Artificial reef footprint in the United States ocean

Abstract

Marine ecosystem declines have spurred global efforts to restore degraded habitats, manage marine life and enhance recreation opportunities by installing built structures called artificial reefs in seascapes. Evidence suggests that artificial reefs generate ecosystem services and risks, yet a fundamental ecological characteristic—the area of seafloor occupied by these constructed reefs—remains poorly quantified. Here we calculate the physical footprint (seafloor extent) of artificial reefs in the US ocean using spatial data from all 17 US coastal states with ocean reefing programmes. Our synthesis revealed that purposely sunk reef structures such as ships and concrete pipes occupy 19.23 km2 of the ocean through 2020. Over the past five decades (1970–2020), the intentional reef footprint increased 20.85-fold (~1,980%), but this rate of increase slowed in the past decade (2010–2020) to 1.12-fold (~12%). These baseline findings will inform sustainable use of built marine infrastructure and generation of ecological functions. Artificial reefs provide important ecosystem services in marine environments. Accurate knowledge of the area covered by such reefs can help evaluate benefits and risks of such structures. This study describes the physical footprint of artificial reefs deployed in coastal waters of the United States.