The USGS Coral Reef Ecosystems Studies project (https://coastal.er.usgs.gov/crest/) provides science that helps resource managers tasked with the stewardship of coral reef resources. This data release contains data on coral-growth rates and time-series photographs taken of colonies of the elkhorn coral, Acropora palmata, grown at five sites on the Florida Keys reef tract from Spring 2018 to Autumn 2019. The data will be used to inform resource managers of the capacity for restoration and growth of this threatened species of coral along 350 kilometers of the Florida reef tract to aid species recovery throughout the western Atlantic. The datasets included here were interpreted in Kuffner and others (2020). Kuffner, I.B., Stathakopoulos, A., Toth, L.T., and Bartlett, L.A. In press. Reestablishing a stepping-stone population of the threatened coral, Acropora palmata, to aid regional recovery. Endangered Species Research.

The U.S. Geological Survey (USGS) Coral Reef Ecosystems Studies (CREST) project (https://coastal.er.usgs.gov/crest/) provides science that helps Department of Interior and other resource managers tasked with the stewardship of coral reef resources. This data release contains data on coral physiology of the elkhorn coral, Acropora palmata, grown at five sites along the Florida outer reef tract including in Biscayne National Park, the Florida Keys National Marine Sanctuary, and Dry Tortugas National Park, from summer 2017 to autumn 2020. The data will be used to inform resource managers of the capacity for restoration and growth of this important, habitat-forming species of coral within U.S. waters. Some datasets included here were interpreted in Chapron and others (2023b). Chapron, L., Kuffner, I.B., Kemp, D.W., Hulver, A.M., Keister, E.F., Stathakopoulos, A., Bartlett, L.A., Lyons, E.O., and Grottoli, A.G., 2023, Heterotrophy, microbiome, and location effects on restoration efficacy of the threatened coral Acropora palmata: Communications Earth and Environment, vol. 4, art. 233, https://doi.org/10.1038/s43247-023-00888-1.

Six replicate fragments from each of twelve A. cervicornis genotypes from the University of Miami (UM) and twelve genotypes from the Nova Southeastern University (NSU) nurseries were collected and brought to the Experimental Reef Lab (ERL). At ERL, the growth rates of all the fragments were assessed using buoyant weight. For the UM genotypes, the maximum photosynthetic yield of the algal symbionts (Fv/Fm) was additionally measured.

These data are from the article “Seasonal carbonate chemistry dynamics on southeast Florida coral reefs: localized acidification hotspots from navigational inlets” published in Frontiers in Marine Science. The data in this package were collected from inlets and reefs along the coast of Southeast Florida. Water was collected bi-monthly from four reefs (Oakland Ridge, Barracuda, Pillars, and Emerald) and three closely-associated inlets (Port Everglades, Bakers Haulover, and Port of Miami). Water samples were collected at these locations either at the surface (~1m depth) or immediately above the benthos measured using a rosette sampler (ECO 55, Seabird). Temperature was recorded at each depth using a CTD (SBE 19V2, Seabird). Turbidity (NTU) was measured at time of water collection. Once collected, water samples were transferred to borosilicate glass bottles, samples were fixed using 200 µL of HgCl2 and sealed using Apiezon grease and a glass stopper. Salinity was measured using a densitometer (DMA 5000M, Anton Paar), while total alkalinity (TA) and dissolved inorganic carbon (DIC) were determined using Apollo SciTech instruments (AS-ALK2 and AS-C3, respectively). All values were measured in duplicate and corrected using certified reference materials following recommendations in Dickson et al. (2007). Aragonite saturation state (ΩArag.), Calcite saturation state (ΩCa), pH (Total scale), and the partial pressure of CO2 (pCO2) were calculated with CO2SYS (Lewis and Wallace, 1998) using the dissociation constants of Mehrbach et al. (1973) as refit by Dickson and Millero (1987) and Dickson (1990). Water samples were reserved for nutrient analyzed at time of collection to determine Total Kjeldahl Nitrogen, Total Phosphorus, and fluorescence of Chlorophyll-a. This research was supported through NOAA’s Coral Reef Conservation Program.

Staghorn coral, Acropora cervicornis, is a threatened species and the primary focus of western Atlantic reef-restoration efforts to date. As part of the USGS Coral Reef Ecosystems Studies project (http://coastal.er.usgs.gov/crest/), scientists investigated skeletal characteristics of nursery-grown staghorn coral reared using two commonly used grow-out methods at Mote Tropical Research Laboratory’s offshore nursery. USGS staff compared linear extension, calcification rate, and skeletal density of nursery-raised A. cervicornis branches reared for six months either on blocks attached to substratum or hanging from monofilament line (on PVC “trees”) in the water column. The results demonstrated that branches grown on the substratum had significantly higher skeletal density, measured using computerized tomography (CT), and lower linear extension rates compared to water-column fragments. Calcification rates determined with buoyant weighing were not statistically different between the two grow-out methods, but did vary among coral genotypes. Whereas skeletal density and extension rates were plastic traits that depended on environment, the calcification rate was conserved. Results show that the two rearing methods generate the same amount of calcium-carbonate skeleton but produce colonies with different skeletal characteristics, and suggest that genetically based variability in coral-calcification performance exists. The data resulting from this experiment are provided in this data release and are interpreted in Kuffner et al. (2017).

Acropora cervicornis fragments of each genotype were evenly and haphazardly assigned to two nutrient treatments: ambient nutrients (Ambient) or elevated ammonium (NH4). Each nutrient treatment was replicated in four independent tanks (n = 3 fragments per genotype per tank). For ~1.5 months (47 d), Ambient tanks were maintained under nutrient levels consistent with the values in Virginia Key, FL, while elevated NH4 tanks were dosed with NH4Cl [3 mM] every 15 minutes using peristaltic pumps. The initial NH4 dose volume was 10 mL of the stock solution, targeting a ~10 μM increase in NH4 concentration. These values were calculated to account for the dilution of the nutrients resulting from adding new ambient seawater to the tanks (200 mL/min in a total tank volume of 180 L). After detecting higher than normal NH4 concentrations in the incoming seawater from Biscayne Bay, the NH4 dose volume was lowered to 5 mL of the stock solution, targeting ~5 μM NH4 increase above ambient values. The fragments were also assigned to disease vs. placebo treatments, the disease treatments involving exposure to homogenates of corals showing signs of white band disease following the protocol found in Rosales & Palacio-Castro (2024). Water samples (~40 mL) were collected to monitor NH4 levels in the treatments and immediately refrigerated at 4C. The elevated NH4 tanks were sampled daily, but the Ambient tanks were sampled less frequently (~2-3 days and no samples were collected during weeks 1 and 3 of the experiment). Nutrient concentrations were measured at NOAA-AOML using an AA3 nutrient analyzer (Seal Analytical, Southampton, UK). The instrument was calibrated before each run using standard solutions and procedures. Initially, only NH4 was monitored, but after high NH4 concentrations in the source seawater were detected, additional measurements of PO4 were included.