coral reefs

Question 1

What are coral polyps?

Answer 1

tiny, soft animals whic attach themselves to a hard surface in shallow seas where there is sufficient light for growth (photosynthesis) => exude calcium carbonate as the grow which form skeletons
polyps have small algae (zooxanthelllae) growing inside them
there is a symbotic relationship between polyps and algae - algae get shelter and food from polyp, polyps grow as algae grows (get food via photosynthesis)

Question 2

Conditions for coral reefs to grow

Answer 2

Temperature: between 23C to 25C
Depth of water: less than 25cm but not exposed to air, below low tide mark
Salinity: between 32psu and 42psu
Light: shallow water because algae in coral reefs photosynthesise
Sediment: minimal as it clogs up their feeding structures and reduces light available
Wave action: strong wave action which ensures oxygenated water; removes any trapped sediment
Global distribution: tropical seas between Tropics of Cancer and Capricorn

Question 3

What are the 4 forms of reef?

Answer 3

Fringing reef
Barrier reef
Atoll
Patch reef

Question 4

Characteristics of fringing reef

Answer 4

Near coastline around islands and continents
Characterised by an outer reef edge capped by an algal ridge
A broad reef flat
A sand floored boat channel close to the shore
Grow sea ward from the land
Grow around newly formed islands which subside, or sea levels rise relative to land

Question 5

Characteristics of barrier reef

Answer 5

Commonly separated from the shore by a wide deep lagoon
Following a rise in sea level or a drop in the level of the land
At their shallowest point they can reach the water’s surface forming a barrier

Question 6

Characteristics of atoll

Answer 6

Rings of coral that create protected lagoons
Usually form when islands surrounded by fringing reefs sink into the sea OR the sea level rises
When the island disappears beneath the sea => atoll is formed

Question 7

Methods of coral reef management

Answer 7

• Damaging fishing practices like dynamiting can be banned.
• Conservation zones where tourists aren’t allowed or there numbers are restricted can be created.
• Areas where coral reef cannot be farmed can be created
• Fish stocks can be enhanced and quotas imposed on amount being caught
• Sewage outlets can be moved downstream of coral reefs
• Banning the dropping of anchors on coral reef.
• the use of fertilisers near coral reefs
• educating people about why coral reefs are important and how we can protect them