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Fluorescent Blue Glow Seen on a Chennai Beach May Be a Sign of an Unhealthy Ocean

Even as people gush over the glow, scientists and coastal experts say it could be an effect of climate change and might be harmful to marine life.
Shamani Joshi
Mumbai, IN
Fluorescent blue glow on Chennai beach may be a sign of climate change
Photo: Screenshot of photo posted by Twitter user @ajaw_

When a fluorescent blue glow appeared in the waves of Chennai’s beaches on Sunday, August 18, it soon became a social media sensation, with people posting photos and videos of the “historic event”. The glow-in-the-dark sheen that hovered over the waves was all anyone who visited the Thiruvanmiyur or Elliot’s beach in the city of Chennai in India could gush about, with people referring to it as one of the most beautiful occurrences.


But turns out, the breathtaking bioluminescence, a phenomenon caused by the Noctiluca scintillans or algae—a type of phytoplankton that converts chemical energy into light energy—could very well spell troubled waters and be an indicator of climate change.

“The phytoplankton burst could have occurred due to heavy rain and discharge of sewage into the ocean on Sunday,” Dr Pravakar Mishra, a specialist in Coastal Processes and Shoreline Management Studies at the National Centre for Coastal Research (NCCR), told The Indian Express. “Factors such as the pattern of the wind and the temperature of the ocean also determine the occurrence of bioluminescent waves.”

A research paper published in the journal Harmful Algae when the same phenomenon was seen on Mumbai beaches last year says that it is a sign of global warming and may also be a result of coastal pollution and agricultural run-off.

Meanwhile, Pooja Kumar from the Coastal Resource Centre states that as pretty as the firefly-like sparkle is, it could also prove harmful for marine life. "Noctiluca is an algae which thrives in areas where there is an oxygen deficit and it points to lack of marine health in the particular area. This blue-green Notiluca also emanates ammonia and eats diatoms, a kind of plankton, which fish depend on (for) food as well," Kumar told The News Minute.

However, she also maintains that as dangerous as the ‘sea tinkle’ can be, such one-off incidents are not enough reason to worry just yet, and that it is more likely to affect marine life in places like Oman and Tanzania where it occurs continuously for weeks.

"It could be due to excess run-off, due to the rain or lack of oxygen in that particular area, due to a multitude of reasons,” she says. “There have also been studies that show that the warming of oceans could be responsible for the spotting of bioluminescence. If that is the case, it is a cause of worry and should be investigated further. We will, however, be looking (at) whether there is fish kill. And if it is not recurring, it is not a cause of worry."

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