Inputs of humic fluorescent dissolved organic matter via submarine groundwater discharge to coastal waters off a volcanic island (Jeju, Korea)

Submarine groundwater discharge (SGD) significantly enhances the inventory of humic-like fluorescent dissolved organic matter (FDOMH) in coastal waters off Jeju Volcanic Island, Korea, increasing its concentration by 2–3 times over all seasons. This finding challenges the conventional understanding that rivers are the primary source of FDOM in surface ocean waters. Researchers used a correlation between radon-222 and salinity to identify fresh groundwater as the main contributor to SGD, while dissolved organic carbon (DOC) and protein-like FDOM inputs were negligible or negative. The conservative behavior of FDOMH suggests that SGD-driven fluxes regulate its inventory, influencing the optical properties of coastal waters and potentially impacting marine ecosystems, including corals.

Kim, J., & Kim, G. (2017). Inputs of humic fluorescent dissolved organic matter via submarine groundwater discharge to coastal waters off a volcanic island (Jeju, Korea). Scientific Reports, 7(1). https://doi.org/10.1038/s41598-017-08518-5