Short communicationThe importance of bacteria in promoting algal growth in eutrophic lakes with limited available phosphorus

Surface waters in Lake Taihu are increasingly threatened by phosphorus (P)-related eutrophication, with a considerable proportion of organic P. A simple experimental model was proposed to characterize “bacterial services” to cyanobacteria. We used the digested solutions of three dissolved organic phosphorus (DOP) compounds (i.e., glucose-6-phosphate, adenosine triphosphate and lecithin) to test the stimulatory effects of nutrient regeneration by bacteria. The growth-promoting effects of six digested solutions on the microalga Microcystis aeruginosa (Ma) were studied. Of these six digested solutions, four had significantly growth-promoting effects on Ma, including the digested solutions of the three DOP compounds by bacteria Gordonia sp. txj1302RI and glucose-6-phosphate by bacteria Burkholderia sp. txj1302Y4. These results demonstrated that bacteria played important roles in decomposing the unavailable organic P into DIP, suggesting that natural bacteria contribute to algal blooms in Lake Taihu.