Study on the Scarcity of Red Tide in the Eutrophicated Waters of ARIAKE Bay-I: Dissolution of Phosphate Ion from Bottom Mud by Hydrogen Sulfide

Soluble sulfide such as hydrogen sulfide was made clear to be able to become the cause of the dissolution of phosphate ion from sea bottom mud. The phosphate which is capable of liberating phosphate ion from the bottom mud into water when met with soluble sulfide was examined and concluded to be ferric phosphate. Calcium hydroxide so interfered with the action of soluble sulfide as not to liberate phosphate ion from ferric phosphate in the bottom mud. The cause of the scarcity of red tide in ARIAKE bay was ascribed to the rapid tidal current which accelerate the oxidation of hydrogen sulfide in bottom mud by dispersing the bottom mud into water with sufficient oxygen.