A research team led by Prof. XIE Yonghong from the Institute of Subtropical Agriculture of the Chinese Academy of Sciences has uncovered how different types of aquatic vegetation regulate the migration and transformation of phosphorus pollutants under varying nutrient levels.

The results were published in Ecological Indicators on December 18.

Aquatic macrophytes are widely used in ecological restoration due to their ability to intercept nutrients and stabilize sediments. However, there is still a lack of clear mechanistic understanding globally of how plant life forms and their rhizosphere microbial communities jointly regulate phosphorus mobility at the sediment-water interface under varying nutrient loadings and across phenological stages.

To address this gap, the researchers constructed controlled macrophyte-water-sediment mesocosms representing three contrasting life forms: the submerged Vallisneria natans, the rooted floating-leaf Nymphoides peltata, and the emergent Typha angustifolia. These systems were exposed to gradient nutrient loadings.

The results revealed life form-specific and phenology-dependent strategies: V. natans acted as a fast but time-variable regulator that strongly suppressed phosphorus release under high nutrient loading via rhizosphere processes and higher microbial diversity. N. peltata followed a conservative pathway, enhancing phosphorus retention within sediments but exerted limited control over sediment-water exchange. T. angustifolia provided stable, long-term phosphorus sequestration through extensive belowground organs, supporting the most complex and resilient rhizosphere microbial network.

Key microbial taxa were consistently associated with phosphorus properties across all systems, suggesting an active microbial role in shaping inorganic phosphorus solubilization, organic phosphorus mineralization, and iron-bound phosphorus dynamics.

This study advances the management of eutrophication from the approach of simply planting vegetation to a more precise, mechanism-based approach of restoration. It shows that controlling phosphorus depends on the coordinated effects of plant life forms, seasonal growth dynamics, and rhizosphere microbial feedbacks.

By identifying these distinct roles, the study establishes principles that can be applied globally to design resilient wetlands under variable nutrient pressures.

"Equally important, it elevates rhizosphere microbial networks from hidden components to strategic targets for restoration by highlighting key taxa linked to phosphorus transformations and system stability. These insights establish a foundation for internationally scalable, nature-based solutions, fostering more durable and predictable outcomes in aquatic ecosystem recovery," said Prof. XIE.

A schematic diagram illustrating the regulation of phosphorus migration and transformation by three types of aquatic plants (Imaged by MA Xiaowen)