About Bioluminescence
- Bioluminescence refers to the natural emission of light by organisms such as bacteria, fungi, and algae triggered by mechanical disturbances in coastal and estuarine waters.
- The species most commonly responsible is Noctiluca scintillans, a type of dinoflagellate plankton, also known as “sea sparkle”.
- This glow results from chemical reactions inside specialized structures called scintillons and appears primarily blue but can also show red or brown hues depending on species concentration.
- The phenomenon is commonly observed from March to May, locally termed as "Kavaru" in Malayalam.
Scientific Background
- Eutrophication—caused by nutrient overload (especially nitrates and phosphates) from industrial runoff and sewage discharge—is a major driver.
- Salinity levels between 30-35 ppt, rising temperatures, and reduced rainfall contribute to their
- When concentrations exceed 500,000 organisms per litre, it leads to red tides, which can severely disrupt marine ecosystems.
Ecological and Economic Impacts
- Plankton, while a key part of marine food chains, in large numbers release substances like dimethyl sulphide, ammonium, and dissolved organic carbon, causing Harmful Algal Blooms (HABs).
- HABs lead to hypoxia (oxygen depletion), resulting in mass fish mortality and affecting biodiversity and aquaculture
- Fishing communities experience significant losses as fish migrate away from bloom-affected zones, leading to declining catches and reduced income.
- Toxins such as domoic acid and those from Alexandrium can cause amnesic or paralytic shellfish poisoning, harming both marine life and human health.
