Download IGCSE Edexcel-Coasts-Coral reefs

Coral reefs – “rainforests of the sea”
Resources:
1. www.garsidej.wordpress.com
2. Textbook pages – 43-44 & 48-50
Coral reefs are a unique marine ecosystem. They are built up entirely of living organisms.
Reefs are huge deposits of calcium carbonate made up mainly of corals. Their global
distribution is shown below:
Using the map above describe the location of the coral reefs.
The global distribution of coral reefs is determined by four factors. Explain each of the
factors.
Temperature –
Light –
Water depth –
Salinity –
At the local level there are other factors. List and explain each.
1
2
3
Coral reefs with the highest biodiversity occur in South-east Asia and northern Australia. The
Great Barrier Reef is in Australia and is renowned not just for its great biodiversity, but also
its extent and excellent condition.
Using the information below, draw a pie chart to show the distribution of world coral reefs by
region.
(a) Using the data in from the figure above and your line graphs, draw two line graphs on
the same axes to show algal and coral cover changes for a Caribbean island.
(b) Between which two years was there the biggest growth in algal cover?
(c) Between which two years was there the biggest decrease in coral cover?
(d) What do you notice about the patterns of the two graphs?
Coral reefs are among the most biologically rich ecosystems on Earth. They are also one of
the most threatened. They have very high levels of biodiversity (a large number of species)
with about 5,000 species of fish and 800 species of reef-building coral. They are also of huge
economic value, from fishing and as a source of materials for jewellery manufacture and
construction. For these reasons, and because of the effects of global warming, they are
massively under threat.
The value of coral reefs (pg48)
1
2
3
4
Case study – Coral reef management St Lucia
Explain how reefs are being managed in St
Lucia.
Types of reefs
Using www.garsidej.wordpress.com explain the formation of each of the reefs
Fringing reef
Barrier reef
Atoll reef