Q. Evaluate the causes and consequences of coral bleaching in tropical oceans. How does this phenomenon affect marine biodiversity and coastal economies? [10 Marks] [150 Words]

Approach:

• Introduction:

• • • Define coral bleaching
    • Mention its increasing frequency

• Body:

• • • Causes of coral bleaching
    • Consequences for marine ecosystems
    • Impact on biodiversity

• Conclusion:

• • Summarise key points
  • Suggest potential solutions or mitigation strategies

Model Answer:

Introduction: Coral bleaching is a phenomenon where corals expel their symbiotic algae, losing colour and becoming vulnerable to death. Recent studies indicate a 20% increase in bleaching events over the past decade, threatening the world's coral reef ecosystems.

Body:

Causes of coral bleaching:

• Rising sea temperatures due to global warming
• Ocean acidification from increased CO2 absorption
• Pollution from agricultural runoff and industrial waste
• Extreme weather events like El Niño
• Overexposure to sunlight, especially during low tides
• Disease outbreaks affecting coral health
• Sedimentation from coastal development and dredging
• Overfishing, disrupting the ecological balance of reef systems

Consequences for marine ecosystems:

• Habitat loss: Many marine species rely on coral reefs for shelter and breeding.
• Food chain disruption: Reef degradation affects the entire marine ecosystem.
• Coral health: Reduced growth and reproduction of coral species.
• Coastal protection: Weakened reefs increase shoreline vulnerability.
• Nutrient cycles: Changes in reef health alter ocean chemistry and nutrient distribution.
• Community shifts: Different species may dominate as reef composition changes.
• Species extinction: Some organisms entirely dependent on coral may disappear.
• Carbon absorption: Healthy coral reefs help absorb CO2, mitigating climate change

Impact on marine biodiversity:

• Fish population decline: Many fish species rely on coral reefs for food and shelter.
• Breeding ground loss: Reefs serve as crucial nurseries for various marine species.
• Coral diversity reduction: Fewer coral species survive in degraded environments.
• Invertebrate displacement: Many small creatures lose their reef homes.
• Endangered species threat: Further pressure on already vulnerable animals.
• Migration pattern changes: Reef loss can alter traditional animal movement routes.
• Algal dominance: Algae often overtake areas where coral has died.
• Undiscovered species loss: Unique species may disappear before being identified.

Conclusion: Coral bleaching poses a critical threat to marine biodiversity and coastal economies worldwide. Urgent action through global cooperation, sustainable practices, and innovative conservation techniques is essential to preserve these vital ecosystems for future generations.