Adequate sunlight Protected from waves 2. Absorb, dissipate wave energy Channels drains eroded sediment to depth 3. Coral reefs are the habitat of thousands of species of invertebrates, vertebrates and algae. The coral animal is the dominant reef-builders. Corals are members of the phylum Cnidaria, the same as jellyfish and sea anemones.
Corals are colonial organisms.
There are a variety of growth forms, including massive, columnar, branching, etc. Zooxanthellae are photosynthetic dinoflagellates that give living coral their characteristic color. Because they are photosynthetic, the presence of symbiotic zooxanthallae limits the depth of active coral growth to the photic zone. Zonation on coral reefs. Horizontal and vertical zones are determined by factors including depth and light intensity, wave action, temperature and salinity of water, and biological factors.