|Microbial ecology of the nitrogen cycle|
Carbon and nitrogen cycling in the ocean are inextricably linked to the microorganisms living there. Despite rapid advances in the abundance and quality of genetic sequences from the sea, the metabolism and geochemical impact of the majority of microorganisms living there are unknown even at the most basic level. I approach this problem in two ways: (1) combining in situ activity and abundance measurements of microorganisms with field stable isotope tracer experiments and (2) cultivating as-yet uncultivated microorganisms for laboratory study and physiological characterization. A particular emphasis of my current research is the nitrogen and carbon metabolism of mesophilic Archaea, organisms long thought to live only in ‘extreme’ environments, but now known to be one of the most common cell types on the planet and vital components of the marine carbon and nitrogen cycles.