[1] Mackenzie applied experimental and field data coupled to a sound theoretical framework to the solution of geological, geochemical, and oceanographic problems at various time and space scales.

[2] Two of his assignments at the time involved studies of the stratigraphy and structure of Ordovician carbonates in the Appalachian Mountains as targets for oil exploration and of the Devonian Marcellus Shale, which in recent years has become a horizon for gas production by fracking and a subject of strong environmental concern.

[2][8] Here between 1967 and 1981, he in association with colleagues Robert Garrels, Hal Helgeson, Abraham Lerman and his many graduate students and national and international colleagues published a number of classic papers involving an interdisciplinary range of scientific topics including early diagenetic processes of reverse weathering and controls on seawater composition, pore water geochemistry, kinetics and thermodynamics of mineral-water reactions, and modeling of Earth's surface environmental system over geological time.

[2] At the University of Hawaii, Mackenzie broadened his research and teaching program even more into the field of marine biogeochemistry, particularly into the biogeochemical interactions involving carbon and oxygen and the nutrient elements of nitrogen, phosphorus, and silicon between the land and coastal waters.

[10] He also investigated CO2 exchange in coastal marine waters, and the biogeochemistry and consequences of ocean acidification for reefs and other carbonate ecosystems.