Effects of Algicidal Substance on Phaeocystis globosa and Its Fatty Acids by the Simulation Experiment

In order to evaluate the effects of algicidal substance on Phaeocystis globosa (P. globosa) and its algal toxin-fatty acids, the changes of chlorophyll-a, pH, dissolved oxygen, permanganate index and N, P concentration were evaluated by the simulation experiment. Fatty acids composition in P. globosa was detected by GC-MS. After adding algicidal substance in simulative water with the volume ratio 1: 100, the levels of chlorophyll-a, pH and permanganate index were reduced, while the concentrations of dissolved oxygen and N, P were increased significantly within 14 days. Comparing with control group after 14 days, pH was reduced to 7. 51 from 8. 50, chlorophyll-a and permanganate index were reduced by 82. 3% (P < 0. 05) and 55. 2% (P < 0. 01), respectively. Dissolved oxygen was significantly increased by 29. 5% (P < 0. 05). The concentrations of NH4+ -N, NO2- -N, NO3- -N and PO(4)3- -P were respectively 0. 46, 1. 50 , 6. 24 and 1. 30 times higher than that in control group. 14 days after the addition of algicidal substance, the total fatty acids of P. globosa were reduced by 83. 4%. The major fatty acids C18:2, C16:0, and C18:1, were reduced by 100%, 97. 7% and 85. 4% (P <0. 01), respectively. Our results indicated that algicidal substance from Bacillus sp. BI can effectively inhibit the growth of P. globosa and reduce the concentration of algal toxin-fatty acid in the simulation experiment. This study provides a theoretical basis for ecological safety of algicidal substance form Bacillus sp. strain Bl.