Author name: Anton Eisenhauer

Calcium and magnesium isotope fractionation, recorded in shells of marine organisms that biomineralize calcium carbonate, is helping scientists to understand the transport of trace elements from seawater to the site of calcification, as well as trends in seawater composition throughout time. This knowledge would be difficult to obtain otherwise, and is important, especially now, for assessing the threat of ocean acidification to shell-producing marine organisms.

Recent advances in mass spectrometry have allowed isotope scientists to precisely determine stable isotope variations in the metallic elements. Biologically influenced and truly inorganic isotope fractionation processes have been demonstrated over the mass range of metals. This Elements issue provides an overview of the application of metal stable isotopes to low-temperature systems, which extend across the borders of several science disciplines: geology, hydrology, biology, environmental science, and biomedicine. Information on instrumentation, fractionation processes, data-reporting terminology, and reference materials presented here will help the reader to better understand this rapidly evolving field.