Dr. Edmond Grin With an academic background in hydrogeology, it’s hardly surprising that for three dozen years Edmond Grin worked on dam and hydropower projects. His familiarity with the characteristics of lakes and rivers on Earth makes him especially valuable when it comes to looking for similar features on Mars, where NASA’s exploration strategy has been to “follow the water.”
Grin, together with his wife, Nathalie Cabrol, championed Gusev crater – an apparent lake basin – as the landing site for the Spirit rover. He’s now busy pursuing how rovers in the future can go Spirit one better: not just look for signs of water, but signs of life. A new three-year project in which Grin is involved, called “Life in the Atacama”, will demonstrate that autonomous robot rovers can reliably detect primitive microorganisms. The rovers will be field tested in Chile’s Atacama desert, an earthly analog for the landscapes of Mars. While it may be many decades before human biologists plant their boots on the Red Planet, Grin’s wheeled proxies might get there much sooner. Major discovery could be theirs.
Projects
Ultra Violet Radiation: The Key to Understanding Evolution and Survival of Life on Earth and Beyond NNX07AE62A The overall objective of our research is to understand ultraviolet radiation (UVR) as a limiting environmental factor for life on earth and beyond. UVR is unique in that it places limits on the range of life through the destruction of biopolymers as well as acting directly on the genetic material through DNA damage and mutation. Extraterrestrial life would likely be based on organic biopolymers, and thus subject to UVR effects. Terrestrial life arose under a higher UVR flux and different spectrum than modern life endures, thus the replication of early earth UVR conditions is imperative for astrobiological applications.
In the proposed work we focus on four objectives:
1. To determine the upper limits of UVR on the earth today. Specifically, areas will be targeted that are likely to have the highest levels of UVB radiation and potentially UVC. We will do broad-band measurements and complete solar spectra (200-1100 nm) in locations and during times when, based on NASA’s TOMS data, the highest UVB fluxes should occur. In several of these locations, continuous monitoring stations will be deployed to measure broad-band changes during the course of the day and over the year.
2. To determine the relative contribution of UVB and possibly UVC to DNA damage as a proxy for the hazards of these forms of radiation to living organisms. DNA dosimeters will be subjected to unfiltered and filtered solar radiation using a solar simulator, and during radiation measurements in the field, to assess several common forms of DNA damage as a proxy for severity of exposure and likely lethality and mutagenesis.
3. To assess the microbial ecosystem composition of locations with the highest levels of UV radiation. In the sites identified as being subjected to the highest levels of UVR, community composition will be assessed from morphological and sequence-based identification techniques.
4. To screen microbes collected from the ecosystems studied in objective 3 for radiation resistance for their potential to survive exposure to the space environment.
Significance. The major significance to astrobiology will be to obtain data showing high levels of UVR with broad-band and spectral resolution, and to understand the limits of ecosystems in nature in a high UVB radiation environment. This will have implications for a diversity of fields from medicine to human evolution.
Planetary Biology, Evolution and Intelligence NNA04CC05A
The survival of microorganisms in very high UV environments can also be tested empirically through the exploration of Earth's highest altitude lakes and ponds, in Bolivia and Chile. We propose (Drs. Nathalie Cabrol and Edmond Grin) a series of investigations of these lakes to examine the strategies employed by these microorganisms.
Just as global-scale changes in oxygen (or iron) were critical for the early biosphere, so too would have been global processes involving other key "biogenic" elements such as carbon (Dr. Bakes) or nitrogen (Drs. Rocco Mancinelli, Amos Banin, David Summers, and Bishun Khare).
We propose coupled laboratory and field research to understand the partitioning of nitrogen on early Earth-and on Mars-between different possible reservoirs, and the abiotic to biotic transition in this cycling.
The work described so far examines the evolution of planetary surface habitability. With the recognition that a subsurface ocean likely exists on Jupiter's moon Europa, we know that habitability in possibly entirely subsurface environments must also be explored. We propose spacecraft data analysis and modeling to examine the geology of Europa and its implications for the free energy sources that would be needed to power a europan biosphere (Dr. Cynthia Phillips). We will then couple these results with terrestrial analog work and direct low-temperature laboratory experiments (Dr. Max Bernstein) to make predictions about the possible abundance and survivability of any oceanic biomarkers that might reach Europa's surface through active geology. These results will have implications for astrobiological exploration of Europa from either an orbiter or a surface lander.
Finally, we suggest research (Drs. Peter Backus and Jill Tarter) to examine the prospects of planets orbiting dwarf M stars being habitable for either microscopic or complex life.
The results of this work will directly influence the strategy employed in the next generation SETI search program.
Co-Investigators:
Peter Backus
Amos Banin
Max Bernstein
Janice Bishop
Nathalie Cabrol
Christopher Chyba
Friedemann Freund
Edmond Grin
Bishun Khare
Cynthia Phillips
Lynn Rothschild
Seth Shostak
David Summers
Jill Tarter SETI Institute NAI NASA Astrobiology Institute (NAI)
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