Evaluation of the potential role of the macroalga Laminaria japonica for alleviating coastal eutrophication

► We studied the biofiltration capacity of Laminaria japonica under laboratory conditions. ► L. japonica showed a significant nutrients uptake and the average N and P removal efficiency was around 44% and 41%. ► The optimum N/P ratio for its nutrient uptake was 7.4 and L. japonica prefered NO3–N other than NH4–N as nitrogen source. ► Temperature and irradiance affected uptake rates significantly. The rapid development of human activities has caused serious eutrophication of coastal waters in China in the recent decades. The study of the biofiltration capacity of Laminaria japonica under laboratory conditions showed a significant nutrient uptake. After 36h of incubation, around 42%, 46%, 44% of N and 45%, 42%, 35% of P were removed from three gradients of medium concentrations, respectively. In the conditions of different ratios of N/P and NO3–N/NH4–N, the optimum N/P ratio for nutrient uptake was 7.4 and L. japonica prefered NO3–N rather than NH4–N as nitrogen source. Temperature and irradiance affected uptake rates significantly. The maximal N uptake rate appeared at 10°C and 18μmol photons m−2s−1 and the maximal P uptake rate was found at 15°C and 144μmol photons m−2s−1. Moreover, further studies were needed to investigate the bioremediation potential of L. japonica in the open sea.