This Symbiodinium dependence is the reason why the great majority of coral species can only live at depths of 30 meters or less, since the algae require sufficient sunlight in order to carry out photosynthesis.
這就是為什麼多數珊瑚必須生長在水深 30 公尺以內的淺海，因為這樣才有足夠的光線給共生藻行光合作用。