Low net carbonate accretion characterizes Florida’s coral reef

Abstract

Coral reef habitat is created when calcium carbonate production by calcifiers exceeds removal by physical and biological erosion. Carbonate budget surveys provide a means of quantifying the framework-altering actions of diverse assemblages of marine species to determine net carbonate production, a single metric that encapsulates reef habitat persistence. In this study, carbonate budgets were calculated for 723 sites across the Florida Reef Tract (FRT) using benthic cover and parrotfish demographic data from NOAA’s National Coral Reef Monitoring Program, as well as high-resolution LiDAR topobathymetry. Results highlight the erosional state of the majority of the study sites, with a trend towards more vulnerable habitat in the northern FRT, especially in the Southeast Florida region (− 0.51 kg CaCO3 m−2 year−1), which is in close proximity to urban centers. Detailed comparison of reef types reveals that mid-channel reefs in the Florida Keys have the highest net carbonate production (0.84 kg CaCO3 m−2 year−1) and indicates that these reefs may be hold-outs for reef development throughout the region. This study reports that Florida reefs, specifically their physical structure, are in a net erosional state. As these reefs lose structure, the ecosystem services they provide will be diminished, signifying the importance of increased protections and management efforts to offset these trends.

Coral Reef Carbonate Chemistry Reveals Interannual, Seasonal, and Spatial Impacts on Ocean Acidification Off Florida

“…Overall, yearly net calcification and photosynthesis were found only in the LK and the MK regions, while the northernmost reefs in BB and UK seem to be closer to their tipping point (average ΔTA and ΔDIC values close to zero). Similar regional patterns have been observed in earlier (2009)(2010)(2011) carbonate chemistry surveys (Manzello et al, 2012;Muehllehner et al, 2016) and in carbonate budget studies (Enochs et al, 2015;Morris, Enochs, Besemer, et al, 2022), highlighting the higher risk of reef erosion in the northeast areas of the FCR compared to the southwest. Reefs in the BB and UK regions are in closer proximity to the city of Miami and thus could be exposed to more frequent anthropogenic disturbances.…”

“…The persistence of these services relies on the growth and maintenance of the reef framework. However, the loss of coral cover due to disease outbreaks (Aronson & Precht, 2001; Walton et al., 2018), hurricane impacts (Gardner et al., 2005), coastal development and land‐based sources of pollution (Patterson et al., 2002; Ward‐Paige et al., 2005), as well as both warm and cold‐water and mass bleaching events (Lirman et al., 2011; Ruzicka et al., 2013) are pushing the FCR into an erosional state (Enochs et al., 2016; Morris, Enochs, Besemer, et al., 2022).…”

Coral reef structural complexity loss exposes coastlines to waves

“…Wave attenuation relies mainly on reef accretion and structural complexity 28 , for which the projections are not encouraging. Under a high greenhouse gas emissions scenario by the year 2050, 94% of the reefs worldwide may cease to accrete and start to flatten due to ocean acidification and warming 47 as it is already the case in other regions, including Florida 48 and some Caribbean islands 49 . Thus, the effects of rising seas are expected to be further amplified by the loss of living corals, painting a grim picture for the future safety of tropical coastal societies and highlights the critical importance of emission mitigation and coral preservation efforts.…”

Coral restoration for coastal resilience: Integrating ecology, hydrodynamics, and engineering at multiple scales

“…Sea‐level rise will exacerbate the flood vulnerability of low‐lying tropical coastlines, and if reef accretion cannot keep up with sea‐level rise, larger waves will be able to pass over the reef and increase coastal flooding (Storlazzi et al, 2011; Storlazzi, Gingerich, et al, 2018) and erosion (Grady et al, 2013). Severe loss of coral cover has already compromised the carbonate budgets of coral reefs, and many reefs are bioeroding rather than accreting (Morris et al, 2022; Perry et al, 2013). Future ocean acidification and reduced aragonite saturation state conditions may compromise the calcification of living coral (Pandolfi et al, 2011), and the expectation of reef accretion through restoration may not be realistic everywhere (Toth et al, 2022; Webb et al, 2023).…”