UWAB hosts a biannual colloquium series every spring and fall, featuring speakers from both UW and other institutions presenting on a wide range of astrobiology related topics. Here, you can find the schedule for upcoming colloquia and seminars, as well as an archive of abstracts and live recordings of past events.
If you would like to be notified about upcoming events, you can email us at and request to be added to our events mailing list.
You can also watch a live broadcast of our events by logging in remotely during the scheduled colloquium time!
Fall 2013 Series:
See below for the current schedule. Titles and abstracts will be added as more information becomes available.
Events are held in PAA 118, Tuesdays at 3:00PM.
Eddie Schwieterman (University of Washington)
UWAB Research Rotation Talk:
From Microbiology to Radiative Transfer: Investigating the Spectral Reflectance of a Cross-section of Microrganisms on Earth and the Possible Implications for Surface Reflectance Biosignatures on other Earth-like Worlds
Investigations of the possible remotely detectable surface reflectance biosignatures on Earth-like planets focus on analogies to the vegetation red edge and “green bump” spectral features on Earth. Inherent in these studies are assumptions regarding types of organisms and the function of pigments that may produce these discernible features. We present in vivo visible reflectance spectra of a cross section of pigmented microorganisms with various evolutionary histories to illustrate to the spectral diversity of biologically produced pigments on Earth. These spectra are compared quantitatively with those of red-edge producing land plants. We use synthetic broadband colors to show a significant spread in color space of pigmented organisms compared to common planetary surface types (soil, snow, ocean, etc.). Pigmentation has evolved for multiple purposes other than photosynthesis, including photo-protection and adaptation to extreme environments. We review the prevalence of macroenvironments on Earth that host organisms with non-chlorophyll visible pigmentation, especially the case of pigmented halophiles in hypersaline lakes and ponds. Finally, we explore the detectability of a scenario where a pigmented organism of this type is widespread on an Earth-analog planet. Eddie worked for three months at the University of Edinburgh and the UK Centre for Astrobiology with Professor Charles Cockell as his rotation supervisor.
Peter Driscoll (University of Washington)
Topic: Planetary internal processes, magnetism and habitability
David Crisp (NASA Jet Propulsion Laboratory)
Measuring Atmospheric Carbon Dioxide from Space – the NASA Orbiting Carbon Observatory -2 (OCO-2)
Fossil fuel combustion, deforestation, and other human activities are now adding more than 35 billion tons of carbon dioxide (CO2) to the atmosphere each year. These emissions are superimposed on an active natural surface-atmosphere carbon cycle that exchanges more than 20 times as much CO2 each year, and is currently absorbing about half of the human emissions. The existing greenhouse gas network provides an accurate integral constraint on the net global CO2 emissions and trends, but does not have the resolution or coverage needed to quantify natural CO2 fluxes or discriminate human CO2 emissions from the natural background on regional scales. The Orbiting Carbon Observatory – 2 (OCO-2) is the first NASA satellite designed specifically to address this need. OCO-2 will be launched in July 2014. Once in orbit, its spectrometers will record over a million CO2 soundings each day. Here, we will summarize the OCO-2 measurement approach, status, and plans.
Jon Toner (University of Washington)
Liquid Water on Mars Down to –120°C: Experimental Evidence for Supercooled Brines and Low-Temperature Perchlorate Glasses
Life as we know it requires liquid water, but on Mars pure liquid water is unstable due to extremely cold, dry, and low pressure conditions. A way in which water could be stabilized on Mars is in concentrated salt solutions, which lower the freezing point of water. The maximum equilibrium freezing‑point depression possible for a given salt solution is the eutectic temperature, ranging from near 0°C for carbonates and sulfates to as low as –75°C for perchlorates. Eutectic temperatures suggest a lower temperature limit for liquid water on Mars; however, salt solutions will typically supercool below their eutectic before crystallization occurs. Our research into supercooled MgSO4, MgCl2, NaCl, and NaClO4 solutions shows that supercooling 5–15°C below the eutectic is common. Remarkably, we have found that Mg(ClO4)2 and Ca(ClO4)2 solutions never crystallize during slow cooling, but remain in a supercooled, liquid state until forming an amorphous glass near –120°C, even when mixed with soil. Large supercooling effects have the potential to prevent water from freezing over diurnal and possibly annual cycles on Mars. Furthermore, low-temperature glasses are potentially important for astrobiology because of their far greater ability to preserve pristine cellular structures compared to solutions that crystallize.
John Schutt (Haughton-Mars Project)
Meteorites and Ice - A Cosmic Cocktail
Antarctica has been a prolific source of meteorites since the discovery of large numbers of specimens in the 1970's. Nearly 50,000 specimens have since been recovered from the icy continent. "Meteorites and Ice - A Cosmic Cocktail" tells the story of the importance of meteorites to the understanding of our solar system and the U.S. expeditions that travel to Antarctica to search for them.
Zachary Adam (Montana State University)
Once More Unto the Evolutionary Breach: Microfossils and the Mesoproterozoic Rise of Complexity
The Mesoproterozoic has been referred to as the dullest time in Earth’s history. However, rocks from this period contain some of the earliest evidence available of a leap made across a great evolutionary chasm: the emergence and diversification of eukaryotes in a prokaryote-dominated world. Here we present newly discovered protistan-grade microfossils from the 1.45 billion-year-old Belt Supergroup of Montana. These include forms that grade within and between different morphological groups, providing tentative clues to the reconstruction of ontogenetic, reproductive or ecophenotypic variation signals of the original organisms. This microfossil assemblage and others of similar age present a unique opportunity to explore the emergence, development, ecology and evolutionary biology of some of Earth’s oldest eukaryotes. Precambrian micropaleontology, in conjunction with molecular biomarker, stable isotope and paleoenvironmental data, is critical for assessing the extent to which we may use paleobiology to infer the likelihood of finding complex life on extrasolar planets.
Melissa Rice (Callifornia Institute of Technology)
The New Colors of the Red Planet: Reflectance Spectroscopy and the Habitability of Ancient Mars
Reflectance spectroscopy is currently revolutionizing our understanding of Mars’ environmental history and habitability. The traditional view of Mars’ unidirectional evolution from an early warm, wet environment to a younger cold, dry environment no longer holds; new, high-resolution orbital data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is revealing the importance of local alteration environments and potential niches for habitability on small spatial and temporal scales. Here I will discuss Gale Crater as a case study for this emerging view of complexity in ancient aqueous environments on Mars, and the implications for habitability. From orbit, CRISM has discovered a complex stratigraphy of phyllosilicate, sulfate and iron oxide minerals. On the ground, reflectance spectra from the Curiosity rover’s Mastcam instrument reveal centimeter-scale distributions of hydrated minerals, in addition to minerals that formed in a variety of redox states, with colors never before seen on the surface of Mars.
Chris Glein (Carnegie Institution of Washington)
Organic Geochemistry: From Hydrothermal Vents on Earth to the Great Lakes of Titan
Organic compounds are degraded and synthesized in hydrothermal systems on Earth. For example, the degradation of organic matter in sedimentary environments leads to the formation of petroleum; while abiotic organic synthesis may occur in hydrothermal vents, which may play a critical role in the origin of life. The key to understanding these important processes is to understand the detailed reaction mechanisms, particularly how carbon-carbon bonds can be broken and formed under geochemically relevant conditions. I will show how experiments guided by principles of physical organic chemistry have significantly improved our understanding of decarboxylation and abiotic CO2 fixation. In the second half of this talk, I will introduce the new field of cryogenic fluvial geochemistry, as applied to Saturn's planet-like moon, Titan. Liquefied natural gases are present on Titan's surface, most famously as lakes. Solid organic compounds are also thought to be widespread as a result of deposition from the atmosphere. A fundamental question is: What kinds of geochemistry can occur when these materials meet? I will show how thermodynamic modeling can be used to calculate the solubilities of organic minerals in the cryogenic hydrocarbon solvents on Titan. Despite the extreme differences in physical and chemical conditions on Titan and Earth, we will discover intriguing parallels in the fluvial geochemistry of the only wet worlds in the Solar System.
Matthew Pasek (University of Southern Florida)
An Early Earth Predisposed to Phosphorylation of Organics
The element phosphorus is important in the development and possibly origin of life on the earth. The formation of phosphorylated organics, such as those found in all life today, does not occur easily under plausible prebiotic conditions. Here I present new results on the chemistry of phosphorus in the Archean as sampled from the 3.52 billion year old limestone that shows a fundamental difference between archean phosphorus and the modern phosphate cycle. Additionally, I will show how these differences could have influenced the prebiotic chemistry of early environments from a "just add water" perspective.
Drew Gorman-Lewis (University of Washington)
Ammonia Oxidizing Archaea Survival Mechanisms in Low-Nutrient Environments
The ammonia-oxidizing archaeon (AOA) Nitrosopumilus maritimus strain SCM1 (N. maritimus strain SCM1), a representative of the Thaumarchaeota archaeal phylum, can sustain high specific rates of ammonia-oxidation at ammonia concentrations too low to sustain metabolism by ammonia-oxidizing bacteria (AOB). One structural and biochemical difference between N. maritimus and AOB that might be related to the adaptation of N. maritimus to low nutrient conditions is the cell surface. A proteinaceous surface layer (S-layer) comprises the outermost boundary of the N. maritimus cell envelope, as opposed to the lipopolysaccharide coat of Gram-negative AOB. In this work, we characterized the surface of two archaea having an S-layer with that of four-representative AOB with chemical techniques to evaluate differences in surface reactivities. Since these alternative boundary layers mediate interaction with the local external environment, these data provide the basis for further comparisons of surface reactivity toward essential nutrients.
Past Colloquium Series: