| Citation | John Hayes is a pioneering geochemist who illuminated the biogeochemical processes that generate and preserve isotopic records of the global carbon cycle. His discovery and documentation of the fractionation of carbon and hydrogen isotopes within organic molecules furnished an unparalleled source of new knowledge about the evolving interplay between life and its environment. His landmark contributions link insights from the disciplines of analytical chemistry, biochemistry, geology, oceanography, and planetary sciences. The fundamental concepts and high sensitivity tools he developed are now widely used in fields as disparate as archaeology, ecology, forensic science, and palaeoclimatology. |