What is bioluminescence?

Bioluminescence is the ability of living organisms to produce light. It happens because of a chemical reaction inside the organism. A light-producing molecule called luciferin reacts with oxygen, catalysed by an enzyme called luciferase, releasing light.

The glow can be blue, green, or sometimes yellow, depending on the organism. It is found in many forms of life, including plants, animals, fungi and bacteria. In the ocean, several creatures, such as algae, jellyfish, small crustaceans, worms, fish, and even some sharks, can glow. This glowing effect is most commonly seen in plankton and deep-sea species.

Why do these organisms glow?

Scientists believe glowing helps these organisms protect themselves. The sudden flash of light can confuse or scare predators, allowing the organisms to escape. Another reason could be that glowing helps them gather together, forming larger groups.

Is this common along Indian beaches?

Along India’s west coast, bioluminescence has occasionally been observed, mostly during November and December. While uncommon, similar glowing waves have been reported earlier in places such as Ratnagiri and along the Dakshina Kannada–Udupi coast.

Its appearance depends on several factors, including water temperature, nutrient levels, rainfall and wind. Because these conditions change, the glowing waves remain unpredictable and rare rather than routine.

Is the blue tide harmful?

Small glowing patches are usually harmless. However, larger and slow-moving blooms can affect marine life and fishing activity. Blue tides can also be a warning sign of stress in the marine environment.

Factors such as rising sea temperatures, heavy rainfall, sewage discharge, fertiliser runoff, low oxygen levels and changing wind patterns can trigger such events.