Application of three species of Pseudomonas bacterium in inhibiting of the Nodularia bloom

The Nodularia microalga has the potential for bloom at low salinity, brackish and saline waters. The algal bloom is endangered as a serious problem of living aquatic organisms in the southern part of Caspian Sea. In this study, the effect of algal bloom inhibition were investigated with three species of Pseudomonas spp. including aeruginosa, putida and fluorescence, which were isolated and identified from the estuaries of the Tajan River in basin of the southern of Caspian Sea, in a laboratory scale. Also, fluctuation of chlorophyll-a, dissolved oxygen, phosphate and nitrate were simultaneously evaluated. The results showed that the trend of chlorophyll-a, dissolved oxygen and nitrate were significantly reduced in all treatments containing bacteria, especially aeruginosa (68%) and mixture of bacteria (71%) (p<0.05) and this trend of the parameters was almost constant in the control treatment. Although, phosphate concentrations decreased relative at different times, but there was no significant difference (p>0.05). In addition, the rate of phosphate consumption was higher than nitrate at different times. As a result, these species can be used as indicator bacteria for inhibiting of the algae bloom in a larger ecosystem.