Dr. Bronk's research focuses on the fluxes of nitrogen in open-ocean, coastal, and estuarine environmentswith emphasis on the role of dissolved organic nitrogen (DON) in microbial food webs. Her early work involved extensive method development with the goal of quantifying in situ rates of DON release and uptake using 15N tracer techniques. She now uses these techniques to address a host of questions relating to the release of DON from phytoplankton and zooplankton and subsequent reincorporation of DON as a nitrogen source for phytoplankton and bacteria. More recently, she has investigated photochemical processes as a mechanism that facilitates the uptake of organic nitrogen by both phytoplankton and bacteria. She continues to be intrigued by methods development, and she has most recently been working on linking flow cytometry with 15N-tracer techniques to quantify nitrogen flow into autotrophs versus heterotrophs in open-ocean systems.