Experimental coral-physiology data for Acropora palmata in Florida, U.S.A.

Coral collection and experimental design- Acropora palmata genets were originally sourced from different upper Florida Keys reefs by the Coral Restoration Foundation (CRF) prior to being cultivated in CRF’s offshore coral nurseries. The forty-one corals sampled in the study were replicates (ramets) from six unique genets (CF4, CN2, HS1, ML2, SN1, and DT1), which were mounted on labeled Polyvinyl chloride (PVC discs), buoyantly weighed (Jokiel and others, 1978), and deployed on fixed, concrete stations at five USGS calcification-assessment-network sites along the Florida Keys reef tract (Morrison and others, 2013). These sites, from west to east, were Pulaski West and Pulaski Light in Dry Tortugas National Park, Sombrero Reef and Crocker Reef in the Florida Keys National Marine Sanctuary, and Fowey Rocks in Biscayne National Park. Thirty-five surviving ramets from an assisted-migration experiment initiated in Spring of 2018 (Kuffner and others 2020b) were sampled after the end of that study in the Autumn of 2020. To increase sample size, six additional ramets were sampled at that time (from three of the same CRF-nursery genets) that had been deployed at Crocker Reef in 2017, for a discontinued experiment that was interrupted by Hurricane Irma. Generally, n = 2 ramets from each of the five upper Florida Keys genets were placed at each of the five sites, and an additional n = 2 ramets from the Dry Tortugas genet (DT1) were placed at the two Dry Tortugas sites. Ramets sourced from the Dry Tortugas genet were not reciprocally transplanted to the main Florida Keys sites because of permitting and logistical restrictions. As part of the assisted-migration study, calcification rates, linear extension, and planar area of the translocated corals were measured every six months from May 2018 to October 2019 and are reported elsewhere (Kuffner and others, 2020a; 2020b).

Tissue biomass, endosymbiont density, chlorophyll a, and energy reserves- The surface area of the ramet section designated for physiological analyses was determined using the aluminum foil method (Marsh, 1970). Then, ground to a homogeneous paste (skeleton, host, and endosymbiont) and divided into 5 sub-samples, each used for individual physiological analysis. Tissue biomass was measured using methods described by Mclachlan and others (2020a). Endosymbiont density was measured using 4 replicated counts on a Countesso II FL Automated Cell Counter (Mclachlan and others, 2020b). Chlorophyll a was extracted using a double 100% acetone extraction and quantified with a spectrophotometer using the equation from Jeffrey and Humphrey (1975). Tissue biomass, endosymbiont density, and chlorophyll a were standardized to surface area based on the proportional representation of each of their respective sub-samples. Total lipids were extracted using a chloroform:methanol solution and proteins were extracted using the Bio-Rad© protein assay solution following established methods of Mclachlan and others, (2020c) and Bradford (1976), respectively. The energetic value of total lipids and proteins concentrations were reported in Joules (Gnaiger and Bitterlich, 1984), and standardized to ash-free dry weight of the coral tissue.

Stable isotopic analysis- Isotopic analyses were assessed on separated animal host and algal endosymbiont fractions using methods described in Price and others, (2020). From the ramet section designated for isotopic analyses, between 4 to 8 square centimeters (cm2) of coral tissue was removed using an airbrush, and the host and endosymbiont fractions were separated by centrifugation and filtration. Each sample was individually combusted using a PDZ Europa ANCA-GSL element analyzer interfaced to a PDZ Europa 20-20 isotope ratio mass spectrometer (Sercon Ltd., Cheschier, UK) at the University of California Davis Stable Isotope Facility. The carbon (C) and nitrogen (N) isotopic composition of the animal host (δ13Ch, δ15Nh) and algal endosymbiont (δ13Ce, δ15Ne) were reported as the per mil deviation of the stable isotopes 13C:12C relative to Vienna-Peedee Belemnite Limestone Standard (v-PDB) and 15N:14N relative to air, respectively. Repeated measurements of internal standards had a standard deviation of ±0.2‰ and ±0.23‰ for δ13C and δ15N, respectively. The difference between δ13Ch and δ13Ce (δ13C-e) and the δ15Nh and δ15Ne (δ15N-e) both represent the relative contribution of photoautotrophic versus heterotrophic carbon to coral tissues (Price and others, 2021; Rodrigues and Grottoli, 2006).

Lipid class analyses- The total lipids were dried under nitrogen gas over a water bath at 55 degrees Celsius (°C). The vials containing the dried total lipids were frozen at -80°C and transported on dry ice to the University of Alabama in Birmingham for lipid class analysis. The dried total lipids were resuspended in 100% chloroform at a concentration of 10 milligrams per milliliter (mg/mL). Lipid class composition was analyzed by an Iatroscan MK 6S thin layer flame ionization detector (NTS) according to the methods modified from Conlan and others, (2014). Briefly, 1 microliter (µL) of the solution, in duplicate, was spotted onto each thin layer quartz-impregnated rod (Chromarods Mitsubishi Kagaku Iatron, Inc.) of the Iatroscan rack using a metal and glass syringe. The rack, containing ten loaded rods was placed in the first closed development chamber containing 50:20:1 (v:v:v) chloroform:methanol:Milli-Q and developed to half height (~7 minutes). The rack was then dried for two minutes at room temperature and transferred to the second closed development chamber containing 57:14.2:1.4 (v:v:v) hexane:ethyl ether:formic acid and developed to full height (~17 minutes). The rack of rods was dried in the oven at 100°C for 10 minutes prior to being scanned, using flame ionization detection with an Iastroscan MK 6S detector (Air pressure at 2, Hydrogen flow at 165 mL/minute). The amount of each lipid class (wax esters, triacylglycerol, sterols, acetone mobile polar lipids, and phospholipids) on each rod was determined by comparison to a standard curve produced from 1 microliter (µL) standards of known concentrations for each lipid class, ranging from 0.078 mg/mL to 10 mg/mL. Each lipid class concentration was normalized to the amount of total lipid initially extracted and standardized to ash-free dry weight for each sample. Each sample was run in duplicate, and the results of the duplicate runs averaged to produce one lipid class value for each coral ramet sample.