EFFECTS OF ACID TREATMENT ON GEO-ENVIRONMENTAL CONDITIONS IN THE ARIAKE SEA, JAPAN

摘要

The Ariake Sea, located in the Kyushu region, is one of the best-known semi-closed shallow seas in Japan. In this study, the results of a field test as well as a laboratory column test are presented that demonstrate the effects of acid treatment in cultivating sea laver {Porphyra Spp.} in the Ariake Sea. The sulphide content (SC), oxidation-reduction potential (ORP), salinity and pH of the Ariake mud were measured in the samples collected from the surface mud. The ORP and sulphide content of the mud is < -200 mV and > 0.5 mg/ g dry mud, respectively. All four parameters (SC, ORP, salinity, pH) were also measured in the laboratory column under four different levels of acid treatment. The results of both laboratory and field tests indicate a strong reduction condition in the mud, which causes an imbalance of the marine eco-system. Consequently, there is a dramatic decrease of catch shells in the affected area of the Ariake Sea during the last 20 years.