Submerged macrophytes are important primary producers in aquatic ecosystems. They can significantly alter the nitrogen (N) cycling processes in sediments. However, the effects of invasive submerged macrophytes on sediment N cycling under complex environmental conditions remain largely unknown.

In this study, we conducted a 3-year field experiment to investigate the effects of the invasive submerged macrophyte Hydrilla verticillata on sediment N cycling in a subtropical lake. We measured sediment N transformation rates, microbial abundances, and environmental variables.

The results showed that H. verticillata significantly altered the sediment N cycling processes. It increased the rates of denitrification and N2O production, while decreasing the rates of nitrification and NH4+ production. These changes were mainly attributed to the effects of H. verticillata on sediment oxygen concentration, microbial community composition, and organic matter decomposition.

Our findings suggest that invasive submerged macrophytes can significantly affect sediment N cycling in complex environments. This may have important implications for the management of aquatic ecosystems and the control of N pollution.

Here are the key findings of the study:

Invasive submerged macrophytes can significantly alter the sediment N cycling processes.

H. verticillata increased the rates of denitrification and N2O production, while decreasing the rates of nitrification and NH4+ production.

These changes were mainly attributed to the effects of H. verticillata on sediment oxygen concentration, microbial community composition, and organic matter decomposition.

Our findings suggest that invasive submerged macrophytes can significantly affect sediment N cycling in complex environments. This may have important implications for the management of aquatic ecosystems and the control of N pollution.