Dataset: Measurements of respiration, net photosynthesis, and gross photosynthesis of five different genotypes of Symbiodinium microadriaticum in culture at three different temperatures

To investigate the physiological responses of isolated symbiont genotypes to temperature, we grew replicate cultures of each of the five genotypes in growth chambers set to 26°C, 30°C, and 32°C. The mean temperatures (+/- 1 s.d.) in the three chambers were 25.5°C (+/- 0.5), 30.1°C (+/- 0.3), and 31.6°C (+/- 0.2). We initiated 12 replicate cultures of each genotype in sterile flasks with 75 milliliters (mL) of sterile f/2 media with 750,000 cells (10,000 cells/mL) from the appropriate stock culture. Replicate cultures of each genotype were randomly distributed among three identical growth chambers (Percival I-36LLVL) set to each of the three temperatures (n=4 replicate cultures of each genotype at each temperature). We systematically rotated the position of cultures in the growth chamber daily to minimize the effect of any small differences in light and temperature within the chamber. Lights were set on a 12:12 day:night cycle, with an average illumination during the day of 4533 (+/- 456) Lux. We performed this experiment in October 2019.

We measured respiration and photosynthetic rate using a SDR SensorDish Reader (Loligo Systems, Viborg, Denmark). We filled two wells with 2 mL sampled from each culture and filled two wells with DI water as controls. We placed plates in each of the three growth chambers set to 26°, 30°, and 32° C and dark-acclimated plates for five minutes before measuring oxygen concentration every 15 seconds for 15 minutes in the dark. We then turned on the lights in each growth chamber and measured oxygen concentration again in the same way. We also quantified algal density using the average of four replicate hemocytometer counts.