Autonomous Large-Scale Radon Mapping and Buoyant Plume Modeling Quantify Deep Submarine Groundwater Discharge: A Novel Approach Based on a Self-Sufficient Open Ocean Vehicle

Thomas Müller*, Jonas Gros, Patrick Leibold, Hajar Al-Balushi, Eric Petermann, Mark Schmidt, Warner Brückmann, Mohammed Al Kindi, Omar S. Al-Abri

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Groundwater discharge into the sea occurs along many coastlines around the world in different geological settings and constitutes an important component of global water and matter budget. Estimates of how much water flows into the sea worldwide vary widely and are largely based on onshore studies and hydrological or hydrogeological modeling. In this study, we propose an approach to quantify a deep submarine groundwater outflow from the seafloor by using autonomously measured ocean surface data, i.e., 222Rn as groundwater tracer, in combination with numerical modeling of plume transport. The model and field data suggest that groundwater outflows from a water depth of ∼100 m can reach the sea surface implying that several cubic meters per second of freshwater are discharged into the sea. We postulate an extreme rainfall event 6 months earlier as the likely trigger for the groundwater discharge. This study shows that measurements at the sea surface, which are much easier to conduct than discharge measurements at the seafloor, can be used not only to localize submarine groundwater discharges but, in combination with plume modeling, also to estimate the magnitude of the release flow rate.

Original languageEnglish
Pages (from-to)6540-6549
Number of pages10
JournalEnvironmental Science and Technology
Issue number16
Publication statusPublished - Apr 25 2023


  • Arabian coastal groundwater
  • autonomous offshore surface measurement
  • cyclone rainwater infiltration
  • radon
  • TAMOC plume modeling
  • Water
  • Oceans and Seas
  • Environmental Monitoring
  • Groundwater
  • Radon/analysis
  • Water Movements
  • Seawater

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry

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