Abstract
Recent studies have reported that submarine groundwater discharge (SGD) is not negligible as a nutrient source from land to coastal sea. In order to evaluate SGD rate and its influence on water quality of sea bottom water in Osaka Bay, field surveys and analyses were conducted utilizing 222Rn as a natural tracer.
As the results, 222Rn concentration represented the higher value in the bay head than the offshore. Principal component analysis indicated that the water quality of bottom layer in the north port area was affected by SGD. Moreover, numerical analyses showed that 222Rn flux from the sea bottom was estimated at 0 to 120 Bq/m2/day and that local flow field and estuary circulation played an important role in 222Rn distribution in the bay.
