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Project Progress

Chris Chyba, Cynthia Phillips, Kevin Hand- The project has two components. The first, an overview of the astrobiological potential of various geological features on Europa, is proceeding well — we are continuing study of various proposed formation mechanisms for different features types such as ridges, bands, and chaotic terrain. The second, a search for current geological activity by comparing Galileo images taken on different orbits, is also in progress. We have performed a first-stage search of the Galileo Europa images to find overlapping images, and are currently working on an automated search method to make sure that we find all possible comparison images. We are also working on automated processing techniques.

Max Bernstein- As part of performing lab measurements to enable the detection of signs of life and the discrimination between these and false biomarkers we have measured IR spectra of Nitrogen Heterocycles, the class of compounds found in meteorites that include nucleobases. We have been concentrating on the kind of conditions found on icy outer Solar System bodies such as Europa.

Rocco Mancinelli- We have collected soil samples from The Yungay region of the Atacama desert and have anayled them for thjier mineralogy and chemical consitiuents, especially salts. Additionally we have condiuced in situ tests in the field for determine potential rates of N-fixation, denitrification, and nitrification. All of these tests were negativeincluding when the soil was wet. This suggests that either there are no organisms capable of N-cyclein in the soil, or the soil contains somethin inhibiting their activity.

Peter Backus, Jill Tarter-We have organized a two and a half day workshop to be held July 18-20, 2005 on the topic of the Habitability of Planets Orbiting M Stars. A total of forty-one scientists from twenty-one institutions in the US and UK will participate. Twenty-two of the participants are from eight NAI Teams. We established a web site to help organize the workshop and provide a focus for post-workshop discussions.

Nathalie Cabrol- All goals set for the 2004 Licancabur expedition were completed, which will allow the team to move on to another high-altitude volcanic lake in 2005 (Poquentica) as planned in our proposal. Achievements include: (1) characterization of Laguna Blanca and Verde geology and paleobiology through sampling (geochemistry, petrography, palynology, diatoms, cyanobacteria, and paleoenvironment); (2) Geochemistry: Sucessful retrieval of 1-year worth of UV data (UVA, UVB, PAR) as well as temperature from our Eldonet UV dosimeters both at the Lagunas and the summit lake of Licancabur. UV at those lakes is between 200 and 216% that of sea level and the level of UVB recorded is similar or exceeds that of current UVB on Mars at the equator. Positioning of two Hobo meterological station (lagunas and summit); (3) Bathymetry of the summit lake (thawed part). This becomes the very first bathymetry of this lake. 4) Biology: Characterization of cyanobacterial colonies building stromatolotic structure; Documentation of life diversity both at the lagunas and summit lake; Discovery of a large colony of ostracods and copepods in the summit lake of Licancabur (sampling and photodocumentation); Successful dives; and (5) Acquisition of physiological data during the expedition.

David Summers & Bishun Khare- This work has experimentally verified that the abiotic fixation of NO to nitrite and nitrate would indeed occur, as had been postulate theoretically. It has been show that two mechanisms exist for this fixation. One proceeds in the presence of liquid was and appears to be consistent with the proposed pathway through HNO. Another proceeds to NO₂ in the absence of liquid water but, in presence of absorbed water, the NO₂ can be converted to nitric acid. We are in the process of preparing a communication for submission to Nature.

Emma Bakes- We have begun to map chemical sequences for anions, neutrals and cationic nitrogenated aromatic molecules in Titan’s organic haze layer. At this stage, we require the participation of a quantum chemist to map the chemical energetics and the plausibility of each suggested reaction pathway. We have also begun to extend our study of molecular charging to Martian regolith dust to determine how this affects the UV radiation penetration to the Martian surface. This UV penetration directly affects the survival or destruction of organic molecules and the irradiation of potential life forms. We have also begun a laboratory study hydrogen molecule synthesis on aromatics and aerosols to see if the suggested theoretical pathway is a plausible mechanism to the accelerated oxidation of Titan and the early Earth.

Friedmann Freund- The major objective of my project is to study the causes for the slow but inextricable oxidation of the Earth over the first 3 Gyr of its history. During this reporting period our work received a boost from progress achieved by performing new physical measurements on igneous rocks, which lead us towards a quantitative analysis of peroxy oxygen in rocks ranging from ultramafic (peridotite, gabbro) to felsic (andesite, granite).

Janice Bishop & Lynn Rothschild- We have completed a number of lab experiments showing that nanophase iron oxide-bearing minerals facilitate growth of photosynthetic organisms by providing protection from UV radiation. Based on the spectral properties of iron oxides and the results of experiments with photosynthetic organisms, Euglena and Chlamydomonas, we propose a scenario where photosynthesis, and ultimately the oxygenation of the atmosphere, depended on the protection of early microbes by nanophase ferric oxides/oxyhydroxides. Such niches may have also existed on Mars.

We are preparing to evaluate visible/near-infrared (VNIR) spectra of Mars in an effort to characterize deposits of nanophase ferric oxide-bearing minerals that could provide UV protected niches for photosynthetic microbes if they were present on Mars. Concurrent with other projects, we are evaluating the spectral properties of Fe-bearing Mars analog sites on earth and analyzing spectra of Mars for Fe oxide-bearing components.

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