Eutrophication and harmful algal blooms (HABs) pose a severe threat to freshwater ecosystems, creating an urgent demand for experimentally validated, environmentally sustainable control strategies. Reservoirs are particularly susceptible to eutrophication and HABs due to unique hydrological and ecological traits, including limited water exchange and weak hydrodynamic conditions. Here, we evaluated the efficacy of an integrated environmental-ecological control approach (combining nano-aeration and microbiological techniques) through a one-year in-situ experiment in three eutrophic reservoirs in Fujian Province, China. We found that the dominant phytoplankton phylum shifted from bloom-forming Cyanophyta to Bacillariophyta across all reservoirs. Specifically, total phytoplankton density decreased significantly by 87.2%, and the relative abundance of Cyanophyta averagely declined by 60.3%, while the relative abundance of Bacillariophyta increased by 225.2%. These ecological shifts were closely associated with elevated dissolved oxygen levels and reduced nutrient concentrations (e.g., total phosphorus and total nitrogen) induced by the integrated intervention, especially for the regulation of Cyanophyta dynamics. We revealed positive correlations between changes in nutrient concentrations and shifts in Cyanophyta relative abundance during the intervention period ( P < 0.05), emphasizing the necessity of long-term monitoring and adaptive management. This study demonstrates the potential of integrating nano-aeration and microbiological techniques for sustainable eutrophication and HAB’s management, and highlights the importance of continuous monitoring to prevent HAB recurrence.
Ling et al. (Wed,) studied this question.