Molecular indicators of metabolic and biogeochemical fluxes

Molecular biomarkers are building blocks or degradation products of organic matter that accumulate all over Earth in living cells, sediments, particulate organic matter, and dissolved organic matter (DOM).  Because biomarkers are associated with specific organisms or evolutionary lineages, this approach has provided unequivocal evidence of the biogeochemical reactions and metabolisms performed by mixed communities and uncultured microorganisms.  The goal of my research is to identify and quantify globally important biogeochemical fluxes by deciphering the chemical information imparted to biomarkers.  Specifically, I measure the elemental composition and molecular structure of proteins, sugars, lipids, and other metabolites to trace key processes occurring in (i) the open ocean, the size of which renders global implications for molecular-level processes, and (ii) active sediments, which harbor high densities of microorganisms performing unknown metabolisms.  The life-essential functions of biomarkers and the wide array of molecular targets that are amenable to chemical characterization promote innovative research questions and support comprehensive investigations that will help to unravel the biocomplexity of oceanic food webs and subsurface ecosystems.