G eomicrobiology & E nvironmental M icrobiology S tudies G eomicrobiology & E nvironmental M icrobiology S tudies	Louisiana State University Dr. Annette Summers Engel Department of Geology and Geophysics E235 Howe-Russell Geoscience Complex Louisiana State University Baton Rouge, LA 70803 office: 225-578-2469 fax: 225-578-2302 G eomicrobiology & E nvironmental M icrobiology S tudies
	Hot Spring Geomicrobiology and Microbial Ecology Research Louisiana State University, Geomicrobiology & Environmental Microbiology Studies Group
	Biogeochemical Controls on Antimony and Arsenic Mobility in Siliceous Hydrothermal Systems El Tatio is the world’s 3^rd largest geyser field, and is located at 4200 m above msl, making it the world’s highest geyser field. There are hundreds of active features at El Tatio. Microbes in the thermal pools are exposed to boiling water, high arsenic concentrations, tremendous UV flux, and solutions supersaturated with respect to silica. The flux of damaging UV radiation is more than 3x what we are bombarded with in the central US. The high arsenic concentrations, coupled to UV-A and UV-B radiation, cause rapid and irreversible DNA damage to unsuspecting microorganisms. The extreme conditions at El Tatio (low latitude, high altitude, high temperatures) make it ideal for study, as the conditions are similar to what we believe early life would have experienced in the Precambrian. In collaboration with researchers from the US, Chile, and Canada, examination of the El Tatio microbial mats shows that cells are covered with amorphous silica. We are investigating how silica interacts with the cell walls and retards UV penetration into the cell, thereby diminishing damage. Molecular-based studies of the changes in microbial ecology and biodiversity related to physicochemical variations, such as changing arsenic concentrations or temperature, are currently underway. Inquire with Dr. Engel if you are interested in the work.		Cyanobacterial mats growing on geyser discharge apron, El Tatio geyser basin, Chile. Photo by A.S. Engel This research is supported by NSF (link to project description)

	Project Background and Research Results Dr. Bennett testing light absorption in microbial mats at one of the geyser discharge channels at El Tatio. Photo by A.S. Engel.	El Tatio Geology & Hydrogeology Logistics and Tourism Research Overview El Tatio Collaborators: P.C. Bennett at Univ. Texas-Austin Pablo Pastén at Universidad Catolica de Chile, Santiago Vern Phoenix, University of Glasgow Pictures from 2005 trip Pictures from 2006 trip (scroll to the bottom of the page)

	Related Publications Phoenix, V.R., Bennett, P.C., Engel, A.S., Tyler, S.W., and Ferris, F.G. (2006) Chilean high-altitude hot spring sinters: a model system for UV screening mechanisms by early Precambrian cyanobacteria. Geobiology. 4:15-28. pdf link

Please contact Dr. Annette Engel for more information regarding the research or photographs. Call (225) 578-2469 or email.
Address: Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803.