Dataset: Temperature and pCO2 effects on survivability of 25 genotypes of Acropora cervicornis coral at Mote Marine Laboratory in Nov-Dec 2019

A full factorial experiment was completed to determine the survival probability and photochemical efficiency of 25 unique genotypes of Acropora cervicornis in high temperature, high pCO₂ treatment, or the combination of high temperature and high pCO2.

• High temperature was 33 ± 0.6°C and 463 ± 31 µatm
• High pCO₂ treatment was 29 ± 0.2°C and 798 ± 78 µatm
• Combination high temperature and high pCO2 was 33 ± 0.8°C and 823 ± 83 µatm 

Prior to exposure, dark-acclimated photochemical efficiency was measured in all fragments (n=600) using a pulse amplitude modulation chlorophyll fluorometer (I-PAM, Walz GmbH, Effeltrich, Germany). Photochemical efficiency factors include:

• ETR _(max)
• F_v/F_m (max)
• Initial slope of ETR v. PAR plot

Additionally, the starting color index was gathered for each fragment based on the coral health chart provided by CoralWatch.  The starting colors ranged from D1 for bleached to D5 for full color/healthy. During the exposure period, water quality for each tank was measured daily and color index was assessed daily for all fragments. Water samples were collected in acid-washed amber bottles (125 mL) for carbonate chemistry analysis bi-weekly and fixed with mercuric chloride (60 µL). Water samples were filtered (0.2 microns) prior to analysis on the dissolved inorganic carbon (DIC) machine (Apollo SciTech Analyzer).

As replicates started to show signs of stress (paling activity) and subsequent mortality, the following was recorded:

• the date of mortality,
• the time (days) till mortality,
• the mechanism of mortality (i.e. showed signs of Tissue loss, Bleaching, or both occurring simultaneously)

Each replicate coral was categorized as a binomial rank, classified as either 0, no event/alive, or a 1, event occurred/dead, on each day of the study. As coral fragments reached mortality, they were removed from their treatment tank to limit negative effects on the remaining fragments in the tank. Once LD50 was reached for each genotype in each treatment, the dark-acclimated PAM Chlorophyll Fluorometry outputs (ETR _(max), F_v/F_m (max), and initial slope of ETR v. PAR plot) was measured for the remaining fragments of that genotype in that same treatment to derive change of yield over time.

Treatment tank water quality was monitored using a YSI Professional Plus (Pro Plus) Multi-parameter handheld with a quarto containing a Pro Series Galvanic Dissolved Oxygen Sensor, a Pro Series pH Sensor (calibrated using 4, 7, and 10 buffers), Pro Series temperature and conductivity sensor. PAR was measured using the Licor handheld (Li-COR LI-1500) with an underwater quantum senor (Li-Cor LI-192). Dissolved inorganic carbon (DIC) was analyzed using the Apollo SciTech DIC analyzer model AS-C151. Total Alkalinity (TA) was analyzed using the Metrohm 905 Titrando analyzer. Both DIC and TA were standardized each day with certified reference material (CRM) provided by A.G. Dickson. Imaging-PAM Chlorophyll flurometer (Walz GmbH, Effeltrich, Germany) was used to measure photochemical efficiencies and the coral health chart/ color index card was provided by CoralWatch.