Abstract

Severe anoxic conditions in black-odorous waterbodies drive persistent release of S 2- and H 2 S, which critically threatens aquatic ecosystems and public health, necessitating effective remediation strategies. Here we propose an integrated strategy for sustainable regulation of S 2- and H 2 S release by combining submerged macrophytes with oxygen-loaded porous materials. Five types of porous materials were screened to identify optimal oxygen carriers, with their oxygen-loading capacity and release performance evaluated as substrates. Although activated carbon exhibited superior oxygen-loading capacity, volcanic stone was significantly more effective in sustaining elevated dissolved oxygen (DO) levels. In laboratory-scale simulations, the integrated system of submerged macrophytes with oxygen-loaded volcanic stone capping maintained stable DO concentrations at approximately 2.24 mg/L for over 36 days, which was significantly higher than that of either macrophyte-only or oxygen-loaded material-only treatments. Physiological assessments confirmed that oxygen supplied by volcanic stone effectively mitigated environmental stress, thereby promoting macrophyte growth. Furthermore, this combined application remarkably inhibited SO 4 2- reduction, leading to substantial reductions of 90.95 % in S 2- release and 94.61 % in H 2 S release compared to the control over an 80-day incubation. Notably, this study delves into the regulatory mechanisms of sulfur metabolism from the perspective of microbial community and functional gene responses. The integrated system significantly enhanced bacterial diversity within both sediment and leaf biofilms. In contrast to the control, the abundance of specific sulfate-reducing bacteria significantly decreased in the combined treatment, while populations of certain sulfur-oxidizing bacteria proliferated. Additionally, functional genes related to sulfate reduction were suppressed, whereas those associated with sulfur oxidation were upregu