2011 Annual Science Report

Astrobiology Roadmap Objective 6.2 Reports Reporting  |  SEP 2010 – AUG 2011

Project Reports

  • AIRFrame Technical Infrastructure and Visualization Software Evaluation

    We have analyzed over four thousand astrobiology articles from the scientific press, published over ten years to search for clues about their underlying connections. This information can be used to build tools and technologies that guide scientists quickly across vast, interdisciplinary libraries towards the diverse works of most relevance to them.

    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
  • 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
  • Amino Acid Alphabet Evolution

    We study the question why did life on this planet “choose” a set of 20 standard building blocks (amino acids) for converting genetic instructions into living organisms? The evolutionary step has since been used to evolve organisms of such diversity and adaptability that modern biologists struggle to discover the limits to life-as-we-know-it. Yet the standard amino acid alphabet has remained more or less unchanged for 3 billion years.
    During the past year, we have found that the sub-set of amino acids used by biology exhibits some surprisingly simple, strikingly non-random properties. We are now building on this finding to solidify a new insight into the emergence of life here, and what it can reveal about the distribution and characteristics of life elsewhere in the universe.

    ROADMAP OBJECTIVES: 3.1 3.2 4.1 4.2 4.3 5.2 5.3 6.2 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 5.3 6.1 6.2 7.1 7.2
  • Analogue Environment Deployments on the Big Island

    We are using the saddle region on the Big Island of Hawaii, in collaboration with NASA teams and the Canadian Space Agency in order to test technology related to sustainable living on the moon. My group will evaluate the utility of 3-D visualization in robotic navigation, in particular for the ex-ploration of lava tubes.

    ROADMAP OBJECTIVES: 1.1 2.1 4.1 4.3 6.1 6.2 7.1
  • 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 over geologic time. As part of our integrated plan, we will study geochemical, isotopic, and sedimentary signatures of life in order to understand the context in which these biosignatures formed.

    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
  • Biosignatures in Extraterrestrial Settings

    The focus of this project is to explore indicators of life outside of Earth, both within the Solar System and on extrasolar planets. The work includes studies of the chemistry and composition of the Solar System, and the past history of conceivable sites for life in the Solar System. We also look for habitable planets outside the Solar System; work on developing new techniques to find and observe potentially habitable planets; and model the dynamics, evolution and current status of a variety of extrasolar planets.

    ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 4.1 4.3 6.2 7.1 7.2
  • Project 5: Geological-Biological Interactions

    This project involves multiple researchers exploring life in extreme environments, the signature of life (chemical, isotopic and mineralogical), and the adaption of life. All together the many sub-topics of this project seek to inform us about where to search for life on other worlds and how to seek evidence that life once existed on other worlds.

    ROADMAP OBJECTIVES: 4.1 5.1 6.1 6.2 7.1
  • Evolution of Metabolism

    Our astrobiology research focus for VPL is to understand the evolution of different metabolic groups of microorganisms during the course of Earth’s history, and how the emergence of different metabolisms, such as methanogenesis, anoxic and oxygenic photosynthesis, and other anaerobic metabolisms that involve sulfur, metal, and nitrogen could effect the chemical composition of the atmosphere.

    ROADMAP OBJECTIVES: 5.1 5.3 6.2
  • Deep (Sediment-Buried Basement) Biosphere

    The ocean crust comprises the largest aquifer on earth. Deep sediment cover provides an environ-ment for a unique biosphere hosting microorganisms surviving under extreme conditions. Frac-tured rock provides abundant surfaces that can be colonized by diverse microbes and water-rock reactions promote chemical conditions that influence key geochemical cycles within the Earth’s crust and oceans. Team members participated in a 14-day research cruise to study the sediment-buried basement (basaltic crust) biosphere, to provide unprecedented and unique insight into the mobility and origin of microorganisms within this remote biosphere.

    ROADMAP OBJECTIVES: 4.1 4.2 5.2 5.3 6.1 6.2 7.1 7.2
  • Modelling Planetary Albedo & Biomarkers in Rocky Planets’/moons Spectra

    Using data from Kepler and new ground-based detections, Lisa Kaltenegger and Dimitar Sasselov have identified which confirmed and candidate planets orbit within the Habitable Zone and could provide environments for basic and complex life to develop. They have also developed atmosphere models for extrasolar planetary environments for different geological cycles and varied environments for the advent of complex life. The team modeled detectable spectral features that identify such planetary environments for future NASA missions like the James Webb Space Telescope.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 6.2 7.2
  • Postdoctoral Fellow Report: Steven Mielke

    This project seeks to resolve the long-wavelength limit of oxygenic photosynthesis in order to constrain the range of extrasolar environments in which spectral signatures of biogenic oxygen might be found, and thereby guide future planet detecting and characterizing observatories.

    ROADMAP OBJECTIVES: 5.1 6.1 6.2 7.2
  • Ice Chemistry Beyond the Solar System

    The molecular inventory available on the prebiotic Earth was likely derived from both terrestrial and extraterrestrial sources. Many molecules of biological importance have their origins via chemical processing in the interstel-lar medium, the material between the stars. Polycyclic aromatic hydrocarbons (PAHs) and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block, the aromatic ben¬zene molecule, has remained elusive for decades. Formamide represents the simplest molecule contain-ing the peptide bond. Conse¬quently, the formamide molecule is of high interest as it is considered as an important precursor in the abiotic synthesis of amino acids, and thus significant to further prebiotic chemistry, in more suitable environments. Ultra-high vacuum low-temperature ice chem-istry experiments have been conducted to understand the formation pathways in the ISM for many astrobiologcally important molecules.

    ROADMAP OBJECTIVES: 1.1 1.2 3.1 3.2 3.3 6.2 7.1
  • Stromatolites in the Desert: Analogs to Other Worlds

    In this task biologists go to field sites in Mexico to better understand the environmental effects on growth rates for freshwater stromatolites. Stromatolites are microbial mat communities that have the ability to calcify under certain conditions. They are believed to be an ancient form of life, that may have dominated the planet’s biosphere more than 2 billion years ago. Our work focuses on understanding these communities as a means of characterizing their metabolisms and gas outputs, for use in planetary models of ancient environments.

    ROADMAP OBJECTIVES: 4.1 4.2 5.2 5.3 6.1 6.2
  • The Subglacial Biosphere – Insights Into Life-Sustaining Strategies in an Extraterrestrial Analog Environment

    Sub-ice environments are prevalant 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
  • Ice Chemistry of the Solar System

    The overall goals of this project are to understand the chemical evolution of the Solar System, in particular leading to the development of astrobiologically important molecules. This is being achieved by investigation the formation of key organic carbon-, hydrogen-, oxygen-, and nitrogen-bearing (CHON) molecules in ices of Kuiper belt objects by reproducing the space environment experimentally in a unique ultra-high vacuum surface scattering machine. During this reporting period, our team worked on six projects towards our research goal to better understand the ice-based astrochemistry of chemical synthesis for carbon-containing compounds within the solar system. The Keck Astrochemistry Laboratory was also completed during this reporting period.

    ROADMAP OBJECTIVES: 1.1 2.2 3.1 3.2 3.3 6.2 7.1
  • 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
  • The Long Wavelength Limit for Oxygenic Photosynthesis

    Photosynthesis is process where plants and bacteria use solar energy to produce sugar and oxygen. It is also the only known process that produces signs of life (biosignatures) on a planetary scale. And, because starlight (or solar energy) is one of the most common sources of energy, it is expected that photosynthesis will be successful on habitable extrasolar planets. Our team is studying how photosynthetic pigments – the molecules that make photosynthesis possible – might function in unique or extreme environments on other planets. In our experiments, we use a bacteria called Acaryochloris marina to study how different photosynthetic pigments work. This bacterium is useful for our research because it uses a pigment known as chlorophyll d instead of chlorophyll a, which is more common on our planet. Chrolophyll a works well in Earth’s environment but, by studying chlorophyll d, we can begin to understand how photosynthesis might work on planets with different environments than Earth. So far, our research is revealing that photosynthesis can occur quite efficiently in environments that are very different from our planet.

    ROADMAP OBJECTIVES: 3.2 4.2 5.1 5.3 6.2 7.2
  • Stoichiometry of Life – Task 1 – Laboratory Studies in Biological Stoichiometry

    This project component involves a diverse set of studies of various microorganisms with which we are trying to better understand how living things use chemical elements (nitrogen, phosphorus, iron, etc) and how they cope, in a physiological sense, with shortages of such elements. For example, how does the “elemental recipe of life” change when an organism is starved for phosphorus? Is this change similar for diverse species of microorganisms? Are the changes the same if the organism is limited by a different key nutrient? Furthermore, how does an organism shift its patterns of gene expression when it is starved by various nutrients? This will help in interpreting studies of gene expression in natural environments. At an even more profound level: can an organism substitute an element that is similar to the one that is limiting, as in the case of arsenic for phosphorus?

    ROADMAP OBJECTIVES: 5.2 5.3 6.1 6.2
  • Stoichiometry of Life, Task 2a: Field Studies – Yellowstone National Park

    Field work and subsequent laboratory analysis is an integral part of following the elements. One of our field areas is the hot spring ecosystems of Yellowstone, which are dominated by microbes, and where reactions between water and rock generate diverse chemical compositions. These natural laboratories provide numerous opportunities to test our ideas about how microbes respond to different geochemical supplies of elements. Summer field work and lab work the rest of the year includes characterizing the natural systems, and controlled experiments on the effects of changing nutrient and metal concentrations (done so as to not impact the natural features!).

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.2
  • The VPL Life Modules

    The Life Modules team at VPL works on developing models of how biological processes – such as photosynthesis, breathing, and decay of organic materials – work on a planetary scale. When this is combined with the work of the atmospheric and planetary modeling teams, we are able simulate how these processes impact the atmosphere and climate of a planet. This information, then, helps us understand how might be able to detect whether or not a planet has life by looking at its atmosphere and surface. The Life Modules team has engaged in previous work coupling early Earth biogeochemistry and 1D models in the VPL’s suite of planetary models. Current work now focuses on biosphere models that simulate geographic distributions of life adapted to different climate zones and capable of coupling to 3D general circulation models (GCMs). Current project areas are: 1) development of a model of land-based ecosystem dynamics suitable for coupling with GCMs and generalizable for alternative planetary parameters, and 2) coupling of an ocean biogeochemistry model to GCMs.

    ROADMAP OBJECTIVES: 1.2 6.1 6.2 7.2
  • Stoichiometry of Life, Task 2b: Field Studies – Cuatro Cienegas

    Cuatro Cienegas is a unique biological preserve in México (state of Coahuila) in which there is striking microbial diversity, potentially related to extreme scarcity of phosphorus. We aim to understand this relationship via field sampling of biological and chemical characteristics and a series of enclosure and whole-pond fertilization experiments.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2
  • Permafrost in Hawaii

    We investigate microclimates on the Hawaiian Islands that serve as possible analogues to Mars. The summit of Mauna Kea is exceptionally dry, but sporadic permafrost exists in cinder cones near the summit. Additionally, ice caves are known to exist on the flanks of Mauna Loa. They are the world’s most isolated ice caves. Theoretical models have been developed for microclimatic effects in craters and caves. Preparations for upcoming fieldwork have been made and interdisciplinary collabora-tions have been developed.

    ROADMAP OBJECTIVES: 2.1 5.3 6.2
  • Stoichiometry of Life – Task 2c – Biological Soil Crusts: Metal Use and Acquisition

    Desert biological soil crusts (BSCs) are a complex consortia of microorganisms including cyanobacteria, algae, and fungi. BSCs are the primary colonizers of desert soils, supplying both carbon and nitrogen to these arid-land ecosystems. As such, they may represent an analog for soil development on the early Earth. BSCs occupy an extremely nutrient-poor niche, and meet their nutrient and metal requirements by manipulating their surroundings via the production of metal-binding ligands called siderophores. The soil crust’s metabolism affects the chemical composition of soil porewaters and soil solid phases; these alterations to soil metal contents may represent a biosignature for biological soil crusts that can be preserved over long time scales.

    ROADMAP OBJECTIVES: 4.1 5.3 6.1 6.2 7.1