List of Session Topics

Session Topics —
Astrobiology is an inherently interdisciplinary endeavor. Given the wide variety of disciplinary tools and topics to be presented at the conference, the success of AbSciCon 2015 will be built upon the community’s involvement in the organization of topical sessions. Fifty-one diverse session topics within seven themes have been selected for presentation at the conference.

Themes:

How to Build a Habitable Planet
The Origins and Subsequent Evolution of Life
Sustained Habitability on a Dynamic Early Earth
Habitable Worlds in Our Solar System
Habitability of Exoplanets
Identifying and Characterizing Habitable Environments and Habitation
Habitability of Learning:  Astrobiology Education and Public Outreach

How to Build a Habitable Planet

Theme:  How to Build a Habitable Planet
Session Title:  What We Know About Water and Life on Earth:  Implications for Potential Life Forms Elsewhere in the Solar System and Universe
Topic Short Title (listed on abstract submission form):  What We Know About Water and Life on Earth
Organizer:  Armando Azua-Bustos (Blue Marble Space Institute of Science), armando@bmsis.org
Summary:  Although Earth is known as the "water planet," this molecule is present only as a thin film covering 70% of its surface. In addition, one-third of Earth’s exposed surface falls in the desert category, and water present as ice or as salty solutions is unavailable or difficult to be used by life. Nevertheless, life has been able to adapt and evolve in these habitats using physiological and molecular mechanisms that, once understood, could guide us on where to search for similar life forms elsewhere in the solar system and other planets in the universe. In this session, abstracts focused on the relation between water and life on Earth from the ecological, physiological, and molecular point of view are welcome, in particular those focused on terrestrial analog environments. Works on how "life as we do not know it" could have evolved using water analogs elsewhere are also welcome.

Theme:  How to Build a Habitable Planet
Session Title:  Getting into Planets:  Interior Planetary Processes, Life, and Habitability
Topic Short Title (listed on abstract submission form):  Getting Into Planets
Organizer:  Steve Desch (Arizona State University), steve.desch@asu.edu
Summary:  Habitability of a planet is defined in terms of factors on its surface. However, the habitability of a planet depends not just on whether the planet is in the Goldilocks zone or started with some bulk composition; habitability is sensitive to how chemicals are moved to and around the planet’s surface, and on many planetary interior processes. The availability of bioessential elements is one factor that in turn depends not just on the planet’s bulk chemical composition, but also on its geochemical cycles, the creation of continental land that can be weathered, the chemical and physical communication between the surface and mantle via outgassing, the tectonic mode, possibly magnetic fields, and other interior processes. On the other hand, life itself might shape such interior processes by mediating crustal properties and geochemical cycles, and therefore also impacts surface habitability. We invite interdisciplinary presentations that explore the links between planets’ diverse chemical compositions, interior processes, life, and the habitability of their surfaces — on Earth, in our solar system, and on exoplanets. This session will be co-organized by Vlada Stamenkovic (MIT).

Theme:  How to Build a Habitable Planet
Session Title:  Extraterrestrial Materials and the Emergence of Life
Topic Short Title (listed on abstract submission form):  Extraterrestrial Materials and Emergence of Life
Organizer:  Lydia Hallis (University of Glasgow), lydia.hallis@glasgow.ac.uk
Summary:  A wealth of information about how life developed in our solar system can be gained through the study of meteorites, micrometeorites, and samples returned by missions. Primitive chondritic meteorites are known to contain chemically diverse and heterogeneously distributed organic material. Studying enantiomeric and isotopic enrichments in these organic molecules can indicate where in the solar system they were sourced (e.g., comets, asteroids) and whether they were the source of life’s building blocks on Earth. The discovery of organic carbon in martian meteorites, as well as other chemical (e.g., volatile element content) and mineralogical studies (e.g., to determine ancient weathering conditions) of martian meteorites, highlights the possibility of life on Mars. In this session we will discuss how extraterrestrial materials can indicate how life’s building blocks may be formed in comets and asteroids, the habitability of Mars, and how they may have aided the development of life on Earth and other places. This session is co-organized by  José C. Aponte (NASA Goddard Space Flight Center/Catholic University of America), Zita Martins (Imperial College London), Maitrayee Bose (Arizona State University), and Sandra Pizzarello (Arizona State University).

Theme:  How to Build a Habitable Planet
Session Title:  Radiation and Habitability: Friends or Foes?
Topic Short Title (listed on abstract submission form):  Radiation and Habitability:  Friends or Foes?
Organizer:  Reggie L. Hudson (NASA Goddard Space Flight Center), reggie.hudson@nasa.gov
Summary:  Ionizing radiation provides challenges and opportunities for astrobiologists.  Radiolytic formation and destruction of molecules influence the evolution of biologically-important compounds and radiation can provide the chemical energy needed for biospheres, but radiation also can alter biosignatures and generate false positives, with important implications for the search for extraterrestrial life.  This session will feature a diverse group of presentations related to radiation and habitability.  Particularly welcome are relevant studies of Europa and other moons; molecular survival and habitability at Mars; alterations of planetary atmospheres, surfaces, and subsurfaces, including past and present Earth; radiation and exoplanet habitability; preservation and detection of biosignatures; radio-tolerance and mutations of microorganisms; and the evolution of cosmic-ray fluxes.  Observational, theoretical, and laboratory contributions are invited, including studies related to radiation sources both steady and intermittent, such as nearby supernovae, gamma-ray bursts, and, according to recent research, solar-type stars.  Implications and insights for current and planned space missions are also invited.  This session is co-organized by Lewis Dartnell (University of  Leicester), Perry Gerakines (NASA Goddard Space Flight Center), Adrian Melott (University of  Kansas), Alexander Pavlov (NASA Goddard Space Flight Center), and Henry Sun (Desert Research Institute).

Theme:  How to Build a Habitable Planet
Session Title:  Interstellar Chemical Evolution:  Astrochemistry from Atoms to Amino Acids
Topic Short Title (listed on abstract submission form):  Interstellar Chemical Evolution
Organizer:  Brett A. McGuire (National Radio Astronomy Observatory/California Institute of Technology), bmcguire@caltech.edu
Summary:  The seeding of nascent worlds by (pre-)biotic molecules as the genesis of life-essential biopolymers has been an exciting line of inquiry for decades.  The detection of the simplest amino acid, glycine, by the Stardust mission has only intensified this interest in recent years.  Yet the chemical-evolutionary routes leading to the formation of glycine, and other (pre-)biotic molecules in the interstellar medium, remain an open question.  As these chemical inventories comprise the building blocks from which habitable planets may eventually form, understanding their formation and reaction pathways is critical. This session invites contributions from observational, laboratory, and theoretical astrochemistry examining all aspects of complex chemical evolution in the interstellar medium.  Special emphasis is placed on the role of physical environment, in particular the chemistry occurring on and within the icy mantles of dust grains, and the interplay between these reactions and the gas-phase chemistry, in driving molecular inventories toward increased complexity.  This session is co-organized by Lahouari Krim (Université Pierre et Marie Curie-Paris VI) and Brandon Carroll (California Institute of Technology).

Theme:  How to Build a Habitable Planet
Session Title:  Beyond the Catastrophe:  Impact-Generated Environments and the Search for Life
Topic Short Title (listed on abstract submission form):  Beyond the Catastrophe:  Impacts and the Search for Life
Organizer:  Haley Sapers (The University of Western Ontario), haley.sapers@gmail.com
Summary:  Meteorite impact events create unique microbial niches that may have served as significant habitats on early Earth and are important astrobiological targets on other rocky bodies such as Mars. Impact-generated lithologies represent understudied microbial habitats both for microbial colonization as well for the potential to preserve evidence of biological activity. During the late heavy bombardment (LHB) (a period affecting the early inner solar system), the impact flux on the early Earth and other inner planets was significantly higher. Intriguingly, the earliest evidence for life on Earth coincides with the end of the LHB, thereby suggesting that impact events profoundly influenced the early evolution, if not origin, of life. Considering the ubiquity of impact events in the solar system and the effect they undoubtedly have on the habitability of a planet, a better understanding of the biological potential of such environments has implications for current and future life-detection missions. This session will explore the habitability of ancient and modern impact-generated substrates and environments, the possible effects on the origins and evolution of life, and the potential of such systems to preserve biosignatures. The co-organizers of this session are Alexandra Pontefract (The University of Western Ontario), Peter Schultz (Brown University), and Greg Fournier (Massachusetts Institute of Technology).

Theme:  How to Build a Habitable Planet
Session Title:  The Habitability of Water-Rock-Supported Ecosystems
Topic Short Title (listed on abstract submission form):  The Habitability of Water-Rock-Supported Ecosystems
Organizer:  Alexis Templeton (University of Colorado), alexis.templeton@colorado.edu
Summary:  Rocky planets can power living systems through chemical energy released through the interaction of rocks with water. Astrobiological investigations commonly use a thermodynamic framework to predict the habitability of planetary environments based upon the disequilibrium between rocks, minerals, aqueous species, and gases. Rock-hosted chemosynthetic ecosystems play a key role in sustaining contemporary life in near-surface environments and are likely to have done so since early in Earth history. This session invites papers that focus on recent investigations of water-rock systems that explore mechanisms of energy transduction supporting resident microbial populations.  Of particular interest are studies that combine theoretical, experimental, and observational approaches to extend the habitably boundaries or limits for life in contemporary water-rock supported ecosystems, with application toward processes that fueled early life or that can guide the search for signatures of life on other planets. This session is co-organized by Eric Boyd (Montana State University) and Eric Roden (University of Wisconsin.)

Theme:  How to Build a Habitable Planet
Session Title:  Extreme Earth:  Omics Research on Microbial Communities, Their Chemistries, and What it Means for Life in the Solar System
Topic Short Title (listed on abstract submission form):  Extreme Earth:  Omics Research on Microbial Communities
Organizer:  Samantha Marie Waters (Georgia Institute of Technology), samwaters@gatech.edu
Summary:  Understanding how life on Earth adapts to and contributes to the chemistry of extreme environments may elucidate how life has shaped the planet, ultimately broadening our definition of habitability in our search for extraterrestrial life. Advances in next-generation technologies have revolutionized the ability to describe members of communities (metagenomics), how these communities respond to environmental changes (metatranscriptomics), what functional role these organisms contribute to biogeochemical cycles (metaproteomics and metabolomics), and how select organisms have evolved to thrive (adaptive mutation). This session will cover all aspects of extremeomics and welcomes presenters to share their research and how it informs on (1) the search for extraterrestrial life, (2) how Earth life has evolved and adapted to extreme environments, and (3) how microorganisms have ultimately shaped our planet and possibly more distant worlds. This session is co-organized by Wesley Swingley (Northern Illinois University) and Katrina Twing (Michigan State University).

Theme:  How to Build a Habitable Planet
Session Title:  Gravity and Its Impact on Life
Topic Short Title (listed on abstract submission form):  Gravity and Its Impact on Life
Organizer:  Jamie S. Foster (University of Florida), jfoster@ufl.edu
Summary:  Gravity is one of the few constant environmental factors on Earth, yet little is known about how this force has impacted the evolution of life. Through experimentation using simulated microgravity and spaceflight, new insights have been gained to understand how microbes, plants, and animals have responded to changes in gravity across the g-spectrum. This session will examine what happens to life when gravity changes and whether by removing gravity we can learn new processes by which life responds to changes in its environment that may otherwise go undetected in normal terrestrial conditions. This session is co-organized by Giorgio Casaburi (University of Florida).

Theme:  How to Build a Habitable Planet
Session Title:  Determining the Origin and Nature of Prebiotic Species in Comets
Topic Short Title (listed on abstract submission form):  Determining the Origin and Nature of Prebiotic Species in Comets
Organizer:  Stefanie Milam (NASA Goddard Space Flight Center), stefanie.n.milam@nasa.gov
Summary:  Sublimated molecular ice, silicate dust, and solid-state carbonaceous materials are the major components of cometary comae that can be studied by space- and groundbased observations, as well as by rendezvous missions. Multiple organic molecules are now routinely detected, including ethylene glycol and formamide, as well as a number of unidentified lines in bright comets that suggest that other organic/prebiotic molecules may be present and detectable in comets. New facilities, such as ALMA, with improved sensitivity using state-of-the-art detectors, will facilitate the detection of additional new species in comets and will dramatically increase the number of possible comets in which to conduct searches. This session invites contributions from comet observations at all wavelengths, investigating the inventory and origin of cometary organics. A special emphasis is placed on the roles of new facilities, instruments, and techniques to decipher the molecular origin and distribution of prebiotic species in cometary comae.

Theme:  How to Build a Habitable Planet
Session Title:  Life in the Anthropocene: The Future of Earth's Biosphere
Topic Short Title (listed on abstract submission form):  Life in the Anthropocene: The Future of Earth's Biosphere
Organizer:  Jacob Haqq-Misra (Blue Marble Space Institute of Science), Jacob@bmsis.org
Summary: The distant future of Earth's biosphere will be shaped by the balance among factors such as orbital variations in solar insolation, cycles in glacial coverage, the carbonate-silicate cycle, and the resonating effects of anthropogenic climate change. Even longer geologic timescales will force the climate to adapt to a steadily brightening sun by drawing down atmospheric carbon dioxide until habitable conditions no longer remain. This poster session invites contributions that consider potential threats or challenges to the future of civilization, life, and climate from factors that will affect the Earth system over the next 100,000 to million years or longer.

The Origins and Subsequent Evolution of Life

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Mechanisms for the Prebiotic Emergence of Homochirality
Topic Short Title (listed on abstract submission form):  Mechanisms for the Prebiotic Emergence of Homochirality
Organizer:  Jose C. Aponte (NASA Goddard Space Flight Center), jose.c.aponte@nasa.gov
Summary:  Although homochirality is essential to life on Earth, the mechanism behind its emergence remains an unanswered question in astrobiology and origins of life research. The lefthanded enantiomeric excess found for a few chiral meteoritic amino acids may trace a link between these extraterrestrial molecules and all living systems on Earth. In this session we will discuss the various processes that may have influenced the emergence of homochirality in life on Earth. These include processes that occurred before the formation of our solar system, during parent body accretion/alterations, or on the prebiotic Earth, as well as the influence of chirality on the emergence of early life. This session is co-organized by Jamie Elsila (NASA Goddard Space Flight Center) and Ronald Breslow (Columbia University).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Co-Evolution of Compartmentalization, Metabolism, and Informational Polymers
Topic Short Title (listed on abstract submission form):  Co-Evolution of Compartmentalization, Metabolism, and Informational Polymers
Organizer:  Aaron Engelhart (Massachusetts General Hospital/Harvard Medical School), engelhart@molbio.mgh.harvard.edu
Summary:  This session is devoted to examining the co-evolution of compartmentalization, metabolism, and informational polymers, which were the essential ingredients for the emergence of cellular life. Considerable progress has been made toward understanding and constructing simple chemical systems in which these ingredients are utilized to recapitulate primitive cell-like behaviors. Special emphasis has been placed on compartmentalization, which is perhaps the key hallmark of cellular life. Attention has been focused on fatty acid vesicles, which are likely models for ancestors of phospholipid cell membranes, as well as recently described, very distinct compartmentalization methods, such as electrostatic coacervates and aqueous two-phase systems. Toward elaborating these assemblies into protocells, topics of particular interest in this session include recent advances in (1) potential pathways for the evolution of prebiotic compartments into contemporary cell membranes and (2) the coupling between compartment dynamics (e.g., growth, permeability, and division) and internal metabolic processes. This session is co-organized by Andrew Pohorille (NASA Ames Research Center).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Exploring the Effects of Stress on Microbial Mutation Rates and Survival Strategies
Topic Short Title (listed on abstract submission form):  Exploring the Effects of Stress on Microbial Mutation Rates and Survival Strategies
Organizer:  Bruce Fouke (University of Illinois at Urbana-Champaign), fouke@illinois.edu
Summary:  The origins of life were almost certainly accompanied by an explosion of diversity caused both by inaccurate replication and selection for different strategies under varied environmental conditions. As some species prevailed, however, greater replication fidelity would be favored to avoid deleterious errors, leading to lower mutation rates. Yet the severe and fast-changing environment on early Earth meant that adaptations were transient, and that novel solutions could be accessed once again by new mutations, perhaps induced by high-gradient physical and chemical stressors or made more frequent by error-prone replication. The forces that govern this mutation-selection balance remain uncertain, represent an active area of research enabled by contemporary genomics and experimental evolution, and are central to understanding the evolution of biocomplexity. The evolution of lineages with high mutation rates — mutators — is commonly seen today in clonally reproducing microbes and tumor cells. This session will explore how gradients in environmental complexity and stress may indirectly favor mutators at different rates, and even influence the behavior of organisms in ways affecting their mutagenicity, evolution, and survival. This session is co-organized by Vaughn Cooper (University of New Hampshire), Susan Rosenberg (Baylor College of Medicine), Philip Hastings (Baylor College of Medicine), and Charles Werth (University of Texas at Austin).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  The Beginning and End of the RNA World from the Perspective of Ribosome Origins and Evolution
Topic Short Title (listed on abstract submission form):  The Beginning and End of the RNA World from Ribosome Origins and Evolution
Organizer:  George E. Fox (University of Houston), fox@uh.edu
Summary:  Being an RNA machine, the ribosome is often cited as strong evidence for the existence of an ancestral RNA world in which RNA was the principal informational molecule and catalyst. But is it? The advent of ribosomal protein synthesis with its ability to provide peptides that could augment or replace RNA catalysts may have instead almost immediately ended the RNA world in favor of an RNA/peptide world. But what do we know about the origin and evolution of the ribosome? Or, for that matter, the origin and evolution of the RNA that is essential to creating a protoribosome? This session will focus on both ends of this RNA story:  where RNA came from and how primitive ribosomes generated protein that (mostly) took its place.  Topics will include:  (1) investigations into how chemical evolution may have produced the RNA needed to establish a primitive ribosome prior to replication on the prebiotic Earth and (2) insights into the order and manner in which various ribosomal subsystems arose.  This session is co-organized by Harold Bernhardt (University of Otago).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Laws of Life:  Exploring Universal Biology Through Computer Simulation
Topic Short Title (listed on abstract submission form):  Laws of Life:  Exploring Universal Biology Through Computer Simulation
Organizer:  Nigel Goldenfeld (University of Illinois at Urbana-Champaign), nigel@illinois.edu
Summary:  This session will feature papers that report on applications of digital life in areas relevant to astrobiology, including but not limited to evolution of chemical networks, role of fluctuating environments in evolutionary ecology, dynamics of information systems, evolutionary transitions, dynamics of horizontal gene transfer, genome dynamics over evolutionary time, rapid evolution and co-evolution, and the open-ended growth of complexity. This session is co-organized by Chris Adami (Michigan State University) and Piet Hut (Princeton University).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  New Life in the Laboratory
Topic Short Title (listed on abstract submission form):  New Life in the Laboratory
Organizer:  Michael Hecht (Princeton University), hecht@princeton.edu
Summary:  The field of astrobiology focuses on three questions:   (1) How did life on Earth originate?  (2) Is there life in the universe beyond planet Earth?  (3) Can we create new life in the laboratory?   This session will focus on the third question by exploring recent experimental and theoretical work aimed at devising novel genes, proteins, cells, and organisms on our path toward the ultimate goal of creating life from scratch.  As noted by the Swiss organic chemist, Albert Eschenmoser, “The origin of life cannot be discovered, it has to be re-invented.”  Presentations in this session will highlight how far we have come toward “Life Reinvented.”  This session is co-organized by Rafal Wieczorek (Harvard University).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  From Prebiotic Chemistry to Functional Biopolymers:  Mapping the Origins and Evolution of Possible Chemistries for Life
Topic Short Title (listed on abstract submission form):  From Prebiotic Chemistry to Functional Biopolymers
Organizer:  Nicholas V. Hud (Georgia Institute of Technology), nicholas.hud@chemistry.gatech.edu
Summary:  The origin of functional biomolecules and macromolecular catalysts was a critical step in the emergence of life. An important question is therefore:  How were functional biopolymers first selected, and what were their properties? More specifically, are life’s biopolymers somehow special, or are alternative chemistries possible — particularly in the earliest stages of chemical evolution? To address these questions, we seek contributions that explore the evolution of functional nucleic acids and peptides, including those composed of monomers or backbones not utilized in modern biological systems spanning the gamut of possible chemistries for life. Other topics of interest include covalent synthesis and non-covalent assemblies of biopolymers, and the relationship between information content and function. We invite contributions from researchers working in both experiment and theory that bridges the chemical/biological interface to contribute to this session. By exploring early functional evolution we hope to identify why nature settled on the molecules found in life today and how life may have differed when it first originated. This session is co-organized by Sara Walker (Arizona State University) and Raghav Poudyal (University of Missouri).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Chance and Necessity:  From Molecules and Viruses to Cells and Populations
Topic Short Title (listed on abstract submission form):  Chance and Necessity:  From Molecules and Viruses to Cells and Populations
Organizer:  Betul Kacar (Georgia Institute of Technology), betul@gatech.edu
Summary:  Scientists have limited means with which to infer the exact evolutionary events that occurred to produce contemporary living systems. This historical limitation obscures our ability to confidently assess the relative impacts of chance and necessity upon life’s origins and subsequent radiation across Earth. Are the evolutionary paths of living systems inherently random and subject to completely different outcomes if repeated under identical initial conditions? Or are the shapes of these paths predominantly constrained by internal or external controlled processes? This session will focus on inferring how evolutionary mechanisms such as chance events, population bottlenecks, genetic drift, the virus-host arms race, or environmental selection pressure affect evolutionary outcomes at the level of nucleic acids, proteins, viruses, cells, and populations. We invite studies that include perspectives from nucleic acid or protein evolution, virology, bioinformatics, molecular and synthetic biology, and culture-based analyses, with the common goal of elucidating the evolutionary mechanisms of life at both the molecular and population levels. By exploring the molecular mechanisms that led to life, as we now know it, we ultimately hope to arrive at a better understanding of why life on Earth is the way it is and how it may have developed elsewhere. This session is co-organized by Rika Anderson (NASA Postdoctoral Program/University of Illinois at Urbana-Champaign), Jim Cleaves (Earth Life Science Institute), Gustavo Caetano-Anolles (University of Illinois at Urbana-Champaign), and Ken Stedman (Portland State University).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Major Transitions in Evolution:  Catalysts and Constraints in the Origins of Biological Complexity
Topic Short Title (listed on abstract submission form):  Major Transitions in Evolution:  Catalysts and Constraints
Organizer:  William Ratcliff (Georgia Institute of Technology), will.ratcliff@biology.gatech.edu
Summary:  How and why complex organisms evolve remain fundamental questions in astrobiology. On Earth, complex life has evolved through a series of “‘major transitions’,” in which formerly autonomous individuals become parts of new, higher-level individuals. For example, chromosomes are thought to have evolved from autonomous genetic replicators, eukaryotes from multiple prokaryotic ancestors, multicellular organisms from unicellular ancestors, and eusocial “‘superorganisms”‘ from solitary multicellular ancestors. Despite this clear historical signature, the evolutionary dynamics underlying major transitions remain poorly understood. In this session, we will take an interdisciplinary approach to answering the question:  What factors promote and hinder the evolution of biological complexity? We are especially interested in talks focusing on the evolutionary balance between cooperation and conflict; how the spatial dynamics of group formation affect evolutionary feedbacks; how nascent higher-level entities gain the capacity to evolve as Darwinian individuals; the causes and consequences of novel, higher-level life cycles; and how the presence of complex life may be inferred or detected elsewhere in the universe. This session is open to both theorists and experimentalists. This session is co-organized by Matthew Herron (University of Montana) and Zach Adam (Harvard University).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  How Can Modern Microbes Inform our Understanding of Ancient Earth Ecosystems?
Topic Short Title (listed on abstract submission form):  How Can Modern Microbes Inform Ancient Earth Ecosystems?
Organizer:  Paula Welander (Stanford University), welander@stanford.edu
Summary:  The history of life on Earth has been dominated by microorganisms whose metabolic inventions have had, and continue to have, a significant impact on Earth environments. Studies of microbial physiology therefore have the potential to unlock geobiological secrets preserved in the rock record. However, linking modern molecular, geochemical and environmental studies to our interpretation of ancient ecosystems remains a challenge. Recent advances in this field have been made by integrating biochemistry, molecular evolution, isotopes, gene/protein phylogeny and “(meta)-omes” (metagenomes, transcriptomes, proteomes). This session invites presentations on any aspect of microbial physiology in a geological or astrobiological context with a particular focus on interdisciplinary studies linking geochemistry, microbiology, inorganic/organic biochemistry, molecular evolution and other fields.  This session is co-organized by Jennifer Glass (Georgia Institute of Technology).

Theme:  The Origins and Subsequent Evolution of Life
Session Title:  Crossing the Darwinian Threshold
Topic Short Title (listed on abstract submission form):  Crossing the Darwinian Threshold
Organizer:  Rachel Whitaker (University of Illinois at Urbana-Champaign), rwhitaker@life.illinois.edu
Summary:  The Darwinian Threshold, in which independent lineages first appeared, changed biological systems from an exclusively communal lifestyle to one more based on individuality.  Evolution within individual lineages increased the complexity of biological systems irreversibly.  What evolutionary innovations were responsible for the initial bifurcations in the domains of life? Did each of these domains cross this threshold at the same time, and in the same way?  What features of modern bacteria distinguish them from the Archaea/Eukaryote ancestor?  How would this affect the initial bifurcations that took place? What features are present in today’s microbial world that maintain species as individual units?  This session will examine the common cellular features that hold individual lineages together, and keep them apart. In addition, we will identify cellular, genetic, physiological, and biochemical features that may have determined when and how lineages crossed the threshold of individuality. This session is co-organized by R. Thane Papke (University of Connecticut).

Sustained Habitability on a Dynamic Early Earth

Theme:  Sustained Habitability on a Dynamic Early Earth
Session Title:  Earth’s Early Biosphere:  Life on an "Alien" Planet
Topic Short Title (listed on abstract submission form):  Earth’s Early Biosphere:  Life on an "Alien" Planet
Organizer:  Andrew D. Czaja (University of Cincinnati), andrew.czaja@uc.edu
Summary:  Unraveling the early history and evolution of life on Earth is fundamental for understanding our origins. But studying Earth’s early biosphere, which evolved under environmental conditions very different than today’s, also expands our frame of reference for understanding life elsewhere in the universe. Our main lines of evidence for early life are fossilized microorganisms, fossilized microbial structures, and geochemical proxies of microbial metabolisms. Work in this field has accelerated recently due in part to advancements in microscopy, spectroscopy, and mass spectrometry. This work includes the discovery of previously unknown and unique types of microfossils, as well as the development of organic and inorganic geochemical and isotopic proxies that have expanded our understanding of the metabolic diversity and evolutionary history of early life. This session will explore the evolution and diversity of early life as revealed by such morphological and geochemical evidence. Studies combining multiple and/or novel techniques are particularly encouraged.

Theme:  Sustained Habitability on a Dynamic Early Earth
Session Title:  Phototrophic Life and Earth’s Redox Evolution
Topic Short Title (listed on abstract submission form):  Phototrophic Life and Earth’s Redox Evolution
Organizer:  Trinity Hamilton (University of Cincinnati), trinity.hamilton@uc.edu
Summary:  Photosynthesis is the only significant solar energy storage process on Earth, and this type of metabolism dominates modern as well as ancient surface environments. In this session, we aim to highlight the current understanding of the origin and evolution of photosynthesis and provide a platform for new hypotheses and future challenges. Important topics include (but are not limited to) the role of phototrophs in Earth’s redox evolution, key events in the development of photosynthetic machinery, the transition from anoxygenic to oxygenic photosynthesis, isotopic and geochemical biosignatures of photosynthesis in modern and ancient environments, and characterization of the biochemistry, physiology, or ecology of extant phototrophs and their ecological niches.  This session is co-organized by Bob Blankenship (Washington University in St. Louis), Nikki Parenteau (SETI Institute), Nancy Kiang (NASA Goddard Institute for Space Studies), and Jenn Macalady (Pennsylvania State University).

Theme:  Sustained Habitability on a Dynamic Early Earth
Session Title:  The Emergence of Life at the Intersection of Prebiotic Chemistry and Early Earth Environments:  Putting Scenarios to the Test
Topic Short Title (listed on abstract submission form):  The Emergence of Life at Prebiotic Chemistry and Early Earth Environments
Organizer:  Linda B. McGown (Rensselaer Polytechnic Institute), mcgowl@rpi.edu
Summary:  The interplay between prebiotic chemistry and the environment(s) in which life emerged is a complex yet essential consideration in understanding origins of life. The dynamic geological landscapes of early Earth undoubtedly played an active role in the chemical transformations leading to the first biomolecules and their appropriation into the earliest “cells.” Environments such as deep crustal domains, deep-sea hydrothermal systems, and shallow surface pools offered diverse conditions with wide ranges in temperature, pressure, pH, redox potential, mineralogy, and hydration state, often with gradients or cyclical changes. These parameters could not only constrain the synthesis and stability of molecular precursors to life, but also affect sequence and chiral selectivity. For example, it has been proposed that alkaline vents resulting from serpentinization acting in the floor of the Hadean ocean generated a suite of essential preconditions for the initial events in the emergence of life, preconditions that necessarily entail specific structural, geochemical, and (non-equilibrium) thermodynamic components. The focus of the session will be on the status of ongoing efforts to put the core mechanisms of this and other scenarios to experimental test. We will bring together researchers from both sides of the problem — experts in early Earth environments and experts in prebiotic chemistry — to explore this and alternative scenarios in this highly interdisciplinary approach to origins of terrestrial life.  This session is co-organized by Michael Russell (Jet Propulsion Laboratory/ California Institute of Technology) and Karyn L. Rogers (Rensselaer Polytechnic Institute).

Theme:  Sustained Habitability on a Dynamic Early Earth
Session Title:  Early Earth as an Extrasolar Planet
Topic Short Title (listed on abstract submission form):  Early Earth as an Extrasolar Planet
Organizer:  Sanjoy Som (Blue Marble Space Institute of Science), sanjoy@bmsis.org
Summary:  The quantity and range of planets detected by ongoing planet searches suggests that Earth-sized terrestrial planets within the habitable zone of their host star are within detection capabilities. Work is underway to constrain the spectral signatures of how modern Earth would appear at a distance. Yet the spectral signature of early Earth would have been significantly altered from present-day Earth because of the impact of different biogeochemical processes on atmospheric properties. This session invites contributions that seek to characterize early Earth’s environment through theoretical, experimental, and field investigations, with particular emphasis toward research that will better constrain the past spectral signature of the early Earth. This includes, but is not limited to, research on past "strange" epochs in Earth history (e.g., snowball Earth, pre-rise of oxygen), work on the differences in active metabolisms at different points in Earth history, and work on the global properties of a prebiotic Earth.

Theme:  Sustained Habitability on a Dynamic Early Earth
Session Title:  Mission to Early Earth:  Co-Evolving Archean and Proterozoic Oceans, Atmospheres, and Life
Topic Short Title (listed on abstract submission form):  Mission to Early Earth:  Archean and Proterozoic Oceans, Atmospheres, and Life
Organizer:  Timothy Lyons (University of California-Riverside), timothyl@@ucr.edu
Summary:  Despite experiencing changes as dramatic as a warming Sun and cooling interior; continents nucleating and growing, stabilizing, and then interacting for the first time; extreme glaciations; and fundamental shifts in the redox state of surface environments, Earth has remained habitable and indeed inhabited for most of its dynamic history.  This session explores the processes and feedbacks that favored these persistently favorable but diverse “‘alternative Earths”‘ from a systems perspective that spans numerical simulations of the oceans and atmosphere, novel biogeochemical proxy approaches, plate tectonic and climatic drivers, nutrient models, initial and varying biospheric oxygenation, deep-shallow Earth interactions, and the backdrop of co-evolving life — all with an eye toward the early Earth as a search engine for habitability and life in the broader universe. This session is co-organized by Christopher T. Reinhard (Georgia Institute of Technology) and Noah J. Planavsky (Yale University).

Habitable Worlds in Our Solar System

Theme:  Habitable Worlds in Our Solar System
Session Title:  Astrobiology and the Next Mars Rover Missions:  Site Selection, In Situ Science, and Returned Sample Science
Topic Short Title (listed on abstract submission form):  Astrobiology and the Next Mars Rover Missions
Organizer:  Abigail Allwood (Jet Propulsion Laboratory), Abigail.C.Allwood@jpl.nasa.gov
Summary:  The past decade of Mars exploration has revealed diverse ancient aqueous environments that exhibit varying degrees of habitability and likelihood for preservation of biosignatures. The Mars 2020 and ExoMars rovers will take the next logical step and search for potential signatures of past life through extensive in situ investigations and, in the case of the Mars 2020 rover, selecting and caching samples for possible future return to Earth. Together, the in situ and returned sample analyses will bring unprecedented scientific capability to focus on the search for evidence of life on Mars. In preparation for this important opportunity, this session seeks diverse contributions relating to the search for potential clues to past life on Mars, including terrestrial analog studies; field or laboratory research on biosignature preservation and biosignature detection; novel methods, instruments or techniques for biosignature analysis in returned samples; and papers on sample integrity, contamination, and receiving/handling.  The selection of the landing site for each of these missions is of critical importance, and therefore we particularly seek contributions relating to assessment of the astrobiological potential of Mars landing sites. This session will continue the discussion of habitability issues raised at the first Mars 2020 landing site meeting and discussed at the 2014 AGU fall meeting. The synthesis of this session will be carried forward to future landing site meetings and to the mission science teams. This session is co-organized by Kennda Lynch (Colorado School of Mines), Briony Horgan (Purdue University), David Beaty (Jet Propulsion Laboratory), and Ken Williford (Jet Propulsion Laboratory).

Theme:  Habitable Worlds in Our Solar System
Session Title:  The Habitability of Icy Worlds
Topic Short Title (listed on abstract submission form):  The Habitability of Icy Worlds
Organizer:  Patricia M. Beauchamp (Jet Propulsion Laboratory/Caltech), pbeaucha@jpl.nasa.gov
Summary:  This session will be a follow-on to the workshop by the same name, held in Pasadena in February 2014. The primary objective is similar and will focus on the astrobiological potential of icy worlds in the outer solar system — including Europa, Ganymede, Enceladus, Titan, and beyond — with discussion on future research directions and spacecraft missions that can best assess that potential given the unique planetary environments of the outer solar system. Comparative planetology presentations are encouraged as well as research involving terrestrial analogs.  Topics covered include (but are not necessarily limited to) water and exotic solvents, chemical energy for life, organics and their detection, ocean physics and chemistry, icy world activity and habitability over time, and continuing and future outer solar system exploration. This session is co-organized by David Senske (Jet Propulsion Laboratory).

Theme:  Habitable Worlds in Our Solar System
Session Title:  Environmental Change and the Evolution of Planetary Habitability
Topic Short Title (listed on abstract submission form):  Environmental Change and the Evolution of Planetary Habitability
Organizer:  Nathalie A. Cabrol (The SETI Institute Carl Sagan Center/NASA Ames Research Center), Nathalie.A.Cabrol@nasa.gov
Summary:  Environmental change can be used as a scientific bridge relating astrobiology to Earth, planetary, and space sciences in the study of how life may adapt through abrupt climate crises. Recent discoveries inspire us to reexamine our understanding of how rapidly planetary habitats can be redistributed. Past habitable environments on Mars from the Curiosity rover, possible subsurface lakes and oceans on Europa or Enceladus, methane lakes on Titan, and potentially habitable exoplanets from the Kepler spacecraft continue to expand our definition of the habitable zone. Abstracts on the intertwined aspects of changing habitability, including the complex interactions among astronomical, geological, and climatic forces, on Earth and beyond, are welcome.

Theme:  Habitable Worlds in Our Solar System
Session Title:  Habitability of Dwarf Planets:  State of the Landscape (Right) Before Dawn and New Horizons
Topic Short Title (listed on abstract submission form):  Habitability of Dwarf Planets:  Before Dawn and New Horizons
Organizer:  Julie Castillo-Rogez (Jet Propulsion Laboratory/Caltech), julie.c.castillo@jpl.nasa.gov
Summary:  Icy dwarf planets have been identified early on as targets of major astrobiological significance. 2015 celebrates these objects with two missions, Dawn and New Horizons, which will reach Ceres (April) and Pluto and Charon (July), respectively. This conjunction of missions offers the prospect for exciting comparative planetology between the warm icy body Ceres and the frigid Pluto and Charon. All display evidence for recent or ongoing activity and are suspected to have hosted extensive hydrothermal activity. This session will review our state of understanding of that class of objects in the anticipation of imminent new observations of Ceres and Pluto/Charon, but more generally in the context of the many observations of dwarf planets returned over the past decade.

Theme:  Habitable Worlds in Our Solar System
Session Title:  Titan’s Organic Chemistry and Insights Into Habitability
Topic Short Title (listed on abstract submission form):  Titan’s Organic Chemistry and Insights Into Habitability
Organizer:  Martin Cordiner (NASA Goddard Space Flight Center/Catholic University of America), martin.cordiner@nasa.gov
Summary:  Titan’s atmosphere and surface are rich in organic, possibly prebiotic material. Underpinned by laboratory simulations, remote and in situ measurements of hydrocarbons, nitriles, and oxygen-bearing species provide insight into Titan’s organic atmospheric chemistry.  These studies yield information regarding the likely conditions prevalent on young (nonaqueous) planets in our own solar system and beyond. The scope of this joint observational and laboratory-focused session is two-fold:  (1) to include new work on observations and modeling of molecules in Titan’s atmosphere, including multi-wavelength groundbased observations, in situ (Cassini) measurements, and photochemical and dynamical modeling; and (2) to explore the nonaqueous chemistry of Titan’s surface and how this challenges our current definitions of habitability, based both on experimental data (from the lab or mission science) and modeling results.  An emphasis will be placed on topics relating to the formation and evolution of molecules that could be relevant to the chemistry of life. This session is co-organized by Morgan Cable (Jet Propulsion Laboratory/California Institute of Technology).

Theme:  Habitable Worlds in Our Solar System
Session Title:  Past and Extant Life Search Strategies for Habitable Environments on Mars:  How Should We Proceed?
Topic Short Title (listed on abstract submission form):  Past and Extant Life Search Strategies for Habitable Environments on Mars
Organizer:  Alexander A. Pavlov (NASA Goddard Space Flight Center), alexander.pavlov@nasa.gov
Summary:  Because Mars exhibits diverse environments that have varied greatly with location, age, and duration, multiple complementary strategies for exploration should be considered. Searching for “past” vs. “extant” life on Mars requires different and sometimes mutually exclusive approaches in landing site selection and the choice of instruments for future martian rovers. Current and near-future missions to Mars focus on the search for the evidence of past life in the surface rocks. But recent experimental results on the bacterial growth under martian conditions and evidence of atmospheric methane variability indicate that the search for “extant life” on Mars should not be discarded. “Past" life search strategies must respond to observations from recent and current surface missions (e.g., MSL) and experimental studies of organic preservation under martian conditions. This session invites scientists to present new experimental studies, observations, or modeling results that would enhance “past” or “extant” life search strategies in future missions to Mars. We seek to initiate a comprehensive discussion among proponents of diverse strategies to characterize any past or present habitable environments and life.  This session is co-organized by David J. Des Marais (NASA Ames Research Center) and Dirk Schulze-Makuch (Washington State University).

Theme:  Habitable Worlds in Our Solar System
Session Title:  Life in the Clouds:  Recent Advances in Upper Atmosphere Exploration
Topic Short Title (listed on abstract submission form):  Life in the Clouds:  Recent Advances in Upper Atmosphere Exploration
Organizer:  David J. Smith (NASA John F. Kennedy Space Center), david.j.smith-3@nasa.gov
Summary:  Maybe the sky is not the limit after all. Microbial taxa from every major biological lineage have been detected in Earth’s upper atmosphere and a vast region of the sky is awaiting further biological exploration. This session invites research aerobiology research relevant to the astrobiology community. The upper altitude biosphere boundary, airborne microbial activity in clouds, habitable atmospheres (solar system and exoplanets), extremophiles, contamination control, and planetary protection are just some of the broader astrobiology topics that can be examined in this session.

Theme:  Habitable Worlds in Our Solar System
Session Title:  Martian Habitability as Informed by Past and Ongoing Orbital, Lander, and Rover Missions
Topic Short Title (listed on abstract submission form):  Martian Habitability by Past and Ongoing Orbital, Lander, and Rover Missions
Organizer:  Mary Beth Wilhelm (Georgia Institute of Technology/NASA Ames Research Center), wilhelm.marybeth@gmail.com
Summary:  The last few decades of Mars exploration by orbital assets, landers, and rovers has focused on building our perspective on martian habitability by understanding the planet’s many environments with an integrated set of measurements. While the definition of what makes an environment habitable has evolved as the field of astrobiology has matured, so has our understanding of potentially currently habitable regions as Mars, sites of ancient habitability, and regions of increased preservation potential for biomarkers. The purpose of this session is to highlight the recent advances in understanding of martian habitability through current and previous observations of Mars’ climate, glaciology, mineralogy, surface geochemistry, and organic chemistry.  We invite abstracts with emphasis on data return from landers, rovers, and orbiters on the habitability potential (present or past) of specific regions on Mars, but are particularly interested in contributions that integrate lessons from more than one platform into a holistic perspective on martian habitability. These results might derive from the Mars Science Laboratory at Gale Crater, the Opportunity and Spirit Rovers, recent observations made by instruments onboard orbiters such as the Mars Reconnaissance Orbiter and Mars Express, and further interpretation from the Phoenix and Viking Landers. This session is co-organized by James Wray (Georgia Institute of Technology).

Theme:  Habitable Worlds in Our Solar System
Session Title:  Ice-Covered Seas on Earth and Icy Moons as Biogeochemical Systems
Topic Short Title (listed on abstract submission form):  Ice-Covered Seas on Earth and Icy Moons as Biogeochemical Systems
Organizer:  Dale P. Winebrenner (University of Washington), dpw@uw.edu
Summary:  It now appears that ice-covered lakes and seas may be numerous in the outer solar system, notably including those on Europa and Enceladus, as well as on Earth.  Whether such seas are inhabited, however, remains completely unknown, even for most Antarctic subglacial lakes (with the exceptions of the Dry Valley lakes, Lake Whillans and perhaps Lake Vostok).  The question hinges not on the presence of water, but rather on the energy required for life, i.e., quantitative habitability.  Investigation of actual and possible biogeochemistry in ice-covered seas is thus important for understanding whether  ice-covered seas on Earth are analogous to outer solar system seas, and for clarifying what chemical analyses of icy moon surfaces and plumes should be pursued.  This session seeks to bring together work pertaining to a variety of ice-covered seas to better understand biochemical scenarios that may be common, or distinct, among seas on various planetary bodies.

Theme:  Habitable Worlds in Our Solar System
Session Title:  Habitability from Afar:  Challenges and Triumphs of Exploring Icy Worlds from Orbital and Flyby Missions
Topic Short Title (listed on abstract submission form):  Habitability from Afar:  Exploring Icy Worlds from Orbital and Flyby Missions
Organizer:  Alex Patthoff (Jet Propulsion Laboratory), Donald.A.Patthoff@jpl.nasa.gov
Summary:  The canon of potentially habitable icy worlds includes worlds with strong evidence for present-day oceans — Callisto, Enceladus, Europa, Ganymede, and Titan — and potentially many more.  Robotic missions to explore these worlds, such as the upcoming Jupiter Icy Satellite Explorer, are limited by available resources and technology, so that constraints on habitability must be obtained from orbit or through multiple flybys.  This session invites discussion of mission and measurement strategies for determining the habitability of icy worlds from afar. This session is co-organized by Catherine Walker (Georgia Institute of Technology).

Habitability of Exoplanets

Theme:  Habitability of Exoplanets
Session Title:  Water in Solar System and Extrasolar Habitable Planets
Topic Short Title (listed on abstract submission form):  Water in Solar System and Extrasolar Habitable Planets
Organizer:  Nader Haghighipour (University of Hawaii), nader@ifa.hawaii.edu
Summary:  Water is the medium in which the chemistry of all Earth life takes place. It has modified Earth’s geology and climate to a degree that has allowed life to persist to the present epoch. However, how water appeared on Earth is still an unresolved issue. With the discovery of many super-Earth planets in the habitable zone, this issue has now extended to other planetary systems as well. Whether any of these planets is suitable for life depends critically on the availability of water. We propose a topical session to present and discuss the results of current research on the origin of Earth’s water and its implications for other habitable planets. We plan to bring experts from key areas related to this topic, and will also accept abstracts from the members of the community. By bringing together diverse experts, our session will facilitate progress in this area.

Theme:  Habitability of Exoplanets
Session Title:  Definition and Boundaries of Habitable Zones
Topic Short Title (listed on abstract submission form):  Definition and Boundaries of Habitable Zones
Organizer:  Zsolt Keszthelyi (University Observatory Munich), z.keszthelyi@campus.lmu.de
Summary:  The habitable zone (HZ) is traditionally defined as the region around a star in which liquid water could exist on the surface of a rocky planet, assuming an inventory of H2O and carbon, and the operation of an Earth-like carbonate-silicate cycle. However, some have questioned these premises, arguing that  they are too anthropocentric and that the HZ could be wider if other greenhouse gases (e.g., H2) are considered, restrictions on relative humidity are relaxed, other liquids drive the hydrologic cycle (e.g., CH4), or dense atmospheres are dismissed altogether (e.g., Europa). Other researchers have defined alternative HZ boundaries, such as the continuous HZ, ultraviolet HZ, photosynthesis-sustaining HZ, tidal HZ, and galactic HZ. HZs can also be defined around both young and evolved stars, brown/white dwarfs, and even planets themselves.  This session explores these considerations to determine the HZ definition most suited for the detection and characterization of potentially habitable environments. This session is co-organized by Ramses Ramirez (Cornell University) and Rory Barnes (University of Washington).

Theme:  Habitability of Exoplanets
Session Title:  Finding Habitable Worlds and Life Beyond the Solar System
Topic Short Title (listed on abstract submission form):  Finding Habitable Worlds and Life Beyond the Solar System
Organizer:  Victoria Meadows (University of Washington), vsm@astro.washington.edu
Summary:  What could the near future hold for detecting habitable, and eventually inhabited, extrasolar planets?  This session will focus on the science and technology requirements for the next generation of observatories that will undertake the search for life beyond the solar system.  Topics to be covered in this session include signs of exoplanet habitability and global biosignatures that can be sought with upcoming instrumentation; instrument requirements and technologies to detect these markers; strategies for target selection and prioritization; and impacts of planetary system properties, telescope architecture, and instrument capabilities on the yield of potentially inhabited exoplanets. This session will also be an opportunity to discuss longer term, visionary ideas for finding Earth 2.0 and even technological civilizations — potentially answering the question "Are we alone?"  We encourage abstracts on space- and groundbased facilities and on concepts that can discover potentially habitable worlds around other stars (such as MEarth, Kepler, TESS, and PLATO), as well as characterize them spectrally and temporally (such as groundbased ELTs, JWST, WFIRST, Exo-C, Exo-S, and ATLAST) and search for signs of intelligent life (such as the SKA).  The session will review current perspectives on these topics, consider some even bolder ideas, and imagine where we could be in one, two, or three decades. This session is co-organized by Avi Mandell (NASA Goddard Space Flight Center), Frank Marchis (SETI Institute), and Margaret Turnbull (Global Science Institute).

Theme:  Habitability of Exoplanets
Session Title:  The Diversity of Worlds:  Comparative Planetology and Habitability
Topic Short Title (listed on abstract submission form):  The Diversity of Worlds:  Comparative Planetology and Habitability
Organizer:  Tyler Robinson (NASA Ames Research Center), tyler.d.robinson@nasa.gov
Summary:  Near-future telescopes will observe the atmospheres of rocky exoplanets to search for signs of habitability and global biospheres.  Interpreting the spectral signatures from these worlds will be a difficult task, especially considering the range of potentially habitable or inhabited worlds, from desert planets devoid of life to super-habitable worlds.  By studying Earth’s biosphere as well as the similarities and differences in the rules that govern the atmospheres and interiors of solar system worlds, we can begin to understand how planets, as systems, work.  However, holes exist in our understanding of many key atmospheric and geophysical processes relevant to the origin, maintenance, and development of life on a planet.  We invite presentations on observations and models of the processes that influence planetary habitability and its evolution through time, as well as studies of prototype biospheres that produce spectral or photometric signatures that could be detected by the next generation of exoplanet characterization missions.  This session is co-organized by Abel Mendez (University of Puerto Rico at Arecibo), Rene Heller (McMaster University), and Dirk Schulze-Makuch (Washington State Univeristy).

Theme:  Habitability of Exoplanets
Session Title:  Biosignatures and Technosignatures:  The Search for Inhabited Planets
Topic Short Title (listed on abstract submission form):  Biosignatures and Technosignatures:  The Search for Inhabited Planets
Organizer:  Jill Tarter (SETI Institute/University of Washington), tarter@seti.org
Summary:  The co-evolution of life with its planetary host can modify the planetary environment in many complex ways that can potentially be sensed remotely at great distance. Biosignatures are life’s global footprint on the environment. Their detection relies on being able to identify phenomena that are “out of place” in a sufficiently well-characterized environment. We must also be able to discriminate these life-mediated characteristics from the results of abiotic planetary and atmospheric processes that may act as false positives. Technosignatures are deliberate or inadvertent modifications of the planetary environment as the result of technology, and involve their own set of false positives. It will be important to understand what the generic characteristics of an advanced technological civilization might be in order to discriminate against the false positives. This session encourages the broadest possible discussion of how it may be possible to tell which potentially habitable worlds are actually inhabited. This session is co-organized by Vikki Meadows (University of Washington) and Mario Livio (Space Telescope Science Institute).

Theme:  Habitability of Exoplanets
Session Title:  Understanding Your Parents:  The Challenges of Host Star Characterization for Exoplanet Science
Topic Short Title (listed on abstract submission form):  Understanding Your Parents:  Host Star Characterization for Exoplanet Science
Organizer:  Lucianne Walkowicz (Adler Planetarium/Global Science Institute), LWalkowicz@adlerplanetarium.org
Summary:  The study of exoplanets is intimately enmeshed with our understanding of exoplanetary host stars. As exoplanet detection techniques have become more refined and have pressed discoveries into new regimes (e.g., smaller, more potential Earth-like planets, as well as outward to true Jupiter-like analogs), the field has come to find that in many cases, our limit on what is knowable about the exoplanets discovered is driven by limits on the host star characterization. We invite talks describing what we do and do not know about exoplanet host stars, and which specific new observations or studies could help us the most in characterizing exoplanets. We anticipate that several reports on forthcoming and proposed missions will have been freshly released close to the time of the meeting, making this a particularly timely topic. This session is co-organized by Maggie Turnbull (Global Science Institute).

Identifying and Characterizing Habitable Environments and Habitation

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  Planetary Protection in the Age of Exploration
Topic Short Title (listed on abstract submission form):  Planetary Protection in the Age of Exploration
Organizer:  Ariel Anbar (Arizona State University), anbar@asu.edu
Summary:  Life detection and other missions to astrobiologically relevant solar system bodies are constrained both by treaty and by good practice to exert great care in ensuring minimal contamination potential of microbial passengers and biological materials on spacecraft, and to minimize the risk from returning extraterrestrial organisms on Earth-bound samples. These considerations are driven by the goals of astrobiology research and ethical considerations. With developments ongoing for ExoMars 2018 and Mars 2020, and planning underway for Europa and Enceladus missions, Mars sample return, and future human missions beyond Earth orbit, the need for robust planetary protection policies, procedures, and designs are of increasing importance. This session will address the following questions:  What is the state of the art today, and where must we go to develop new or improved methodologies for accomplishing our planetary protection goals while still producing nimble and capable missions? How do we deal with the eventual conundrum of human exploration while still protecting potentially biologically sensitive sites? What research must be done on the microbiota that may be taken to other worlds by robotic and human spacecraft? This session is co-organized by Penelope Boston (New Mexico Tech), Rakesh Mogul (Cal Poly Pomona), and Margaret Race (SETI Institute).

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  Challenges for the Next Generation of Biosignature Detection Strategies
Topic Short Title (listed on abstract submission form):  Challenges for the Next Generation of Biosignature Detection Strategies
Organizer:  Sherry L. Cady (Pacific Northwest National Laboratory), sherry.cady@pnnl.gov
Summary:  Detection and characterization of potential biosignatures in geological materials on Mars that have high preservation potential and formed in potentially habitable environments are prioritized themes of upcoming space missions, which include the ESA ExoMars 2016 orbiter mission and rover missions by ESA in 2018 and NASA in 2020. The next generation of biosignature detection strategies face key challenges:  Organic compounds near the surface will be altered/destroyed by UV/galactic cosmic rays and difficult to detect using pyrolysis techniques, and evidence for the biogenicity of larger-scale structures can be taphonomically modified. This session invites contributions that address innovatively these technical, experimental, and theoretical challenges via orbital and high-resolution in situ and lab-based technologies that target chemical and morphological evidence for life across multiple spatial scales in outcrop and via drill cores.  This session is co-organized by Charles Cockell (University of Edinburgh),  Lewis Dartnell (University of Leicester), Magnus Ivarsson (Swedish Museum of Natural History), Chris McKay (NASA Ames Research Center), Anna Neubeck (Stockholm University), Russell S. Shapiro (California State University, Chico), and Manish R. Patel (Open University).

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  Energy in Extreme Environments
Topic Short Title (listed on abstract submission form):  Energy in Extreme Environments
Organizer:  Yuri Gorby (Rensselaer Polytechnic Institute), gorbyy@rpi.edu
Summary:  Electron transfer is central to all of life’s energy conversion pathways. Microorganisms, in particular, have evolved into formidable energy scavengers by diversifying the range of potential electron donors and acceptors during their approximately 3.8 billion years on Earth. It is now clear that microbes wield clever strategies to tap into the redox active elements of the planet, while mediating long-distance electron transport to couple redox half-reactions that are more spatially separated than previously thought. During the last decade alone, observations of microbial electron transport distances have jumped 7 orders of magnitude, from nanometer- to centimeter-length scales. This session provides a cross-disciplinary forum to discuss established and novel electron transport systems in microbes with special emphasis on systems that operate under low energy conditions and that may leave “fingerprints” of life here on Earth and throughout the universe. This session is co-organized by Moh El-Naggar (University of Southern California).

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  The Downsides of Detection:  False Positives in the Search for Life
Topic Short Title (listed on abstract submission form):  The Downsides of Detection:  False Positives in the Search for Life
Organizer:  Sonny Harman (Pennsylvania State University), ceharmanjr@psu.edu
Summary:  The search for life in the universe often discovers previously unknown processes that mimic the signals for life. The purpose of this session is to discuss under what circumstances the standard metrics for life detection (spectral, geological, chemical, or even technological bioindicators) might be compromised by non-biological processes. If these metrics have been compromised, the open discussion of such false positives ultimately leads to more discerning techniques or enhanced metrics. Whether we’re looking for the red edge of chlorophyll in the spectra of another world, or preserved biomarkers of Earth’s earliest life, it is critical to eliminate the physical processes that would generate such signals in the absence of life. Only then can we be sure of the result — that life is out there. Abstracts from any discipline of astrobiology working to understand or separate true from false positives are welcome.

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  Habitability of Extraterrestrial Analog Environments
Topic Short Title (listed on abstract submission form):  Habitability of Extraterrestrial Analog Environments
Organizer:  Magdalena Osburn (Northwestern University/University of Southern California), maggie@northwestern.edu
Summary:  A key focus in the search for extraterrestrial life is the study of analog environments on Earth. These analogs are often extreme environments that share physical or geochemical similarity to extraterrestrial targets. The study of these sites can inform on the limits, physiology, and phylogeny of resident organisms, preservation potential for biosignatures, energetic constraints of ecosystems, as well as geological and geochemical diversity of analogs themselves. An example analog type of particular interest to many is the deep subsurface biosphere owing to combined habitability and preservation potential. Recent studies have shown broad phylogenetic ranges in geochemically and physically diverse subsurface settings, many of which have direct extraterrestrial geological equivalents. The study of analog environments often requires major technological advancements to access and monitor field sites, experimentation, and even dedicated facilities. In this session we will explore recent advances in the study of analog environments including new analog sites, laboratory experimentation techniques, technical advances, theoretical approaches, remote sensing, and/or field work to the study the habitability of these key sites. This session is co-organized by Jan Amend (University of Southern California), Charles Cockell (University of Edinburgh),  Richard Leveille (McGill University), Frances Westall (CNRS), and Olga Prieto-Ballesteros (Centro de Astrobiología-INTA-CSIC).

Theme:  Identifying and Characterizing Habitable Environments and Habitation
Session Title:  Methods for Detection of Habitability, Biosignatures, and Their Variations in Astrobiological Materials
Topic Short Title (listed on abstract submission form):  Methods for Detection of Habitability, Biosignatures, and Their Variations
Organizer:  Michael Tice (Texas A&M University/Jet Propulsion Laboratory), mtice@geos.tamu.edu
Summary:  Habitability and the presence of organisms in any planetary setting, either now or in the past, must be established by multiple supporting lines of evidence. A variety of new and emerging techniques (e.g., FTIR, Raman, and fluorescence spectroscopy; XRF; SIMS; LIBS; etc.) allow for correlation between spatially structured features and chemical proxies for habitability and biological processes by spatially resolved characterization of astrobiological materials. Identifying such correlations can be powerful because organisms both set up and depend on chemical gradients over cellular to planetary scales. This session invites submissions that (1) identify potential patterns of biosignatures or habitability proxies by modeling, experimental, or analog studies; and/or (2) explore techniques for detecting such patterns by combining spatially resolved chemical measurements (elements, minerals, organics, isotopes) and visual imaging for environmental and biological interpretation. This session is co-organized by Abigail Allwood (Jet Propulsion Laboratory), Rohit Bhartia (Jet Propulsion Laboratory), Penelope Boston (New Mexico Tech), Louisa Preston (The Open University), Keith Schubert (Baylor University), Randall Smith (Portland State University), Sanjoy Som (Blue Marble Space Institute of Science/ NASA Ames Research Center), Victoria Orphan (Caltech), and Greg Wanger (University of Southern California).

Habitability of Learning:  Astrobiology Education and Public Outreach

Theme:  Habitability of Learning:  Astrobiology Education and Public Outreach
Session Title:  Astrobiology Education and Public Outreach and its Impact:  21st Century Ideas and Experienced Perspectives
Topic Short Title (listed on abstract submission form):  Astrobiology Education and Public Outreach:  21st Century Ideas and Perspectives
Organizer:  Lev Horodyskyj (Arizona State University), LevH@asu.edu
Summary:  New to E/PO?  Or are you a seasoned professional? Are your efforts having an impact? How do you know? We encourage submissions to this session across the spectrum from tried-and-true, battle-tested programs to innovative, next-generation initiatives. Hands-on demos are welcomed — bring your own Internet-connected device to participate. This session is designed to be a dynamic and enriching exchange of information and aims to prompt food for thought on how best to engage all audiences with astrobiology, with a focus on measuring the impact of our efforts on those audiences. A companion workshop later in the conference will bring together best practices and fresh ideas in evaluation techniques to ensure you’ll always be able to appropriately and rigorously measure your impact.  This session is co-organized by Carol Oliver (University of New South Wales) and Ben Kotrc (Massachusetts Institute of Technology).

Theme:  Habitability of Learning:  Astrobiology Education and Public Outreach
Session Title:  Astrobiology Research and Education at Minority-Serving Institutions
Topic Short Title (listed on abstract submission form):  Astrobiology Research and Education at Minority-Serving Institutions
Organizer:  Melissa Kirven-Brooks (NASA Astrobiology Institute), melissa.kirven-brooks@nasa.gov
Summary:  This session highlights the contributions of Minority-Serving Institutions (MSIs) to the larger astrobiology community. Presentations from faculty at Hispanic-Serving Institutions (HSI), Historically Black Colleges and Universities (HBCU), and Native American-Serving Institutions (NASI) will illustrate the diversity of current astrobiology research at MSIs. Contributions to the scientific and the larger outreach effort will be presented. This session invites researchers to share their research progress and astrobiology experiences, and explore topics such as institutional support, student interest, and models for sustaining or expanding opportunities for diversity in astrobiology.

Other

The “Other” category should only be used for unusual cases in which no other topic seems appropriate. All abstracts must be categorized in order to be reviewed for placement in a session.  If you don’t choose a specific topic, a member of the science organizing committee will select the most appropriate topic.