Polyps Sea Anemones Corals
Corals Reef building corals are hermatypic, meaning they are mound builders. Bodies contain masses of single-celled, symbiotic dinoflagellates called zoozanthellae, which carry on photosynthesis, absorb waste products, grow, and divide within the coral host. Coral polyps provide dinoflagellates with a safe and stable environment, carbon dioxide, and nutrients. Zooxanthellae provide oxygen, carbohydrates, and pH necessary to deposit calcite. Also give corals their color.
Corals Reefs grow in the photic zone Depend on light and warmth Grow best in brightly lit water of about 5 to 10 meters (16-33 feet) deep. Prefer clear water with little sediment Coral polyps can also retract into their shells to escape strong sunlight and predators. Exposure to fresh water is fatal