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2001 Annual Science Report

Arizona State University Reporting  |  JUL 2000 – JUN 2001

Executive Summary

Executive Summary — ASU (dm)

During the third year of ASU’s Astrobiology Program (The Origin, Evolution and Distribution of Life in the Solar System) we achieved substantial progress toward meeting our research and educational goals. This work involved a team of some eighty-five research Co-I’s,collaborators and students located at seventeen institutions. It resulted in twenty-two publications in first-tier peer-reviewed journals and six additional publications still in press. The following highlights outline the major achievements of the ASU team during this review period.

â?¢ In the study of carbonaceous meteorites, Laurie Leshin determined that Hydrogen isotope values for magmatic water entrapped in a martian meteorite indicate the potential for ~2-3 times more water in the crust today than previously thought, thus increasing the potential for life.

â?¢ In laboratory simulations of deep sea vent (black smoker) environments, the research team of John Holloway and Peggy O’Day showed that methanol, an important pre-biotic organic molecule, can be synthesized under natural geologic conditions occurring on the Earth’s seafloor and should be a byproduct of the large amounts of carbon dioxide and hydrogen liberated by volcanic eruptions on the seafloor. They also used synchrotron X-ray tomography to determine the volume of micropores in a modern sulfide chimney from an active seafloor vent system. Such micropores may provide important sites for concentrating smaller organic molecules needed for the synthesis of more complex precursor molecules needed for the origin of life.

â?¢ Robert Blankenship’s team reported a new molecular phylogenetic analysis of the genes for photosynthesis which was published in a featured cover article in Science magazine (Xiong et al. 2000).

â?¢ In July 2000 a group of nine scientists in Robert Blankenship’s team made several dives on the submersible Alvin to hydrothermal vents of the Endeavor field on the Juan de Fuca Ridge. Samples were collected and an analysis of pigments and cultures indicate that chlorophyll-like pigments are ubiquitous in the ocean and that small numbers of photosynthetic organisms are present both near vents and throughout the water column. The work has been accepted for publication in the journal Science.

â?¢ In a study of fossilization processes in thermal springs in Yellowstone National Park, Jack Farmer and collaborators determined that mat-sinter frameworks store large amounts of photosynthetic oxygen over a depth profile of several centimeters during peak day-time production. This discovery explains the commonly observed preservational modes in hot-spring environments where surafce encrustation of microbial cells and filaments is followed by rapid degradation of organic matter leaving behind external molds and other microtextural information.

â?¢ Thomas Sharp and John Moreau used methods of Analytical Transmission Electron Microscopy to show that the kerogen-comprising organically preserved microfossils in the Gunflint Iron Formation are associated with nano-scale mineralogical and ultrastructural signatures that indicate that the organic materials enhanced the nucleation of amorphous silica during fossilization, inhibiting recrystallization and growth of crystallites during diagenesis. The ultrastructural features resulting from this inhibition reaction comprise a new type of biosignature.

â?¢ Paul Knauth and Donald Lowe found that oxygen isotope ratios in unaltered Archean cherts suggest climatic temperatures vastly warmer than those of today (surface temperatures of 50º – 80ºC).

â?¢ Paul Knauth and Donald Burt published a letter in Science which showed that eutectic brines, a logical consequence of current ideas about martian geologic and atmospheric history, can readily account for the recently observed seep features found at many high latitude locations on Mars.

â?¢ During 2000-2001, a large interdiscipinary team lead by James Elser began a study of extreme desert spring environments near Cuatro Cienegas, an ancient arid basin in central Mexico. By studying living algal-cyanobacterial mats and stromatolites and their grazers, they hope to gain clearer insights into the structure and energy flow of simple ecosystems comparable to those that emerged at the end of Proterozoic.

â?¢ Phil Christensen and team obtained new results from the Thermal Emission Spectrometer (TES instrument) presently mapping from Mars orbit. An important result was the discovery a region at Sinus Meridiani covered by hundreds of square kilometers grey, coarse-grained crystalline hematite. On Earth this mineral is only known to form in the presence of large amounts of water, indicating that this site was probably hydrologically active earlier in the planet’s history. On this basis, Sinus Meridiani is now a leading candidate site for 2003 Mars rover mission.

â?¢ Remote sensing analog studies in Death Valley lead by Jeffrey Moersch and Jack Farmer showed that at TES spatial resolution of 3 km/pixel, carbonates and sulfates are difficult to detect in mixtures. However, at 100 m/pixel (teh resolution to be obtained by the THEMIS instrument presently in route to Mars), both mineral groups were easily detected.

â?¢ Site selection studies for the Mars 2003 mission by Jack Farmer, Ron Greeley and David Nelson produced a list of high priority landing sites for astrobiology that were presented to mission planners. In addition, completion of 1:2M scale geological map of the Elysium Basin-Terra Cimmeria region of Mars (which includes several candidate sites for 2003) revealed a prolonged geological history of aqueous sedimentary activity.

â?¢ Ronald Greeley and collaborators synthesized a general review of the geology of Europa and made calculations to determine the amount of heat necessary to account for some of the dark features seen on the surface of this icy jovian moon. Standards were derived for the geological mapping of Europa and applied to one part of the surface. Studies were completed of two areas where sub-ice materials have been brought to the surface by impact processes.

â?¢ ASU carried out a diverse E&PO effort last year which included several campus-wide events. More than 125 science teachers and students attended a poster session held in conjunction with a public lecture given by NAI Director Barry Blumberg. The lecture event drew >2500 attendees. The teacher workshop included an NAI-hosted display and a review of recent curriculum materials in Astrobiology.