Nearshore Hardbottom Reefs of East Florida and the Regional Shelf Setting

Geological, hydrographic, and climatic conditions of Florida’s east coast nearshore hardbottom reefs (0–4 m depth) vary along a north-south gradient associated with a warm-temperate to tropical transition that influences distributions of algae, invertebrates, fishes, and sea turtles. Nearshore reef habitats from the Anastasia Limestone or Miami Limestone geological formations are present in nine of the ten east Florida counties in our study area. These limestone formations intergrade with mixed relict Holocene ridges in southeast Florida. The shoreline length of a county is often not directly related to its estimated acreage of hardbottom reefs. The availability of data on reef habitat also varies considerably. Changing patterns of sediment burial and erosion dynamics complicate the evaluation of reef areal distributions. Longshore currents and wind events influence sediment distributions. The northern nearshore reefs show cooler water temperatures, more frequent cold-water upwellings, higher proportions of quartz sediments, higher turbidity, and more intense wave energy. Nearshore hardbottom reefs south of the Jupiter Inlet area show smaller, lower-energy waves, and have higher proportions of carbonate sediments, lower turbidity, and warmer water temperatures. The proximity of the Gulf Stream relative to the southeast Florida coast is an important factor in influencing sediment and nutrient distributions, larval and propagule dispersal, and water temperature on nearshore reefs.