Invasive aquatic macrophytes have the potential to alter the biogeochemistry of inland waters. Hydrilla verticillata is a submerged aquatic macrophyte that has invaded the lower Connecticut River in recent years, impacting habitats, hydrology, and recreation. H. verticillata has the strong potential to alter carbon cycling in and greenhouse gas emissions from impacted areas. In summer 2024, the US Army Corps of Engineering conducted an ecosystem-scale herbicide application in affected coves along the lower Connecticut River. We leveraged this herbicide application as an experimental treatment to assess the effects of H. verticillata on carbon cycling and greenhouse gas emissions. We will present observations of water chemistry and greenhouse gas dynamics from before and after the herbicide application in treated and untreated areas to start to unravel the potential impacts of H. verticillata on carbon cycling in and greenhouse gas emissions from the lower Connecticut River. As climate change is increasing the prevenance of invasive aquatic species, shifts in carbon cycling and greenhouse gas emissions associated with invasives may represent important climate feedbacks.