Paul Quay is an oceanographer who studies the ways that gases and chemicals move through freshwater and marine systems. He does this by completing stable and radioisotope measurements on biogeochemical cycles. He looks also at how carbon and oxygen cycle in lakes, rivers and oceans, at the cycling of trace gases in the atmosphere, and also at large-scale ocean circulation rates using anthropogenic tracers, such as chlorofluorocarbons, or CFCs. He has participated in several large, interdisciplinary projects throughout the world, including the Joint Global Ocean Flux Study, the World Ocean Circulation Experiment, and Carbon in the Amazon River Experiment.