1.1 WHERE DO CORAL REEFS GROW?
Reef-building corals need warm water, best between 18°C and 29°C. They also require a strong salt
content in the water (25-40ppt), fresh water will kill them. They also need lots of sunlight and do
not like sediment or turbid water. Findings suggest that net rates of coral growth are between 0.8
to 26 mm/year.
ACTIVITY 1: Locating Coral reefs
Grade 10: LO2 – AS 1 Use prescribed methods to access information
Grade 8 & 9: LO2 – AS 3 Interpret information & make predictions
What you need:
The introductory information about coral reefs
The “Locating Reefs” worksheet
Coloured pencils or pens for each learner
What to do:
Explain to learners how to read longitude and latitude lines and sets of co-ordinates.
Discuss why warmer water is near the equator and colder water is near the poles.
Explain the movement of our South African currents – the warm Agulhas Current
down our east coast, and the cold Benguela Current up our west coast.
Let the learners complete the worksheet.
Locating Coral reefs
Use the latitudes and longitudes in the table below to locate the following coral reefs. Then colour
in the reef belt. Between which two latitudes does it lie?
Location
Latitude
Longitude
Great barrier Reef
Maui in Hawaii
Key West, Florida
French Polynesia
Red Sea
Jamaica
Seychelles
Philippines Islands
Bahamas Islands
19°10’S
20°45’N
24°33’N
16°S
25°N
18°15’N
8°S
13°N
24°15’N
149°E
156°20’W
81°48’W
145°W
38°W
77°30’W
55°E
122°E
76°W
60°
45°
30°
0°
30°
150
120
90°
60°
30°
0°
30°
60°
90°
120
150
45°
1. Do the reefs grow every where in the tropics? Why?
2. Using arrows to show direction, draw our South African currents onto your map (use red for the
warm current & blue for the cool current). Use this to help you predict the direction of the currents
for Australia and South America – draw them onto your map.
3. What is the relationship between the water temperature and coral distribution?
4. Where do you think you would you find coral reefs in South Africa?