Bank erosion drastically reduces oyster reef filtration services in estuarine environments

Abstract

Oyster reefs near estuarine channels have experienced substantial mortality over the last decades, primarily due to bank erosion, potentially exacerbated by boat activity. Using aerial imagery, we measured bank erosion along the Intracoastal Waterway and its main tributaries in the Guana-Tolomato-Matanzas estuary, finding that erosion outweighs progradation. This notably threatens oyster reefs and their filtration capabilities. By modeling the impact of bank erosion on oyster habitats and filtration using hydrodynamic, water quality, and particle tracking models, we observed a 12% filtration reduction due to reef mortality. Erosion results in an exponential decrease in reef area and filtration services, due to the removal of channel-adjacent reefs, which play a critical role in water filtration. If current erosion rates continue, simulations suggest a potential 20% filtration reduction over 100 years, potentially worsening water quality. Our findings highlight the urgency to protect and restore reefs near banks to mitigate erosion and maintain filtration services.