抄録
Shrimp aquaculture growth in Asia has suffered many problems in recent years. Disease outbreaks are one of the serious problems. To reduce the risk of disease contamination without antibiotics from externally polluted water supply, the intensive shrimp culture has evolved to closed system. However, the rapid eutrophication in closed ponds could become stressful to shrimps. We tried to apply seaweed Ulva spp. to controlling the fluctuation of water quality and to remove nutrients from culture pond water for prevention of undesirable microalgae blooms. Ammonia-nitrogen uptakes by Ulva spp. were experimentally measured. The initial uptake rate obeyed Michaelis-Menten equation with the concentration of ammonia and the constants in this equation were in the ranges of those in the previous works. The relationship between algae surface area irradiation area ratio and specific ammonia-N uptake rate revealed that optimal algae surface area irradiation area ratio probably exists. Uptake rate was higher when internal ammonia-N concentration was lower. We showed the importance to consider algae surface area/irradiation area ratio in design of reactors using algae, and potential of macroalgae to control of ammonia content fluctuation in closed shrimp-culture ponds.
