Status of Coral Reefs of the World 2020 report

Global Coral Reef Monitoring Network (GCRMN), a network of scientists and organisations that monitor the underwater ecosystems has released the sixth edition of its report, “Status of Coral Reefs of the World 2020” after a gap of 13 years.

Coral reefs

• Coral reefs are large underwater structures composed of the skeletons of colonial marine invertebrates called coral.
• The coral species that build reefs are known as hermatypic, or “hard,” corals because they extract calcium carbonate(CaCO3) from seawater to create a hard, durable exoskeleton that protects their soft, sac-like bodies.
• Other species of corals that are not involved in reef building are known as “soft” corals. These types of corals are flexible organisms often resembling plants and trees and include species such as sea fans and sea whips.
• Most reef-building corals contain photosynthetic algae, called zooxanthellae, which live in their tissues. The corals and algae have a symbiotic relationship.
• The coral provides the algae with a protected environment and compounds they need for photosynthesis. In return, the algae produce oxygen and help the coral to remove wastes. The presence of the zooxanthellae also provides colored pigments to help protect the coral’s white skeleton from sunlight.

 

Significance of Coral reefs

• Coral reefs only occupy 0.1% of the area of the ocean but they support 25% of all marine species on the planet.
• Because of the diversity of life found in the habitats created by corals, reefs are often called the “rainforests of the sea.”

Coral reefs in India

• Coral reefs are present in the areas of Gulf of Kutch, Gulf of Mannar, Andaman & Nicobar, Lakshadweep Islands and Malvan coast of Maharashtra.

Key findings of the report

• The network estimates that the world has lost about 14 percent of its coral reefs in the past decade.
• The report says before the decade (2009-2019), on average, there was twice as much coral on the world’s reefs as algae. However now there was 13.7 percent less hard coral on reefs in 2015-19 compared with 2005-09.
• Maldives, India and Sri Lankasee anthropogenic stresses due to overfishing, coastal development, pollution and sedimentation.

East Asia’s Coral Triangle that accounts for more than 30 percent of the world’s reefs, has also been less impacted. (The Coral Triangle (CT) is a roughly triangular area in the tropical waters around Indonesia, Malaysia, Papua New Guinea, the Philippines, the Solomon Islands and Timor-Leste.)