Lakshadweep Coral Reef Decline

Context

A 24-year-long coral reef monitoring study in Lakshadweep reveals a nearly 50% decline in coral cover since 1998, linked to repeated marine heatwaves intensified by climate change.

Location and Scope of Study:

The study, conducted by the Nature Conservation Foundation (NCF), monitored coral reefs at three atolls—Agatti, Kadmat, and Kavaratti—in the Lakshadweep archipelago over 24 years (1998–2022).

Decline in Coral Cover:

Coral cover declined from 24% in 1998 to 19.6% by 2022, marking an approximate 50% reduction.
The key driver of this decline is recurring marine heatwaves, especially those associated with El Niño–Southern Oscillation (ENSO) events in 1998, 2010, and 2016.

Bleaching and Recovery Patterns:

While coral mortality has decreased with each successive event, the rate of post-bleaching recovery has also diminished, indicating long-term stress accumulation.
The study highlights that a six-year bleaching-free period is critical for meaningful recovery.

Local Environmental Filtering:

Reef resilience was influenced by site-specific environmental factors, such as depth and wave exposure, implying that not all reef systems respond identically to thermal stress.
The study proposes a predictive ecological framework to identify vulnerable and potentially resilient reefs using long-term data.

Climate Change Connection:

The frequency and intensity of marine heatwaves in the Indian Ocean have increased, in alignment with IPCC AR6 findings, placing tropical coral systems at heightened risk.
This reaffirms India’s vulnerability to climate-induced marine ecosystem degradation, with implications for fisheries, livelihoods, and biodiversity conservation.

Global Implication and India’s Role:

The findings gain prominence in the backdrop of India’s leadership in Ramsar Wetlands Conservation and the need for integrating coastal marine ecosystems in climate adaptation frameworks.

Coral Reefs:

Underwater ecosystems formed by calcium carbonate skeletons of coral polyps.
Location: Found in warm, shallow tropical waters (23.5°N to 23.5°S).
Ecological Role: Called "Rainforests of the Sea" – host high biodiversity (fish, mollusks, turtles, etc.).

Ecosystem Services

Coastal Protection: Act as natural barriers against waves, storms, and erosion.
Economic Value: Support fisheries, marine tourism, and livelihoods.
Carbon Sink: Sequester carbon via calcification, aiding climate regulation.

Threats to Coral Reefs