Note4Students
From UPSC perspective, the following things are important :
Prelims level: Coral Bleaching and Coral Regeneration
Why in the News?
A study conducted at Moorea, French Polynesia, has revealed that the network of dead coral skeletons left behind by bleaching events prevents reefs from regenerating.
About Corals
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Challenges due to Dead Corals
- Shelter for Seaweed: Dead coral skeletons create a complex structure that offers protection to macroalgae (seaweed) from herbivores. This allows seaweed to colonize the reef quickly, outcompeting young coral.
- Impeded Herbivory: The complex landscape of dead corals prevents herbivores, which normally graze on algae, from accessing the macroalgae effectively. This leads to unchecked algae growth.
- Increased Competition: Macroalgae grow faster and reproduce more frequently than coral, leading to increased competition for space, light, and nutrients, which further inhibits young coral from settling and growing.
- Annual Coral Reproduction: Coral typically spawns only once a year, while algae reproduce continuously. This gives algae a competitive advantage in newly available spaces left by dead coral skeletons.
- Altered Ecosystem Balance: The presence of dead coral shifts the balance between herbivores, algae, and coral, making it difficult for the reef to regenerate naturally.
Conditions for Reef Regeneration
- Flat Substrate: After events like cyclones, which remove coral but leave behind a flat surface, reefs tend to recover more easily, as young coral can settle and regrow without much competition from macroalgae.
- Herbivore Activity: Active herbivory is crucial for reef recovery, as herbivores control the growth of macroalgae, allowing space for coral recruits to settle and thrive.
- Clear Space for Coral Recruits: To regenerate effectively, coral needs open space free from excessive algae. Removing dead coral skeletons might help create these conditions.
- Frequent Disturbances: Coral reefs are better adapted to recover from frequent but non-lethal disturbances like storms, which scrape off coral and allow for fresh regrowth, compared to bleaching events, which leave the dead coral structure intact.
- Water Quality and Temperature: Coral recovery depends on optimal water conditions, including the absence of pollutants and suitable temperatures.
PYQ:[2018] Consider the following statements
Which of the statements given above is/are correct? (a) 1 and 2 only (b) 3 only (c) 1and 3 only (d) 1, 2 and 3 |
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