Effects of flocculation of Prorocentrum micans by modified clay on nitrogen and phosphorus
LU Guang-yuan;SONG Xiu-xian;YU Zhi-ming;CAO Xi-hua;YUAN Yong-quan;Key Laboratory of Marine Ecology and Environmental Sciences,Institute of Oceanology, Chinese Academy of Sciences;University of Chinese Academy of Sciences;
Harmful algal blooms(HABs) occurred frequently in coastal water around the world over the past decades. Flocculation of algal cells by modified clay has been proven to be an effective method and was the only practical strategy applied in the field, particularly in Asia. To assess the long-term ecological effects of this method, the study investigated the variation of two major nutrients during succession of cultured dinoflagellate Prorocentrum micans Ehrenberg(P. micans, A1) flocculated with modified clay(MC,A2). More than 60% of P. micans cells were efficiently removed by 0.4g/L of MC within 3.5h, and cells were no rebooming in A2. The results indicated that MC removed 26% of TN, 42% of TP, 85% of DIP, 35% of DIN, respectively. compared with TON and TOP concentrations in A1, it has been decreased of 120μmol/L and 6μmol/L by MC on day 33, respectively. Simultaneously, the study speculated that MC treatment controlled the nutrient exchange(between water and sediment) by blocking and sealing the organic-clay matrix in the surface areas of sediments. The study would benefit the further explore of long term environmental effects of the MC application for HABs' mitigation.