentrated sulfuric acid. We find that single-chain saturated lipids with sulfate, alcohol, trimethylamine, and phosphonate head groups are resistant to sulfuric acid degradation at room temperature. Furthermore, we find that they form stable higher-order structures typically associated with lipid membranes, micelles, and vesicles. Finally, results from molecular dynamics simulations suggest a molecular explanation for the observed robustness of the lipid structures formed in concentrated sulfuric acid. We conclude with implications for the study of Venus as a target of experimental astrobiology.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727633","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}
AstrobiologyPub Date : 2025-03-26DOI: 10.1089/ast.2024.0084
Luca Stigliano, Karim Benzerara, Philippe Ackerer, Nicolas Menguy, Cynthia Travert, Fériel Skouri-Panet, Damien Daval
{"title":"Traces of Bacterial Contribution to Calcite Weathering Detected by Statistical Characterizations of Surface Microtopography.","authors":"Luca Stigliano, Karim Benzerara, Philippe Ackerer, Nicolas Menguy, Cynthia Travert, Fériel Skouri-Panet, Damien Daval","doi":"10.1089/ast.2024.0084","DOIUrl":"https://doi.org/10.1089/ast.2024.0084","url":null,"abstract":"<p><p>There is a crucial need to identify reliable imprints of microbe-mineral interactions to quantify the contribution of microorganisms to chemical weathering and detect traces of life in the geological record. Yet conventional methods based on qualitative descriptions of supposedly bioinduced etching features have often proven equivocal. Here, calcite dissolution experiments were carried out at various solution compositions, in the presence or absence of cyanobacterial biofilms. Nanoscale chemical and crystallographic characterizations failed to detect any distinctive biogenicity feature. Conversely, high-elevation regions at the calcite surface were detected through statistical characterizations of the microtopography, which made microbially weathered surfaces quantitatively distinguishable from their abiotic counterparts. Interestingly, the high-elevation regions that formed beneath clusters of microbial cells are at odds with the etching features that resemble cell morphologies and are usually sought as bioweathering markers. Atomic-scale stochastic simulations of the dissolution process suggested that these regions resulted from a local increase in fluid saturation state at the biofilm-mineral contact, which led to a localized reduction in dissolution rates. Overall, this study offers a new avenue for the nondestructive identification of bioweathering signatures in natural settings.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143708238","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}
AstrobiologyPub Date : 2025-03-26DOI: 10.1089/ast.2024.0093
Jun Korenaga
{"title":"Tectonics and Surface Environments on Early Earth.","authors":"Jun Korenaga","doi":"10.1089/ast.2024.0093","DOIUrl":"https://doi.org/10.1089/ast.2024.0093","url":null,"abstract":"<p><p>The mode of tectonics that governed early Earth is controversial. This makes it challenging to infer surface environments relevant to the origin of life. The majority of the literature published in the past two decades was inclined to favor the appearance of plate tectonics sometime around the mid-Archean (∼3 Ga), with the operation of stagnant lid convection (or its variants) dominant in the earlier part of Earth's history. However, the available and increasing geological record from early Earth is actually equivocal, and there is no theoretical basis to prefer stagnant lid convection over plate tectonics. In fact, such a delayed onset of plate tectonics would inhibit the emergence of life in the Archean, let alone in the Hadean. On the contrary, rapid plate tectonics in the early Hadean, enabled by the fractional crystallization of a magma ocean, could quickly transform inclement young Earth into a habitable planet, with formation of multiple surface environments potentially conducive to abiogenesis.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143727636","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}
AstrobiologyPub Date : 2025-03-01Epub Date: 2025-03-05DOI: 10.1089/ast.2024.0023
Afonso Mota, Stella Koch, Daniel Matthiae, Nuno Santos, Marta Cortesão
{"title":"How Habitable Are M Dwarf Exoplanets? Modeling Surface Conditions and Exploring the Role of Melanins in the Survival of <i>Aspergillus niger</i> Spores Under Exoplanet-Like Radiation.","authors":"Afonso Mota, Stella Koch, Daniel Matthiae, Nuno Santos, Marta Cortesão","doi":"10.1089/ast.2024.0023","DOIUrl":"10.1089/ast.2024.0023","url":null,"abstract":"<p><p>Exoplanet habitability remains a challenging field due to the large distances separating Earth from other stars. Using insights from biology and astrophysics, we studied the habitability of M dwarf exoplanets by modeling their surface temperature and flare ultraviolet (UV) and X-ray doses using the martian atmosphere as a shielding model. Analyzing the Proxima Centauri and TRAPPIST-1 systems, our models suggest that Proxima b and TRAPPIST-1 e are likeliest to have temperatures compatible with surface liquid water, as well as tolerable radiation environments. Results of the modeling were used as a basis for microbiology experiments to assess spore survival and germination of the melanin-rich fungus <i>Aspergillus niger</i> to exoplanet-like radiation (UV-C and X-rays). Results showed that <i>A. niger</i> spores can endure superflare events on M dwarf planets when shielded by a Mars-like atmosphere or by a thin layer of soil or water. Melanin-deficient spores suspended in a melanin-rich solution showed higher survival rates and germination efficiency when compared to melanin-free solutions. Overall, the models developed in this work establish a framework for microbiological research in habitability studies. Finally, we showed that <i>A. niger</i> spores can survive harsh radiation conditions of simulated exoplanets, which also emphasizes the importance of multifunctional molecules like melanins in radiation shielding beyond Earth.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"161-176"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143555576","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}
AstrobiologyPub Date : 2025-03-01Epub Date: 2025-02-19DOI: 10.1089/ast.2024.0078
Jennifer Huidobro, Julene Aramendia, Cristina García-Florentino, Leire Coloma, Iratxe Población, Gorka Arana, Juan Manuel Madariaga
{"title":"Understanding Sulfate Stability on Mars: A Thermo-Raman Spectroscopy Study.","authors":"Jennifer Huidobro, Julene Aramendia, Cristina García-Florentino, Leire Coloma, Iratxe Población, Gorka Arana, Juan Manuel Madariaga","doi":"10.1089/ast.2024.0078","DOIUrl":"10.1089/ast.2024.0078","url":null,"abstract":"<p><p>This work examines the impact of high temperatures from celestial shock events on the stability of sulfates found on Mars (gypsum) and those expected to be present (syngenite and görgeyite). Raman spectroscopy, a cutting-edge technique in space exploration, was used to track their stability. Specifically, a Renishaw inVia<sup>™</sup> micro-Raman confocal spectrometer was coupled with an external Linkam THMS600/HF600 temperature-controlled stage to monitor the sample temperature while measuring the main Raman band positions of the sulfates and those of water molecules in these salts across temperatures ranging from 313 to 673 K. Results showed a shift toward lower wavenumbers with increasing temperature for all compounds, up to each compound's inflection temperature, where phase transformations occurred. The linear trends identified in this study provide valuable insights for interpreting data from space missions equipped with Raman instruments and understanding Earth-based measurements. These trends enable the estimation of Raman band wavenumbers at specific temperatures, as well as the determination of the temperature at which a given spectrum was acquired. Additionally, the research demonstrated that the three heated salts fully rehydrated after at least 1 month under standard environmental conditions (23°C, 1 atm, and ∼80% relative humidity). This finding on reversibility is crucial for interpreting time-dependent results, such as characterizing meteorites that contain evaporite salts.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"189-200"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143456780","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}
AstrobiologyPub Date : 2025-03-01Epub Date: 2025-02-17DOI: 10.1089/ast.2024.0075
Isabel Egea-González, Christopher P McKay, John E Hallsworth, Alberto Jiménez-Díaz, Javier Ruiz
{"title":"Ammonia or Methanol Would Enable Subsurface Liquid Water at the Martian South Pole.","authors":"Isabel Egea-González, Christopher P McKay, John E Hallsworth, Alberto Jiménez-Díaz, Javier Ruiz","doi":"10.1089/ast.2024.0075","DOIUrl":"10.1089/ast.2024.0075","url":null,"abstract":"<p><p>The notion of liquid water beneath the ice layer at the south polar layered deposits (SPLD) of Mars is an interesting possibility given the implications for astrobiology and possible human habitation. A body of liquid water located at a depth of 1.5 km has been inferred from radar data in the South Polar Cap. However, the high temperatures that would facilitate the existence of liquid water or brine at that depth are not consistent with estimations of heat flow that are based on the lithosphere's flexure. Attempts to reconcile both issues have been inconclusive or otherwise unsuccessful. Here, we analyze the possible role(s) of subsurface ammonia and/or methanol in maintaining water in a liquid state at subsurface temperatures that are compatible with the lithosphere strength. Our results indicate that the presence of these compounds at the base of the SPLD can reconcile the existence of liquid water with previous estimations of surface heat flow.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"201-208"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143439715","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}
AstrobiologyPub Date : 2025-03-01Epub Date: 2025-02-26DOI: 10.1089/ast.2024.0098
Solomon Hirsch, Jonathan S Tan, Keyron Hickman-Lewis, Mark A Sephton
{"title":"Preservation of Extracellular Sheaths Produced by Iron-Oxidizing Bacteria: An Analog for Potential Morphological Biosignatures on Mars.","authors":"Solomon Hirsch, Jonathan S Tan, Keyron Hickman-Lewis, Mark A Sephton","doi":"10.1089/ast.2024.0098","DOIUrl":"10.1089/ast.2024.0098","url":null,"abstract":"<p><p>In the search for life on Mars, evaluating the biogenicity of morphological structures may be important, as they can provide a primary independent line of evidence for past life and can be used to target areas to focus further analyses. However, our experience with terrestrial materials indicates that the deleterious effects of diagenetic processes regularly make the assessment, and even detection, of microfossils and other microscopic biosignatures challenging. To improve our understanding of these effects on Mars, we collected samples that contained sheath-shaped extracellular structures produced by iron-oxidizing bacteria (FeOB) from a Mars analog circumneutral iron deposit and subjected them to artificial maturation by hydrous pyrolysis. Simulated diagenesis induced a phase change in the mineralogy of the structures, from ferrihydrite to crystalline iron oxides. We found that conditions associated with the onset of this phase change were correlated with the start of significant degradation of the extracellular structures. Our results reveal the sensitivity of remains of FeOB to diagenesis, which provides insights for improved targeting of astrobiological missions to areas on Mars that are most conducive to morphological biosignature preservation. Additionally, these results compel increased scrutiny of FeOB-like purported biosignatures if their mineralogy is dominated by crystalline iron oxides.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"151-160"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143498154","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}
AstrobiologyPub Date : 2025-03-01Epub Date: 2025-02-17DOI: 10.1089/ast.2024.0065
Anais S Gentilhomme, Kusum Dhakar, Emma Timmins-Schiffman, Matthew Chaw, Erin Firth, Karen Junge, Brook L Nunn
{"title":"Proteomic Insights into Psychrophile Growth in Perchlorate-Amended Subzero Conditions: Implications for Martian Life Detection.","authors":"Anais S Gentilhomme, Kusum Dhakar, Emma Timmins-Schiffman, Matthew Chaw, Erin Firth, Karen Junge, Brook L Nunn","doi":"10.1089/ast.2024.0065","DOIUrl":"10.1089/ast.2024.0065","url":null,"abstract":"<p><p>Since the discovery of perchlorates in martian soils, astrobiologists have been curious if and how life could survive in these low-water, high-salt environments. Perchlorates induce chaotropic and oxidative stress but can also confer increased cold tolerance in some extremophiles. Though bacterial survival has been demonstrated at subzero temperatures and in perchlorate solution, proteomic analysis of cells growing in an environment like martian regolith brines-perchlorate with subzero temperatures-has yet to be demonstrated. By defining biosignatures of survival and growth in perchlorate-amended media at subzero conditions, we move closer to understanding the mechanisms that underlie the feasibility of life on Mars. <i>Colwellia psychrerythraea</i> str. 34H (Cp34H), a marine psychrophile, was exposed to perchlorate ions in the form of a diluted Phoenix Mars Lander Wet Chemistry Laboratory solution at -1°C and -5°C. At both temperatures in perchlorate-amended media, Cp34H grew at reduced rates. Mass spectrometry-based proteomics analyses revealed that proteins responsible for mitigating effects of oxidative and chaotropic stress increased, while cellular transport proteins decreased. Cumulative protein signatures suggested modifications to cell-cell or cell-surface adhesion properties. These physical and biochemical traits could serve as putative identifiable biosignatures for life detection in martian environments.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"177-188"},"PeriodicalIF":3.5,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143439718","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}