Photovoltaic coverage reshapes the bacterial communities and interaction networks in aquaculture ponds: Divergent responses between seawater and sediment

The Fishery-Photovoltaic Complementarity (FPC), which integrates photovoltaic power generation with aquaculture, is a promising renewable energy solution that has gained increasing attention. However, the effects of these structural changes on the aquatic and sedimentary environment, as well as on prokaryotic communities, remain unclear. In the present study, the dynamics of bacterial communities and co-occurrence networks in both seawater and sediments were investigated across four different aquaculture ponds (with and without photovoltaic coverage). Results have shown that the photovoltaic (PV) coverage significantly reduced seawater temperature, salinity, and dissolved oxygen (DO), but enhancing nutrients (total organic carbon, TOC, total nitrogen, TN and total phosphorus, TP) accumulation in sediments. In seawater, both the composition and structure of bacterial communities were shaped by seasonal temperature variations rather than by the presence of PV. In contrast, in sediments, PV induced enhancement of nutrients significantly altered the bacterial communities, characterized by higher diversity, greater heterogeneity, and an increase in anaerobic bacteria such as Atribacteria and sulfate-reducing bacteria. Co-occurrence network analysis further revealed that photovoltaic shading induced distinct topological shifts in bacterial networks between seawater and sediments. The application of PV promoted the formation of modular associations among functionally related taxa, e.g., Alphaproteobacteria and Actinobacteria , resulting in decreased network connectivity and stability in seawater. In sediments, however, bacteria with diverse metabolic capabilities, e.g., Latescibacteria , Bacteroidetes , and Synergistetes , exhibited enhanced cooperative interactions, forming a more interconnected, tightly organized, and stable network structure. In summary, our present study demonstrates habitat-specific responses of bacterial communities, where the seawater communities were only affected by seasonal temperature, while sediment communities were directly reshaped by photovoltaic-induced nutrients enrichment. These findings provide critical insights for the ecological risk assessment and sustainable management of FPC, highlighting the importance of balancing renewable energy production with aquatic ecosystem health.