Hydrogen isotope biogeochemistry reactors in 1988, but nuclear weapons testing in the 1950s added large spikes of radioactive elements to the atmosphere, especially radiocarbon and tritium. This complicated measurements for geologists using radiometric dating of carbon. However, some oceanographers benefited from the tritium increase, utilizing the signal in the water to trace physical mixing of water masses. In biogeochemistry, scientists focused primarily on the stable isotope of deuterium as a tracer for environmental processes, especially the water cycle. The American geochemist Harmon Craig, once a graduate student of Urey's, discovered the relationship between rainwater's hydrogen and oxygen isotope ratios. The linear correlation between
Willis Resilience Expedition of the deposition rate of Tritium, a radioactive isotope of hydrogen, across Antarctica. The relatively short half-life of Tritium means it can be used to date snow and ice up to around 150 years old. The data can then be used to better understand the global water cycle, which is intrinsically linked to changes in climate. This will be the first large-scale study of Tritium in Antarctica since Tritium returned to normal levels following the spike caused by thermonuclear tests in the 1960s. The samples will be sent to GNS Science, a New Zealand Crown Research Institute, for analysis. Once