Ecological Shifts along the Florida Reef Tract: The Past as a Key to the Future

Species composition, habitat, and water quality influence coral bleaching in southern Florida

“…Other studies have shown that both the Florida current and the proximity of Florida Bay have a direct impact on water quality, which, in turn, affects coral-community structure (Marszalek et al 1977). The close proximity of the reef tract to the passes interspersed throughout the Middle Keys allows water from Florida Bay to flow into the Atlantic, bathing the reef system in warmer, hyper-saline waters in the dry season (Precht & Miller 2007) and hypo-saline water in the wet season (Precht & Miller 2007, Wagner et al 2008. During thermal stress events these osmotic extremes may couple to exacerbate the bleaching response (Mayfield & Gates 2007).…”

“…It is also important to identify the environmental processes associated with the geographic positioning of coral reefs, such as ocean currents, temporal and spatial effects of cloud cover, turbidity, upwelling, rainfall, and salinity (Precht & Miller 2007). Coupling these variables with the inherent resistance of specific coral taxa to bleaching allows the predictive modeling necessary to identify future 'winners and losers' following wide-scale coral-bleaching events (Loya et al 2001).…”

“…1). This ~500 km expanse represents a vast array of environmental conditions, from extreme wave exposure in the north to more sheltered conditions in the Lower Florida Keys (Murdoch & Aronson 1999, Precht & Miller 2007. The northern reefs support few corals, and reef growth appears to have ceased approximately 4000 yr ago (Banks et al 2007).…”

The effects of nitrogen and phosphorus enrichment on algal community development: Artificial mini-reefs on the Belize Barrier Reef sedimentary lagoon

“…However, some reef scientists recently have countered that such changes in benthic community structure are dependant on natural stochastic events (Precht and Miller, 2007;Littler et al, 2009), overfishing of herbivorous fish stocks (Hughes, 1994;Pandolfi et al, 2003) and/or loss of keystone grazers such as the long-spined sea urchin Diadema antillarum (Jackson et al, 2001). These last conclusions are supported by the numerous grazer-reduction experiments in nutrient-replete systems but not in strictly oligotrophic environments that, for the most part, have reported an expansion of low-growing fleshy algal forms, algal turfs and/or filamentous forms (<3 cm high) rather than macroalgal blooms (as predicted in the RDM; see Lapointe, 1999).…”

Herbivory, Nutrients, Stochastic Events, and Relative Dominances of Benthic Indicator Groups on Coral Reefs: A Review and Recommendations

“…In the conceptual relative dominance model (RDM; see Figure 1), grazing physically reduces biomass (top-down) and nutrients control production (bottom-up). The complex natural interactions between herbivory and nutrients are most dramatically impacted by large-scale catastrophic disturbances such as tropical storms (Done, 1992), warming events (Macintyre and Glynn, 1990;Lough, 1994), cold fronts (Precht and Miller, 2007), diseases (Santavy and Peters, 1997), and predator outbreaks (Cameron, 1977). These events serve to trigger or accelerate the ultimate long-term phase shifts postulated in the RDM.…”