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Project Reports

• Investigation 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: 2.1 2.2 3.2 4.1 5.1 5.2 5.3 6.2 7.1 7.2

• Biogenic Gases From Anoxygenic Photosynthesis in Microbial Mats

  This lab and field project aims to measure biogenic gas fluxes in engineered and natural microbial mats composed of anoxygenic phototrophs and anaerobic chemotrophs, such as may have existed on the early Earth prior to the advent of oxygenic photosynthesis. The goal is to characterize the biogeochemical cycling of S, H, and C in an effort to constrain the sources and sinks of gaseous biosignatures that may be relevant to the detection of life in anoxic biospheres on habitable exoplanets.

  ROADMAP OBJECTIVES: 4.1 5.2 5.3 6.1 6.2 7.2

• Life Underground

  Our multidisciplinary team from USC, Caltech, JPL, DRI, and RPI is developing and employing field, laboratory, and modeling approaches aimed at detecting and characterizing microbial life in the subsurface—the intraterrestrials. We posit that if life exists, or ever existed, on Mars or other planetary body in our solar system, evidence thereof would most likely be found in the subsurface. This study takes advantage of unique opportunities to explore the subsurface ecosystems on Earth through boreholes, mine shafts, and deeply-sourced springs. Access to the subsurface, both continental and marine, and broad characterization of the rocks, fluids, and microbial inhabitants is central to this study. Our focused research themes require subsurface samples for laboratory and in situ experiments. Specifically, we seek to carry out in situ life detection and characterization experiments, employ numerous novel and traditional techniques to culture heretofore unknown intraterrestrial archaea and bacteria, and incorporate new and existing data into regional and global metabolic energy models.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 3.3 4.1 5.1 5.2 5.3 6.1 6.2 7.2

• Biosignatures in Ancient Rocks – Kasting Group

  The work by Ramirez concerned updating the absorption coefficients in our 1-D climate model. Harman’s work consisted of developing a 1-D code for modeling hydrodynamic escape of hydrogen from rocky planets.

  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

• Habitability, Biosignatures, and Intelligence

  Understanding the nature and distribution of habitable environments in the Universe is one of the primary goals of astrobiology. Based on the only example of life we know, we have devel-oped various concepts to predict, detect, and investigate habitability, biosignatures and intelli-gence occurrence in the near-solar environment. In particular, we are searching for water vapor in atmospheres of extrasolar planets and protoplanets, developing techniques for remote detec-tion of photosynthetic organisms on other planets, have detected a possible bio-chemistry sig-nature in Martian clays contemporary with early life on Earth, developed a comprehensive methodology and an interactive website for calculating habitable zones in binary stellar systems, expanded on definitions of habitable zones in the Milky way Galaxy, and proposed a novel ap-proach for searching extraterrestrial intelligence.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 4.1 4.2 6.2 7.1 7.2

• Investigation 2: Survivability on Icy Worlds

  Investigation 2 focuses on survivability. As part of our survivability investigation, we examine the similarities and differences between the abiotic chemistry of planetary ices irradiated with ultraviolet photons (UV), electrons, and ions, and the chemistry of biomolecules exposed to similar conditions. Can the chemical products resulting from these two scenarios be distinguished? Can viable microbes persist after exposure to such conditions? These are motivating questions for our investigation.

  ROADMAP OBJECTIVES: 1.1 2.2 3.2 5.1 5.3 6.1 6.2

• Dynamics of Self-Programming Systems

  Living systems are unique in that they have the capacity to evolve. Evolving systems can reprogram themselves and so they are able to respond to perturbations by creating new functionality. This feature is something very different from physical systems, which obey a fixed or predetermined equation of motion. This project is a theoretical attempt to describe this state of affairs mathematically, and to construct computer programs that have the capacity to evolve and thus become more complex without this being “built in” by the original programmer.

  ROADMAP OBJECTIVES: 3.2 4.1 4.2 5.3 6.2

• Investigation 3: Detectability of Icy Worlds

  Detectability of Icy Worlds investigates the detectability of life and biological materials 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.The primary component of Investigation 3 is the field campaign in Barrow, AK to characterize and quantify methane release from the Alaskan North Slope region and to understand the origin and fate of the methane.

  ROADMAP OBJECTIVES: 1.1 2.2 5.3 6.1 6.2

• Experimental Evolution and Genomic Analysis of an E. Coli Containing a Resurrected Ancestral Gene

  In order to study the historical pathways and modern mechanisms of protein evolution in a complex cellular environment, we combined ancestral sequence reconstruction with experimental evolution. Our first goal was to identify how ancestral states of a protein effect cellular behavior by directly engineering an ancient gene inside a modern genome. We could then identify the evolutionary steps of this organism harboring the ancient gene by subjecting it to laboratory evolution, and directly monitoring the resulting changes within the integrated ancient gene as well as the rest of the host genome.

  ROADMAP OBJECTIVES: 3.4 4.1 5.1 5.2 6.1 6.2

• Biosignatures in Extraterrestrial Settings

  We are working on finding potentially habitable extrasolar planets, using a variety of search techniques, and developing some of the technology necessary to find and characterize low mass extrasolar planets. We also work on modeling and numerical techniques relevant to the problem of identifying extrasolar sites for life, and on some aspects of the prospects for life in the Solar System outside the Earth. The ultimate goal is to find signatures of life on nearby extrasolar planets.

  ROADMAP OBJECTIVES: 1.1 1.2 2.1 2.2 3.1 4.1 4.3 6.2 7.1 7.2

• Project 5: Geological-Biological Interactions

  We continue to study the intersection between geology and biology. We continue to explore how sub-seafloor interactions support deep ocean hydrothermal ecosystems. We study life’s adaption to extremes of pressure, cold, and salinity. We adapt and apply multiple isotopic sulfur geochemistry towards the understanding of microbial metabolism and as a means of detecting ancient metabolisms recorded in the rock record through characteristic sulfur isotopic signatures. We apply state-of-the-art methods to derive chemical and isotopic biosignatures of life in the Earth’s most ancient rocks.

  ROADMAP OBJECTIVES: 4.1 5.1 6.1 6.2 7.1

• Project 1E: Metagenomic Analysis of Novel Chemolithoautotrophic Bacterial Cultures

  Metagenomic sequence information was obtained from two chemolithoautotrophic bacterial cultures: (1) an iron-oxidizing, nitrate-reducing culture that is capable of growth with either soluble or insoluble, mineral-bound (biotite, smectite) Fe(II) as the sole energy source; and (2) an aerobic iron/sulfur-oxidizing culture that grows with insoluble framboidal pyrite as the sole energy source. Both of these cultures carry-out novel neutral-pH lithotrophic microbial pathways, the discovery of which broadens our view of potential Fe/S based life on Earth (past and present) and other rocky planets. We hypothesize that genetic components of Fe/S oxidation identified in the metagenome of the cultures will bear resemblance to analogous components to be identified in other iron-oxidizing pure cultures being sequenced at JGI, together with existing published and unpublished information from other chemolithoautotrophic microorganisms. Identification of such genetic systems will enable comparative genomic analysis of mechanisms of extracellular phyllosilicate Fe/S redox metabolism, and facilitate development of techniques to detect the presence and expression of genes associated with chemolithotrophic Fe/S metabolism in various terrestrial environments.

  ROADMAP OBJECTIVES: 3.2 5.1 5.3 6.2

• Genetic Evolution and the Origin of Life

  In this task biologists and chemists use field and laboratory work to better understand the environmental effects on growth rates for freshwater stromatolites and the mechanisms that govern their adaptation to their environment. 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 understanding environmental impacts on evolution, and characterizing their metabolisms and gas outputs, for use in planetary models of ancient environments. This year we also started a new project looking at the chemical affinities of the building blocks of life, as a way to understand how life might have initially formed from these chemical precursors.

  ROADMAP OBJECTIVES: 3.2 3.4 4.1 4.2 5.2 5.3 6.1 6.2

• Subsurface Exploration for Astrobiology: Oceanic Basaltic Basement Biosphere

  While extraterrestrial life is likely to exist within the subsurface of water-occupied objects such as Enceladus and Europa, the continued investigation of the subsurface biosphere on the earth provides important insight and implications for astrobiology. This research investigates a deep sub-seafloor basement biosphere. At the ocean floor, lying underneath an often times thick layer of sediment is hard basaltic rock, or basement. Seawater enters the basement and circulates within. It is now known that low temperature hydrothermal fluids (<100oC) circulate everywhere within the porous and permeable volcanic rocks of the upper ocean basement, providing temperature and chemical gradients that host extensive alteration of basement rocks and fluids and form plausible habitats for microbial life. While microbial activity has been observed in deeply buried sediments and exposed basement rock, few direct tests have been carried out in deep subseafloor basement rocks or fluids. A majority of the crustal hydrothermal flow and seawater-crustal fluid exchange, and the corresponding advective heat and mass output, occurs on the flanks of the mid-ocean ridge with basement ages of >1 million years old. This low-temperature ridge flank flow rivals the discharge of all rivers to the ocean and is about three orders of magnitude greater than the high temperature discharge at mid-ocean ridges. The resulting ridge flank chemical flux impacts ocean biogeochemical cycles and may sustain deep basement microbial communities. Access to uncontaminated fluids from subseafloor basement is problematic, especially where ridge flanks and ocean basins are buried under thick, impermeable layers of sediment (i.e., thick enough to act as a barrier to rapid exchange of fluids). We rely on custom designed instrumentation to collect large volume high integrity basement fluids, where the concentrations of microorganisms are often very low (e.g. about 1/10 of bottom seawater concentrations). By studying the chemical composition of crustal fluids, we have learned that several important energy sources, such as dissolved methane and hydrogen, are available. In addition, the isotopic signature of dissolved methane suggests that microbial production and consumption occurs in the basement environment. By filtering microbial biomass from the fluids and investigating their nucleic acids, we are investigating the evolutionary and functional characteristics of the diverse bacterial, archaeal, and viral communities that inhabit the deep subsurface of Earth. Our on-going research includes the investigation of temporal (at hourly-resolution) and spatial (at a few hundred meter scale) biogeochemical and biological variability in order to more effectively constrain our measured parameters. We are also characterizing the dissolved organic carbon pool in basement fluids to investigate the role that basement environment plays in the global carbon cycle.

  ROADMAP OBJECTIVES: 4.1 5.1 5.2 5.3 6.1 6.2

• Water and Habitability of Mars and the Moon and Antarctica

  Water plays an important role in shaping the crusts of the Earth and Mars, and now we know it is present inside the Moon and on its surface. We are assessing the water budgets and total inventories on the Moon and Mars by analyzing samples from these bodies.

  We also study local concentrations of water ice on the Moon, Mars, and at terrestrial analogue sites such as Antarctica and Mauna Kea, Hawaii. We are particularly interested in how local phenomena or microclimates enable ice to form and persist in areas that are otherwise free of ice, such as cold traps on the Moon, tropical craters with permafrost, and ice caves in tropical latitudes. We approach these problems with field studies, modeling, and data analysis. We also develop new instruments and exploration methods to characterize these sites. Several of the terrestrial field sites have only recently become available for scientific exploration.

  HI-SEAS (Hawaii Space Exploration Analog and Simulation, hi-seas.org) is a small habitat at a Mars analog site in the saddle area of the Island of Hawaii. It is a venue for conducting research relevant to long-duration human space exploration. We have just completed our first four-month long mission, and are preparing for three more, of four, eight and twelve months in length. The habitat is a 36’ geodesic dome, with about 1000 square feet of floor space over two stories. It is a low-impact temporary structure that can accommodate six crewmembers, and has a kitchen, a laboratory, and a flexible workspace. Although it is not airtight, the habitat does have simulated airlock, and crew-members don mockup EVA suits before going outside. The site is a disused quarry on the side of a cinder/splatter cone, surrounded by young lava fields. There is almost no human activity or plant life visible from the habitat, making it ideal for ICE (isolated/confined/extreme) research.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 5.3 6.1 6.2 7.1

• The Long Wavelength Limit of Oxygenic Photosynthesis

  Oxygenic photosynthesis (OP) produces the strongest biosignatures at the planetary scale on Earth: atmospheric oxygen and the spectral reflectance of vegetation. Both are controlled by the properties of Chlorophyll a, its ability to perform the water-splitting to produce oxygen, and its spectral absorbance that is limited to red and shorter wavelength photons. We seek to answer what is the long wavelength limit at which OP might remain viable, and how. This would clarify whether and how to look for OP adapted to the light from red dwarfs or M stars, which emit little visible light but abundant far-red and near-infrared. Very recently discovered cyanobacteria have been found to harbor alternative chlorophylls adapted to spectral light environments very much like that of M stars. This projects uses field, lab, and modeling studies to study these far-red adapted cyanobacteria as analogues for extrasolar oxygenic photosynthesis pushing the long wavelength limit.

  ROADMAP OBJECTIVES: 3.2 4.2 5.1 5.3 6.2 7.2

• Project 3B: Carbon Isotope Analysis of Archean Microfossils

  We have completed a study of petrography, Raman microspectroscopy, and in situ analyses of carbon isotope and H/C ratios using secondary ion mass spectrometry (SIMS) of diverse organic microstructures, including possible microfossils. This work has focussed on two localities of the 3.4-billion-year-old Strelley Pool Formation (Western Australia). For the first time, we show that the wide range of carbon isotope ratios recorded at the micrometer scale correlates with specific types of texture for organic matter (OM), arguing against abiotic processes to produce the textural and isotopic relations. These results support the biogenicity of OM in the Strelley Pool Formation.

  ROADMAP OBJECTIVES: 1.1 2.1 4.1 4.2 5.2 6.2 7.2

• Stoichiometry of Life – Task 1 – Laboratory Studies in Biological Stoichiometry

  This project component involves a set of studies of 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 or nitrogen or iron? Is this change similar for different 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.

  ROADMAP OBJECTIVES: 5.2 5.3 6.1 6.2

• Task 3.5.1: Titan as a Prebiotic Chemical System

  Six years ago, NASA sponsored a National Academies report that asked whether life might exist in environments outside of the traditional habitable zone, where “weird” genetic molecules, metabolic processes, and bio‐structures might avoid the water‐based biochemistry that is found across the terran biosphere. In pursuit of this “big picture” question, we turned to Titan, which has exotic solvents both on its surface (methane‐hydrocarbon) and sub‐surface (perhaps super‐cooled ammonia‐rich water). This work sought genetic molecules that might support Darwinian evolution in both environments, including non‐ionic polyether molecules in the first and biopolymers linked by exotic oxyanions (such as phosphite, arsenate, arsenite, germanate) in the second. Further, we asked about the possibility that Titan might inform our understanding of prebiotic chemical processes, including those on “warm Titans”. Our experimental activities found few possibilities for non‐phosphate-based genetics in subsurface aqueous environments, even if they are rich in ammonia at very low temperatures. Further, we showed that polyethers are insufficiently soluble in hydrocarbons at very low temperatures, such as the 90‐100 K found on Titan’s surface. However, we did show that “warm Titans” could exploit propane as a biosolvent for certain of these “weird” alternative genetic biopolymers; propane has a huge liquid range (far larger than water). Further, we integrated this work with other work that allows reduced molecules to appear as precursors for more standard genetic biomolecules, especially through interaction with various mineral species.

  ROADMAP OBJECTIVES: 1.1 1.2 2.2 3.1 3.2 4.1 4.2 5.3 6.2 7.1 7.2

• Stoichiometry of Life, Task 2a: Field Studies – Yellowstone National Park

  Yellowstone National Park harbors an array of hydrothermal ecosystems with widely varying geochemical characteristics and microbial communities. Our research aims to understand how the geochemistry of these hot springs shapes their constituent microbial communities including their composition and function. To accomplish this aim, we measure (1) physical and geochemical properties of hot spring fluids and sediments, (2) the rates of biogeochemical processes (i.e., methane oxidation, nitrogen fixation, microbial Fe cycling, photosynthesis, de-nitrification, etc.), and (3) markers for microbial community diversity (i.e., SSU rRNA, metabolic genes, lipids, proteins).

  ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.2

• Undergraduate Research Associates in Astrobiology (URAA)

  2013 featured the Tenth URAA offering (Undergraduate Research Associates in Astrobiology), a ten-week residential research program at the Goddard Center for Astrobiology (GCA) (http://astrobiology.gsfc.nasa.gov/education.html). Competition was very keen, with an oversubscription ratio of 3.0. Students applied from over 19 colleges and universities in the United States, and 6 Associates from 6 institutions were selected. Each Associate carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse laboratories and gaining a broader view of astrobiology as a whole. At summer’s end, each Associate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 6.2 7.1

• 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. We performed two studies to evaluate ecological impacts of nitrogen and/or phosphorus fertilization in a P-deficient and hyperdiverse shallow pond in the valley of Cuatro Cienegas, Mexico.

  ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2

• Undergraduate Research Associates in Astrobiology (URAA)

  2013 featured the Tenth URAA offering (Undergraduate Research Associates in Astrobiolo-gy), a ten-week residential research program at the Goddard Center for Astrobiology (GCA) (http://astrobiology.gsfc.nasa.gov/education.html). Competition was very keen, with an oversubscription ratio of 3.0. Students applied from over 19 colleges and universities in the United States, and 6 Associates from 6 institutions were selected. Each Associate carried out a defined research project working directly with a GCA scientist at Goddard Space Flight Center or the University of Maryland. As a group, the Associates met with a different GCA scientist each week, learning about his/her respective area of research, visiting diverse la-boratories and gaining a broader view of astrobiology as a whole. At summer’s end, each As-sociate reported his/her research in a power point presentation projected nation-wide to member Teams in NASA’s Astrobiology Institute, as part of the NAI Forum for Astrobiology Research (FAR) Series.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 6.2 7.1