Keystone species of the coral reef
Algae
Algae provide the basis of many organisms nutritional needs. They act as one of the producers of the sea, providing oxygen and taking in carbon dioxide.
Zooanthellae
They are a key part of any coral polyp's life. These organisms live in the inner linings of coral which aids coral growth. They are in part the reason for the coral reef's success in a poor nutrient environment. Metabolic waste of the coral is used by the algae and in turn fats, oils, and sugar, synthesized by the algae, are used by the coral.
Sharks
Sharks swim in the top of the food chain in coral reefs. Their importance involves whittling down the populations of carnivorous fish. If carnivorous fish are allowed to multiply out of control, herbivores will decrease in number which in turn will result in an outbreak of algae.
Coral
The importance of coral is distributed widely. They provide food, shelter, and protection for many of the organisms that live in the reefs.