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Photochemical Evolution of Alanine in Association with the Martian Soil Analog Montmorillonite: Insights Derived from Experiments Conducted on the International Space Station.
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-27 DOI: 10.1089/ast.2024.0034
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
{"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":"https://doi.org/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 (CO<sub>2</sub>), a byproduct of alanine photolysis, as a tracer of the amino acid. CO<sub>2</sub> 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":""},"PeriodicalIF":3.5,"publicationDate":"2025-01-27","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}
引用次数: 0
Beyond Homochirality: Computer Modeling Hints of Heterochiral Proteins in Early and Extraterrestrial Life. 超越同手性:早期和地外生命中异手性蛋白质的计算机建模提示。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 Epub Date: 2024-12-26 DOI: 10.1089/ast.2024.0072
Gianluigi Casimo, Gaia Micca Longo, Savino Longo
{"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}
引用次数: 0
Production of Organic Precursors via Meteoritic Impacts and Its Implications for Prebiotic Inventory of Early Planetary Surfaces.
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 DOI: 10.1089/ast.2023.0031
Benjamin Farcy, Ziqin Ni, Ricardo Arevalo, Michael Eller, Veronica T Pinnick, Emile A Schweikert, William B Brinckerhoff
{"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 <sup>13</sup>C<sub>60</sub><sup>+</sup> projectiles and laser ablation. In the first approach, a <sup>13</sup>C<sub>60</sub><sup>+</sup> beam was accelerated to collide with ammonium nitrate (NH<sub>4</sub>NO<sub>3</sub>) 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 (CaCO<sub>3</sub>) and either ammonium chloride (NH<sub>4</sub>Cl) or sodium nitrate (NaNO<sub>3</sub>) to induce atomization and enable the study of molecular recombination in the postimpact plume. Additionally, isotopically spiked starting material, namely, Ca<sup>13</sup>CO<sub>3</sub>, <sup>15</sup>NH<sub>4</sub>Cl, Na<sup>15</sup>NO<sub>3</sub>, and <sup>15</sup>NH<sub>4</sub><sup>15</sup>NO<sub>3</sub>, was also employed to disambiguate the source of prebiotic molecule production in the resulting recombination plume. Both experiments independently demonstrated the formation of CN<sup>-</sup> 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 NH<sub>4</sub>Cl or NaNO<sub>3</sub> indicate that nitrate enables more efficient production of CN<sup>-</sup> than ammonium. Thermodynamic software modeling of the laser ablation plume confirmed and further elucidated the experimental yield results, producing good agreement of modeled CN<sup>-</sup> yield with observed yield curves. These models indicate that the reduction of atomic N from incomplete NH<sub>4</sub><sup>-</sup> atomization during the ablation pulse may have contributed to the lower CN<sup>-</sup> yield from the ammonia source relative to the nitrate source. The results of these experiments demonstrated that CN<sup>-</sup>, 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}
引用次数: 0
The Space Radiobiological Exposure Facility on the China Space Station. 中国空间站空间辐射生物学暴露设施。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 Epub Date: 2025-01-08 DOI: 10.1089/ast.2024.0027
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
{"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}
引用次数: 0
Informing Planetary Protection Policies for the Future Exploration of Ceres: State of Understanding after the Dawn Mission.
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 DOI: 10.1089/ast.2024.0066
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
{"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":"https://doi.org/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}
引用次数: 0
Amplicon Sequencing Reveals Diversity in Spatially Separated Microbial Communities in the Icelandic Mars Analog Environment Mælifellssandur. 扩增子测序揭示了冰岛火星模拟环境中空间分离微生物群落的多样性。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 Epub Date: 2025-01-10 DOI: 10.1089/ast.2023.0124
George Tan, Chloe N LeCates, Anna Simpson, Samuel Holtzen, D Joshua Parris, Frank J Stewart, Amanda Stockton
{"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}
引用次数: 0
A One-Dimensional Energy Balance Model Parameterization for the Formation of CO2 Ice on the Surfaces of Eccentric Extrasolar Planets. 偏心系外行星表面CO2冰形成的一维能量平衡模型参数化。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 Epub Date: 2025-01-14 DOI: 10.1089/ast.2023.0103
Vidya Venkatesan, Aomawa L Shields, Russell Deitrick, Eric T Wolf, Andrew Rushby
{"title":"A One-Dimensional Energy Balance Model Parameterization for the Formation of CO<sub>2</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> 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 CO<sub>2</sub> 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}
引用次数: 0
Waste Heat and Habitability: Constraints from Technological Energy Consumption.
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2025-01-01 Epub Date: 2025-01-09 DOI: 10.1089/ast.2024.0082
Amedeo Balbi, Manasvi Lingam
{"title":"Waste Heat and Habitability: Constraints from Technological Energy Consumption.","authors":"Amedeo Balbi, Manasvi Lingam","doi":"10.1089/ast.2024.0082","DOIUrl":"https://doi.org/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}
引用次数: 0
Mesoarchean Microbial Cd, Ba, and Ni Cycling: Evidence for Photosynthesis in Pongola Group Stromatolites through Novel Stable Isotopes and High-Resolution Trace Element Maps. 中太古代微生物Cd、Ba和Ni循环:Pongola组叠层石光合作用的新稳定同位素和高分辨率微量元素图证据。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2024-12-01 Epub Date: 2024-11-29 DOI: 10.1089/ast.2024.0041
Simon V Hohl, Yiwen Lv, Yi-Bo Lin, Yinggang Zhang, Yuxiang Jiang, Guang-Yi Wei, Sebastian Viehmann
{"title":"Mesoarchean Microbial Cd, Ba, and Ni Cycling: Evidence for Photosynthesis in Pongola Group Stromatolites through Novel Stable Isotopes and High-Resolution Trace Element Maps.","authors":"Simon V Hohl, Yiwen Lv, Yi-Bo Lin, Yinggang Zhang, Yuxiang Jiang, Guang-Yi Wei, Sebastian Viehmann","doi":"10.1089/ast.2024.0041","DOIUrl":"10.1089/ast.2024.0041","url":null,"abstract":"<p><p>Nontraditional stable isotopes of bioactive metals emerged as novel proxies for reconstructing the biogeochemical cycling of metals, which serve as cofactors in major metabolic pathways. The fractionation of metal isotopes between ambient fluid and microorganisms is ultimately recorded in authigenic minerals, such as carbonates, which makes them potentially more reliable than standard biomarkers in organic matter. Stromatolitic carbonates are geochemical archives that allow for the study of the long-term interplay of the biosphere, atmosphere, and hydrosphere through deep time, with the unique potential to investigate early life environments and the evolution of the metallome. The present study uses stromatolites from the ∼2.95-billion-year-old Pongola Supergroup (S. Africa) as a field laboratory for combined <i>in situ</i> trace metal mapping and layer-specific, novel stable metal isotope compositions to infer early Earth microbial metal cycling via phototrophic and chemo-litho-autotrophic metabolisms. Quantitative <i>in situ</i> trace element maps reveal intrinsic biosedimentary enrichments of nickel (Ni), cadmium (Cd), phosphorus (P), iron (Fe), and manganese (Mn) in stromatolitic laminae. In contrast, barium (Ba) shows a more homogeneous distribution. Authigenic carbonates from pristine stromatolite laminae show distinct δ<sup>138</sup>Ba and δ<sup>112</sup>Cd fractionation above detrital background and bulk silicate Earth values, but opposing correlation with trace metal concentrations. Authigenic δ<sup>60</sup>Ni values overlap with Mesoarchean diamictite compositions. Nickel isotopic compositions in authigenic stromatolitic carbonates, potentially a new proxy for methanogenic metal uptake, do not show any proof of the presence of this metabolism in the samples of this study. Meanwhile, Cd isotopic compositions in authigenic carbonates follow typical Rayleigh-type isotope fractionation; that is, the isotopic composition of Cd evolves to heavy values close to modern surface compositions. Correlations of δ<sup>112</sup>Cd with the micronutrients copper (Cu), molybdenum (Mo), and P, at positively fractionated carbon (C) isotopes (δ<sup>13</sup>C ∼+2‰), argue for active photosynthesis in the Pongola microbial habitat. We show that Ba isotopes can be used to infer carbonate precipitation rates similar to modern microbial carbonates. Thus, the combination of Cd and Ni isotopes has the unique potential as novel isotope biomarkers for the biochemical sedimentary record of early Earth where traditional lipid biomarkers are not applicable due to the incomplete preservation of organic matter.</p>","PeriodicalId":8645,"journal":{"name":"Astrobiology","volume":" ","pages":"1196-1207"},"PeriodicalIF":3.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142749659","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}
引用次数: 0
Alternative Solvents for Life: Framework for Evaluation, Current Status, and Future Research. 生命的替代溶剂:评估框架、现状和未来研究。
IF 3.5 3区 物理与天体物理
Astrobiology Pub Date : 2024-12-01 Epub Date: 2024-12-02 DOI: 10.1089/ast.2024.0004
William Bains, Janusz J Petkowski, Sara Seager
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