What are the main factors that induce coral bleaching?
Naturally, there are several influential factors, but research has shown that sustained periods of increased temperature above 86-89°F are most often responsible for the loss of zooxanthellae. In the home aquarium, the two most common causes of coral bleaching include sudden exposure to high intensity lighting and the rapid addition of hyposalinic water to the tank. Since zooxanthellae algae are photosynthetic, they have specific cells designed to harvest the light in the most efficient manner using specific biological pathways. However, if these cells receive a sudden increase in light intensity, key photosynthetic pathways are inhibited and tissue damaging oxygen radicals form. Therefore, the coral will expel the radical-forming zooxanthellae algae from its tissues in effort to protect itself. Enthusiastic aquarists often unintentionally induce coral bleaching through the abrupt introduction of new lights, such as metal halides. While beneficial in time, metal halides produce a much
