ScienceDirect Editorial
Four radium isotopes, decay products of the 238U–232Th–235U series radionuclides, occur in nature: 224Ra (t1/2=3.66 days), 223Ra (t1/2=11.4 days), 228Ra (t1/2=5.75 years), and 226Ra (t1/2=1600 years). Beginning with the GEOSECS program of the late 1960s – early 1970s, these radium isotopes have been widely applied to the study of a variety of oceanographic processes (Moore, 1972; Trier et al., 1972). In the
GEOSECS era, upper-ocean and bottom boundary layer mixing were quantified using 228Ra (Sarmiento et al., 1976). Coastal ocean mixing was a notable application of the radium quartet in the 1980s (Moore, 1987).
Beginning in the mid-1990s, radium underwent a renaissance in the ocean sciences, when it was used to quantify the importance of submarine groundwater discharge (SGD) on the oceanic budget of many trace metals and nutrients (Moore, 1996; Burnett et al., 2006 and references therein). Concurrent with this discovery was the production of a commercially available delayed coincidence counter (RaDeCC; Moore and Arnold, 1996), which greatly simplified the measurement of the two short-lived Ra isotopes, 224Ra and 223Ra.
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Marine Chemistry special issue: The renaissance of radium isotopic tracers in marine processes studies