Coral reefs

Question 1

coral reef

Answer 1

a ridge of rock near the surface of the sea formed by the growth and deposition of coral

Question 2

formation of coral reefs

Answer 2

1. Planula settles and attaches itself to a hard surface located in shallow, warm and clear waters.
2. The planula metamorphosis into a polyp.
3. Polyps multiply by budding (asexual reproduction).
4. A young Elkhorn colony forms.
5. As more corals continue to settle and grow, the combination of their skeletons creates a large platform that promotes the settlement and growth of other coral species.
6. The coral then grows vertically.

Question 3

conditions required for development

Answer 3

• Temperature
• Depth of water
• Light
• Salinity
• Sediment
• Wave action
• Exposure to air
• Nutrients

Question 4

temperature

Answer 4

18-32 degrees celcius

Question 5

depth of water

Answer 5

less than 25 metres

Question 6

light

Answer 6

shallow water required for photosynthesing tiny algae which provide the coral with 98% of their food

Question 7

salinity

Answer 7

only live in seawater but cannot tolerate high salinity

Question 8

sediment

Answer 8

sediment and pollution reduces light penetration of the water and clogs up the feeding structures of corals

Question 9

wave action

Answer 9

• prefer areas with wave action as it ensures freshly oxygenated water
• if waves are too strong coral is destroyed

Question 10

exposure to air

Answer 10

corals die if exposed to air for too long

Question 11

nutrients

Answer 11

supply of nutrients such as plankton required

Question 12

location of coral reefs

Answer 12

found in tropical & sub-tropical seas between 30 degrees N & S of the Equator