Why in news?
Australia’s Great Barrier Reef is suffering its worst coral bleaching in recorded history with 93 per cent of the World Heritage site affected.
About coral bleaching
Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their colour.
When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.
Corals can recover if the water temperature drops and the algae are able to re-colonise them.
Other threats to corals
Pollution due to agricultural run-off leading to eutrophication, sediments run-off, mining and oil spill pollution.
Crown-of-thorns starfish prey on coral polyps
Unsustainable overfishing of keystone species can disrupt food chains vital to reef life.
Shipping accidents.
About Great Barrier Reef
It is world’s largest coral reef system composed of over 2,900 individual reefs.
The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms.
UPSC 2007
Q. The largest coral reef in the world is found near the coast of which one of the following countries?
(a) Australia
(b) Cuba
(c) Ghana
(d) Philippines
Australia’s Great Barrier Reef is suffering its worst coral bleaching in recorded history with 93 per cent of the World Heritage site affected.
About coral bleaching
Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their colour.
When a coral bleaches, it is not dead. Corals can survive a bleaching event, but they are under more stress and are subject to mortality.
Corals can recover if the water temperature drops and the algae are able to re-colonise them.
Other threats to corals
Pollution due to agricultural run-off leading to eutrophication, sediments run-off, mining and oil spill pollution.
Crown-of-thorns starfish prey on coral polyps
Unsustainable overfishing of keystone species can disrupt food chains vital to reef life.
Shipping accidents.
About Great Barrier Reef
It is world’s largest coral reef system composed of over 2,900 individual reefs.
The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms.
UPSC 2007
Q. The largest coral reef in the world is found near the coast of which one of the following countries?
(a) Australia
(b) Cuba
(c) Ghana
(d) Philippines
