Estimating submarine groundwater discharge in Jeju volcanic island (Korea) during a typhoon (Kong-rey) using humic-fluorescent dissolved organic matter-Si mass balance

We examined the residence time, seepage rate, and submarine groundwater discharge (SGD)-driven dissolved nutrients and organic matter in Hwasun Bay, Jeju Island, Korea during the occurrence of a typhoon, Kong-rey, using a humic fluorescent dissolved organic matter (FDOMH)-Si mass balance model. The study period spanned October 4-10, 2018. One day after the typhoon, the residence time and seepage rate were calculated to be 1 day and 0.51 m day(-1), respectively, and the highest SGD-driven fluxes of chemical constituents were estimated (1.7 x 10(6) mol day(-1) for dissolved inorganic nitrogen, 0.1 x 10(6) mol day(-1) for dissolved inorganic phosphorus (DIP), 1.1 x 10(6) mol day(-1) for dissolved silicon, 0.5 x 10(6) mol day(-1) for dissolved organic carbon, 1.6 x 10(6) mol day(-1) for dissolved organic nitrogen, 0.4 x 10(6) mol day(-1) for particulate organic carbon, and 38 x 10(6) g QS day(-1) for FDOMH). SGD-driven fluxes of dissolved nutrient and organic matter were over 90% of the total input fluxes in Hwasun Bay. Our results highlight the potential of using the FDOMH-Si mass balance model to effectively measure SGD within a specific area (i.e., volcanic islands) under specific weather conditions (i.e., typhoon/storm). In oligotrophic oceanic regions, SGD-driven chemical fluxes from highly permeable islands considerably contribute to coastal nutrient budgets and coastal biological production.

Automated summary

The study analyzed the residence time, seepage rate, and submarine groundwater discharge (SGD)-driven dissolved nutrients and organic matter in Hwasun Bay, Jeju Island, Korea during a typhoon using a humic fluorescent dissolved organic matter (FDOMH)-Si mass balance model. Results showed that SGD plays a significant role in nutrient cycling and coastal biological production.