Why in the News?
A 24-year-long study conducted by the Nature Conservation Foundation reveals that coral cover in Lakshadweep has declined by 50% since 1998.
Coral Decline in Lakshadweep: Key Highlights
- Study Duration: Based on a 24-year study (1998–2022).
- Findings: 50% decline in live coral cover—from 37.2% to 19.6%.
- Main Cause: Repeated marine heatwaves linked to climate change.
- Study Locations: Monitored across Agatti, Kadmat, and Kavaratti atolls.
- Response Clusters: Six coral groups identified based on:
- Depth and wave exposure
- Heat resistance and recovery patterns
- Recovery Timeline: Requires at least 6 years without bleaching for healthy regeneration.
Back2Basics: Corals and Coral Bleaching:
- About: Corals are colonies of tiny animals called polyps, which build calcium carbonate skeletons.
- Symbiotic Algae: Host zooxanthellae, microscopic algae that provide nutrients via photosynthesis.
- Coral Types:
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- Hard Corals: Form reef structures (e.g., brain coral, staghorn coral).
- Soft Corals: Flexible, grow on reef surfaces but do not build reefs.
- Habitat Requirements:
- Water Quality: Must be clean and low in sediment.
- Temperature Range: Prefer 20–21°C.
- Depth: Typically found in waters less than 90 metres deep.
- Salinity: Optimal range is 27–30 parts per thousand (ppt).
- Ocean Currents: Require nutrient-rich water flow.
- Coral Bleaching:
- Cause: Triggered by heat stress, pollution, or acidification, which drive algae out.
- Effect: Coral turns white due to loss of algae; Loses its main food source. Dies if stress persists for long periods.
| [UPSC 2022] “Biorock Technology” is talked about in which one of the following situations?
Options: (a) Restoration of damaged coral reefs * (b) Development of building materials using plant residues (c) Identification of areas for exploration/extraction of shale gas (d) Providing salt licks for wild animals in forests |
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