I am an oceanographer interested in the role of marine biota in global biogeochemical cycles and Earth's climate system. My research focuses on understanding how marine phytoplankton and other ocean biota influence the cycling of key elements (carbon, nitrogen, phosphorus, silicon, iron) in the oceans, and on the biogeochemical links between the ocean, atmosphere, and land through atmospheric transport and riverine runoff. These topics are approached through computer modeling of marine ecosystem dynamics and biogeochemical cycles, and by analysis of satellite remote sensing data of ocean physical and biological properties.