Dr. Casciotti's research focuses on nitrogen cycle biogeochemistry, including how nitrate, nitrite, and nitrous oxide (N₂O) are produced and consumed in ocean waters. Nitrate and nitrite are important nutrients for marine photosynthesis, and N₂O is a climatically important trace gas. I take an interdisciplinary approach to these questions, applying tools from stable isotope geochemistry, geochemical modeling, microbiology and molecular biology.