As the ocean absorbs one fourth of the carbon dioxide (CO2) released into the atmosphere by human activities, the carbonate chemistry and acidity of seawater is modified in a process known as ocean acidification. This has emerged as a key global issue in the last decade because of its potential to affect marine organisms and ecosystems. The IAEA’s Environment Laboratories conduct research to better understand the potential environmental and economic impacts of ocean acidification. The Agency uses nuclear and isotopic techniques to study the rates of biological processes in marine organisms, such as mussels, oysters and corals.