Professor Weiss’s career has been devoted to the application of chemical and isotopic measurements to the study of natural processes in the atmosphere, oceans, and deep lakes. He has authored or co-authored more than 160 research papers appearing in the international peer-reviewed scientific literature. Among his major research contributions are: The discovery and characterization of the increase and global distribution of atmospheric nitrous oxide, a stratospheric ozone depleter and a greenhouse gas regulated by both the Montreal and Kyoto Protocols; the first experimental proof of the existence of deep-sea hydrothermal vents; the practical application of the measurement of dissolved atmospheric chlorofluorocarbons to determine the rates of ventilation, transport and mixing processes in the deep ocean and in deep lakes; the first geochemical study of mixing processes in the Weddell Sea, a major source of deep water for the world oceans; and, the first accurate calibration of the global abundance and variations of the atmospheric hydroxyl radical, the atmosphere’s primary cleansing agent.