Waves hitting Maharashtra’s shoreline, including Juhu Beach, have been a shimmering shade of blue over the past few nights. The phenomenon called ‘blue tide’, when luminescent marine life makes the sea appear a deep shade of blue, was observed across several coastal areas this year.
The spectacle occurs when phytoplankton (microscopic marine plants), commonly known as dinoflagellates, produce light through chemical reactions in proteins, said researchers. Waves disturb these unicellular microorganisms and makes them release blue light, they added.
The sight was observed at Juhu on Wednesday night, and at Devgad and Velas beaches in Ratnagiri. Across India’s coast, the spectacle has been witnessed from November to January and, in some instances, even in March. Recently, the ‘blue tide’ was witnessed along Dakshina Kannada-Udupi coast. The sight has been observed in many beaches across the world, such as Maldives, Vietnam, Indonesia, USA, and Australia.
Bioluminescence was first reported from Mumbai in November 2016 when it was spotted for two weeks. According to marine experts, light pollution in Mumbai, especially around beaches, could be a major reason for this phenomenon not being seen or reported as the glow is visible in the dark.
Shaunak Modi, director, Coastal Conservation Foundation, captured the bioluminescence on Wednesday night on Juhu Beach. “It is a recurring phenomenon, but a difficult one to capture on city beaches. One reason is light pollution on our beaches.”
Experts point out that high temperature, high quantity of organic material, such as sewage and effluents and increased turbulence/wave action of the water, could be one of the reasons behind the blue tide.