Expulsion of Symbiodinium by pulsed inflation under hyperthermal stress in Heliofungia actiniformis
KeywordsThermal Stress Burial Photography Coral Tissue Scleractinian Coral
The biological or physical mechanisms that cause differences in the susceptibility of corals to thermal stress are not well defined (Wooldridge 2014). Understanding coral responses to thermal stress and tolerance mechanisms is important for predicting how corals will fare with elevated ocean temperatures. Using time-lapse photography, we observed the scleractinian coral Heliofungia actiniformis employ pulsed inflation to expel symbionts while under thermal stress.
Pulsed inflation has been observed during other types of environmental stress including burial by sediment (Bongaerts et al. 2012). It also appears to be a physiological response to thermal stress which facilitates the rapid expulsion of Symbiodinium, increasing the chance of non-lethal bleaching. A high level of resilience to thermal stress has been described in H. actiniformis (Hoeksema 1991).
The project was funded by Australian Research Council Discovery Project DP1096184 to L.D. Nothdurft.
Supplementary material 1 (MP4 171943 kb)