CORAL REEFS – ECOLOGICAL IMPORTANCE & CURRENT SCENARIO

Coral Reefs are also called as rainforests of the seas.

What are Coral and Coral Reefs?

Coral are marine animals which make a calcium carbonate skeleton (Like rocks) and have symbiotic relation with “zooxanthellae”. These zooxanthellae live in soft tissues of coral polyps and produce food by photosynthesis, creating a bi- product which coral uses as food.
Hard Corals are reef builders, while soft corals provides spine to support it. When many coral polyps build their Skelton close together, they create a calcium carbonate structure called Coral Reef.
Geography of reefs & associated threats
• Coral reefs are developed in tropical warm saline & Shallow Ocean waters where zooxanthellae can make food.
• Most of coral reefs are on western margins of continents and there are three areas each with distinct biota.
i) The Indo Pacific
ii) The Red Sea
iii) The Wider Carrabin
The level of threat is different in all three zones.
Threats so far
• Coral reefs are under seviour threat & it’s predicated that by .
• 19% of reefs are seriously damaged & 35% of remaining are under imminent risk of degradation due to humans.
Factors effecting coral reefs
Both natural and anthropogenic factors affect the coral reefs. Some of the main anthropogenic advertise like over- fishing, pollution, habitat destruction, climate change, increase in disease & ocean acidification has affected the corals.
Climate Change
• Warmer waters brought by climate change adversely prompt coral bleeching which is sensitive to changes in temperature.
• In higher temperatures zooxanthellae leave their tissue zooxanthellae is food source of coral & without it they start to turn white (coral bleaching). Bleached corals are weak & prone to diseases.
Ocean Acidification
• Much of co2 entering atmosphere dissolves into ocean & decreasing its Ph, ocean turns acidic.
• The acidic oceans doesn’t allow corals to absolute calcium carbonate to maintain their skeleton.
• It also impacts snails, clams & urchins which also absorb calcium carbonate.
Other factors
i) Coral bleaching from warmer seawater.
ii) Rising concentration of CO2
iii) Diseases, Invasive species & human pressure
iv) Pollution and chemicals arising from poorly managed land.
v) Over fishing.
vi) Unsustainable & destructive development of coastal areas
Ecological importance of coral reefs.
• Coral reef occupies only 0.2% area of ocean yet they host 25% of marine species.
• They have an annual economic value of $ 375mn, providing food& resources to over 500mn people in 94 countries.
• The reefs act as carbon sinks fisheries & attract tourists.