Research in my laboratory involves studies on the origins of life and the possibility of life on other planetary bodies, especially Mars. We work in collaboration with Dr. Christopher P. McKay from NASA Ames Research Center in California. Most of our projects deal with the physiology, metabolism, and ecology of methanogens grown under environmental conditions mimicking those on Mars. Methanogens are microorganisms found in the domain Archaea, and are considered to be some of the most primitive organisms on planet Earth. They inhabit extreme environments such as hydrothermal vents in the oceans, and deep within the Earth's crust. They are strictly anaerobic, can use molecular hydrogen as a sole energy source, and produce methane as a metabolic by-product. The discovery in the spring of 2004 of methane in the Martian atmosphere adds relevance to our use of methanogens as models for Martian life. Additionally, we have worked in collaboration with Dr. Derek Sears, Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, on Martian and lunar meteorites. Comparing electron photomicrographs of fracture surfaces from both types of meteorites, we have discovered that the structures on Martian meteorites, thought by some researchers to be microfossils, are also found on lunar meteorites. Thus, the structures found on the Martian meteorites are not of Martian biological origin.
Astrobiology/Exobiology; methanogen physiology, metabolism, and ecology.
Ph.D. University of Florida, 1978.
Kral, T.A., C.R. Bekkum and C.P. McKay. 2004. Growth of methanogens on a Mars soil simulant under simulated Martian conditions. Bioastronomy 2002: Life Among the Stars. R.P Norris and F.H. Stootman (eds.), International Astronomical Union, p.389-393.
Kral, T.A., C.R. Bekkum and C.P. McKay. 2004. Growth of methanogens on a Mars soil simulant. Orig. Life. Evol. Biosphere. 34(6): 615-626.
Sears, D.W.G., P.H. Benoit, S.W.S. McKeever, D. Banerjee, T. Kral, W. Stites, L. Roe, P. Jansma,, and G. Mattioli. 2002. Investigation of biological, chemical, and physical processes on and in planetary surfaces by laboratory simulation. Planet. Space Sci. 50(9):821-828.
Sears D. W. G. and Kral T. A. 1998. SEM imaging of martian and lunar meteorites and implications for microfossils in martian meteorites. Lunar Planet. Sci XXIX, CD-ROM, paper 1934.
Kral, T.A., K.M. Brink, S.L. Miller, and C.P. McKay. 1998. Hydrogen consumption by methanogens on the early Earth. Origins Life Evol. Biosphere 28:311-319.