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Surviving Mars: new insights into the persistence of facultative anaerobic microbes from analogue sites 幸存的火星:对类似地点兼性厌氧微生物持久性的新见解
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-03-24 DOI: 10.1017/s1473550422000064
K. Beblo-Vranesevic, Johanna Piepjohn, André Antunes, P. Rettberg
Mars analogue environments are some of the most extreme locations on Earth. Their unique combination of multiples extremes (e.g. high salinity, anoxia and low nutrient availability) make them valuable sources for finding new polyextremophilic microbes, and for exploring the limits of life. Mars, especially at its surface, is still considered to be very hostile to life but it probably possesses geological subsurface niches where the occurrence of (polyextremophilic) life is conceivable. Despite their well-recognized relevance, current knowledge on the capability of (facultative) anaerobic microbes to withstand extraterrestrial/Martian conditions, either as single strains or in communities, is still very sparse. Therefore, space experiments simulating the Martian environmental conditions by using space as a tool for astrobiological research are needed to substantiate the hypotheses of habitability of Mars. Addressing this knowledge gap is one of the main goals of the project MEXEM (Mars EXposed Extremophiles Mixture), where selected model organisms will be subjected to space for a period of 3 months. These experiments will take place on the Exobiology facility (currently under development and implementation), located outside the International Space Station. Such space experiments require a series of preliminary tests and ground data collection for the selected microbial strains. Here, we report on the survivability of Salinisphaera shabanensis and Buttiauxella sp. MASE-IM-9 after exposure to Mars-relevant stress factors (such as desiccation and ultraviolet (UV) radiation under anoxia). Both organisms showed survival after anoxic desiccation for up to 3 months but this could be further extended (nearly doubled) by adding artificial Mars regolith (MGS-1S; 0.5% wt/v) and sucrose (0.1 M). Survival after desiccation was also observed when both organisms were mixed before treatment. Mixing also positively influenced survival after exposure to polychromatic Mars-like UV radiation (200–400 nm) up to 12 kJ m−2, both in suspension and in a desiccated form.
火星模拟环境是地球上最极端的环境之一。它们独特的多种极端组合(例如高盐度、缺氧和低营养可用性)使它们成为寻找新的多极端微生物和探索生命极限的宝贵来源。火星,尤其是它的表面,仍然被认为是非常不适合生命的,但它可能拥有地下地质环境,在那里(多极端)生命的出现是可以想象的。尽管它们具有公认的相关性,但目前关于(兼性)厌氧微生物承受地外/火星条件的能力的知识,无论是作为单个菌株还是在群落中,仍然非常稀少。因此,需要利用空间作为天体生物学研究的工具,模拟火星环境条件的空间实验来证实火星可居住的假设。解决这一知识差距是MEXEM(火星暴露极端微生物混合物)项目的主要目标之一,在该项目中,选定的模式生物将在太空中进行为期3个月的研究。这些实验将在位于国际空间站外的外太空生物学设施(目前正在开发和实施中)进行。这种空间实验需要对选定的微生物菌株进行一系列初步试验和地面数据收集。在此,我们报道了Salinisphaera shabanensis和Buttiauxella sp. MASE-IM-9暴露于火星相关应激因子(如干燥和缺氧下的紫外线辐射)后的生存能力。这两种生物在缺氧干燥后都能存活3个月,但通过添加人造火星风化层(MGS-1S;0.5% wt/v)和蔗糖(0.1 M)。在处理前将两种微生物混合,也观察到干燥后的存活率。混合也对暴露于多色火星样紫外线辐射(200-400 nm)高达12 kJ m - 2后的存活产生积极影响,无论是悬浮形式还是干燥形式。
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引用次数: 3
Reaching out to early-career astrobiologists: AbGradE's actions and perspectives 接触早期职业天体生物学家:AbGradE的行动和观点
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-03-18 DOI: 10.1017/S1473550422000040
Philippe Nauny, A. Cassaro, N. Kopacz, L. Noack, Hayk Palabikyan, Silvana Pinna, Alex Price, Hector A. Stavrakakis, R. Taubner
Abstract Astrobiology Graduates in Europe (AbGradE, pronounced ab-grad-ee) is an association of early-career scientists working in fields relevant to astrobiological research. Conceptualized in 2013, it was initially designed as a mini-conference or workshop dedicated to early-career researchers, providing a friendly environment where early-career minds would be able to present their research without being intimidated by the possibility of facing a more traditional audience, composed mainly of senior scientists. Within the last couple of years, AbGradE became the first point of call for European, but also for an increasing number of non-European, early-career astrobiologists. This article aims to present how AbGradE has evolved over the years (in its structure and in its way of organizing events), how it has adapted with the COVID-19 pandemic, and what future developments are considered.
欧洲天体生物学毕业生(AbGradE,发音为ab-grad-ee)是一个由从事天体生物学相关研究领域的早期职业科学家组成的协会。它于2013年提出概念,最初被设计为一个专门针对早期职业研究人员的小型会议或研讨会,提供一个友好的环境,让早期职业人员能够展示他们的研究,而不会因为面对主要由资深科学家组成的更传统的观众的可能性而感到害怕。在过去的几年里,AbGradE成为欧洲人的首选,但也吸引了越来越多的非欧洲的、早期职业的天体生物学家。本文旨在介绍AbGradE多年来的演变(其结构和组织活动的方式),如何适应COVID-19大流行,以及考虑了未来的发展。
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引用次数: 1
Computer simulations of biotic chiral selection scenarios 生物手性选择场景的计算机模拟
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-03-14 DOI: 10.1017/S147355042200009X
S. Longo, Carmela Mundo, G. Micca Longo
Abstract The biotic scenario of the selection of biological homochirality is one of the most interesting applications of computer modelling to astrobiology. These scenarios have been studied for more than 70 years, yet there are plenty of studies to better assess them, in particular in the development of models of the selective extinction process. In this paper, we review former studies performed by biology-grounded models of this process and present a new class of computer programs: they further demonstrate the complexity of the selective extinction dynamics and the role played into it by non-trivial chemical-physical concepts. Indeed, the results display large and persistent differences between the populations of the two different chiral types, made possible by the freedom of individual populations to fluctuate wildly while the total population is stabilized by the limited availability of chemical energy. Such strong differences ultimately lead to the selective extinction of one of the two types. This way, computer simulations provide increasing evidence in favour of the biotic scenario.
生物同手性选择的生物场景是计算机建模在天体生物学中最有趣的应用之一。这些情景已经被研究了70多年,但仍有大量的研究可以更好地评估它们,特别是在选择性灭绝过程模型的发展中。在本文中,我们回顾了以前的研究,这些研究是基于这一过程的生物学模型,并提出了一类新的计算机程序:它们进一步证明了选择性灭绝动力学的复杂性,以及非平凡的化学物理概念在其中所起的作用。事实上,结果显示两种不同手性类型的种群之间存在巨大而持久的差异,这是由于个体种群的自由波动很大,而总体种群由于有限的化学能而稳定。这种强烈的差异最终导致两种类型中的一种选择性灭绝。通过这种方式,计算机模拟提供了越来越多的证据,支持生物的设想。
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引用次数: 1
Survival of Xanthoria parietina in simulated space conditions: vitality assessment and spectroscopic analysis 黄原菌在模拟空间条件下的存活:活力评估和光谱分析
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-03-08 DOI: 10.1017/s1473550422000076
Christian Lorenz, E. Bianchi, R. Benesperi, S. Loppi, A. Papini, G. Poggiali, J. Brucato
Xanthoria parietina is a widespread foliose lichen growing on barks and rocks showing a broad spectrum of tolerance to air pollutants such as NOX and heavy metals, and resistance to UV-radiation because of the screening properties provided by the secondary metabolite parietin. The aim of this study was to evaluate the ability of this lichen species to survive in the following simulated space conditions, UV-radiation in N2 atmosphere and UV-radiation in vacuum. The efficiency of the photosynthetic apparatus was used as an indicator of vitality, and was expressed in terms of chlorophyll a fluorescence (FV/FM) and Normalized Difference Vegetation Index (NDVI), which were measured within 72 h from the exposure. Additionally, during the irradiation, the IR reflectance spectrum of the lichen was monitored in situ to assess changes in spectral bands. The results showed significant differences in physiological recovery trends between the treatments, highlighting that UV-radiation in vacuum causes stronger effects on FV/FM values. The IR analysis revealed several spectral band changes in the fingerprint region. The most visible variation was the 5200 cm−1 water band that disappeared in the overtone region. Nevertheless, X. parietina was able to survive UV-radiation in N2 atmosphere and in vacuum, and for this reason it may be considered a candidate for further evaluations on its survival capacity in extreme conditions.
parietina黄病菌(Xanthoria parietina)是一种生长在树皮和岩石上的广泛生长的毛叶苔藓,由于其次生代谢物parietin提供的筛选特性,对NOX和重金属等空气污染物具有广泛的耐受性,并对紫外线辐射具有抗性。本研究的目的是评估该地衣物种在模拟空间条件下的生存能力,即氮气大气和真空环境下的紫外线辐射。叶绿素a荧光(FV/FM)和归一化植被指数(NDVI)是在暴露后72 h内测量的,以光合机构的效率作为活力指标。此外,在辐照过程中,原位监测地衣的红外反射光谱,评估光谱波段的变化。结果表明,不同处理间的生理恢复趋势存在显著差异,表明真空紫外线辐射对FV/FM值的影响更大。红外光谱分析显示指纹区有多个光谱带变化。变化最明显的是5200 cm−1水带在泛音区消失。然而,X. parietina能够在N2大气和真空中存活紫外线辐射,因此它可以被认为是进一步评估其在极端条件下生存能力的候选者。
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引用次数: 2
Intelligence as a planetary scale process – CORRIGENDUM 作为行星尺度过程的智能。勘误表
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-03-02 DOI: 10.1017/s1473550422000088
Adam Frank, D. Grinspoon, S. Walker
© The Author(s), 2022. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited. International Journal of Astrobiology (2022), 21:2 62 doi:10.1017/S1473550422000088
©作者,2022。剑桥大学出版社出版。这是一篇开放获取的文章,在知识共享署名许可(http://creativecommons.org/licenses/by/4.0/)的条款下分发,该许可允许不受限制的重复使用、分发和复制,前提是原始文章被适当引用。国际天体生物学杂志(2022),21 (2):62 doi:10.1017/S1473550422000088
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引用次数: 0
Von Neumann probes: rationale, propulsion, interstellar transfer timing 冯·诺伊曼探测器:原理,推进,星际转移时间
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-02-28 DOI: 10.1017/S1473550422000027
G. Matloff
Abstract A Von Neumann probe is a self-reproducing intelligent device with interstellar capabilities. A space-faring civilization could conceivably use such constructs to occupy much or all of the Milky Way galaxy and perhaps the entire universe. This paper presents several reasons that a civilization might decide to produce and deploy Von Neumann probes. Physically possible interstellar propulsion methods for such devices are discussed, as is a launch strategy minimizing the duration of an interstellar transfer. Various solar system locations could be investigated to determine whether Von Neumann probes are present in our vicinity.
冯·诺伊曼探测器是一种具有星际能力的自我复制智能装置。可以想象,一个太空文明可以使用这样的结构来占领银河系的大部分或全部,甚至整个宇宙。本文提出了一个文明可能决定生产和部署冯·诺伊曼探测器的几个原因。讨论了这种装置在物理上可能的星际推进方法,以及最小化星际转移持续时间的发射策略。可以对太阳系的不同位置进行调查,以确定冯·诺伊曼探测器是否在我们附近。
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引用次数: 3
AbGradCon 2021: lessons in digital meetings, international collaboration, and interdisciplinarity in astrobiology AbGradCon 2021:数字会议、国际合作和天体生物学跨学科的经验教训
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-02-24 DOI: 10.1017/S1473550422000258
Tony Z. Jia, Kristin N. Johnson-Finn, Osama M. Alian, I. Bonati, K. Fujishima, N. Grefenstette, T. Heenatigala, Yamei Li, Natsumi Noda, Petar I. Penev, Paula Prondzinsky, Harrison B. Smith
The Astrobiology Graduate Conference (AbGradCon) is an annual conference both organized for and by early-career researchers, postdoctoral fellows, and students as a way to train the next generation of astrobiologists and develop a robust network of cohorts moving forward. AbGradCon 2021 was held virtually on 14-17 September 2021, hosted by the Earth-Life Science Institute (ELSI) of Tokyo Institute of Technology after postponement of the in-person event in 2020 due to the COVID-19 pandemic. The meeting consisted of presentations by 120 participants from a variety of fields, two keynote speakers, and other career-building events and workshops. Here, we report on the organizational and executional aspects of AbGradCon 2021, including the meeting participant demographics, various digital aspects introduced specifically for a virtual edition of the meeting, and the submission and evaluation process. The evaluation process of AbGradCon 2021 is unique in that all evaluations are done by the peers of the applicants, and as astrobiology is inherently a broad discipline, the evaluation process revealed a number of trends related to multidisciplinarity of the astrobiology field. We believe that meetings like AbGradCon can provide a unique opportunity for students and early career researchers in astrobiology to experience community building, inter- and multidisciplinary collaboration, and career training and would be a welcome sight in other fields as well. We hope that this report provides inspiration and a basic roadmap for organizing future conferences in any field with similar goals.
天体生物学研究生会议(AbGradCon)是一个由早期职业研究人员、博士后研究员和学生组织的年度会议,旨在培养下一代天体生物学家,并建立一个强大的团队网络。AbGradCon 2021于2021年9月14日至17日以虚拟方式举行,由东京工业大学地球生命科学研究所(ELSI)主办。由于2019冠状病毒病大流行,2020年的现场活动被推迟。会议包括来自不同领域的120名参与者的演讲,两位主题演讲者,以及其他职业建设活动和研讨会。在这里,我们报告AbGradCon 2021的组织和执行方面,包括会议参与者的人口统计数据,专门为会议的虚拟版本介绍的各种数字方面,以及提交和评估过程。AbGradCon 2021的评估过程是独一无二的,因为所有的评估都是由申请人的同行完成的,而且由于天体生物学本身是一门广泛的学科,评估过程揭示了天体生物学领域多学科性的一些趋势。我们相信,像AbGradCon这样的会议可以为天体生物学的学生和早期职业研究人员提供一个独特的机会,让他们体验社区建设、跨学科和多学科合作以及职业培训,并且在其他领域也会受到欢迎。我们希望本报告为今后在任何具有类似目标的领域组织会议提供启发和基本路线图。
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引用次数: 0
On possible life-dispersal patterns beyond the Earth 关于地球以外可能的生命扩散模式
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-02-15 DOI: 10.1017/S1473550421000379
A. Kovačević
The assumption that exoplanets are ‘in equilibrium’ with their surroundings has not given way to life's transmissivity on large spatial scales. The spread of human diseases and the life recovery rate after mass extinctions on our planet, on the other hand, may exhibit spatial and temporal scaling as well as distribution correlations that influence the mappable range of their characteristics. We model hypothetical bio-dispersal within a single Galactic region using the stochastic infection dynamics process, which is inspired by these local properties of life dispersal on Earth. We split the population of stellar systems into different categories regarding habitability and evolved them through time using probabilistic cellular automata rules analogous to the model. As a dynamic effect, we include the existence of natural dispersal vectors (e.g. dust, asteroids) in a way that avoids assumptions about their agency (i.e. questions of existence). Moreover, by assuming that dispersal vectors have a finite velocity and range, the model includes the parameter of ‘optical depth of life spreading’. The effect of the oscillatory infection rate ( $b( t,; , d)$ ) on the long-term behaviour of the dispersal flux, which adds a diffusive component to its progression, is also taken into account. The life recovery rate ( $g( t,; , d)$ ) was only included in the model as a link to macrofaunal diversity data, which shows that all mass extinctions have a 10 Myr ‘speed rate’ in diversity recovery. This parameter accounts for the repopulation of empty viable niches as well as the formation of new ones, without ruling out the possibility of genuine life reemergence on other habitable worlds in the Galaxy that colossal extinctions have sterilized. All life-transmission events within the Galactic patch have thus been mapped into phase space characterized by parameters $b$ and $g$ . We found that phase space is separated into subregions of long-lasting transmission, rapidly terminated transmission, and a transition region between the two. We observed that depending on the amplitude of the oscillatory life-spreading rate, life-transmission in the Galactic patch might take on different geometrical shapes (i.e. ‘waves’). Even if some host systems are uninhabited, life transmission has a certain threshold, allowing a patch to be saturated with viable material over a long period. Although stochastic fluctuations in the local density of habitable systems allow for clusters that can continuously infect one another, the spatial pattern disappears when life transmission is below the observed threshold, so that transmission process is not permanent in time. Both findings suggest that a habitable planet in a densely populated region may remain uninfected.
系外行星与其周围环境“处于平衡”的假设并没有让位于大空间尺度上的生命透过率。另一方面,人类疾病的传播和我们星球上大规模灭绝后的生命恢复速度可能表现出空间和时间尺度以及分布相关性,从而影响其特征的可绘制范围。我们利用随机感染动力学过程在单个银河系区域内模拟假设的生物扩散,这是受到地球上生命扩散的这些局部特性的启发。我们根据宜居性将恒星系统分成不同的类别,并使用类似于该模型的概率元胞自动机规则随着时间的推移对它们进行演化。作为一种动态效应,我们以一种避免对其代理(即存在问题)的假设的方式包括自然扩散向量(例如尘埃,小行星)的存在。此外,通过假设传播向量具有有限的速度和范围,该模型包含了“生命传播的光学深度”参数。振荡感染率($b(t,;, d)$)也考虑了扩散通量的长期行为,它在其进程中增加了扩散分量。寿命回收率($g(t,;, d)$)只是作为与大型动物多样性数据的链接而包含在模型中,这些数据表明,所有大灭绝在多样性恢复方面都有10兆元的“速度”。这个参数考虑了空的可行生态位的重新繁殖以及新生态位的形成,不排除在银河系中其他可居住的星球上真正的生命重新出现的可能性,这些星球已经被大规模的灭绝灭绝了。因此,银河系斑块内的所有生命传输事件都被映射到以参数$b$和$g$为特征的相空间中。我们发现相空间被分为持久传输、快速终止传输和两者之间的过渡区域。我们观察到,根据振荡生命传播速率的振幅,银河系斑块中的生命传播可能呈现不同的几何形状(即“波”)。即使一些寄主系统是无人居住的,生命传播也有一定的阈值,允许一个补丁在很长一段时间内充满可存活的物质。虽然可居住系统的局部密度的随机波动允许集群可以不断地相互感染,但当生命传播低于观察到的阈值时,空间格局就消失了,因此传播过程在时间上不是永久的。这两项发现都表明,在人口稠密地区的宜居行星可能不会受到感染。
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引用次数: 0
Intelligence as a planetary scale process 智能是一个行星规模的过程
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-02-07 DOI: 10.1017/s147355042100029x
Adam Frank, David Grinspsoon, S. Walker
Conventionally, intelligence is seen as a property of individuals. However, it is also known to be a property of collectives. Here, we broaden the idea of intelligence as a collective property and extend it to the planetary scale. We consider the ways in which the appearance of technological intelligence may represent a kind of planetary scale transition, and thus might be seen not as something which happens on a planet but to a planet, much as some models propose the origin of life itself was a planetary phenomenon. Our approach follows the recognition among researchers that the correct scale to understand key aspects of life and its evolution is planetary, as opposed to the more traditional focus on individual species. We explore ways in which the concept may prove useful for three distinct domains: Earth Systems and Exoplanet studies; Anthropocene and Sustainability studies; and the study of Technosignatures and the Search for Extraterrestrial Intelligence (SETI). We argue that explorations of planetary intelligence, defined as the acquisition and application of collective knowledge operating at a planetary scale and integrated into the function of coupled planetary systems, can prove a useful framework for understanding possible paths of the long-term evolution of inhabited planets including future trajectories for life on Earth and predicting features of intelligentially steered planetary evolution on other worlds.
传统上,智力被视为个人的财产。然而,它也被认为是集体的财产。在这里,我们扩大了智慧作为集体财产的概念,并将其扩展到全球范围。我们认为,技术智能的出现可能代表着一种行星尺度的转变,因此可能被视为不是发生在行星上的事情,而是发生在行星上的事情,就像一些模型认为生命的起源本身是一种行星现象一样。我们的方法遵循了研究人员的认识,即理解生命及其进化的关键方面的正确尺度是行星,而不是更传统地关注单个物种。我们探索了这一概念在三个不同领域可能被证明有用的方法:地球系统和系外行星研究;人类世与可持续性研究;以及技术签名和搜寻外星智慧(SETI)的研究。我们认为,对行星智能的探索,被定义为在行星尺度上操作的集体知识的获取和应用,并整合到耦合行星系统的功能中,可以证明是一个有用的框架,用于理解可居住行星长期进化的可能路径,包括地球上生命的未来轨迹,以及预测其他世界上智能引导的行星进化的特征。
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引用次数: 23
Physical and chemical mechanisms that impact the detection, identification, and quantification of organic matter and the survival of microorganisms on the Martian surface – a review 影响火星表面有机物检测、鉴定和定量以及微生物生存的物理和化学机制——综述
IF 1.7 4区 物理与天体物理 Q2 Physics and Astronomy Pub Date : 2022-01-31 DOI: 10.1017/S1473550421000392
E. Bak, P. Nørnberg, S. Jensen, Jan Thøgersen, K. Finster
Abstract The iconic Viking Landers that landed on Mars in 1976 demonstrated that the Martian surface is an extreme place, dominated by high UV fluxes and regolith chemistry capable of oxidizing organic molecules. From follow-on missions, we have learned that Mars was much warmer and wetter in its early history, and even some areas of Mars (such as crater lakes, possibly with sustained hydrothermal activity) were habitable places (e.g. Grotzinger et al. (2014). Science (New York, N.Y.) 343; Mangold et al. (2021). Science (New York, N.Y.). However, based on the Viking results we have learnt that the search for life and its remains is challenged by abiotic breakdown and alteration of organic material. In particular, the harsh radiation climate at the Martian surface that directly and indirectly could degrade organics has been held accountable for the lack of organics in the Martian regolith. Recent work simulating wind-driven erosion of basalts under Mars-like conditions has shown that this process, comparable to UV- and ionizing radiation, produces reactive compounds, kills microbes and removes methane from the atmosphere. and thereby could equally jeopardize the success of life-seeking missions to Mars. In this review, we summarize and discuss previous work on the role of physical and chemical mechanisms that affect the persistence of organics, and their consequences for the detection of life and/or its signatures in the Martian regolith and in the atmosphere.
摘要1976年登陆火星的标志性维京登陆者证明,火星表面是一个极端的地方,主要由高紫外线通量和能够氧化有机分子的风化层化学组成。从后续任务中,我们了解到,火星在其早期历史上要温暖潮湿得多,甚至火星的一些区域(如火山口湖,可能有持续的热液活动)也是宜居之地(例如Grotzinger等人(2014)。《科学》(纽约,纽约)343;Mangold等人(2021)。科学(纽约,纽约)。然而,根据维京人的研究结果,我们了解到,寻找生命及其遗迹受到非生物分解和有机物质变化的挑战。特别是,火星表面恶劣的辐射气候可能直接或间接降解有机物,这被认为是火星风化层缺乏有机物的原因。最近模拟类似火星条件下玄武岩风力侵蚀的工作表明,这一过程与紫外线和电离辐射相当,可以产生活性化合物,杀死微生物,并从大气中清除甲烷。从而同样可能危及火星生命探索任务的成功。在这篇综述中,我们总结并讨论了以前关于影响有机物持久性的物理和化学机制的作用,以及它们对探测火星风化层和大气中的生命和/或其特征的影响的工作。
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引用次数: 1
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International Journal of Astrobiology
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