People: Astrobiology Faculty

Jim Staley
Microbiology

Astrobiology is remarkable in that various science and engineering disciplines work together to address major unanswered questions about life in the Universe. Our own microbiological research on the Black Sea and on desert varnish requires that we collaborate with chemical oceanographers and geologists, respectively. In this way, students in our astrobiology program achieve a fuller understanding of other disciplines in contrast to a typical doctoral program.

The Black Sea is of interest to Astrobiology because it is the largest anoxic basin on Earth. Accordingly, it is an analog for studying the anoxic oceans of early Earth and Jupiter's moon Europa. In our Black Sea research we are interested in the bacteria that carry out the ANAMMOX (anaerobic ammonium oxidation) reaction, a newly discovered process in which ammonium and nitrite are converted into N2 gas. The discovery of this reaction has changed our conception of the nitrogen cycle. An unusual, poorly understood bacterial group, the Planctomycetes, carry out the ANAMMOX reaction. We aim to better understand this process and learn what other activities are carried out by the diverse Planctomycete lineages we have found in the Black Sea.

Desert varnish is a brown to black coating formed on desert rocks and resembles rock coatings seen on Mars. We have found that desert varnish contains biological signatures for life such as amino acids and DNA. Surprisingly, amino acid analyses of desert varnish show that it consists primarily of only 12-14 amino acids, fewer than the 20 found in living organisms. We have also extracted DNA from desert varnish and are determining which microorganisms can be identified based upon 16S rDNA analyses. The data we obtain will aid in understanding varnish formation on Earth and serve as a baseline for comparative analyses of rock coatings from Mars and elsewhere in the solar system.

Sonoran Desert rocks showing black coating typical of desert varnish.