Our research is focused on the biogeochemical cycling of marine carbon and nitrogen on modern to millennial timescales. We use stable isotopic (δ13C, δ15N) measurements coupled with radiocarbon dating (14C) and novel analytical chemistry tools to constrain sources, sinks and chemical transformations of dissolved and particulate organic matter in the sea. We are particularly interested in understanding how marine microbes transform detrital organic matter, ultimately allowing for atmospheric C to be stored in the deep sea.