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RESEARCH UPDATES

Eric Roden Research Group:

BioMARS-funded research in the Roden subproject is occurring on two fronts: (1) experimental studies of Fe isotope fractionation coupled to dissimilatory microbial Fe(III) oxide reduction and lithotrophic Fe(II) oxidation; and (2) studies of microbial Fe redox cycling in a neutral-pH groundwater Fe seep environment in Tuscaloosa, AL, and in unsaturated Triassic-age weathered basalt materials from Box Canyon, ID.

The Fe isotope fractionation studies have resulted in a major research paper (Johnson et al., 2005) and a book chapter (Johnson et al., 2004).  We anticipate continuing our work on Fe isotope fractionation coupled to biological Fe metabolism in collaboration with both UCB and University of Wisconsin Madison (UWM) colleagues.  A UWM graduate student who interned at UA has conducted detailed studies of isotope fractionation during enzymatic reduction of goethite and hematite (Crosby et al., 2005a; Crosby et al., 2005b).  Near-term goals include development of a detailed understanding of the mechanisms for kinetic vs. equilibrium fractionation during enzymatic Fe(III) oxide reduction, and conducting preliminary experiments on the potential for Fe isotope fractionation during lithotrophic oxidation of aqueous and solid-phase Fe(II) compounds.  Such studies are critical for evaluating the extent to which the Fe isotope composition of minerals and fluids may provide a “biosignature” of Fe-based microbial life, e.g. in shallow subsurface environments on Mars.

Culture-based studies in the Fe seep material and weathered basalt have revealed significant numbers of both Fe(III)-reducing and Fe(II)-oxidizing microorganisms, which suggested the potential for microbially-catalyzed Fe redox cycling.  Several highly-purified Fe(III)-reducing and Fe(II)-oxidizing cultures have been obtained and are currently being physiologically and phylogenetically characterized.  A 16S rRNA gene clone library indicated the presence of a variety of lithotrophic ammonium- and Fe(II)-oxidizing phylotypes in the Fe seep community (Blothe and Roden, 2005a, b), and additional clone libraries are being constructed for both the Fe seep and weathered basalt communities.  Incubation of amorphous Fe(III) oxide-rich seep material under anaerobic conditions demonstrated the potential for rapid Fe(III) oxide reduction.  These results are conceptually consistent with those from the experimental cocultures of Fe(III)-reducing and Fe(II)-oxidizing bacteria (Sobolev and Roden, 2002; Roden et al., 2004), and suggest that tight coupling of microbial Fe oxidation and reduction takes place in the seep materials.  Similar results were obtained with the weathered basalt materials, which are unique in that they contain magnetic Fe(III) oxide phases (presumably maghemite), which may or may not be converted to the magnetite during microbial reduction.  The end-products of microbial reduction of the Fe seep and Box Canyon materials are currently being analyzed by XRD and Mössbauer spectroscopy.   The Fe seep and weathered basalt systems provide models for how microbially-catalyzed Fe redox cycling could take place in subsurface Martian environments where reduced fluids/solids contact oxygen-bearing water or water vapor.  Simultaneous operation of Fe(III) oxide reduction and Fe(II) oxidation reactions could in principle support a self-sustaining Fe redox cycle-based microbial life system that could be sustainable over geological time scales.

G. Luther & D. Emerson Research Group

David Emerson, Ph.D, Co-Investigator, Research Scientist, ATCC; George Luther, Ph.D, Co-Investigator, U. Delaware; Jeremy Rentz, Ph.D, postdoctoral, ATCC; Charoenkwan Kraiya, Ph.D, postdoctoral, U. Delaware; Melissa Floyd (graduate student, George Mason Univ.); Tommy Moore (graduate student, U. Delaware) Cynthia Lydell (technician, ATCC, partial support from NAI)

Accomplishments:
Much of the work in our labs has focused on determining in-situ rates of Fe-oxidation at local field sites that are dominated by microbial mats of Fe-oxidizing bacteria (FeOB). In addition, we are carrying out community analysis of these same sites to determine the overall abundance and population structure of FeOB at these sites. Drs. Rentz (Emerson Lab) and Kraiya (Luther Lab) made several sets of measurements in the Fall and early Winter at two sites using voltammetric electrodes to measure rates of Fe(II) oxidation and O2 levels simultaneously.  The findings confirmed that FeOB are playing a significant role in catalyzing Fe-oxidation in these neutrophilic systems, previous studies have not been as controlled and precise and are more open to interpretation. Dr. Rentz is in the process of more fully characterizing the communities at these sites. Toward this end he has developed a real-time PCR assay for a specific group of FeOB thought to be abundant in these habitats. Part of this work was presented at the NAI meeting in April in Boulder, CO. We are also active in writing up our metal cluster work which has been stimulated by our finding of Fe(Mn)S clusters at our Virginia field site.

Melissa Floyd, Tommy Moore and Tommy Floyd participated in a BioMars field expedition to Box Canyon in Idaho with other team members to investigate the potential for Fe-cycling bacteria to exist in old basalts associated with this site. Tommy Floyd made some measurements for redox active Fe and S species in this environment, although these turned out not to be abundant. Melissa made several isolations and is in the process of characterizing these. In addition, she has been working on a mesocosm that simulates the oxic-anoxic boundary environments where FeOB thrive. This system can be used to study community dynamics of FeOB under more realistic field conditions. From this system she has isolated  novel whose growth appears to be stimulated by Fe(II) organisms. Part of this work was presented at the NAI meeting in April in Boulder, CO.

Both Emerson and Luther participated in a group field trip to Alum Rocks State Park near Hayward, CA that has numerous small sulfureta associated with groundwater flows from the host rock. Emerson has subsequently worked with one of Banfield’s students, Jonathon Giska, and performed MPNs for S-oxidizing bacteria from this site as well as direct counts of total cell numbers. Initial results suggest there is significant variability between localized sites. This work is being followed up on with more culture studies as well as molecular analysis.

Janice Bishop Research Group
(from the SETI website
"Seeing the Invisible Color of Mars" and a Space.com USA Today article)

The color of Mars tells us which minerals are present, and these minerals provide information about water and environmental factors on Mars. The red color comes from iron oxides and varies from orange to red to violet depending on the mineral structure. In the visible region a spectrometer acts like our eyes do and recognizes colors such as green, blue and red. The Pancam on Spirit and Opportunity records these colors in spectral images. The Mini-Thermal Emission Spectrometer (Mini-TES) is another spectrometer on the Mars Exploration Rovers (MER) and measures infrared radiation. Our eyes cannot "see" the infrared radiation, but the spectrometer can. Rocks are composed of minerals and each mineral has a certain spectrum that can be measured by the spectrometer.

Spectroscopy involves measuring the energy absorbed or reflected at certain wavelengths. Infrared spectroscopy primarily measures vibrational energies of the atomic bonds in the mineral structure. Bonds such as Si-O, Fe-O, H2O (water), SO4, CO3 each have different vibrational energies that are measured by the spectrometer. These clusters of atoms are the building blocks of minerals and each mineral has several infrared absorptions in its spectrum. The Mini-TES instruments on Spirit and Opportunity and the TES instrument on the Mars Odyssey orbiter are measuring these mineral components and the scientists must try to recreate which minerals are present in the martian rocks and soil by comparing the infrared energies detected with the known spectral properties of minerals from lab measurements. The Mars Express orbiter also has a spectrometer called Omega that is measuring the near-infrared region. This works in a similar way to the Mini-TES, but collects data from a complimentary wavelength region. A third spectrometer called CRISM will cover visible and near-infrared wavelengths (some that we can see, plus some that are similar to those measured by Omega) and is scheduled to fly to Mars on the Mars Reconnaissance Orbiter in 2005. Combining visible, near-infrared and mid-infrared spectra provides the most clues to scientists trying to figure out the mineralogy of Mars.

The rocks and soils on Mars are composed of a variety of minerals such as silicates (pyroxene, feldspar and olivine), iron oxides, sulfates, and carbonates. The minerals tell a story about how each rock or soil unit formed and what has happened to it since it formed. We know a lot about the minerals present on Mars from detailed studies of the martian meteorites and from chemistry and spectroscopy of the surface. Still, we only have some pieces to the puzzle and many that are needed to assemble the full picture are missing.

In order for scientists to be able to interpret the spectral data of Mars, it is necessary to measure the spectral patterns of rocks and minerals in the lab and in the field on Earth. Mars scientists are studying rocks from a number of field sites including volcanoes, deserts, hydrothermal areas, impact craters, the Arctic and the Antarctic. My field sites have focused on alteration of volcanic material (e.g. Hawaii, Iceland), sedimentation of volcanic material in Antarctic lakes, and rocks forming in hydrothermal regions associated with volcanoes. These samples include a number of minerals such as iron oxides/oxyhydroxides, clays, carbonates and sulfates that provide information about aqueous processes, temperature, pH, etc. Pure samples of these minerals are obtained as well in order to characterize their spectral properties. In many cases, small differences in chemistry or grain size can influence the spectral properties.

I am a Co-Investigator for the UC Berkeley NAI team called BioMars and we are particularly interested in finding ways to characterize and identify Fe and S-bearing minerals that may be associated with life. My team is in the process of measuring spectra of rocks collected at new field sites. Our goal is to learn how to remotely characterize rocks that can provide information about whether or not conditions were supportive of life on Mars. Because each instrument on the many Mars orbital and landed missions measures spectra covering a different wavelength range and resolution, the lab and field data measured for this project will also be modified to match the various spectrometers collecting data of Mars. This will enable us to know what the spectrum of key rocks and minerals associated with life would like on Mars if they are observed by any of the martian spacecraft. [end of article]

Michael Manga Research Group

We focused on the interaction between Martian geodynamic and hydrologic processes. Matsyama et al. (2005) developed models for
the effect of polar wander and internal dynamic processes on the surface deformation of Mars. Matsuyama et al. (2004) used these models,
and observations of inferred paleoshorelines, to determine the evolution of the rotation pole on Mars. This analysis also shows that the features mapped as potential shorelines, which currently exhibit relief of up to 2 km, could indeed by paleoshorelines from large, vanished oceans. We have continued developing numerical models for water-ice-magma interactions in the Martian crust. The model will be added to the USGS code HYDRORTHERM and will be eventually be made available to the public. We have also completed an analysis on Martian landslides in Valles Marineris and conclude that they were probably dry (Soukhovitskaya and Manga, 2005). Finally, we proposed that some (or even many) of the Martian outburst floods may have been triggered by large impacts and that the resulting liquefaction provides a source of water and may form chaotic terrain (Wang et al., 2005).

People involved, year 2: Yoshiko Ogawa (postdoc: hydrothermal processes in the Martian crust), Mark Wenzel (graduate student: mantle
convection on Mars), Veronika Soukhovitskaya (undergraduate: mobility of granular flow and the evidence for water on Mars),
Rob Lillis (history of the Martian magnetic field), Taylor Perron, Jerry Mitrovica and Isamu Matsuyama (polar wander on Mars), Chi Wang and Alex Wang (impacts and floods).

PAPERS PUBLISHED / SUBMITTED:

Banfield JF, Cervini-Silva J, Nealson, KN. Molecular Geomicrobiology. In Molecular Geomicrobiology. From genomes to ecosystems. Reviews in Mineralogy and Geochemistry. Mineralogical Society of America, December 2005.

Bishop, J.L. and Murad E., 2005, The visable and infrared spectral properties of jarosite and alunite, Am. Miner., v90: 1100-1107.

Bishop, J.L., Dyar, M.D., Lane, M.D., Banfield, J.F., 2004, Spectral Identification of Hydrated Sulfates on Mars and Comparison with Acidic Environments on Earth, IJA, 3(4): 275-285.

Cervini-Silva J, Larson RA, Stucki JW. Hydration/expansion and cation-charge compensation modulate the Bronsted basicity of adsorbed water in Fe(II)-Fe(III) phyllosilicates. Appl. Catal. B: Environ, (in review)

Cervini-Silva J. Siderophores mobilize nutrients and contaminants in natural porous media. Biogeochemistry. (in review)

Cervini-Silva J, Banfield J.F. Catalytic interactions involving cerium, catecholate, and oxygen may be pivotal to phosphorous bioavailability and humic acid production. Environ. Sci. Technol.

Cervini-Silva J, Fowle D, Banfield J. Biogenic dissolution of soil cerium-phosphate minerals. Am. J. Sci. Biogeochemistry Special Issue 2005 (in press).

Cervini-Silva J, Sposito G. Dissolution of alpha-iron (hydr)oxides by trihydroxamate and catecholate siderophores and oxalate ligands at high salt concentrations and pH 3-6. Environ. Sci. Technol. 2005, 39(10).

Cervini-Silva J. Coupled charge transfer- and hydrophilic- interactions between polychlorinated methanes, ethanes, and ethenes and redox-manipulated smectite clay minerals. Langmuir (Letter) 2004, 20, 9878-9881.

Cervini-Silva J. Alteration of the surface charge of aluminum goethites by a sulfonic acid buffer. J. Colloid. Interface. Sci. 2004, 275, 79-81.

Crosby, H. A., C. M. Johnson, E. E. Roden, and B. L. Beard. 2005b. Fe(II)-Fe(III) electron/atom exchange as a mechanism for Fe isotope fractionation during dissimilatory iron oxide reduction. Environ. Sci. Technol Submitted for publication.

Druschel, G., D. Emerson, B. Glazer, C. Kraiya, R. Sutka and G. W. Luther, III. 2004. Environmental limits of the circumneutral iron-oxidizing bacterial isolate ES-1: Field, culture, and kinetic results from voltammetric analyses. Geochimica Cosmochimica Acta Vol. 68 (11S), p. A387.

Edwards DC & Cervini-Silva J, Myneni S.C.B, Sposito G. The structure of aluminum substituted goethite. Environ. Sci. Technol. (in review)

Emerson, D. and M.M. Floyd. 2005. Enrichment and isolation of iron-oxidizing bacteria at neutral pH. Methods in Enzymology. In Press.

Emerson, D, and J.V. Weiss. 2004. Bacterial iron oxidation in circumneutral freshwater habitats: findings from the field and the laboratory. Geomicrobiol. J. 21:405-414.

Emerson, D., and C. Moyer. 1997. Isolation and characterization of novel lithotrophic iron-oxidizing bacteria that grow at circumneutral pH. Appl. Environ. Microbiol. 63:4784-4792.

Floyd, M.M, and D. Emerson. 2005.FIONA: A laboratory microscosm for investigating natural populations of circumneutral, microaerobic Fe-oxidizing bacteria. Astrobiology. 5:291.

Floyd, M.M., J. Tang, M. Kane, and D. Emerson. 2005. Captured diversity in a culture collection: a case study of the geographic and habitat distribution of environmental isolates held at the American Type Culture Collection. Appl. Environ. Microbiol. 71:2813-2823.

Johnson, C. M., E. E. Roden, S. A. Welch, and B. L. Beard. 2005. Experimental constraints on Fe isotope fractionation during magnetite and Fe carbonate formation coupled to dissimilatory hydrous ferric oxide reduction. Geochim. Cosmochim. Acta 69:963-993.

Johnson, C. M., B. L. Beard, E. E. Roden, D. K. Newman, and K. H. Nealson. 2004. Isotopic constraints on biogeochemical cycling of Fe. In C. M. Johnson, B. L. Beard, and F. Albarède (eds.). Geochemistry of Non-Traditional Stable Isotopes, Reviews in Mineralogy and Geochemistry 55, pp. 359-408. Mineralogical Society of America, Washington, DC.

Kraemer SA, Butler A, Borer P, Cervini-Silva J. Biogenic ligands and the dissolution of iron bearing minerals in marine systems. In Molecular Geomicrobiology: From genomes to ecosystems. Reviews in Mineralogy and Geochemistry. Mineralogical Society of America, December 2005.

Lane, M.D., Dyar, M.D., Bishop, J.L., 2004, Spectroscopic evidence for hydrous iron sulfate in the Martian soil, GRL, vol. 31, L19702, doi:10.1029/2004GLO21231

Luther, III, G.W. and D. T. Rickard. 2005. Metal sulfide cluster complexes and their biogeochemical importance in the environment, Journal of Nanoparticle Research, in press.

Rentz, J.A., C. Kraiya, G.W. Luther, and D. Emerson. 2005. Measurement of environmental biological Fe2+-oxidizing activity. Astrobiology . 5:292.

Roden, E. E., D. Sobolev, B. Glazer, and G. W. Luther. 2004. Potential for microscale bacterial Fe redox cycling at the aerobic-anaerobic interface. Geomicrobiol. J. 21:379-391.

Sobolev, D., and E. E. Roden. 2002. Evidence for rapid microscale bacterial redox cycling of iron in circumneutral environments. Anton. van Leeuw. I81:587-597.

Sobolev, D., and E. Roden. 2004. Characterization of a neutrophilic, chemolithoautotrophic Fe(II)-oxidizing b-Proteobacterium from freshwater wetland sediments. Geomicrobiol. J. 21:1:10.

Trouwborst, R. E., G. M. Koch, G. W. Luther III and B. K. Pierson.  Iron Oxidation by Oxygenic Photosynthesis in the Precambrian: Support from contemporary hot spring microbial mats. Nature, in review.

Wang C., Manga, M. , Wong, M. 2005. Floods on Mars by groundwater released by impact. Icarus. vol. 175, 551-555.

BOOKS/ CHAPTERS PUBLISHED

Molecular Geomicrobiology. Reviews in Mineralogy and Geochemistry. Mineralogical Society of America. Washington, D.C., (J.F. Banfield, J. Cervini-Silva,
and K. Nealson, Eds.), December 2005.

Carbon Stabilization in the Environment. The Clay Minerals Society Workshop Series, Washington, D.C., (J. Cervini-Silva and D. A. Laird, Eds.), June 2007.

Book Chapters: Cervini-Silva J, Larson RA, Stucki JW. Hydration/expansion and cation-charge compensation modulate the Brønsted basicity of adsorbed water in
Fe(II)-Fe(III) phyllosilicates. In Proceedings of the 13th International Clay Conference, Tokyo, Japan, August 21-27, 2005 (Bradley Award recipient).

RECENT TALKS / PRESENTATIONS / ABSTRACTS:

Bishop J. L., Lane M. D., and Dyar M. D. (2005) Spectral identification of hydrated sulfates on Mars and comparison with sulfate-rich terrestrial sites. European Geosciences Union, Vienna, Austria, abs.# EGU05-A-05737.

Bishop J. L., Schiffman P., Lane M. D., and Dyar M. D. (2005) Solfataric alteration in Hawaii as a mechanism for formation of the sulfates observed on Mars by OMEGA and the MER instruments. Lunar Planet. Sci. XXXVI., Lunar Planet. Inst., Houston, CD-ROM #1456 (abstr.).

Bishop, J., Spectral properties of iron oxide-bearing minerals. Presented at the Early Mars Conference, Jackson Hole, WY, October 10-14, 2004.

Bishop, J., The surface of Mars: What we know, and how we are learning more, Indiana University, October 2004. (http://homepages.indiana.edu/102204/text/research.shtml.)

Blothe M., and E. E. Roden. 2005a. Microbial iron cycling in a circumneutral pH iron seep. In Abstract Submitted to the 105th Annual Meeting of the American Society for Microbiology, Atlanta, GA, June 2005.

Blothe, M., and E. E. Roden. 2005b. Microbial iron cycling in a circumneutral pH iron seep. In Abstract Submitted to NAI 2005, the Biennial Meeting of the NASA Astrobiology Institute, Boulder, CO, April 2005.

Cervini-Silva J, Gilbert B, Fakra S, Banfield J. A molecular approach towards understanding the biogenic formation of CeO2 and its interactions with
biomolecules. Geochimica Cosmochim. Acta 69, 2005.

Oral presentation: Cervini-Silva J, Fakra S, Gilbert B, Banfield JF. A Molecular Approach Towards Understanding the Biogenic Formation of CeO2 and its Interactions with
Biomolecules. Annual Meeting of the American Geophysical Union, San Francisco, California, December 3-4, 2005.

Oral presentations: Banfield JF, Bishop J, Cervini-Silva J, Dietrich W, Emerson D, Luther III G, Manga M, Roden E. Earth Analogs for Potential Martian Biomes and the Search for Life on Mars Annual Meeting of the American Geophysical Union, San Francisco, California, December 3-4, 2005.

Oral presentations: Cervini-Silva J, Larson RA, Stucki JW. Hydration/expansion and cation-charge compensation modulate the Brønsted basicity of adsorbed water in
Fe(II)-Fe(III) phyllosilicates. In Proceedings of the 13th International Clay Conference, Tokyo, Japan, August 21-27, 2005 (Bradley Award recipient).

Oral presentations: Cervini-Silva J, Gilbert B, Fakra S, Banfield J. A molecular approach towards understanding the biogenic formation of CeO2 and its interactions with biomolecules. Symposium on Proteins and Minerals: A basis for life-rock interaction. 15th Annual V.M. Goldschmidt Conference, Moscow, Idaho, May 20-25, 2005 (invited).

Poster presentation : Giska JR, Moreau JW, Rowland J.; Cervini-Silva J, Manga M, Banfield JF Microbial Ecology and Resultant Biomarkers Preserved in a Terrestrial Analog of a Martian Spring System. Proceedings of the Annual Meeting of the American Geophysical Union, San Francisco, California, December 3-4, 2005.

Poster presentation: Gilska, J.R., Moreau, J.W., Cervini-Silva, J., Banfield, J.F. Microbial ecology and resultant taphonomy as a function of hydro-geological history in a terrestrial analog of Martian, fault-controlled spring system. Biennial NASA Astrobiology Institute Meeting, Boulder, CO, April 15-18, 2005.

Crosby, H. A., C. M. Johnson, B. L. Beard, and E. E. Roden. 2005a. Mechanisms of Fe isotope fractionation during dissimilatory Fe(III) reduction (DIR). Abstract submitted to the 15th Annual Goldschmidt Conference, Moscow, ID, May 2005.

Druschel, G., D. Emerson, B. Glazer, C. Kraiya, R. Sutka and G. W. Luther, III. Environmental limits of the circumneutral iron-oxidizing bacterial isolate ES-1: Field, culture, and kinetic results from voltammetric analyses, presented at the 2004 Goldschmidt Conference, Copenhagen, Denmark, June 9, 2004.

Druschel, G., R. Sutka, D. Emerson, G. W. Luther, III, C. Kraiya, and B. Glazer. Voltammetric investigation of Fe-Mn-S species in a microbially active wetland profile, presented at the 11th Water-Rock Interaction conference (WRI-11), Saratoga Springs, NY, July 2, 2004.

Druschel, G.K., R. Sutka, D. Emerson, G.W. Luther, C. Kraiya, and B. Glazer. 2004. Voltammetric investigation of Fe-Mn-S species in a microbially active wetland.  In: Proceedings of the Eleventh International Symposium on Water-Rock Interaction WRI-11.  Wanty, R.B. and Seal, R.R (eds.). p. 1191-1194.

Emerson, D., J.A. Rentz, and C. Moyer. Microbial iron oxidation at the Loihi Seamount: parallels with a late Archaean ocean? Gordon Research Conference, Origins of Life, Ventura, CA, Jan 15-20, 2005.

Floyd, M.M, and D. Emerson. FIONA, Ferrous iron oxidizing neutrophilic acatalepsy: A laboratory microscosm for investigating natural populations of circumneutral, microaerobic Fe-oxidizing bacteria. NASA Astrobiology Institute Meeting, Boulder, CO, April 10 –1 4, 2005.

Lamb, M.P. and Dietrich, W.E., 2004, Groundwater sapping as a potential mechanism for the formation of a theatre-headed basaltic canyon, Box Canyon, Idaho.  NASA Workshop on Martian Valley Networks.

Lamb, M.P., Dietrich, W.E. and Howard, A.D., 2004, Can springs cut valleys into bedrock?  Eos Trans. AGU, 85(47) Fall Meet. Suppl., Abstract H53C-1258. 

Lamb, M.P., S. Aciego, W.E. Dietrich, D. DePaolo, A. Howard, T. Perron, and M. Manga, 2005, Formation of amphitheatre-headed canyons on Earth and Mars, European Geophysical Union.

Lillis, R.J., M. Manga, D.L. Mitchell, R.P. Lin, and M.H. Acuna (2005) evidence for a second Martian dynamo from electron reflectionmagnetometry, LPSC XXXVI abs 1578.

Lillis, R.J., M. Manga, D.L. Mitchell, R.P. Lin, and M.H. Acuna (2004) Magnetic Signatures of Martian Volcanoes: Evidence for a Second DynamoEpisode? 2004 AGU fall meeting.

Matsuyama, I., J.X. Mitrovica, J.T. Perron, M. Manga and M.A. Richards (2005). Rotational stability of dynamic planets with lithospheres, LPSC XXXVI abs 2230.

Matsuyama, I., J.T. Perron, J.X. Mitrovica,  M. Manga and M.A. Richards (2004) Long-Wavelength Shoreline Deformation on Mars, 2004 AGU fall meeting.

Rentz, J.A., C. Kraiya, G.W. Luther, and D. Emerson. Measurement of environmental biological Fe2+-oxidizing activity. NASA Astrobiology Institute Meeting, Boulder, CO, April 10 –1 4, 2005.

Soukhovitskaya, V. and M. Manga (2005) Martian landslides in Valles Marineris: Wet or dry? LPSC XXXVI abs 1093.

Wenzel, Manga and Lillis, "Mantle convection and two episodes of martian dynamics activity", LPSC XXXVI abs 1584.

Wang, C.-Y., M. Manga, and A. Wong (2005) Floods on Mars released from groundwater by impact, Icarus, vol. 175, 551-555.

 

FIELD TRIPS AND MEETINGS ATTENDED :

NAI General Meeting, Boulder, Colorado, April 10-14, 2005:
Eight Students and postdocs received grants to attend the NAI biennial meeting:
J. R. Giska (UCB), Taylor Perron (UCB), Mark Wenzel (UCB), Melissa Floyd (George Mason Univ.), Michael Lamb (UCB), Marco Blothe (Univ. of Alabama), Celeste Henrickson (UCB), and Jeremy Rentz (George Mason Univ.).

Snake River, Idaho, November 6-8, 2004
Attendees: Eric Roden (University of Alabama), Marco Bloethe (University of Alabama), Tommy Moore (University of Delaware), Michael Lamb (UC Berkeley), Jill Banfield (UC Berkeley), Javiera Cervini-Silva (UC Berkeley), William Dietrich (UC Berkeley), Mark Yim (University of Pennsylvania), and Melissa Floyd (George Mason University, ATCC)

Dry Valley, Antarctica Field trip, January 2005:
Michael Manga spent January in the Dry Valleys, Antarctica. Groundwater-surface water exchange is very important and will be the topic ofupcoming research, both modeling and experiment. Go to http://www.seismo.berkeley.edu/~manga/antarctica/antarctica2005.html for photos.

Box Canyon Field Trip:
Melissa Floyd, Tommy Moore and Tommy Floyd participated in a BioMars field expedition to Box Canyon in Idaho with other team members to investigate the potential for Fe-cycling bacteria to exist in old basalts associated with this site. Tommy Floyd made some measurements for redox active Fe and S species in this environment, although these turned out not to be abundant. Melissa made several isolations and is in the process of characterizing these. In addition, she has been working on a mesocosm that simulates the oxic-anoxic boundary environments where FeOB thrive. This system can be used to study community dynamics of FeOB under more realistic field conditions. From this system she has isolated  novel whose growth appears to be stimulated by Fe(II) organisms. Part of this work was presented at the NAI meeting in April in Boulder, CO.

Alum Rocks State Park Field Trip:
Both Emerson and Luther participated in a group field trip to Alum Rocks State Park near Hayward, CA that has numerous small sulfureta associated with groundwater flows from the host rock. Emerson has subsequently worked with one of Banfield’s students, Jonathon Giska, and performed MPNs for S-oxidizing bacteria from this site as well as direct counts of total cell numbers. Initial results suggest there is significant variability between localized sites. This work is being followed up on with more culture studies as well as molecular analysis.

TEACHING:

EPS 200, taught by Michael Manga at UC Berkeley, was designed to complement BioMARS activities in the area of hydrology.  Several BIOMARS-supported people participated in this class: Yoshiko Ogawa, Taylor Perron, Michael Lam, and Rob Lillis. A recently published paper,(Wang C., Manga, M. , Wong, M. 2005. Floods on Mars by groundwater released by impact. Icarus. vol. 165, 551-555) grew out of this class.

Department of Astronomy    601 Campbell Hall    Berkeley, CA 94720-3411    510-643-2457