Balanced Radical-Based Cyanobacterial Suppression and Carbon-Driven Community Shift with Butanedione in Aquatic Microcosms

) and acetate (Ac). The results demonstrated that Ac exerted minimal short-term impact on cyanobacterial proliferation. In contrast, BD-derived radicals induced rapid cyanobacterial suppression, improving key water quality parameters in the early phase and subsequently supporting the recovery of eukaryotic algae. These radicals also markedly altered aquatic community structure, enriched beneficial photoheterotrophic bacteria, and suppressed functional pathways related to cell envelope biosynthesis. Notably, BD treatment reduced the abundance of antibiotic resistance genes (ARGs) and virulence factor genes, as well as the total relative abundance of potential bacterial hosts carrying both types of genes to 1/5 of that observed in the Ac-treated group. These results underscore BD's dual functionality as an effective cyanocide with application potential, providing a scientifically grounded strategy for the sustainable management of harmful cyanobacteria-affected aquatic ecosystems.