The roles of polyculture with Eucheuma gelatinae and Gafrarium tumidum in purification of eutrophic seawater and control of algae bloom

To control algae bloom and eutrophication in the tropical semi-closed harbor of the Hongsha Bay in Sanya, China, polyculture systems with macroalgae Eucheuma gelatinae and bivalves Gafrarium tumidum were studied. First, nine polyculture combinations with E. gelatinae and G. tumidum were selected in a pool. Two combinations were then chosen by response surface analysis and used for further study to validate their effect on controlling the microalgae density and reducing the nutrition concentration in the pool. Subsequently, the two selected combinations were used to study the effect on the purification of eutrophic seawater and control of algae bloom in a sea mesocosm. The results indicated that polyculture with E. gelatinae and G. tumidum enhanced the purification of eutrophic seawater and control of algae bloom. These two polyculture combinations are considered suitable for the Hongsha Bay of Sanya in China. The two combinations present an excellent effect on controlling the microalgae density and reducing the nutrition concentration.