RESUMO
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.