Trace gas cycling
In the Earth atmosphere, trace gases, such as methane, nitrous oxide, or molecular hydrogen, are present in small abundances (ppm-ppb range) but their effects on atmospheric photochemistry and the planetary climate are substantial. As electron donors and electron acceptors, they also play important roles for microbial metabolisms.
These are modeled nitrous oxide concentrations throughout the Archean Earth atmosphere (in collaboration with Renyu Hu, JPL).
Methane production activity in a thermophilic culture containing the novel methanogen Methanoglobus sp. that we enriched from Great Boiling Spring in Nevada.
The methane generated by the Methanoglobus species expands the range of C-H isotopic values known to indicate a biological origin of methane.