Robert O. Lawton Distinguished Professor
and Director, Polar Desert Research Center
Ph.D. (1951), University of Vienna, Austria
Foreign Member, Hungarian Academy of Sciences
Concurrent Professor, University of Nanjing, China
of Biological Science
Florida State University
Tallahassee, FL 32306-1100
Office: 320 Conradi Building
Telephone: (850) 644-5438
Fax: (850) 644-9829
Areas of Research
Microbial ecology of absolute extreme environments, astrobiology, experimental and molecular taxonomy of cyanobacteria (blue-green algae).
Microbial ecology of absolute extreme environments. Organisms in extreme environments are adapted to the conditions of their surroundings, such as low or high temperatures and high salinity, but physiological adaptation has its limits, and in some environments on Earth, conditions are beyond these limits. Such "absolute extreme" environments are not lifeless but are inhabited by organisms living "on the edge" near the absolute limits of their physiological potential. Under these conditions, even a slight deterioration in the environment may result in death and extinction. The study of such environments yields information on the limits of life on Earth, as well as on the process of extinction. This research is directly relevant to astrobiology, the study of the possibility of extraterrestrial life. Specifically, extreme cold and dry environments, like the Antarctic desert, are the closest terrestrial analogs to conditions on early Mars. The study of absolute extreme environments yields important information for the reconstruction of events that may have led to the extinction of life on early Mars, as well as for design of life-detection methods for use on Mars.
Our research approach is based on the integration of field work and laboratory investigations. Active field programs are currently going on in polar (Arctic and Antarctic) deserts, in the Negev desert (Israel), Gobi (Mongolia), and the Atacama desert (Chile). The practical organization of field work is made possible through the Polar Desert Research Center. The Culture Collection of Microorganisms from Extreme Environments (CCMEE) maintains living cultures for research purposes. Laboratory work includes ecophysiological measurements, diverse microbiological techniques, scanning and transmission electron microscopy, light microscopy, and other methods. Click here to see photographs, ranging from landscapes to electron micrographs.
top of page
Antarctic and Arctic deserts. The Ross desert (McMurdo Dry Valleys) of Antarctica is an approximately 5000-km2 ice-free area of high mountains and deep valleys. Temperatures are almost always below the freezing point, and low temperature is the most important ecological limiting factor. In the mountains, the rock surfaces are almost lifeless, but rich communities of microorganisms exist under the surface, colonizing the air spaces inside porous sandstone rocks. For the last 20 years, we have been studying this peculiar ecosystem. Many microbial inhabitants (algae, fungi, cyanobacteria, heterotrophic bacteria) of the Ross Desert have been isolated in culture for use in experimental laboratory studies. These cultures are maintained in the Culture Collection of Microorganisms from Extreme Environments. The nanoclimate (the climate in the millimeter range, the environment of microorganisms) was continuously monitored for six years by automated satellite-mediated weather stations. One central goal in these studies is to measure the environmental parameters that limit life in the Antarctic desert. In the geological past, climate fluctuations resulted in extinctions, and fossilized communities bear witness of past periods of cooling in the general climate. Similar studies are also conducted on Ellesmere Island (Canada), an Arctic equivalent of the Antarctic Ross Desert.
Negev desert (Israel) and Gobi desert (Mongolia). We study these two extremely arid deserts on a comparative basis, as the environmental limiting factor, lack of water, is similar in the two, whereas other climatic factors are very different.
Microorganisms, mostly drought-tolerant cyanobacteria, live either inside rocks (in the Negev) or under stones of the so-called desert pavement, small stones covering the desert floor (Gobi and Negev). They survive there because of their ability to tolerate long periods of desiccation.
Atacama desert (Chile). One of the most interesting deserts on Earth, the Atacama is so dry that in some parts no rain has ever been recorded. Our studies are intended to find out whether totally lifeless "absolute deserts" exist in such places. If so, these places constitute an absolute limit for life on Earth. A special feature of the Atacama is the presence of "fog oases," localized areas where fog accumulates even though there is no rain, and where succulent higher plants and specialized microorganisms use atmospheric humidity as their sole water source. The cytological mechanism by which this use is achieved is unclear, and our present research efforts are centered on the solution of this problem.
Bacteria in Arctic and Antarctic permafrost. The taxonomy and physiology of viable bacteria in Arctic and Antarctic permafrost (frozen soil) up to several million years old are being studied in cooperation with Russian scientists. Metabolic activity in permafrost bacteria has been quantified at temperatures as low as -20°C.
Research on cyanobacteria. The molecular taxonomy and ecophysiology of cyanobacteria living in absolute extreme environments are being studied.
top of page
Selected Recent Publications
Friedmann, E. I., and R. Weed. 1987. Microbial trace-fossil formation, biogenous and abiotic weathering in the Antarctic cold desert. Science 236:703-705.
McKay, C. P., E. I. Friedmann, R. A. Wharton, and W. L. Davis. 1992. History of water on Mars: a biological perspective. Advances in Space Research 12(4):231-238.
Friedmann, E. I., editor. 1993. Antarctic Microbiology. Wiley-Liss, New York. 634 pp.
Friedmann, E. I., L. Kappen, M. A. Meyer, and J. A. Nienow. 1993. Long-term productivity in the cryptoendolithic microbial community of the Ross Desert, Antarctica. Microbial Ecology 25:51-69.
Friedmann, E. I. 1994. Permafrost as microbial habitat. In: D. A. Gilichinsky (ed.): Viable Microorganisms in Permafrost. Russian Academy of Sciences, Pushchino, Russia, pp. 21-26.
Friedmann, E. I., and R. Ocampo-Friedmann. 1995. A primitive cyanobacterium as pioneer microorganism for terraforming Mars. Advances in Space Research 15(3):243-246.
Grilli-Caiola, M., D. Billi and E. I. Friedmann. 1996. Effect of desiccation on envelopes of the cyanobacterium Chroococcidiopsis sp. (Chroococcales). Eur. J. Phycol. 31:97-105.
Shi, T, R. H. Reeves, D. A. Gilichinsky, and E. I. Friedmann. 1997. Characterization of viable bacteria from Siberian permafrost by 16S rDNA sequencing. Microbial Ecology 33:169-179.
Wilson, G. S., P. Braddock, S. L. Foreman, E. I. Friedmann, E. M. Rivkina, J. P. Chanton, D. A. Gilichinsky, D. G. Fyodorov-Davidov, V. E. Ostroumov, V. Sorokovikov, and M. C. Wizevich. 1998. Coring for microbial records of Antarctic climate. Antarct. J. U.S. Rev. 1996 31(2):83-84).
McKay, C. P., M. R. Mellon, and E. I. Friedmann. 1998. Soil temperatures and stability of ice-cemented ground in the McMurdo Dry Valleys, Antarctica. Antarct. Science 10:31-38.
Sun, H. and E. I. Friedmann. (1998). Growth on geological time scales in the Antarctic cryptoendolithic microbial community. Geomicrobiology Journal (In press).
top of page