Coral Bleaching

Coral Reefs and Biodiversity

• Coral reefs are highly biodiverse ecosystems, often referred to as the rainforests of the ocean.

• They are facing threats due to rising global temperatures, leading to coral bleaching.

Anatomy of Corals

• Corals are tiny invertebrate animals; they are clones and have tentacles.

• The coral is anchored to the rock and secretes calcium carbonate, contributing to reef formation.

• The vibrant colors of corals come from symbiotic algae known as Symbiodinium or Zooxanthellae, not the corals themselves.

Symbiotic Relationship

• The algae live inside coral cells, entering through phagocytosis.

• They perform photosynthesis, producing sugar and oxygen that benefit the coral.

• Approximately 90% of the coral's energy comes from these algae.

Effects of Rising Temperatures

• Increased carbon dioxide levels raise ocean temperatures, damaging the algae's photosystems.

• Damaged algae are expelled by corals, resulting in visible coral bleaching.

• While corals remain metabolically alive, they are at risk of dying without their algal support.

Ocean Acidification

• Coral reefs also face threats from ocean acidification, which affects carbonate availability for shell-building.

Human Impact: Case Study in Queensland

• The proposed Carmichael Coal Mine in Queensland is a key example of human impact on coral reefs.

• Increased coal production for energy in India could result in job creation but will contribute to global warming.

• This project presents a direct conflict between human economic activity and the health of the Great Barrier Reef.

Conclusion

• Coral bleaching poses a severe threat to coral reefs. Without significant changes, ongoing temperature and ocean chemistry changes may lead to substantial coral die-off.