Kavaru in Kochi’s Backwaters

GS III- Environment, Geography

Context:

The phenomenon known as Kavaru has been observed in the undrained Pokkali rice fields and the Vembanad backwaters of Kerala.

Understanding Kavaru

• Definition: Kavaru refers to bioluminescence, a natural process where microorganisms such as bacteria, algae, and fungi emit light in water.
• Trigger Factors: Increased salinity, water disturbance, and fish movement activate the glowing effect.
• Best Visibility: Dark, moonless nights offer the ideal conditions, whereas artificial lighting, like vehicle headlights, diminishes its visibility.
• Color Variation: In Kochi’s backwaters, Kavaru manifests as a blue glow, but in other regions, it may appear green.

Impact of Kavaru

• Boost to Tourism: The phenomenon attracts large crowds to places like Chellanam and Kumbalanghi, benefiting local businesses.
• Ecological Indicator: It signifies a healthy microbial ecosystem in the water bodies.

Vembanad-Kol Wetland

• Significance: India’s second-largest Ramsar site (after Sundarbans) and longest lake in the country.
• Geographical Spread: Extends across Alappuzha, Kottayam, and Ernakulam districts in Kerala.
• Below Sea Level: The region includes paddy fields such as Pokkali, Kayal, and Kole wetlands, which support both farming and aquaculture.