<div>In addition, our results did not support our third hypothesis, that ocean acidification and irradiance level will interact to determine Symbiodinium level in P. damicornis. Previous studies, including one on Pocillopora damicornis, have found interactive effects of ocean acidification and light on coral calcification (Dufault et al., 2013, Suggett et al., 2013) with high light ameliorating the impact of OA on calcification. Other studies have found an additive, but not interactive, effect of light (at two sub-saturating levels) and ocean acidification on calcification (Vogel et al., 2015), and no effect of high light in offsetting the impact of OA on calcification (Enochs et al., 2014). However, no other studies have yet examined whether the interaction of ocean acidification and light, where an interaction is observed, extends its influence to areal symbiont densities in coral. <br></div>