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2012 Annual Science Report

Astrobiology Roadmap Objective 2.1 Reports Reporting  |  SEP 2011 – AUG 2012

Project Reports

  • Advancing Methods for the Analyses of Organics Molecules in Sediments

    Eigenbrode’s astrobiological research focuses on understanding the formation and preservation of organic and isotopic sedimentary records of ancient Earth, Mars, and icy bodies. To this end, and as part of GCA’s Theme IV effort, Eigenbrode seeks to overcome sampling and analytical challenges associated with organic analyses of astrobiology relevant samples with modification and development of contamination tracking, sampling, and analytical methods (primarily GCMS) that improve the recovery of meaningful observations and provide protocol guidance for future astrobiological missions.

    ROADMAP OBJECTIVES: 2.1 4.1 7.1
  • Habitability of Icy Worlds

    Habitability of Icy Worlds investigates the habitability of liquid water environments in icy worlds, with a focus on what processes may give rise to life, what processes may sustain life, and what processes may deliver that life to the surface. Habitability of Icy Worlds investigation has three major objectives. Objective 1, Seafloor Processes, explores conditions that might be conducive to originating and supporting life in icy world interiors. Objective 2, Ocean Processes, investigates the formation of prebiotic cell membranes under simulated deep-ocean conditions, and Objective 3, Ice Shell Processes, investigates astrobiological aspects of ice shell evolution.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.3 3.4 4.1 5.1 6.1 6.2 7.1 7.2
  • Cosmic Distribution of Chemical Complexity

    The three tasks of this project explore the connections between chemistry in space and the origin of life. We start by tracking the formation and evolution of chemical complexity in space, from simple carbon-rich molecules such as formaldehyde and acetylene to complex species including amino acids, nucleic acids and polycyclic aromatic hydrocarbons. The work focuses on carbon-rich species that are interesting from a biogenic perspective and on understanding their possible roles in the origin of life on habitable worlds. We do this by measuring the spectra and chemistry of analog materials in the laboratory, by remote sensing with small spacecraft, and by analysis of extraterrestrial samples returned by spacecraft or that fall to Earth as meteorites. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.4 4.3 7.1 7.2
  • Astrobiological Exploration of Mars

    MIT Team member John Grotzinger is the Project Scientist of the MSL mission currently underway at Gale Crater on Mars. John, and his team at Caltech, led a major study of potential landing sites which resulted in the selection of Gale Crater. Since then, they have been involved in the Gale Imaging Working Group, which has been identifying key HiRISE and CRISM data products, which will enhance the science mission. Several members of the Grotzinger group have also been involved in creating a geologic map of the landing site. This involves mapping 1.5° square quads in the landing ellipse and nearby areas. Since landing, the mapping focus has shifted from compiling a regional map to understanding the details of the units and geological relationships in the immediate vicinity of Curiosity.

  • Disks and the Origins of Planetary Systems

    This task is concerned with the formation and evolution of complex habitable environments. The planet formation process begins with fragmentation of large molecular clouds into flattened disks. This disk is, in many ways, an astrochemical “primeval soup” in which cosmically abundant elements are assembled into increasingly complex organic compounds and mixed in the dust and gas within the disk. Gravitational attraction among the myriad small bodies leads to planet formation. If the newly formed planet is a distance from its star that is suitable to support liquid water at the surface, it is in the so-called “habitable zone” (HZ). The formation process and identification of such life-supporting bodies is the goal of this project.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.3
  • Biosignatures in Extraterrestrial Settings

    Exploring the prospects for biosignatures in extraterrestrial settings is a multi

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 4.1 4.3 6.2 7.1 7.2
  • Detectability of Life

    Detectability of Life investigates the detectability of chemical and biological signatures on the surface of icy worlds, with a focus on spectroscopic techniques, and on spectral bands that are not in some way connected to photosynthesis.Detectability of life investigation has three major objectives: Detection of Life in the Laboratory, Detection of Life in the Field, and Detection of Life from Orbit.

    ROADMAP OBJECTIVES: 1.2 2.1 2.2 4.1 5.3 6.1 6.2 7.1 7.2
  • Mineralogical Traces of Early Habitable Environments

    The goal of our work is to understand how habitability (potential to support life) varies across a range of physical and chemical parameters, in order to support a long-term goal of characterizing habitability of environments on Mars. The project consists of two main components: 1. We are examining the interplay between physicochemical environments and associated microbial communities in a subsurface environment dominated by serpentinization (a reaction that involves water and crustal rocks, and which occurred on early Mars as indicated by observations of surface mineralogy). 2. We are working to understand how mineral assemblages can serve as a lasting record of prior environmental conditions, and therefore as indicators of prior habitability. This component directly supports the interpretation of mineralogy data obtained by the CheMin instrument on the Mars Science Laboratory.

  • Project 1D: Establishing Biogenicity and Environmental Setting of Precambrian Kerogen and Microfossils

    This study demonstrates new abilities to use in situ measurements of carbon isotope ratios in microfossil kerogen as a biosignature and to establish taxonomic and micro-structural correlations.

    ROADMAP OBJECTIVES: 2.1 4.1 5.1 5.2 6.1 7.1
  • Path to Flight

    The (Field Instrumentation and) Path to Flight investigation’s purpose is to enable in-situ measurements of organics and biological material with field instrumentation that have high potential for future flight instrumentation. The preceding three Investigations (Habitability, Survivability and Detectability) provide a variety of measurable goals that are used to modify or “tune” instrumentation that can be placed in the field. In addition the members involved with Investigation provide new measurement capabilities that have been developed with the specific goal of life-detection and organic detection using both non-contact/non-destructive means and ingestion based methods. The developments under this investigation (Inv 4) incorporate state-of-the-art laboratory instruments and next generation in-situ instrumentation that have been developed under programs that include NASA as well as NSF and DOD. These include mass-spectrometers, gas analyzers, and fluorescence/Raman spectrometry instruments.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 7.1 7.2
  • Project 5: Vistas of Early Mars: In Preparation for Sample Return

    To understand the history of life in the solar system requires knowledge of how hydrous minerals form on planetary surfaces, and the role minerals may play in the development of potential life forms. The minerals hematite and jarosite have been identified on Mars and presented as in situ evidence for aqueous activity. This project seeks to understand (i) the conditions required for jarosite and hematite formation and preservation on planetary surfaces, and (ii) the conditions under which their “radiometric clocks” can be reset (e.g., during changes in environmental conditions such as temperature). By investigating the kinetics of noble gases in minerals, known to occur on Mars and Earth, we will be prepared to analyze and properly interpret ages measured on samples from future Mars sample return missions.

    ROADMAP OBJECTIVES: 1.1 2.1 7.1
  • Habitability of Water-Rich Environments, Task 1: Improve and Test Codes to Model Water-Rock Interactions

    The new computer codes could be used to calculate changes in phase composition during freezing or melting in cold icy environments on Mars, large water-bearing asteroids, icy moons of giant planets, comets, and other trans-neptunian objects. Another model will allow us to calculate composition of liquid hydrocarbons on the surface of Titan.

  • Stellar Radiative Effects on Planetary Habitability

    Habitable environments are most likely to exist in close proximity to a star, and hence a detailed and comprehensive understanding of the effect of the star on planetary habitability is crucial in the pursuit of an inhabited world. We looked at how the Sun’s brightness would have changed with time providing wavelength-dependent scaling factors for solar flux anywhere in the solar system from 0.6 to 6.7Gyr. Extrasolar planetary systems can only be determined through studying the host star; therefore we have also worked on determining the ages of Kepler planet host stars. We have constructed far ultraviolet to mid-infrared stellar spectra for 44 stars for being used as input in climate and photochemical models that are applied for determining habitable zones and possible characteristics of habitable planets. We have looked into the effect of methane (CH4) and hydrogen (H2) on the outer edge of the habitable zone for F, G, and M stars. We have studied the effect of host star stellar energy distribution (SED) and ice-albedo feedback on the climate of extrasolar planets.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 4.1 4.3 7.2
  • The Subglacial Biosphere – Insights Into Life-Sustaining Strategies in an Extraterrestrial Analog Environment

    Sub-ice environments are prevalent on Earth today and are likely to have been more prevalent the Earth’s past during episodes of significant glacial advances (e.g., snow-ball Earth). Numerous metabolic strategies have been hypothesized to sustain life in sub-ice environments. Common among these hypotheses is that they are all independent of photosynthesis, and instead rely on chemical energy. Recently, we demonstrated the presence of an active assemblage of methanogens in the subglacial environment of an Alpine glacier (Boyd et al., 2010). The distribution of methanogens is narrowly constrained, due in part to the energetics of the reactions which support this functional class of organism (namely carbon dioxide reduction with hydrogen and acetate fermentation). Methanogens utilize a number of metalloenzymes that have active site clusters comprised of a unique array of metals. During the course of this study, we identified other features that were suggestive of other active and potentially relevant metabolic strategies in the subglacial environment, such as nitrogen cycling. The goals of this project are 1) identifying a suite of biomarkers indicative of biological CH4 production 2). quantifying the flux of CH4 from sub-ice systems and 3). developing an understanding how life thrives at the thermodynamic limits of life. This project represents a unique extension of the ABRC and bridges the research goals of several nodes, namely the JPL-Icy Worlds team and the ASU-Follow the Elements team.

    ROADMAP OBJECTIVES: 2.1 2.2 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Project 2F: Potential for Lithotrophic Microbial Oxidation of Fe(II) in Basalt Glass

    Ferrous iron (Fe(II)) can serve as an energy source for a wide variety of chemolithotrophic microorganisms (organisms that gain energy from metabolism of inorganic compounds). Fe(II) oxidation may have played a role in past (and possibly, present) life on Mars, whose crust is rich in primary Fe(II)-bearing silicate minerals, as well as Fe-bearing clay minerals formed during weathering of primary silicates. This project examined the potential for microbial oxidation of Fe(II) in basaltic glass. Recent research suggests that near‐surface hydrothermal venting may have occurred during past periods of active volcanic/tectonic activity on Mars. Such activities could have produced basalt glass phases that might have served as energy sources for chemolithotrophic microbial activity. Previous and ongoing NAI‐supported studies have shown that an established chemolithoautotrophic Fe(II)‐oxidizing, nitrate‐reducing culture can grow by oxidation of Fe(II) insoluble Fe(II)‐bearing phyllosilicate phases such as biotite and smectite. The initial goal of this project was to determine whether or not this culture is capable of oxidizing Fe(II) in basalt glass. In addition we tested basaltic glass oxidation by a culture of Desulfitobacterium frappieri, as previous studies demonstrated that D. frappieri is capable of nitrate-dependent oxidation of structural Fe(II) in smectite. Finally, in situ and enrichment culturing experiments were conducted to determine whether indigenous Fe(II)-oxidizing organisms in a groundwater iron seep were capable of colonization and oxidation of basaltic glass. The results of these experiments showed that while the various cultures were readily capable of smectite oxidation with nitrate, none were able to carry-out significant oxidation of Fe(II) in basalt glass. We speculate that Fe(II) atoms in the amorphous glass are somehow occluded and therefore not accessible to outer membrane cytochrome systems thought to be involved in extracellular Fe(II) oxidation.

    ROADMAP OBJECTIVES: 2.1 5.1 5.3
  • Habitability of Water-Rich Environments, Task 4: Evaluate the Habitability of Ancient Aqueous Solutions on Mars

    As a member of the MSL Science team, Prof. Farmer actively supported surface operations of the Mars Science Laboratory rover Curiosity at JPL throughout the first 90 days of the mission (ongoing). During this time he offered a videocon-based upper division/graduate level course from JPL each week. (GLG 455/598: Advanced Field Geology – The MSL Mission Live from Mars). 
Prof. Farmer also completed a Raman-based study of sulfate evaporites to assess the biosignature preservation potential of this important Mars analog rock type. The work was done in collaboration with J.W. Schopf at UCLA and was published last Spring in the journal, Astrobiology. With Dr. Steve Ruff (Research Assoc., ASU), Prof. Farmer continued terrestrial analog studies in Yellowstone National Park and at Mauna Loa, Hawaii, to understand sulfate- and silica-precipitating hydrothermal systems documented at Home Plate in the Columbia Hills of Gusev Crater, Mars in 2011.

    Prof. Zolotov developed models to predict the clay mineralogy of Mawrth Vallis, a potential future landing site for Mars astrobiology. His work suggested that this region of Mars has experienced extensive acidic weathering under a low rock:water ratio. His work also provided insights into the nature of potentially habitable subsurface environments at Mawrth Vallis.

  • Project 3B: In Situ S Isotope Studies in Archean-Proterozoic Sulfides

    Studies of sulfur isotopes constrain atmospheric and marine conditions in the Paleoproterozoic and Archean. We have developed capabilities for analysis of all four sulfur isotopes, including the rarest isotope (36-S) in situ by ion microprobe. In general sulfur 4 isotope data from Archean sulfides fall on the reference array for mass independent fractionation that was established by earlier bulk measurements. Small deviations from the array are resolved and likely result from biological or environmental forcings.

    ROADMAP OBJECTIVES: 2.1 4.1 5.2 6.1 7.1
  • Understanding the Early Mars Environment

    There is no liquid water on modern Mars, although there is plenty of solid ice. Observations from orbiting satellites and rovers on the ground suggest that liquid water may have flowed over the Martian surface in the distant past. VPL researchers are studying the geologic record of Mars for clues of past water, and investigating climate and chemical conditions under which water would be stable. Team members examined different climate feedbacks and geochemical processes that could have warmed the early Mars. Some members are also active members of the MSL science team.

  • Measuring Interdisciplinarity Within Astrobiology Research

    To integrate the work of the diverse scientists working on astrobiology, we have harvested and analyzed thousands of astrobiology documents to reveal areas of potential connection. This framework allows us to identify crossover documents that guide scientists quickly across vast interdisciplinary libraries, suggest productive interdisciplinary collaborations, and provide a metric of interdisciplinary science.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 3.3 3.4 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Permafrost in Hawaii

    Permanent ice can be found on the Hawaiian Islands at extremely few locations and as a result of microclimates. Ice exists in the form of permafrost in craters near the summit of Mauna Kea and in form of ice lakes in lava tubes on Mauna Loa; they are the world’s most isolated ice caves. We investigate the microclimates on the high summits of the Hawaiian Islands that serve as possible analogues to Mars. Exploratory fieldwork has been carried out at four field sites and interdisciplinary collaborations have been developed.

    ROADMAP OBJECTIVES: 2.1 5.3 6.2
  • Remote Sensing of Organic Volatiles in Planetary and Cometary Atmospheres

    In the last year, we have greatly advanced our capabilities to model spectra of cometary and planetary atmospheres (Villanueva et al. 2012a, 2012b). Using these newly developed analytical methods, we derived the most comprehensive search for biomarkers on Mars (Villanueva et al. 2012, submitted) from our extensive database of high-quality Mars spectra. Furthermore, we retrieved molecular abundances of several comets (Villanueva et al. 2012c, Gibb et al. 2012, Paganini et al. 2012a/b), and of several young circumstellar disks (Mandell et al. 2012). These great advancements have allowed us to understand the infrared spectrum of planetary bodies and their composition with unprecedented precision.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 3.2 7.1 7.2
  • Project 4A: Field Analog Geology and Astrobiology in Support of Mars Science Laboratory and Future Mars Surface Missions

    In 2011 we have characterized the mineralogy, organic compounds and microbiology of selected sample sites from desert areas of Utah in the vicinity of MDRS in Hanksville (Foing et al. 2011). The samples were partly analyzed in situ and later distributed to the various laboratories for post-analysis. Among the important findings of this field research campaign in the Utah desert are the diversity in the mineralogical composition of soil samples even when collected in close proximity, the low abundances of detectable polycyclic aromatic hydrocarbons (PAHs) and amino acids, and the presence of biota of all three domains of life with significant heterogeneity (Ehrenfreund et al., 2011). As a follow up study EuroMoonMars campaigns in February-March 2012 collected new samples from the area around the Mars Desert Research Station (MDRS) in Utah, (Canyonlands area), a region known for its geomorphological and geochemical similarity to Mars.

  • Project 4E: Preliminary Studies of Fe Isotope Biogeochemistry in Fe-Rich Yellowstone National Park Hot Springs

    This preliminary project provided background information for future studies of the structure, function, and signatures (living and non-living) of Fe redox-based microbial life in the volcanic terrain of Yellowstone National Park (YNP). The focus on Fe redox-based systems stems from our expanding knowledge of the wide range of microbial energy metabolisms that are known to be associated with Fe redox transformations on Earth and potentially on other planets. Moreover, Fe redox transformations provide the potential for generation of mineralogical, isotopic, and organic biosignatures of past and present microbial life, which represent premier targets for testing the hypothesis that life currently exists or existed in the past on Mars. Preliminary data on Fe geochemistry and isotopic composition, and microbial community composition, was obtained for two contrasting Fe-rich springs in YNP: Chocolate Pots (CP), a warm, circumneutral environment that has formed on top of the Pleistocene-age Lava Creek Tuff, where a mixture of Fe-rich acid-sulfate geothermal fluids and neutral-pH groundwater from the Gibbon River catchment emerge to the surface; and The Gap site, a hot, acid-sulfate spring in the Norris Basin which supports active chemolithotrophic Fe(II) oxidation, analogous to other hot spring environments in YNP. The geochemical data demonstrated significant changes in aqueous Fe abundance and/or speciation along the flow paths at both sites, leading to accumulation of abundant Fe(III) oxides as well as aqueous Fe(III) at the acidic Gap site. A distinct separation in Fe isotope composition between aqueous Fe and deposited Fe(III) oxides (mainly amorphous Fe-Si coprecipitates) was also detected, with the oxide enriched in 56Fe relative to 54Fe as expected for redox-driven Fe isotope fractionation. However, the degree of fractionation was less the value of ca. 3 ‰ expected in closed system at isotope equilibrium. We suggest that internal regeneration of Fe(II) via dissimilatory Fe(III) reduction could enrich the aqueous Fe(II) pool in the heavy isotope, leading a much lower degree of Fe isotope fractionation – and hence a fundamentally different pattern of Fe isotope fractionation – than would occur in a strictly Fe(II) oxidation-driven reaction system. In support of this argument, an initial set of culturing experiments designed to recovery thermophilic Fe(III)-reducing organisms from CP and Gap materials resulted in the recovery of active Fe(III) reducers from both sites. In addition, preliminary pyrosequencing of 16S rRNA genes recovered from Gap solids provide evidence for Fe(III) reduction potential by the resident microflora. Particularly in the case of the Gap, sequences related to known Archaeal fermenters and elemental S/Fe(III) oxide reducers were abundant.

    ROADMAP OBJECTIVES: 2.1 5.1 5.3
  • Project 5A: Improvement in the Accuracy of Stable Isotope Analysis by Laser Ablation

    In-situ isotopic analyses are critical for documenting spatial heterogeneities that can be related to the petrography of a sample. In the last decade, recognition of the power of in-situ analysis has spurred development of instrumentation that has improved the precision of in-situ isotopic analysis to unprecedented levels. With this improved precision, it is necessary to critically re-evaluate accuracy in order to identify true heterogeneities form analytical artifacts. We have evaluated the accuracy of in-situ Fe isotope analyses by femto second laser ablation (fs-LA) by evaluating the size and Fe isotope composition of aerosol particles generated by fs-LA, and to evaluate if fs-LA isotope analysis is free of matrix effects. Aerosols produced by fs-LA are small with ~70% of the particles, by mass of Fe, less than 100 nm in aerodynamic diameter, highlighting that the fs-LA particles can be effectively ionized by the plasma. By isotopic mass balance, the aerosols are a stoichiometric sample of the substrate, however, the smallest sized particles have light 56Fe/54Fe isotope compositions and the larger sized particles have heavy 56Fe/54Fe isotope compositions, which highlights the importance of quantitative transport of the aerosol by the ICP source. Matrix studies that include introduction of elements into the fs-LA aerosol by a desolvating nebulizer coupled with isotope analysis of iron oxide standards with variable chemical compositions suggest that matrix effects are driven by space charge processes where elements with low atomic Z relative to Fe such as Mg, and Si have no effects on the accuracy of the analysis but elements with a similar or higher Z such as Mn or U can produce accuracy issues on the order of +0.5 ‰ in δ56Fe.

    ROADMAP OBJECTIVES: 2.1 4.1 7.1 7.2