6:15 PM - 7:30 PM
[ACG35-P04] Local scale assessment of submarine groundwater discharge in coastal seas (Beppu, Obama and Otuchi Bay)
Keywords:submarine groundwater discharge, 222Rn, land-ocean interaction
Submarine groundwater discharge (SGD) is important as a major pathway for freshwater and nutrients loads from land to ocean. Various natural tracers of SGD have been applied to quantify local to regional SGD fluxes. Radon-222 (222Rn) is a naturally occurring radioactive gas that is typically 2-3 orders of magnitude higher in groundwater than surface waters. Therefore, it is a powerful tracer of groundwater inputs to oceans. We have applied the continuous 222Rn monitoring survey to three local scale coasts (Beppu Bay, Obama Bay and Otsuchi Bay), which have large amounts of groundwater resources in each watershed. As a result, spatial distributions of 222Rn and other parameters displayed not only influence of submarine groundwater discharge but also possibility of submarine hotspring discharge.