2009 Annual Science Report

Astrobiology Roadmap Objective 7.1 Reports Reporting  |  JUL 2008 – AUG 2009

Project Reports

  • Cosmic Distribution of Chemical Complexity

    This project seeks to improve our understanding of the connection between chemistry in space and the origin of life on Earth and possibly other worlds. Our approach is to trace the formation and development of chemical complexity in space, with particular emphasis on understanding the evolution from simple to complex species focusing on those that are interesting from a biogenic perspective and also understanding their possible roles in the origin of life on habitable worlds. We do this by first measuring the spectra and chemistry of materials under simulated space conditions in the laboratory. We then use these results to interpret astronomical observations made with ground-based and orbiting telescopes. We also carry out experiments on simulated extraterrestrial materials to analyze extraterrestrial samples returned by NASA missions or that fall to Earth in meteorites.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.4 4.3 7.1 7.2
  • Biosignatures in Ancient Rocks

    The Earth’s Archean and Proterozoic eons offer the best opportunity for investigating a microbial world, such as might be found elsewhere in the cosmos. The ancient record on Earth provides an opportunity to see what geochemical signatures are produced by microbial life and how these signatures are preserved for geological time. Researchers have recognized a variety of mineralogical and geochemical characteristics in ancient rocks (sedimentary and igneous rocks; paleosols) that may be used as indicators of: (i) specific types of organisms that lived in the oceans, lakes and on land; and (ii) their environmental conditions (e.g., climate; atmospheric and oceanic chemistry). Our project addresses the following questions: Are some or all of these characteristics true or false signatures of organisms and/or indicators of specific environmental conditions? Do a “biosignature” in a specific geologic formation represent a local or global phenomenon? How are the biosignatures on Mars and other planets expected to be similar to (or different from) those in ancient terrestrial rocks?

    ROADMAP OBJECTIVES: 1.1 3.2 4.1 4.2 4.3 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Biomimetic Cluster Synthesis: Bridging the Structure and Reactivity of Biotic and Abiotic Iron-Sulfur Motifs

    Synthetic approaches are being utilized to bridge the gap between Fe-S minerals and highly evolved biological Fe-S metalloenzymes. These studies are focusing on organic template (protein) mediated cluster assembly (biomineralization), probing properties of synthetic clusters, both as homogeneous and heterogeneous catalysts, investigating the impact of size scale on the properties of synthetic Fe-S clusters, and computational modeling of the structure and catalytic properties of synthetic Fe-S nanoparticles in the 5-50 nm range.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2
  • Astrobiology of Icy Worlds

    Icy worlds such as Titan, Europa, Enceladus, and others may harbor the greatest volume of habitable space in the Solar System. For at least five of these worlds, considerable evidence exists to support the conclusion that oceans or seas may lie beneath the icy surfaces. The total liquid water reservoir within these worlds may be some 30 to 40 times the volume of liquid water on Earth. This vast quantity of liquid water raises two questions: Can life emerge and thrive in such cold, lightless oceans beneath many kilometers of ice? And if so, do the icy shells hold clues to life in the subsurface? We will address these questions through four major investigations namely, the habitability, survivability, and detectability of life of icy worlds coupled with “Path to Flight” Technology demonstration. We will also use a wealth of existing age-appropriate educational resources to convey concepts of astrobiology, spectroscopy, and remote sensing; develop standards-based, hands-on activities to extend the application of these resources to the search for life on icy worlds.

    ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 3.3 3.4 4.1 5.1 5.3 6.1 6.2 7.1 7.2
  • NAI ORAU Post Doc Report: CIW-NAI
    ROADMAP OBJECTIVES: 3.1 3.2 7.1
  • AbGradCon 2009

    The Astrobiology Graduate Student Conference (AbGradCon) was held on the UW campus July 17 – 20 2009. AbGradCon supports NAI’s mission to carry out, support and catalyze collaborative, interdisciplinary research, train the next generation of astrobiology researchers, provide scientific and technical leadership on astrobiology investigations for current and future space missions, and explore new approaches using modern information technology to conduct interdisciplinary and collaborative research amongst widely-distributed investigators. This was done through a diverse range of activities, ranging from formal talks and poster sessions to free time for collaboration-enabling discussions, social activities, web 2.0 conference extensions, public outreach and grant writing simulations.

    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
  • AIRFrame Technical Infrastructure and Visualization Software Evaluation

    To create visualizations of interdisciplinary relationships in the field of astrobiology, this component of the AIRFrame project involves creating a data model for source documents, a database structure, and evaluating off-the-shelf visualization software for possible application to the final project.

    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
  • Advancing Methods for the Analyses of Organics Molecules in Microbial Ecosystems

    Eigenbrode’s GCA work over the past year has largely focused on advancing protocols for the extraction and analysis of complex organics molecules in iron-oxide rich samples regarded as analogs to groundwater seeps and ancient surface water environments on Mars and ancient Earth. Eigenbrode has succeeded with some advance in methods for organic extraction and analysis for samples that include iron seep sediments, cultured iron bacteria, and terrace sediments of the Rio Tinto. In addition, Eigenbrode has been part of a successful study aimed at understanding microbial metabolisms and ecological evolution of Neoarchean using Fe, S, and C isotopic records.

    ROADMAP OBJECTIVES: 2.1 4.1 5.1 5.2 5.3 6.1 7.1
  • Computational Chemical Modeling the Link Between Structure and Reactivity of Iron-Sulfur Motifs

    Traditionally, the iron-sulfur mineral catalysis, iron-sulfur enzyme catalysis, and biomimetic thrust areas of ABRC have their own unique ways to probe the structure/function relationships at the surface defect sites, at the enzymatic active sites, or at the interface of biomacromolecular and iron-sulfur particle layers, respectively. Computation chemistry can provide a cohesive link among these thrust areas through bridging the enzymatic/mineral catalysis and molecular structure/chemical reactivity via fundamental physico-chemical properties at the molecule level.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 7.1 7.2
  • Chemolithotrophic Microbial Oxidation of Insoluble Fe(II)-Bearing Minerals

    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). Thought to be one of the oldest forms of microbial metabolism on Earth, Fe(II) oxidation may also have played a role in past (and possibly, present) life on Mars, whose crust is rich in Fe(II)-bearing silicate minerals (e.g. ultramafic basalt rocks). The initial goal of this project is to determine whether an established chemolithoautotrophic Fe(II)-oxidizing, nitrate-reducing culture can grow by oxidation of Fe(II) in basalt glass. Preliminary experiments suggest that the culture is able to oxidize a significant portion of the Fe(II) content of fresh basalt glass from Kilauea, a shield volcano in Hawaii that represents an analog for ancient volcanic activity on Mars.

    ROADMAP OBJECTIVES: 4.1 6.1 7.1
  • Amino Acid Alphabet Evolution

    All life on earth uses a standard “alphabet” of just 20 amino acids. Members of this alphabet links together into different sequences to form proteins that then interact to produce living metabolism (rather like the English of 26 letters can be linked into words that interact in sentences and paragraphs to produce meaningful writing). However, a wealth of scientific research from diverse disciplines points to the idea that many other amino acids are made by non-biological processes throughout the universe: put simply, we have no idea why life has “chosen” the members of its standard alphabet. Our project seeks to gather and organize the disparate information that describes these non-biological amino acids, to understand their properties and potential for making proteins and thus to understand better whether the biology that we know is a clever, predictable solution to making biology – or just one of countless possible solutions that may exist elsewhere.

    ROADMAP OBJECTIVES: 1.1 3.1 3.2 3.4 4.1 4.3 5.1 5.3 6.2 7.1 7.2
  • Evolution of Nitrogen Fixation, Photosynthesis, Hydrogen Metabolism, and Methanogenesis

    We have developed a new line of investigation to complement our work on the biochemistry of complex iron-sulfur cluster enzyme structure, function and biosynthesis with the aim of probing complex iron-sulfur enzyme evolution. We are studying the phylogenetic trajectory of multiple genes involved in complex iron-sulfur cluster function and biosynthesis to probe the evolutionary origin of aspect of hydrogen metabolism and modes of biological nitrogen fixation.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Project 2: Origin and Evolution of Organic Matter in the Solar System

    Through telescopic observations of remote objects, we are learning about the distribution of organic matter in the outer Solar System and how it is thermally processed, as well as about dynamic processes that .could have delivered such organic-rich material to be incorporated into terrestrial planets. Extraterrestrial samples like primitive meteorites and interplanetary dust particles contain significant amounts of carbonaceous material and were likely a source of organic matter to the early Earth. By using a wide variety of advanced techniques to study organic matter in meteorites and other extraterrestrial samples, we are trying to learn how and where it formed, and how it has been modified during 4.5 billion years of solar system evolution. We also perform laboratory experiments to simulate formation of complex organic matter and how it is modified on planetary surfaces. Finally we are studying biological contamination of meteorites once they have landed on Earth to learn how this can affect studies of the indigenous non-biological organic matter.

    ROADMAP OBJECTIVES: 2.2 3.1 7.1
  • Co-Evolution of Microbial Metabolisms in the Neoarchean and Paleoproterozoic

    The interplay between the biosphere, lithosphere, hydrosphere, and atmosphere has produced a complex evolution of microbial metabolisms that significantly affect the geochemical and mineralogical compositions of surface environments. One approach to tracing the evolution of very ancient microbial metabolisms is through studies of the isotopic compositions of elements that are cycled by life and preserved in the rock record. The Neoarchean and Paleoproterozoic (~3.1 to 2.4 billion years ago) record very large changes in C, S, and Fe isotope compositions in marine sedimentary rocks that are interpreted to reflect an explosion in microbial diversity, including establishment of oxygenic and anaerobic photosynthesis, aerobic methanotrophy, methanogenesis, and dissimilatory sulfate and iron reduction. The ecosystems on Earth in the Neoarchean and Paleoproterozoic juxtaposed oxidized and reduced environments, reflecting unique conditions during the time leading up to the first significant increase in atmospheric oxygen at ~2.4 b.y. ago.

    ROADMAP OBJECTIVES: 4.1 5.1 6.1 7.1
  • Biosignatures in Relevant Microbial Ecosystems

    In this project, PSARC team members explore the isotope ratios, gene sequences, minerals, organic biomarkers, and other biosignatures in modern ecosystems that function as analogs for early earth ecosystems, or for life that may be present elsewhere in the solar system and beyond. Many of these environments are “extreme” by human standards and/or have conditions that are at the limit for microbial life on Earth.

    ROADMAP OBJECTIVES: 4.1 4.3 5.1 5.2 5.3 6.1 7.1 7.2
  • Advancing Techniques for in Situ of Complex Organics

    During this year we continued developing techniques and protocols for laser time-of-flight mass spectrometry (TOF-MS) analysis of complex organic molecules and trace elements, which would be of importance on missions to Mars, Titan, comets, and other planetary bodies, where resources for chemical sample manipulation, preparation, and processing are limited. We upgraded the solid sampling and optical configurations for our “Tower TOF” prototype and used the system to further develop peak pattern libraries for Mars and cometary analogs in comparison with other instrument techniques. We examined the effects of sample preparation on fragmentation patterns of benzene di-, tri-, and hexa-carboxylic acid standards, finding that often simpler approaches can yield more reliable results. We also worked toward a new laser pyrolysis-based experiment for analysis of neutral gas from solid samples.

    ROADMAP OBJECTIVES: 2.1 2.2 7.1
  • Molecular Beam Studies of Nitrogen Reactions on Iron-Sulfur Surfaces

    It is generally accepted that surface-mediated reactions occur on defect sites. The role of defects in the formation of ammonia is being systematically evaluated using molecular beam-surface scattering experiments in which a hydrogen atom plasma source (deuterium due to easier detection) is used to hydrogenate a pyrite surface. The hydrogenated surface is subsequently bombarded with a molecular beam of energetic nitrogen molecules and the conversion of nitrogen to products, such as ammonia is probed through mass spectrometry.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2
  • Astrobiology Progress Report

    Scientists at the Cosmic Ice Laboratory with the Goddard Center for Astrobiology study the formation and stability of molecules under conditions found in outer space. During the past year, amino acids found in meteorites were investigated, including some acids not found in terrestrial biology. Investigations into the photostability of glycine under Martian conditions, and environments in the outer solar system, were begun. A project on ethane ice’s spectra and chemistry was initiated. All of this work is part of the Comic Ice Laboratory’s continuing contributions to understanding the chemistry of biologically-related molecules and chemical reactions in extraterrestrial environments.

    ROADMAP OBJECTIVES: 3.1 3.2 7.1
  • Developing New Biosignatures

    The development and experimental testing of potential indicators of life is essential for providing a critical scientific basis for the exploration of life in the cosmos. In microbial cultures, potential new biosignatures can be found among isotopic ratios, elemental compositions, and chemical changes to the growth media. Additionally, life can be detected and investigated in natural systems by directing cutting-edge instrumentation towards the investigation of microbial cells, microbial fossils, and microbial geochemical products. Over the next five years, we will combine our geomicrobiological expertise and on-going field-based environmental investigations with a new generation of instruments capable of revealing diagnostic biosignatures. Our efforts will focus on creating innovative approaches for the analyses of cells and other organic material, finding ways in which metal abundances and isotope systems reflect life, and developing creative approaches for using environmental DNA to study present and past life.

    ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.4 4.1 5.2 5.3 7.1 7.2
  • Bioastronomy 2007 Meeting Proceedings

    The 9th International Bioastronomy coneference: Molecules, Microbes and Extraterrestrial Life was organized by Commission 51 (Bioastronomy) of the International Astronomical Union, and by the UH NASA Astrobiology team. The meeting was held in San Juan, Puerto Rico from 16-20 July 2007. During the reporting period the Proceedings were finalized and will have a publication date of 2009.

    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
  • Evolution of Organic Matter in Space: UV-vis Spectroscopy Investigation on Nanosatellites

    The “Organics” experiment (PI: P. Ehrenfreund) was integrated in March 2009 on the International Space Station ISS. This experiment exposes specific PAHs and fullerene compounds for one year on-board the ISS. Laboratory measurements of the samples after retrieval will greatly enhance our understanding of the evolution of large molecules in space. A new generation of free-fliers and small satellites is also poised to enable in situ monitoring of changes to organic materials induced by space conditions. To optimize the scientific pay-off from frequent low-cost missions, the development of robust and capable in situ measurement technology is essential. We have investigated a research and technology program that includes 1) ground-based monitoring of EXPOSE-R samples in a simulated space environment, 2) development of a laboratory prototype UV-Vis spectrometer for in situ measurements of organic material on future free-fliers and lunar surface exposure facilities, and 3) detailed characterization of the prototype’s performance via in situ spectral measurements of control EXPOSE-R samples versus time in a simulated space
    environment, in direct comparison with a reference laboratory spectrometer. The research program combines the expertise and facilities of two NAI teams (Wisconsin and ARC) and addresses the key objectives of the Astrobiology Small Payloads (ASP) program, as well as Astrobiology Roadmap Goal 3 on cosmic and planetary precursors.

    ROADMAP OBJECTIVES: 3.1 7.1
  • CASS Planning

    The computational astrobiology summer school (CASS) is a two week program, followed by a semester of mentored independent work, which has the following goals:

    - To introduce computer science and engineering (CS&E) graduate students to the field of astrobiology, – To introduce astrobiologists to the tools and techniques that current methods in CS&E can provide, and – To encourage interdisciplinary projects that will result in advances in astrobiology.

    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
  • 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 these minerals play in the development of potential life forms. One hydrous mineral found on Earth and inferred from in situ measurements on Mars, is the mineral Jarosite, KFe3(SO4)2(OH)6. We are investigating whether radiometric ages, specifically 40Ar/39Ar ages on jarosite can be interpreted to accurately record climate change events on Mars. This project not only requires understanding the conditions required for jarosite formation and preservation on planetary surfaces, but also assessing under what conditions its “radiometric clock” can be reset (e.g., during changes in environmental conditions such as temperature). By studying jarosites formed by a variety of processes on Earth, we will be prepared to analyze and properly interpret ages measured from jarosite obtained from future Mars sample return missions.

    ROADMAP OBJECTIVES: 1.1 2.1 7.1
  • Project 5: Geological-Biological Interactions

    This project focuses on a wide range of questions spanning understanding microbial diversity in extreme environments to the identification of biosignatures in modern and ancient rocks. In terms of environments, research in this project focuses on research at deep sea hydrothermal vents, desert sulfate deposits, arctic hydrothermal fields, as well as Paleoproterozoic terrains of Australia, Canada, and India. By learning more how life adapts to extreme environments on Earth, we hope to gain a better understanding of the limits of life on other worlds. By understanding better the signature of life recorded in ancient rocks, we hope to better refine our search stategies for the presence of life on other worlds.

    ROADMAP OBJECTIVES: 4.1 5.1 6.1 6.2 7.1
  • Probing the Structure and Nitrogen Reduction Activity of Iron-Sulfur Minerals

    Iron-sulfur compounds are common in both biological and geological systems. The adaptation of Fe-S clusters from the abiotic world to the biological world may have been an early event in the development of life on Earth and possibly a common feature of life elsewhere in the universe. The iron-sulfur mineral thrust of the ABRC is focused on examining the structure and reactivity of FeS minerals using nitrogen fixation as a model reaction.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 7.1 7.2
  • Extra-Cellular Polymeric Substances as Armor Against Cell Membrane Rupture on Mineral Surfaces

    Our interdisciplinary project examined the hypotheses that bacterial cell membranes are ruptured in contact with specific mineral surfaces, and that biofilm-forming extra-cellular polymeric substances (EPS) may have evolved to shield against membrane rupture (cell lysis). Furthermore, we proposed that mineral reactivity towards membranolysis should depend on its surface properties such as charge, reactive area, or free radicals generated by radiation and impacts on early Earth, Mars, and other worlds. The effect of EPS on preservation in the rock record will also be examined. By understanding the mechanisms for membranolysis, especially under the extreme conditions of high radiation and heavy impacts during early planetary history, the project addresses the NASA Astrobiology Institute’s (NAI) Roadmap goals of understanding the origins of cellularity, the evolution of mechanisms for survival at environmental limits, and preservation of biosignatures, and NASA’s Strategic Goal of advancing scientific knowledge of the origin and evolution of the Earth’s biosphere and the potential for life elsewhere.

    ROADMAP OBJECTIVES: 3.4 5.1 7.1
  • Chemistry, Origin and Evolution of Subduction Zone Fluids Rising Beneath the Mariana Forearc

    Ultramafic rocks make up the mantle of most rocky bodies in the Solar System. When ultramafic rocks come in contact with liquid water they are altered to serpentinite over a wide range of temperatures, from freezing to about 500ºC. On Earth, plate tectonics provides ample opportunity for this contact to occur, especially in subduction zones. In extraterrestrial environments, serpentinization should occur wherever liquid water comes into contact with mantle-type rocks, such as on Mars and on the parent bodies of asteroids. We have collected waters upwelling through serpentinite mud volcanoes in the forearc region of the Mariana subduction zone in the NW Pacific Ocean. These waters are rich in methane produced inorganically during serpentinization. The methane supports chemosynthetic communites of extremophilic Archaea that thrive at an in-situ pH of 13.1.

    ROADMAP OBJECTIVES: 5.3 7.1
  • Iron Isotope Biosignatures: Laboratory Studies and Modern Environments

    The isotopic fingerprints of biological carbon and sulfur cycling in modern and ancient marine environments is well established by research over several decades, but, until recently, potential iron isotope fingerprints of microbial iron cycling in the ancient Earth have not been pursued. Next to carbon, iron was probably the most important element cycled by early life, given the high abundance of iron in early Earth environments and the energy gains that may be obtained by microbes during iron redox changes. Our new laboratory studies moved away from simple systems to those more analogous to nature, and we demonstrated that iron isotope fractionations can be produced by biological cycling in complex systems. Moreover, in a field study, we isolated natural iron cycling microbes and demonstrated that the iron isotope fractionations produced by natural microbial ecosystems are the same as those produced by pure strains in the laboratory; these are key components to confidently applying Fe isotopes as a biosignature for ancient life.

    ROADMAP OBJECTIVES: 2.1 4.1 5.2 6.1 7.1 7.2
  • Structure, Function, and Biosynthesis of the Complex Iron-Sulfur Clusters at the Active Sites of Nitrogenases and Hydrogenases

    Iron-sulfur clusters are thought to be among the most ancient cofactors in living systems. The iron-sulfur enzyme thrust is focused on examining the structure, mechanism, and biosynthesis of the complex Fe-S enzymes nitrogenase and hydrogenase. Biochemical, biophysical, and structure biology approaches are being employed to provide insights into complex iron-sulfur biosynthesis to establish paradigms for complex iron-sulfur cluster biosynthesis that can be placed in the context of the evolution of iron-sulfur motifs from the abiotic to biotic systems.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 6.1 6.2 7.1 7.2
  • Subglacial Methanogenesis and Its Role in Planetary Carbon Cycling

    Methanogens are thought to be among the earliest emerging life forms. Today, 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. The goals of this project are 1) identifying a suite of biomarkers indicative of biological CH4 production 2). quantifying the flux of CH~4~ 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 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Viral Ecology and Evolution

    This project is aimed at probing the occurrence and evolution of archaeal viruses in the extreme environments in the thermal areas in Yellowstone National Park. Viruses are the most abundant life-like entities on the planet and are likely a major reservoir of genetic diversity for all life on the planet and these studies are aimed at providing insights into the role of viruses in the evolution of early life on Earth.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1 7.2
  • Microbial Pyrite Oxidation in Nature and the Lab: Sulfate Mineral Biosignature Investigation

    Deposits of minerals containing the chemical species sulfate, a constituent of ocean water, have been identified on the surface of Mars. Although there might be other methods for its formation, the process we are investigating is one that occurs on Earth and is the result of the metabolic activity of microbes, which oxidize the iron sulfide mineral pyrite (Fool’s Gold) to form sulfate. We have made the oxygen in water in a bacterial culture medium traceable by addition of a non-radioactive isotopic tracer and can thus differentiate oxygen from the atmosphere, used by biological processes, from oxygen in water, used by the non-biological processes. Our new data and approaches defy conventional wisdom, and offer a novel way for investigating the origin of sulfates on Mars by in situ instruments.

    ROADMAP OBJECTIVES: 2.1 7.1
  • New Frontiers in Micro-Analysis of Isotopic Compositions of Natural Materials: Development of Fe Isotopes

    We are developing micro-analytical techniques to perform in situ Fe isotope analysis of Fe-bearing minerals by ion microprobe and laser ablation mass spectrometry. Iron isotope compositions are important signatures in tracking redox processes, chemical weathering, and dissimilatory iron reduction by bacteria. In situ micro analysis procedures will allow us to better apply the Fe isotope system by allowing one to determine Fe isotope compositions within a petrographic framework, minimize sample requirements, evaluate microscale heterogeneity, and inter-mineral isotopic equilibrium. Such in situ procedures are critical for analysis of samples that may be returned from future space missions or for analysis by instruments that can be deployed on space craft.

    ROADMAP OBJECTIVES: 2.1 4.1 7.1 7.2
  • New Frontiers in Micro-Analysis of Isotopic Compositions of Natural Materials: Development of O, S, Si, and Li Isotopes

    The isotope ratios of oxygen and silicon are a sensitive monitor of sedimentary and hydrothermal processes for deposition of banded iron formation. Our focus on banded iron formations reflects the importance these unusual units have in biogeochemical cycling in the early Earth. In particular, we are examining the deposition of microlaminated sections of the Dales Gorge member of the Brockman Iron Formation from the Hamersley basin, which have alternatively been interpreted to represent annual varves in chemical precipitates from seawater, or variations in a sub-surface hydrothermal system. These conflicting models have relevance for interpreting the role of microbial life in precipitation of the Fe-oxides. In addition, δ18O and δ34S values from coexisting minerals can be used to estimate the temperature of the Archean ocean, or of the hydrothermal system. Values of δ7Li and δ18O in zircons allow these tests to be applied to magmas that may have assimilated sedimentary materials, and in the case of pre-4 Ga Jack Hills zircons from SW Australia, provide a record of the earliest Earth before the formation of all known rocks.

    ROADMAP OBJECTIVES: 4.1 7.1
  • Production of Mixed Cation Carbonates in Abiologic and Biologic Systems

    Carbonate minerals commonly occur on Earth and they are found in extraterrestrial materials such as meteorites and interplanetary dust particles. The chemistry of carbonates provides clues about their formation and alteration of over time. For example, carbonate minerals that form inorganically have chemical compositions that are highly constrained by the environmental conditions under which they grow, however, it is now known that microorganisms can produce carbonates that deviate from these generally accepted patterns. As such, when carbonate minerals are placed in the appropriate environmental context, certain compositions may represent a biosignature for microbially mediated formation. The goal of this project is to develop a broader understanding of how carbonate minerals grow so that we may formulate explicit criteria for their origin based on their chemical and isotopic composition.

    ROADMAP OBJECTIVES: 4.1 7.1
  • Research Activities in the Astrobiology Analytical Laboratory

    A little over 4.5 billion years ago, our solar system was a disk of gas and dust, newly collapsed from a molecular cloud, surrounding a young and growing protostar. Today most of the gas and dust is in the spectacularly diverse planets and satellites of our solar system, and in the Sun. How did the present state of the planetary system come to be from such undistinguished beginnings? The telling of that story is an exercise in forensic science. The “crime” occurred a long time ago and the “evidence” has been tampered with, as most planets and satellites display a rich variety of geological evolution over solar system history.

    Fortunately, not all material has been heavily processed. Comets and asteroids represent largely unprocessed material remnant from the early solar system and they a represented on Earth by meteorites and interplanetary dust particles (IDPs). Furthermore, telescopic studies of the birth places of other solar systems allow researchers to simulate those environments in the laboratory so that we may characterize the organic material produced.

    We are a laboratory dedicated to the study of organic compounds derived from Stardust and future sample return missions, meteorites, lab simulations of Mars, interstellar, proto-planetary, and cometary ices and grains, and instrument development. Like forensic crime shows, the Astrobiology Analytical Laboratory employs commercial analytical instruments. However, ours are configured and optimized for small organics of astrobiological interest instead of blood, clothing, etc.

    ROADMAP OBJECTIVES: 3.1 4.3 7.1
  • Stoichiometry of Life, Task 1: Laboratory Studies in Biological Stoichiometry

    Living things require a broad menu of chemical elements to function. This project aims to quantify the chemical elements required by prokaryotes – the class of terrestrial organisms thought most similar to those that might be present in extraterrestrial settings – through laboratory experiments. These experiments will also teach us the ways in which such organisms cope with scarcity of the bioessential elements nitrogen, phosphorus and iron. We are also conducting experiments to isolate micro-organisms that use the element arsenic in place of phosphorus, if they exist. In Year 1 we initiated the first stage of these experiments.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1
  • The Role of Dissolved Sulfide in Controlling Carbonate Mineral Compositions

    Role of microbes in dolomite formation is still under debate. It was proposed that sulfate-reducing bacteria (SRB) can results in dolomite precipitation. We investigated the role of dissolved sulfide (a product of SRB metabolism) in controlling carbonate mineral compositions and even dolomite crystallization at low temperatures. Our results show that very high-magnesium calcite (VHMC) and disordered dolomite can precipitate from aqueous sulfide-bearing solutions at low temperature.

    ROADMAP OBJECTIVES: 4.1 7.1 7.2
  • Mineral-Catalyzed Coupling of Amino Acids to Polypeptides

    Enzymes carry out chemical functions within our body, and are produced from long chains of amino acids called polypeptides. Today, the manufacture of these long chains is made possible within our bodies by large 'machinery’ known as polymerases. However, these are vastly complex, and were almost certainly not present in the early stages of life. One question we are trying to answer here is whether or not it is possible to produce long chains of polypeptides under certain conditions which may be relevant to the origin of life, such as on the surface of a mineral.

    ROADMAP OBJECTIVES: 3.1 3.2 7.1 7.2
  • Quantification of the Disciplinary Roots of Astrobiology

    The questions of astrobiology span many scientific fields. This project analyzes databases of scientific literature to determine and quantify the diverse disciplinary roots of astrobiology. This is one component of a wider study to build a map of relationships between the constituent fields of astrobiology, so relevant knowledge in diverse fields can be most efficiently inform the study of life in the universe.

    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
  • Rare Subduction Zone Carbonate Mineral May Hold Clues to Early Life

    Recent work performed by Erik Melchiorre as part of a NASA Minority
    Institution Research Sabbatical indicates that the rare purple mineral
    stichtite Mg6Cr2[(OH)16|CO3] . 4H2O may provide a record of
    the carbon, hydrogen and ocygen isotope values of serpentizing fluids
    from ancient subduction zones. This could be of significant interest
    in the study of methane signatures on Mars, as well as the study of
    early life on Earth.

    ROADMAP OBJECTIVES: 4.1 4.3 7.1 7.2