My current research focuses on biological deep-sea benthic nitrogen fixation. Nitrogen fixation is an ancient microbial process, thought to have evolved before the divergence of bacteria and archaea, by which N2 gas is converted to NH3 for assimilation into biomass. Nitrogen fixation is like a nitrogen version of photosynthesis, because it converts an abundant, inorganic form of N into a reduced, easily biologically accessible form. This is the beginning of the nitrogen food chain.

My interests shifted from the anaerobic oxidation of methane to the nitrogen cycle when clusters of the microorganisms mediating the anaerobic oxidation of methane -- symbiotic methane oxidizing archaea (ANME) and sulfate reducing bacteria (Desulfosarcina, DSS) -- were found to contain the genes necessary for nitrogen fixation (nif genes). Were the detected nif genes within the ANME or the DSS? Were they functional? Were they expressed in situ? What was the ecological significance? It was a gold mine of research questions, and I started to focus on ANME nitrogen fixation. I was surprised to find how little work existed describing deep-sea diazotrophy, and my questions expanded further. Now I find myself somewhere between the nanoscale interactions of the ANME archaea and their obligate sulfate reducing symbionts, and the entire global nitrogen cycle.