Coral have a mutually beneficial relationship with microalgae that live in their tissues. The corals provide protection and extra surface area, the photosynthetic algae provide the “food.” If the algae become stressed by disease, pollution, or temperatures, then the algae leave the coral. Along with losing their vibrant rich coloring, the corals will lose an important energy source, becoming weak and susceptible to disease. Fortunately, corals do have a significant capacity to bounce back from this damage.
Coral bleaching occurs when corals experience too much stress—i.e. from high water temperatures or poor water quality—and eject their symbiotic zooxanthellae, losing their distinctive colors. If stressful conditions persist, the corals will die, but if conditions return to acceptable levels, some corals can re-absorb zooxanthellae and recover.
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