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Prebiotic Chemistry –Evolution – Exploring |
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Mod
2
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Origin and Early Evolution of PhotosynthesisThe overall theme of this module is to understand the origin and early evolution of photosynthesis and its effect on the biosphere. Photosynthesis is an ancient process that has profoundly changed the Earth by the addition of oxygen to the atmosphere. This has in turn permitted the evolution of complex life. Goals of this module are to better understand the transition from the primitive non-oxygen-evolving form of photosynthesis to the more sophisticated oxygen-evolving form of photosynthesis, as well as to elucidate overall evolutionary relationships among all types of photosynthetic organisms. Additional work is focused on the search for new types of photosynthetic organisms in extreme environments such as deep-sea hydrothermal vents. Finally, artificial models for primitive cells are being investigated. Principal
Co-I: Dr. Robert Blankenship
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Mod
3A
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Microbial Fossilization Processes and Stromatolite Morphogenesis in Extreme EnvironmentsThe goal of this module is to understand the taphonomic processes that govern the fossilization and long-term preservation of biosignatures in extreme sedimentary environments dominated by microbial life. Understanding requirements for the preservation of fossil biosignatures is programmatically important by helping to establish criteria for the recognition of legitimate microfossils in ancient Martian sediments, an important objective driving Mars sample return. The recognition of factors that are important in controlling microbial fossilization has important applications in the development of exploration strategies for a Martian fossil record and has been a driver in the development of payload instrumentation concepts for landed missions. Principal
Co-I: Dr. Jack Farmer
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Mod
3B
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EM-Based Ultrastructural Studies of Microbial BiosignaturesThe purpose of this research is to improve our understanding of microbial biosignatures by developing criteria for biogenicity at the nanometerÐscale using new methods of electron microscopy. This project is not directly related to planned NASA missions, but our mineralogical and ultrastructural criteria for biogenicity will be very important in the search for biosignatures in samples returned from Mars. Principal
Co-I: Dr. Thomas Sharp
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Mod
3C
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Environmental Conditions of the Archean EarthThis module's focus is on the climatic temperature of the early Earth at the time of the oldest microfossil record through the investigation of cherts, aqueous seeps and brines. Work on Martian brines suggests that there may be many locations on Mars where hypersaline waters may exist in the shallow crust of Mars, thus creating potential near surface oases for life. This has important implications regarding site selection for future astrobiological missons to Mars. In addition, our experiments with eutectic brines will refine our understanding of the potential of such environments to sustain life and/or preserve biosignatures of a subsurface Martian biosphere. Finally, our work with brines is also helping to identify the kinds of measurements and instrumentation that will be needed to detect such environments on Mars during future missions. Principal
Co-I: Dr. Paul Knauth
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Mod
3D
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Nanoscale Minerals as BiomarkersSpectacular claims as well as heated controversies have occurred regarding the biogenic character, or lack thereof, of small geologic and meteoritic features that resemble fossils. These disputes will continue with great vigor and without end unless and until clear and unambiguous criteria for the presence of primitive former life are developed, which is a major goal of this module. We will study minerals produced by terrestrial organisms using advanced methods of transmission and scanning transmission electron microscopy including high-resolution electron imaging, holography, and tomography. We will emphasize inorganic bioindicators since these are the most likely to withstand geological and extraterrestrial processes. Our initial focus will be on the chemical and physical properties of magnetic minerals formed by magnetotactic bacteria, and we will combine that work with comparative studies of meteorites and terrestrial samples. The proposed research complements and extends many of the ongoing research projects of the ASU Astrobiology Program. Principal
Co-I: Dr. Peter Buseck
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Mod
4
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Evolution in Microbe-Based Ecosystems: Desert Springs as Analogues for the Early Development and Stabilization of Ecological SystemsThis module involves an intensive study of unique system of desert springs near Cuatro Cienegas, an ancient arid basin in central Mexico. Studying living algal-cyanobacterial mats and stromatolites and their grazers (primarily Cyprinodon fish species and hydrobid snails), we will gain clearer insights into the structure and function of simple microbial mat-grazer ecosystems similar to those that arose during the major biosphere transition that occurred at the end of Proterozoic period. The highly integrated bio-geological studies that are currently underway will lead to a better understanding of the ecological and environmental forces that shaped and eventually stabilized Earth's earliest complex food webs. Principal
Co-I: Dr. James Elser |
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Copyright
© Arizona Board of Regents
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