Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1007/s10661-023-11244-3
Licence creative commons licence
Title (Primary) Quantification of groundwater discharge into a shallow coastal lagoon applying a multi-tracer approach
Author Schubert, M.; Knoeller, K.; Scholten, J.; Daesslé, L.W.; Reyes Bravo, M.M.; Chávez Solís, E.M.
Source Titel Environmental Monitoring and Assessment
Year 2023
Department CATHYD
Volume 195
Issue 5
Page From art. 601
Language englisch
Topic T5 Future Landscapes
Keywords Submarine groundwater discharge; Coastal lagoons; Tracer; 222Rn; 223Ra; 224Ra; δ18O; δ2H
Abstract In many cases, shallow coastal lagoons are, on the one hand, vulnerable habitats for birds and marine ecosystems and, on the other hand, threatened by discharging nutrient-laden surface waters and groundwater. In particular, the localization and quantification of submarine groundwater discharge (SGD) is of key concern in this regard. The presented study aimed at investigating SGD into a vulnerable coastal lagoon that is strongly impacted by evaporation applying a multi-tracer approach. The joint application of radionuclides (222Rn, 223Ra, 224Ra), stable water isotopes (δ18O, δ2H) and the water salinity as environmental water tracers allowed evaluating the suitability of the individual parameters in this specific type of environment. Whilst stable isotope and salinity data were difficult to construe in terms of SGD occurrence due to the intense impact of evaporation, a radon mass balance allowed localising SGD areas within the lagoon and quantifying the related SGD flux rates. In addition, a 224Ra/223Ra ratio analysis revealed information on the apparent age of the discharged groundwater, and hence on the flushing intensity of the lagoon. Besides these site-specific results, the study allowed the following general conclusions regarding the suitability of the applied tracers: (i) we verified the suitability of a radon mass balance approach for proving/disproving SGD occurrence and quantifying SGD fluxes in shallow coastal lagoons strongly impacted by evaporation; (ii) we showed that the impact of evaporation may impede the use of water stable isotope and salinity data as SGD indicators in such specific environments; (iii) we demonstrated that the tidal impact on a lagoon water body during a sampling campaign can be compensated by adapting sampling schedule and cruise track to the tidal cycle.
Persistent UFZ Identifier
Schubert, M., Knoeller, K., Scholten, J., Daesslé, L.W., Reyes Bravo, M.M., Chávez Solís, E.M. (2023):
Quantification of groundwater discharge into a shallow coastal lagoon applying a multi-tracer approach
Environ. Monit. Assess. 195 (5), art. 601 10.1007/s10661-023-11244-3