Stable isotopes are useful tools for understanding the global budgets of many important trace gases.
If various sources and sinks fractionate isotopes differently, stable isotope measurements can provide useful constraints as to what processes dominate at the global scale. High precision measurements are used to monitor temporal and spatial trends in both concentration and isotopic signature of these trace gases. These include investigations of methane emissions from rice paddy fields and natural wetlands and measurements of nitrous oxide from tropical forest and agricultural soils. At UCI, researchers Trumbore and Druffel have pioneered the application of the new AMS technology to the study of carbon cycling on land and in the ocean. Samples are prepared at UCI by converting the carbon first to carbon dioxide, then reducing it to a graphite target that is measured at one of several national accelerator facilities.