Mechanism of cyanobacterial bloom control by magnetic lanthanum-based material

Abstract

In this study, the mechanism of magnetic P-inactivating material on cyanobacterial bloom control was investigated by adding magnetic lanthanum-based material (MLC-10) in different stages of cyanobacterial growth during a 30-day cultivation experiment. The results showed that adding MLC-10 could rapidly reduce the available phosphorus, achieve phosphorus limitation in water body, and inhibit cyanobacterial blooms in the water column. In particular, the addition of MLC-10 at the early stage of cyanobacterial growth (day 0) achieved 97.5% bloom control. Additionally, cyanobacteria was captured and precipitated by MLC-10, and the floating ability of cyanobacteria was reduced. The results of antioxidant enzyme activities showed that adding MLC-10 may cause damage to the activity of cyanobacteria and induce stress response of cyanobacterial cells, which increased with increasing of exposure time. Besides, the results of metabolomics further suggested that adding MLC-10 mainly affected the amino acid metabolism, lipid metabolism and tRNA synthesis of cyanobacteria, which lead to the damage to cells’ activities and membrane transport. These results provide insight into the mechanism of MLC-10 as a magnetic P-inactivating material on cyanobacterial bloom control.