Abstract:o investigate the removal efficiency of nutrient by macroalgae, six species of algae, including Mazzaella japonica, Ulva pertusa, Sargassum thunbergii, Bangia fuscopurpurea, Helminthocladia australis, and Ahnfeltiopsis flabelliformis, were cultured in natural seawater for 72 h, and then the concentrations of ammonia, nitrate, and phosphate in the culture media were measured respectively. The results showed that compared with the other species, M. japonica and U. pertusa showed much higher efficiency in removing all three nutrients. The percentages of the three nutrients absorbed by M. japonica and U. pertusa in 72 h were 98.0% and 97.1% of ammonia, 76.9% and 82.0% of nitrate，90.8% and 86.9% of phosphate, respectively.
