1. Corals

2. Fast Facts Corals are animals Two kinds Soft corals Hard corals (These build reefs!) They are made of tiny polyps that are genetically identical

3. What’s a Polyp? Tentacles release stinging cells when something brushes by them Polyps make their own limestone cup to hide in during the day At night, polyps come out to catch plankton floating by.

5. Hard Corals The Reef Builders Polyps build hard limestone cups around their bases Polyps build hard limestone cups around their bases The cups cement together to make a coral colony The cups cement together to make a coral colony Reefs are made of hundreds of hard coral colonies next to and on top of each other Reefs are made of hundreds of hard coral colonies next to and on top of each other

6. Distribution Most corals in shallow warm water Most corals in shallow warm water Some corals can grow in depths of 3,000 feet! Some corals can grow in depths of 3,000 feet!

7. Symbiosis Inside polyps live zooxanthellae Inside polyps live zooxanthellae Coral obtain most of their nutrients from this photosynthetic unicellular algae Coral obtain most of their nutrients from this photosynthetic unicellular algae Also cause the different colors in coral Also cause the different colors in coral

8. Reproduction Sexual by releasing sperm or eggs Sexual by releasing sperm or eggs Asexual through budding Asexual through budding

9. Conservation Corals are highly sensitive to environmental changes such as water temperature, salinity and pH Corals are highly sensitive to environmental changes such as water temperature, salinity and pH Coral bleaching - expel zooxanthellae, coral tissues become colorless Coral bleaching - expel zooxanthellae, coral tissues become colorless Algae can overwhelm a coral reef if too many nutrients Algae can overwhelm a coral reef if too many nutrients Human activities damage reefs, including mooring, fishing, diving, mining and construction. Human activities damage reefs, including mooring, fishing, diving, mining and construction. Scientists have predicted that over 50% of the world's coral reefs may be destroyed by the year 2030 Scientists have predicted that over 50% of the world's coral reefs may be destroyed by the year 2030