Geochemical tracers for evaluating groundwater discharge and other processes in coastal areas

Abstract

Radioisotopes from the U/Th decay series are used routinely as tracers for submarine groundwater discharge (SGD) worldwide. We present the main principles of radon and radium mass-balance approaches used for quantifying SGD in coastal areas and discuss some challenges. For example, modeling exercises can substantially help interpret field measurements and reduce uncertainties. We showed how the stable isotopes of nitrogen, carbon, and pigments were used to determine the impacts of SGD's quality on coastal water and biota. Finally, we suggest that the novel deep-learning modeling approaches using radioisotopes are projected to be an important future direction in SGD research.