Conditions Required

Question 1

What conditions are required for coral growth?

Answer 1

• temperature
• light
• salinity
• depth of water
• sediment
• wave action
• exposure to air

Question 2

Explain temperature conditions

Answer 2

• no reefs develop where the mean annual temp is below 20°C
• optimal temperature conditions for growth = 23°C - 25°C

Question 3

Explain light conditions

Answer 3

• prefer shallow water since the tiny photosynthetic algae that live in coral need light to be able to supply coral polyps with their food requirements

Question 4

Explain water depth condition

Answer 4

• most reefs grow in depths less than 25m due to light penetration needed
• this means they are generally found on margins of continents + islands

Question 5

Explain salinity condition

Answer 5

• corals can only survive in salty water
• they are marine organisms + therefore intolerant of water with salinity levels below 32 psu but can tolerate high levels (greater than 42 psu)

Question 6

Explain sediment conditions

Answer 6

• has a negative effect on= clogs up feeding structures + cleansing systems
• sediment rich water will reduce light availability

Question 7

Explain wave action conditions

Answer 7

• prefer strong wave action = ensures oxygenated water + strong cleansing action
• this helps remove any trapped sediment + also supplies microscopic plankton to coral
• BUT storm condition waves can be destructive

Question 8

Explain exposure to air conditions

Answer 8

• will die if they are exposed to air for too long
• reefs found below low tide mark