Aquatic macrophytes alleviate algal blooms by synchronously mitigating sediment and nutrient resuspension

Protecting lake ecosystems and providing clean water caters to several sustainable development goals, yet, comprehensive understanding on the role of aquatic macrophytes to mitigate sediment resuspension and improve water quality is lacking. We executed a meta-analysis and constructed a dataset integrated from 657 studies containing 3824 pairs of observations and 38 ecological and environmental parameters (e.g., nitrogen and phosphorus). This enabled us to evaluate ecological restoration performances of three life forms macrophytes (i.e., emergent, floating-leaved, and submerged macrophytes) in global case studies focusing on sediment resuspension. We found that the presence of emergent, floating-leaved, and submerged macrophytes showed negative effects on 81.8%, 65.2%, and 88.9% of the tested parameters, respectively. Aquatic plants synchronously decreased sediment, nitrogen and phosphorus resuspension rates, accompanied by decreases in water shear stress, turbidity, and total suspended solids. There were close relationships between algal blooms with water and sediment nitrogen/phosphorus as well as with sediment and nutrient resuspension rates when aquatic macrophytes mitigated sediment resuspension. Submerged macrophytes showed a better ecological restoration performance than emergent and floating-leaved macrophytes by mitigating sediment and nitrogen and phosphorus resuspension more efficiently. This resulted in decreased algal blooms and improved water quality as water nitrogen and phosphorus were reduced. Our meta-analysis is the first study to report aquatic macrophytes could mitigate algal blooms by synchronously mitigating sediment and nutrient resuspension, and our findings provide a comprehensive understanding on ecological restoration performances of aquatic plants with different life forms, which allows better guidance for lake protection and restoration.