CCS Monthly Forum

Abstract:

The Guana-Tolomato-Matanzas estuary in northeast Florida supports exceptionally dense populations of Eastern oysters (Crassostrea virginica), comparable to historical levels. These reefs provide critical ecosystem services, filtering about 60% of the estuary’s volume over its residence time. Their performance is shaped by reef size, hydrodynamics and particle concentration.

In recent decades, however, oyster mortality has increased due to marsh bank erosion driven largely by boat wakes. Aerial imagery shows widespread erosion along the Intracoastal Waterway, damaging nearby reefs and reducing filtration capacity. Models estimate a current 12% loss in filtration services, which could reach 20% over the next century if erosion continues.

Field observations show a clear contrast: sheltered lateral channels support healthy reefs, while high-traffic main channels are dominated by dead reefs. This pattern indicates that boat wakes — not natural wind waves — are the primary driver of reef degradation and oyster mortality.

Bio:

Alberto Canestrelli, Ph.D., associate professor in the UF Department of Civil and Coastal Engineering, specializes in the dynamics of coastal environments, particularly estuaries, tidal channels and salt marshes. His research combines numerical modeling with field data collected using acoustic instruments and drones to develop sustainable solutions for coastal protection and restoration. A key focus of Canestrelli’s work is on nature-based solutions, designed to enhance coastal defenses and improve estuarine water quality while remaining resilient and self-sustaining in the face of rising sea levels. His dedication to coastal management is further reflected in his leadership of international collaborations, contributing to global efforts to mitigate the impacts of climate change on coastal ecosystems.