ABSTRACT
Investigations of the distribution of radionuclides in the marine environment have provided a wealth of information on their speciation behavior, mobility, fate, and transport. A number of processes control the radionuclides concentration, thus allowing the discernment of their different sources, or a better understanding of the governing biogeochemical and hydrodynamic processes from their partitioning among particulate, colloidal, and dissolved phases. Because of their radioactive decay, they can act as clocks and allow the determination of removal or turnover residence times in marine and freshwater systems. Over the past five to six decades, a large volume of literature has been published on the utility of radionuclides as tracers and chronometers in the marine environment. Reviewing and writing the methodology for all the radionuclides that are used as tracers and chronometers in the marine system would be an overwhelming task. However, several recent papers and book chapters bring out the current methodology for a number of radionuclides, and hence we will refer to those key references wherever it is appropriate (Rutgers van der Loeff and Moore, 1999; Chen et al., 2001; Rutgers van der Loeff et al., 2006; Hou and Roos, 2008) and focus on those nuclides for which the methodology has not been updated for a number of years.
