SEMINAR: MAC Seminar - Dr. Ronald S. Oremland, Monday, March 26, 2012 @ 1:30PM

[Erica Calderon <ecalderon@rsmas.miami.edu>]

MAC Seminar

Dr. Ronald S. Oremland

Acetylene Metabolism and The Search For Extraterrestrial Life In Lieu Of Arsenic

Monday, March 26, 2012

1:30PM

RSMAS campus, SLAB Seminar Rm 103

 

BACKGROUND

Currently a Senior Scientist at the US Geological Survey, Menlo Park, CA (since 1977)

BS: Rensselaer Polytechnic Institute, Troy, New York (1968)
PhD: Marine Sciences, RSMAS, University of Miami, 1976

(currently an adjunct professor at RSMAS)
Postdoctoral Associate, NASA Ames Research Center, Moffett Field, CA (1976 - 1977)

Research Areas: Microbial Geochemistry, Geomicrobiology, Biogeochemistry

 

ABSTRACT

 

Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan.  In contrast, acetylene is only a trace component of Earth’s current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is an inhibitor of many key anaerobic microbial processes, including methanogenesis, anaerobic methane oxidation, nitrogen fixation, and hydrogen oxidation. Fermentation of acetylene was discovered 30 years ago, and Pelobacter acetylenicus was shown to grow on acetylene by virtue of  acetylene hydratase, which forms acetaldehyde. Acetaldehyde subsequently dismutates to ethanol and acetate. However, acetylene hydratase is specific for acetylene and does not react with any analogous compounds.  Anaerobic microbes having acetylene hydratase may have played a role in the evolution of Earth’s early biosphere by exploiting an available, reactive source of carbon from the atmosphere and in so doing formed protective niches that allowed for other microbial processes to flourish. Furthermore, the presence of acetylene in the atmosphere of a planet or planetoid could possibly represent evidence for an extraterrestrial anaerobic ecosystem. Aspects of this hypothesis will be discussed with particular reference to the possibility of life on Enceladus, a satellite of Saturn.

 

 

Erica Calderon
Administrative Assistant
Marine & Atmospheric Chemistry/Marine Geology & Geophysics
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway

N Gros 353/SLAB 112
Miami, FL 33149
(305)421-4662/(305)421-4192
ecalderon@rsmas.miami.edu

http://www.rsmas.miami.edu/academics/divisions/marine-atmospheric-chemistry
http://www.rsmas.miami.edu/academics/divisions/marine-geology-geophysics