My research focuses on marine microbial ecology, biogeochemistry, and earth system science; specific topics include: ecology and physiology of microphytobenthos and phytoplankton; production of exopolymers (EPS) by microorganisms; formation and ecology of transparent exopolymer particles (TEP); aggregate formation by phytoplankton (marine snow); diatoms and climate change; microbial biofilms and mats; nitrogen cycling; biogenic marine aerosol and cloud formation; and trace gas biogeochemistry.