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Project Reports

• Life Underground

  Our multi-disciplinary team from USC, Caltech, JPL, DRI, RPI, and now also Northwestern 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, sediment coring, marine vents and seeps, 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 are carrying out in situ life detection, culturing and isolation of heretofore unknown intraterrestrial archaea and bacteria using numerous novel and traditional techniques, and incorporating 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

  We have been working on two things: 1) the question of whether there are plausible “false positives” for life on extrasolar planets, i.e., high abiotic O2 and/or O3 levels that might be confused with evidence for photosynthesis, and 2) hydrodynamic escape of hydrogen from H2- or H2O-rich primitive atmospheres. We are developing a two-component model to describe this process. Old single-component models evidently do not obey the diffusion limit, so are are trying to remedy that.

  ROADMAP OBJECTIVES: 1.1 2.1 4.1 7.2

• Project 1A: Field Analog Geology and Astrobiology in Support of Mars Exploration

  We report on preliminary results obtained from the field research campaign exploring the area around the Mars Desert Research Station (MDRS) in Utah (Canyonlands area) in February/March 2012. This region has been previously investigated and characterized as geomorphological and geochemical similar to Mars. Soil and rock samples were collected within two formations of a single geological units, the Brushy Basin and Tununk Shale Member. The objective of this research was to characterize samples from plain, cliff and canyon locations using different analysis techniques including Fourier Transform Infra-Red Spectroscopy (FTIR), X-ray diffraction studies (XRD) and elemental composition surface and morphology (SEM-EDX) in order to determine the sample mineralogy and its variability within the geological unit. The analysis of the organic content of the collected samples (extraction of amino acids) is currently underway. Our aim is to compare data from different formations, topographical units, and specific locations in this Utah desert region in order to determine the variations in chemical and physical properties.

  ROADMAP OBJECTIVES: 2.1 5.3

• Astrobiology of Icy Worlds

  Our goal in the Astrobiology of the Icy Worlds Investigation is to advance our understanding of the role of ice in the broad context of astrobiology through a combined laboratory, numerical, analytical, and field investigations. Icy Worlds team pursues this goal through four major investigations namely, the habitability, survivability, and detectability of life of icy worlds coupled with “Path to Flight” Technology demonstrations. A search for life linked to the search for water should naturally “follow the ice”. Can life emerge and thrive in a cold, lightless world beneath hundreds of kilometers of ice? And if so, do the icy shells hold clues to life in the subsurface? These questions are the primary motivation of our science investigations

  ROADMAP OBJECTIVES: 1.1 2.1 2.2 3.1 3.2 4.1 5.1 5.2 5.3 6.2 7.1

• Advancing Techniques for in Situ Analysis of Complex Organics: Laser Mass Spectrometry of Planetary Materials

  In this final reporting period under CAN-5, we extended the development of protocols for laser mass spectrometry (MS) for analysis of complex, nonvolatile organic molecules from the progress made last year. In particular the major area of focus was in (1) the use of tunable laser wavelengths for desorption in two-step laser MS (L2MS), and (2) the use of tandem mass spectrometry (MS/MS) for in situ molecular structure analysis. Each of these protocols has been investigated during the course of the CAN-5 project, jointly supported by NAI and instrument development (PIDDP, MatISSE) and flight (MOMA) programs. The unique aspect of these efforts is their implementation and evaluation using truly miniature, flight-like instrumentation, to optimize the benefit to real mission science.

  ROADMAP OBJECTIVES: 2.1 2.2 3.2 7.1

• Analysis of Prebiotic Organic Compounds in Astrobiologically Relevant Samples

  The Astrobiology Analytical Laboratory (AAL) of the GCA is dedicated to the study of organic compounds derived from past and future sample return missions, meteorites, lab simulations of Mars, interstellar, protoplanetary, and cometary ices and grains, and instrument development. This year, we continued our work analyzing the organic content of carbonaceous chondrites, expanding beyond our previous amino acid and nucleobase analyses to determine distribution and abundances of pyridine carboxylic acids and aliphatic amines. We investigated the effects of cosmic ray irradiation on amino acids. We supported development of a liquid chromatographmass spectrometer aimed at in situ analyses of amino acids and chirality on airless bodies including asteroids and the outer planet’s icy moons Enceladus and Europa. We hosted an undergraduate and participated in numerous public outreach and education events. We continued our participation in the OSIRISREx asteroid sample return mission and provided support for the Sample Analysis at Mars instrument of NASA’s Mars rover Curiosity.

  ROADMAP OBJECTIVES: 2.1 3.1

• Project 2: Cells as Engines and the Serpentinization Hypothesis for the Origin of Life

  All life is, and must be, “powered” since all of its most essential and distinguishing processes have to be driven “up-hill” against their natural thermodynamic direction. By the 2nd law of thermodynamics, however, a process can only be made to proceed up-hill by being mechanistically linked, via a molecular device functioning as an engine, to another, more powerful, process that is moving in its natural, down-hill direction. On fundamental principles, we argue, such engine-mediated conversion activities must also have been operating at, and indeed have been the cause of, life’s emergence. But what then were life’s birthing engines, what sources of power drove them, what did they need to produce, and how did they arise in an entirely lifeless world? Promising potential answers to these and other questions related to the emergence of life are provided by the Alkaline Hydrothermal Vent/serpentinization (“AHV”) hypothesis, whose original propounder and lead proponent, Dr. Michael Russell of JPL, is a co-investigator on this project. The goal of the project is specifically to clarify the essential mechanistic modus operandi of all molecular engines that power life, and to see how the most fundamental and prerequisite of these could have arisen, and operated, in the structures and flows produced by the serpentinization process. Importantly, candidate answers to these questions can be put to definitive laboratory tests.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 3.3 3.4

• Mineralogical Traces of Early Habitable Environments

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

  ROADMAP OBJECTIVES: 2.1 5.3

• Project 1D: Iron Biogeochemistry in Chocolate Pots Hot Spring, Yellowstone National Park

  Small cores were collected from six locations along a transect following the main fluid flow path at Chocolate Pots (CP) hot spring, Yellowstone National Park. The cores were sectioned at 1 cm intervals, and the solids subjected to sequential extraction to isolate different Fe pools. The results showed that cores proximal to the vent outlet contained significant quantities of dissolved/colloidal and HCl-extractable reduced (ferrous) iron [Fe(II)]. Fe recovered from the other cores was present entirely as Fe(III). The most likely explanation for these observations is that internal generation of Fe(II) via microbial reduction is taking place in deposits proximal to the vent. This interpretation is consistent with rapid Fe(II) production during anaerobic incubation of near-vent deposits. Our results provide direct evidence of Fe(III) oxide reduction in deposits proximal to the main vent at CP, and to our knowledge represent the first demonstration of in situ Fe(III) reduction in a circumneutral-pH geothermal environment analogous to those which may have been present on the ancient Earth and Mars. Preliminary stable Fe isotope measurements on the dissolved/colloidal and 0.5M HCl-extractable Fe fractions in the CP cores suggests that Fe(III) reduction influences the isotopic composition of Fe phases proximal to the vent. A comprehensive analysis of all Fe phases in the cores is underway and will be used to develop conceptual models of controls on the stable Fe isotope composition preserved in the hot spring deposits.

  ROADMAP OBJECTIVES: 2.1 4.1 5.3 7.1

• Biosignatures in Extraterrestrial Settings

  The Biosignatures in Extraterrestrial Environments group works on finding and characterizing exoplanets, in particular through very high resolution spectroscopy; and developing new techniques for finding exoplanets and characterizing their properties. It also works on understanding the evolution and dynamics of planetary systems, including the solar system, and the role of astrophysical processes in establishing and sustaining life in extraterrestrial environments.

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

• Project 4: Vistas of Early Mars: In Preparation for Sample Return

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

  ROADMAP OBJECTIVES: 2.1 3.1 7.1

• Project 1E: Microbial Communities in Chocolate Pots Hot Spring, Yellowstone National Park

  DNA was extracted from samples obtained from cores collected at six locations along a transect following the main fluid flow path at at Chocolate Pots (CP) hot spring, Yellowstone National Park. 454 pyrosequencing of 16S rRNA gene amplicons was performed on the extracts, resulting in the generation more than 70 amplicon libraries, each containing a between ca. 2500 and 7500 ca. 300 base pair-long reads. The raw reads were processed and analyzed for their phylogenetic affiliation and other comparisons using the QIIME pipeline. The results indicate that microbial communities in the upper few cm of the Fe/Si-rich CP deposits varied significantly along the sampling transect. Communities at two sites most proximal to the vent source differed substantially from one another and from communities at downstream sites. Although communities at downstream sites were not identical, they were more similar to one another than to the vent-proximal sites. A wide diversity of prokaryotic taxa, including both Bacteria and Archaea, were identified in the libraries, many of which are only distantly (e.g. <90% similarity in 16S rRNA gene sequence) related to known taxa. Communities in cores close to the vent were dominated by anaerobic taxa, many of which have the potential to function as Fe(III) reducers. This result is consistent with the relatively high abundance of reduced (ferrous) iron [Fe(II)] and the rapid rate of Fe(II) production observed in in vitro Fe(III) reduction experiments with material from sites near the vent. Abundant taxa at downstream sites included organisms related to the known Fe(II)-oxidizing organism Sideroxydans paludicola. These results are consistent with Fe geochemical data, which indicate that Fe(II) oxidation is likely the dominant Fe redox cycling pathway in deposits more than 1-2 meters from the vent source. A detailed metagenomic analysis of communities in the upper 1 cm at three sites is underway, with the goal of confirming the function of recognized taxa, and revealing the identity and function of potentially novel Fe redox cycling taxa.

  ROADMAP OBJECTIVES: 2.1 4.1 5.1 5.3 7.1

• Habitability of Water-Rich Environments – Task 1 – Improve and Test Codes to Model Water-Rock Interactions

  Numerical codes have been developed to model chemical alteration of rocks by migrating fluids. One code is for alteration of permeable rocks by percolating fluids. Another code is for alteration of low-permeability rocks disrupted through hydro-fracturing by forming overpressured fluids. The codes could be used to model chemical weathering on Mars and Earth, and metasomatism on asteroids, moons, and planets.

  ROADMAP OBJECTIVES: 2.1 2.2

• Biosignatures of Life in Ancient Stratified Ocean Analogs

  Instigated by Macalady and Kump in 2010, this project investigates biosignatures of life in modern analogs for stratified ancient and/or extraterrestrial oceans. The primary field site is a sinkhole in Florida. Other field site include stratified ocean analogs in the Bahamas, New York State, and the Dominican Republic. A website monitoring the activities of an informal working group on Early Earth Photosynthesis is maintained by Macalady (http://www.geosc.psu.edu/~jlm80/EEP.html).

  ROADMAP OBJECTIVES: 2.1 3.3 3.4 4.1 5.2 5.3 6.1 7.1 7.2

• Project 6. Mining Archaeal Genomes for Signatures of Early Life: Comparison of Metabolic Genes in Methanogens

  Methanogenic archaea derive energy from simple starting materials, producing methane and carbon dioxide in the process. The chemical simplicity of the growth substrates and versatility of the organisms in extreme environments provide for a possibility that they could exist on other planets. By characterizing the evolution of methanogens from the most simple to most complex organism as well as their growth characteristics under controlled environments, we hope to address the question as to whether they could exist on planets such as Mars, where bursts of methane have been seen, yet no source has yet been identified.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 3.3 3.4 4.1 4.2 5.1 5.2 5.3 6.1 6.2 7.1 7.2

• Jon Toner NAI NPP Postdoc Report

  Aqueous salt solutions are critical for understanding the potential for liquid water to form on icy worlds and the presence of liquid water in the past. Salty solutions can form potentially habitable environments by depressing the freezing point of water down to temperatures typical of Mars’ surface or the interiors of Europa or Enceladus. We are investigating such low-temperature aqueous environments by experimentally measuring the low temperature properties of salt solutions and developing thermodynamic models to predict salt precipitation sequences during either freezing or evaporation. These models, and the experimental data we are generating, are being applied to understand the conditions under which water can form, the properties of that water, and what crystalline salts indicate about environmental conditions such as pH, temperature, pressure, and salinity.

  ROADMAP OBJECTIVES: 2.1 5.2 5.3

• Habitability of Water-Rich Environments – Task 4 – Evaluate the Habitability of Ancient Aqueous Solutions on Mars

  Goals are to constrain conditions of Mars habitability and preservation potential through in situ studies with MER rover data, the MSL Curiosity rover operating at Gale Crater, and terrestrial analog studies.

  ROADMAP OBJECTIVES: 2.1

• Laboratory Investigations Into Chemical Evolution in Icy Solids From the Interstellar Medium to the Outer Solar System to Meteorites

  NAI-GCA support in 2014 helped us continue our work on amino-acid stability. In 2014, we performed radiation experiments to measure the destruction rate of glycine in CO₂ ice. In particular, we found that this rate depends on concentration and temperature, and is 20-40 times greater than for glycine in H₂O-ice.

  ROADMAP OBJECTIVES: 2.1 2.2 3.1 7.1 7.2

• Understanding the Early Mars Environment

  In this task VPL team members use Mars mission data and atmospheric models to understand the early environment on Mars. Areas of research include: the atmospheric formation of salts that have been found on the Martian surface, Early Mars volcanism and atmospheric composition, and possible atmospheric means of warming early Mars. Several VPL team members are also active on the MSL mission and have contributed to scientific discussions of modern geochemistry and the ancient habitability of Mars.

  ROADMAP OBJECTIVES: 1.1 2.1

• Project 2G: Iron Isotope Fractionations Among Oxide Minerals Under Acidic Conditions

  The study of Fe isotope exchange and fractionation between aqueous Fe(II) and goethite was motivated by the inferred acidic environment for early Mars, where iron oxides (i.e. jarosite, goethite) were likely present. We found that the extent of atom exchange positively correlates with increasing pH during interactions between Fe(II)_aq and goethite. The decrease in extent of exchange correlates with a decrease in the amount of sorbed Fe(II) to the goethite surface, which strongly suggests that sorbed Fe(II) is the primary catalyst for inducing Fe isotope exchange. The slow rate of isotopic exchange at acidic pH suggests that stable Fe isotope compositions may be resistant to change in acidic aqueous environments, thus leading to preservation of signatures that might contribute to the understanding of ancient Mars paleoenvironments.

  ROADMAP OBJECTIVES: 2.1 5.3 7.1 7.2

• Taphonomy, Curiosity and Missions to Mars

  Members of our team continue to be involved in both the MER and MSL missions on Mars. On the latter mission, team members have recently documented a long-lived, habitable environment in Gale Crater dominated by rivers and lakes. Research on the mineralogy and geochemistry of rocks at the base of Mt Sharp has improved our understanding of their complex diagenetic history. Progress has also been made in linking orbital observations with those made by the rovers; this has been advanced particularly by field research at Rio Tinto and detailed laboratory experiments that constrain the relationship between mineral combinations and their signatures in infrared reflectance spectroscopy—and their effect on our ability to detect organics.

  ROADMAP OBJECTIVES: 2.1 4.1 4.2 6.1 7.1

• Remote Sensing of Organic Volatiles on Mars and Modeling of Cometary Atmospheres

  During this period, Dr. Villanueva mainly worked on processing high-resolution (spectral and spatial) data of Mars acquired in January/2014 and in the observational campaigns of 2008, 2009 and 2010, using the recently developed new analytical and modeling capabilities. Unprecedented maps of the D/H ratio in water were extracted from these data, and a paper was recently accepted by Science (see below). In addition, he participated in several international conferences and collaborated on several Titan and cometary projects.

  ROADMAP OBJECTIVES: 1.1 2.1 3.1 3.2 4.1 7.1