MASIS: Towards best practices for Measuring and Archiving Stable Isotopes in Seawater

The stable isotopic composition of seawater and the carbon isotopic composition of dissolved inorganic carbon are essential ocean tracers that have been widely measured since the 1960s. They fingerprint current changes in the hydrological and bio-geochemical cycles, as well as anthropogenic carbon penetration. However, substantial issues of data collection, quality control, and compilation have amplified: common reference materials in seawater are not available; analysis methods have strongly diversified; regular intercomparison exercises are lacking; and, as a result, large differences exist between data sets. These differences if they persist will hinder the community effort from making full use of stable isotopes to identify climatic changes. MASIS