2007 Volume 51 Pages 481-486
Submarine Groundwater Discharge (SGD) is now recognized as an important pathway between land and sea. This paper takes a first step for estimating nutrient inputs through SGD to Ariake Bay. SGD rates and its quality along the coast of the Ariake Bay off Oura region were investigated. As a result, it was shown that on-site SGD rate ranged from 0.01 to 20.52μm/s, and SGD flowed through shallow confined aquifers which consist of basalt and superposition pyroclastic fall with shorter residence time. Then, it was estimated that reduction reaction for SGD proceeded just up to denitrification, and SGD associated nutrient loads (N, P, SiO2) are estimated at 1.40g/day, 0.07g/day, and 52.78g/day respectively. The results of this study demonstrate that SGD must be considered as a significant source of nutrient to the coastal sea area in Ariake Bay.
