Photophysiological responses of thermally stressed symbiodium harboured by reef building corals common to Tanzania and Mauritius

The study aimed at comparing the photosynthetic responses of selected different reef building corals common to Tanzanian and Mauritian water. Equally of interest was to determine whether there has a significant difference in photosynthetic response between isolated Symbiodinium common to Mauritius and Tanzania. A Diving-PAM (Walz; Germany) was used to measure the maximum quantum yield (dark-adapted Fv/Fm) of lsolated and in hospite Symbiodinium from Acropora muricata, Galaxia fascicularis, Pocillopora verrucosa, and Porites cylindrica. The use of chlorophyll fluorescence showed no significant variation in isolated Symbiodinium PSll responses to thermal (28, 30 and 33 0C) and/ or light (170 and 750 µmol quanta m2s -1) between Zanzibar and Mauritius samples. Significant variation (p<0.001 ) was observed in photosynthetic yield of isolated Symbiodinium from the coral species investigated. Significant variation (P<0.01) in in-hospite Symbiodinium PSll responses to thermal and light stresses were observed between the four candidate coral species collected in Tanzania. Poritescylindrical and Galaxea fascicularis were more resilient to high light and high heat stresses in both Tanzania and Mauritius. The in hospite Symbiodinium from Galaxea fascicularis, Porities cylindrical, Aeropora muricata, Pocillopora verrucosa occur in order of most to less tolerant ones in Tanzania.