Corals and other species associated with a reef provide food and shelter for a variety of organisms.
The coral also sometimes uses nutrients produced during photosynthesis.
That reef may have been impacted by coral bleaching. The beautiful colors in tropical corals come from small dinoflagellate algae called zooxanthellae.
These organisms provide the coral's brilliant color.
The zooxanthellae can provide up to 90% of the energy the coral needs.
Coral bleaching happens when coral polyps, the animals that build corals, shed the algae (zooxanthellae) that give them their color, and which are necessary for their survival. Warming water is the most likely culprit of coral bleaching.