On Oct.19 and 20, the Chennai beaches were washed by blue-illuminated waves. This is not the first instance for Chennai. An earlier instance was reported in August 2019. Here is a report from that time.
When the beach was illuminated blue
Late Aug 18, many visitors to the Thiruvanmiyur beach noticed bright blue luminescent waves hitting the beaches. Soon the social media was flooded with pictures of the phenomenon and the beaches pulled visitors in awe.
Dr. P. Nammalwar, Former Principal Scientist – Central Marine Fisheries Research Institute – ICAR, Govt of India, explained, “This event was caused by a particular variety of plankton that bloom in warm waters. There has been a rise in the temperature of the sea lately thus attracting the plankton. These plankton deplete the oxygen levels in the ocean / sea causing death among fishes.”
T.D. Babu, SPARK, further explained, “the blue luminance of the beach was caused by a particular variety of plankton – Noctiluca scintillans. Its bloom is an alarm that we have been polluting our waters with trash cause ocean temperatures to rise.”
Noctiluca scintillans, commonly known as the sea sparkle is one of the most commonly occurring bioluminescent organisms in coastal regions of the world. It exhibits bioluminescence when disturbed during bloom (population increase).
According to the Marine Species Identification Portal, “Toxic blooms of N. Scintillans have been linked to massive fish and marine invertebrate kills. Although this species does not produce a toxin, it has been found to accumulate toxic levels of ammonia which is then excreted into the surrounding waters possibly acting as the killing agent in blooms. Extensive toxic blooms have been reported off the east and west coasts of India, where it has been implicated in the decline of fisheries.”
According to a research paper in https://www.ias.ac.in, “Aiyar (1935) observed in June 1935 mortality in fish and marine animals near Madras caused by the occurrence of Noetiluca in exceptional abundance. He surmised that the mortality was due to the rapid utilisation by the organisms of available oxygen in sea water.”
The bio-luminescence, that has been spotted currently, is reported to be visible till Sadras (Kalpakkam). It’s ironic that Kovalam, which has been certified as a Blue-Flag beach, is living up to its name now! The recurrence of bio-luminescence only highlights that more serious efforts need to be put into cleaning and maintaining our water bodies. The cleaning of our rivers needs to be expedited and the Solid Waste Management Rules (2016) must be implemented strictly.
Though the bio-luminescence is a sight to behold, one must remember that it is not a phenomenon to be proud of!