2010 Annual Science Report

Astrobiology Roadmap Objective 5.2 Reports Reporting  |  SEP 2009 – AUG 2010

Project Reports

  • Biosignatures in Ancient Rocks

    This team of geologists, geochemists, paleontologists and biologists seeks signs of early life in ancient rocks from Earth. Working mostly on that part of Earth history before the advent of skeletons and other preservable hard parts in organisms, our group focuses on geochemical traces of life and their activities. We also investigate how life has influenced, and has been influenced by changes in the surface environment, including the establishment of an oxygen-rich environment and the initiation of extreme climate states including global glaciations. For this we use a combination of observations from modern analogous environments, studies of ancient rocks, and numerical modeling.

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

    Eigenbrode’s GCA work over the past year has largely focused on developing thermochemolysis methodologies for extracting components of complex organics molecules from samples that pose unique analytical challenges because of their mineral composition. These include iron-oxide rich samples regarded as analogs to ancient aqueous environments on Mars and ancient Earth, as well as perchlorate-laden samples. Eigenbrode is making progress with the method development and has observed some interesting biosignatures relevant to understanding microbial contributions and sedimentary preservation. In addition, Eigenbrode has begun a new collaboration with MIT and Wisconsin teams with the intention of applying innovative techniques to understanding the distribution of stable carbon isotopes in the Archean rock record.

    ROADMAP OBJECTIVES: 4.1 5.1 5.2
  • AbGradCon 2010

    The Astrobiology Graduate Student conference is a conference organized by astrobiology graduate students for astrobiology grad students. It provides a comfortable peer forum in which to communicate and discuss research progress and ideas.

    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

    The Astrobiology Integrative Research Framework (AIRFrame) analyzes published and unpublished documents to identify and visualize implicit relationships between astrobiology’s diverse constituent fields. The main goal of the AIRFrame project is to allow researchers and the public to discover and navigate across related information from different disciplines.

    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
  • Biomechanics of the Rangeomorph Fauna

    Some of the oldest, multicellular organisms in the fossil record are enigmatic creatures called rangeomorphs. Although there is much debate as to whether the rangeomorphs are animals, fungi, or something completely unique, recent studies of the fossils suggest that the rangeomorphs used high surface areas to capture dissolved organic matter (DOM) as an energy source. In this project, we attempt to model how nutrients would have flowed over these deep-water organisms, to see how their large size might have helped them compete with bacteria for DOM. Our work suggests that competition with bacteria was a driving force in the evolution of the first complex organisms.

    ROADMAP OBJECTIVES: 4.2 5.2 6.1
  • Functional Based Habitability – Defining the Environmental Factors That Constrain Modes of Microbial Metabolism

    To set the stage for space exploration and the search for life in the universe, it is necessary to establish the boundaries that define habiltability on Earth. Previous studies have emphasized using simple binary parameters to establish where life occurs and where life does not occur on Earth. We are attempting to take this to another level and establish through mutlivariable statistics the parameters that not only constrain the life but what parameters constrain the set of metabolic processes that sustain life as a function of environment.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2
  • Biosignatures in Relevant Microbial Ecosystems

    In this project, PSARC team members explore the isotope ratios, gene sequences, minerals, organic molecules, and other signatures of life in modern environments that have important similarities with early earth conditions, or with 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
  • Bioastronomy 2007 Meeting Proceedings

    This is the published volume of material from an astrobiology meeting hosted by our lead team in 2007 in San Juan Puerto Riceo. The book includes 60 papers covering the breadth of astrobiology, and developed a new on-line astrobiology glossary.

    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
  • 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. Our efforts are focused 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 3.2 3.4 4.1 5.2 5.3 7.1 7.2
  • Molecular Paleontology of Iron-Sulfur Enzymes

    In this project we are attempting to trace back in the evolutionary record using specific genetic events as markers. We are using specific gene fusion and gene duplication events in the genetic record to place a chronological sequence to the advent of nitrogen fixation, certain modes of hydrogen metabolism, and both anoxygenic and oxygenic photosynthesis.

    ROADMAP OBJECTIVES: 3.1 3.2 3.3 3.4 4.1 5.1 5.2 5.3 6.1
  • PHL 278: A Gateway Course for a Minor in Astrobiology

    We have recently developed obtained Montana Board of Regents for an undergraduate minor in Astrobiology at Montana State University. The Minor includes courses in Earth Sciences, Physics, Astronomy, Microbiology, Ecology, Chemistry, and Philosophy. Two new courses have been developed as part of the minor, one of which is a gateway or introductory course examines the defining characteristics of life on earth as well as the challenges of a science that studies life and its origin. The other course which will be offered fall 2011 is the capstone course for the minor which will delved into the science of Astrobiology in more detail and targeted for Juniors and Seniors that have fulfilled the majority of the requisite course requirements for the curriculum.

    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
  • Computational Astrobiology Summer School

    The Computational Astrobiology Summer School (CASS) is an excellent opportunity for graduate students in computer science and related areas to learn about astrobiology, and to carry out substantial projects related to the field.

    The two-week on-site part of the program is an intensive introduction to the field of astrobiology. NASA Astrobiology Institute scientists present their work, and the group discusses ways in which computational tools (e.g. models, simulations, data processing applications, sensor networks, etc.) could improve astrobiology research. Also during this time, participants define their projects, with the help of the participating NAI researchers. On returning to their home institutions, participants work on their projects, under the supervision of a mentor, with the goal of presenting their completed projects at an astrobiology-related conference the following year.

    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
  • Metabolic Networks From Single Cells to Ecosystems

    We use mathematical and computational approaches to study the dynamics and evolution of metabolism in individual microbes and in microbial ecosystems. In particular, we take advantage of sequenced genomes to study the complete network of biochemical reactions present in an organism. We have been extending these approaches from single genomes to multiple genomes, generating ecosystem-level models of metabolism, which can help us understand some of the key transitions in the history of life on our planet.

    ROADMAP OBJECTIVES: 4.1 4.2 5.1 5.2 6.1
  • Planetary Surface and Interior Models and SuperEarths

    We use computer models to simulate the evolution of the interior and the surface of real and hypothetical planets around other stars. Our goal is to work out what sorts of initial characteristics are most likely to contribute to making a planet habitable in the long run. Observations in our own Solar System show us that water and other essential materials are continuously consumed via weathering (and other processes) and must be replenished from the planet’s interior via volcanic activity to maintain a biosphere. The surface models we are developing will be used to predict how gases and other materials will be trapped through weathering over time. Our interior models are designed to predict how much and what sort of materials will come to a planet’s surface through volcanic activity throughout its history.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 5.2 6.1
  • Deep (Sediment-Buried Basement) Biosphere

    The ocean crust comprises the largest aquifer on earth and there is increasing evidence that supports the presence of actively growing microbial communities within basaltic porewaters.

    Advanced Integrated Ocean Drilling Program (IODP) circulation obviation retrofit kit (CORK) observatories provide a unique opportunity to sample these otherwise inaccessible deep subseafloor habitats at the basalt-sediment transition zone. Aging porewaters remain isolated within this sediment-buried upper oceanic basement, subjected to increasing temperatures and pressures as plates move away from spreading ridges.

    ROADMAP OBJECTIVES: 4.1 4.2 5.2 5.3 6.1 6.2 7.1 7.2
  • Project 3A: Quantifying the Amount of Free Oxygen in the Neoarchean Photic Zone Through Combined Fe and Mo Isotopes

    The history of Earth’s atmospheric evolution is critical for understanding the interplay between life and the physical environment, both here on Earth, and potentially on other worlds. The majority of models for Earth’s atmospheric evolution, and evidence from the geologic record, suggest that the atmosphere was virtually devoid of free oxygen through the Archean and into the earliest Proterozoic, and became more oxygen-rich over time in a punctuated fashion. The earliest significant increase in atmospheric oxygen has been termed the “Great Oxidation Event” (GOE), and is commonly considered to have occurred between ~2.4 and 2.2 Ga (Holland, 1984, 2006 and references therein). However, some geologic evidence indicates that the free oxygen content of the atmosphere-hydrosphere system may have been similar to that of the modern Earth since prior to 3.5 Ga (e.g., Hoashi et al. 2009), or that it may have had a more complex history with numerous instances of oxygen production and consumption prior to the GOE, but perhaps on a more localized scale (Anbar et al., 2007; Frei et al., 2009; Godfrey and Falkowski, 2009). Additionally, evidence from biomarkers (Brocks et al., 1999; Eigenbrode et al., 2008; Waldbauer et al., 2009) and carbon isotopes (Hayes, 1983; Eigenbrode and Freeman, 2006) suggest that both oxygen producers and consumers existed by ~2.7 Ga.

    ROADMAP OBJECTIVES: 4.1 5.2 6.1 7.1
  • Project 3B: Do Iron-Rich Carbonates From Banded Iron Formations Record Ancient Seawater?

    Carbonates are ubiquitous in the geologic record over Earth’s history, and their chemical and isotopic compositions have been key to discussions on the compositions of the ancient oceans, as well as the evolution of life. Moreover, the abundance of Fe-carbonates, common in banded iron formations (BIFs), and the Archean sedimentary rock record in general, has led many workers to use such carbonates as a proxy for surface conditions and to provide insights into seawater chemistry of the ancient Earth. For carbonates to yield information about ancient ocean compositions, however, they must be demonstrated to have been a direct precipitate from ocean water and not subsequently modified. One approach to test if ancient carbonates record seawater is through studies of the isotopic compositions of elements that usually reflect seawater compositions in carbonate minerals.

    ROADMAP OBJECTIVES: 4.1 4.3 5.2 7.1
  • Subglacial Methanogenesis and Implications for 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 7.1 7.2
  • Project 3C: Iron Isotope Biosignatures: Laboratory Studies and Modern Environments

    Ancient rocks often carry chemical and isotopic signatures of ancient microbiological processes. However, fluids important in the generation of these signatures are lost upon lithification. Experimental studies in geochemical systems analogous to ancient rock precursors are therefore critical to gain insight into the biogeochemical processes responsible for generating unique chemical or isotopic compositions in ancient rocks. New laboratory studies were conducted to extend our recent work on Fe isotope fractionation during microbial dissimilatory iron reduction (DIR) in the presence of dissolved silica, which was likely abundant in Precambrian oceans. Iron isotope fractionation was investigated during microbial reduction of an amorphous iron oxide-silica coprecipitate in high-silica, low-sulfate artificial Archean seawater to determine if such conditions alter the extent of reduction, or the isotopic fractionations relative to those previously observed in simple systems. These new results show that, relative to simiple systems, significantly larger quantities of low-isotopically-light reduced iron were produced during reduction of the Fe-Si coprecipitate. These findings provide strong support for DIR as a mechanism for producing Fe isotope variations observed in Neoarchean and Paleoproterozoic marine sedimentary rocks.

    ROADMAP OBJECTIVES: 2.1 4.1 5.2 6.1 7.1 7.2
  • 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
  • Viral Ecology and Evolution

    We are interested in studying the viruses inhabiting the acidic hot springs within Yellowstone. We hypothesize that further understanding the viral dynamics, diversity, and composition will aid in the understanding of early Earth and how cellular life may have evolved.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2
  • Stoichiometry of Life, Task 1a: Experimental Studies – Cellular Stoichiometry Under Nutrient Limitation in Chemostats

    In this project we are raising several species of “extremophile” microbes at different growth rates under different kinds of element limitation (N, P, and Fe) in order to determine how their “elemental recipes” (in terms of C, N, P, Fe, and other metals) change with environmental conditions. These data will help us understand similar data to be obtained from microbes in natural ecosystems.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3 6.1 6.2 7.1
  • Understanding Past Earth Environments

    We study the chemical and climate evolution of the Earth as the best available proxy for what other inhabited planets might be like. A particular focus is on the “Early Earth” (formation through to the 1.6 billion years ago) which is poorly represented in the geological record but comprises half of Earth’s history. We have studied the total pressure of the Archean atmosphere (prior to 2.5 billion years ago), developed constraints on CO2 concentration, studied the oxygen and nitrogen cycles, the fractionation of sulfur isotopes and explored the effect of hazes on early Earth climate.

    ROADMAP OBJECTIVES: 1.1 1.2 4.1 4.2 5.1 5.2 6.1
  • Stoichiometry of Life – Task 1f – Concept Studies – Nickel-Molybdenum Co-Limitation and Evolution of Mo-Nitrogenase

    The element molybdenum (Mo) is critical for key processes in the cycling of nitrogen (N); for example, it is essential for the enzyme nitrogenase which bacteria use to convert gaseous N to “fixed” N that can be used in biological processes. However, this process costs a lot of energy. In some microbes, this energy can be captured and used via enzymes that involve both Mo and nickel (Ni). This project investigates the role of these Ni-Fe enzymes in making nitrogenase-driven processes more energetically efficient and how these enzymes may have evolved in the deep past when Ni concentrations were lower.

    ROADMAP OBJECTIVES: 4.1 5.1 5.2 6.1
  • 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
  • Stoichiometry of Life, Task 2b: Field Studies – Cuatro Cienegas

    Cuatro Cienegas is a unique biological preserve 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
  • Stoichiometry of Life, Task 3b: Ancient Records – Genomic

    The goal of Task 3b is to advance understanding of elemental cycling in ancient ecosystems. Team members are developing experimental and computational approaches aimed at genomic analysis of modern ecosystems, and extending these approaches in novel ways to infer the function and composition of ancient communities.

    ROADMAP OBJECTIVES: 5.1 5.2 5.3
  • Stoichiometry of Life, Task 4: Biogeochemical Impacts on Planetary Atmospheres

    Oxygenation of Earth’s early atmosphere must have involved an efficient mode of carbon burial. In the modern ocean, carbon export of primary production is dominated by fecal pellets and aggregates produced by the animal grazer community. But during most of Earth history the oceans were dominated by unicellular, bacteria-like organisms (prokaryotes) causing a substantially altered biogeochemistry. The NASA Ocean Biogechemical Model (NOBM) is applied using cyanobacteria (blue-green algae) as the only photosynthetic group in the oceans. The analyses showed that the early Earth ocean had 19% less primary production and 35% more nitrate due to slower growth by the cyanobacteria, and reduced nutrient uptake efficiency relative to modern phytoplankton Additionally there was 8% more total carbon in the oceans as a result of higher atmospheric pCO2. We plan to optimize this early Proterozoic ocean model in combination with a 1 D model to account for changes in aggregate formation and sinking speed in response to varying nutrients.

    ROADMAP OBJECTIVES: 1.1 4.1 4.2 5.2 6.1 7.2
  • Quantification of the Disciplinary Roots of Astrobiology

    While astrobiology is clearly an interdisciplinary science, this project seeks to address the question of how interdisciplinary it is. We are reviewing published works across a broad range of scholarly databases, comparing disciplinary indicators such as subject terms, journal titles and author affiliations, and creating a computational model to identify and compare the makeup of astrobiological research literature in terms of the proportion of work that come from constituent fields.

    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