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

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 36 h 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 degrees C and 18 mu mol photons m(-2) s(-1) and the maximal P uptake rate was found at 15 degrees C and 144 mu mol photons m(-2) s(-1). Moreover, further studies were needed to investigate the bioremediation potential of L japonica in the open sea. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.