Chouldari, South Andaman | June 13: Just after dusk in Chouldari, a quiet stretch of road near the sea turns into something out of a dream. As the tide comes in and waves lap against the shore, the water shimmers a surreal shade of blue, glowing faintly with every movement. Families gather near the railing. Some take photos. Others simply stand in silence, watching the ocean light up, one wave at a time.
Over the past two weeks, Chouldari Marine Drive has become the stage for a rare natural phenomenon: marine bioluminescence. Caused by microscopic plankton known as dinoflagellates, the glow appears when these organisms are disturbed by waves, boats, or even bare feet in the shallows. The result is a quiet but astonishing light show, an ocean that sparkles from within.
Marine scientists say the glow is likely due to a bloom of Noctiluca scintillans, a bioluminescent species known to thrive in tropical waters under certain seasonal conditions. “It’s rare to see something this vivid, and for this long,” said a researcher from the Indian National Centre for Ocean Information Services (INCOIS). “We’re seeing ideal conditions this year, warm temperatures, low turbulence, and a spike in nutrients.”
A Moment of Wonder
Satellite data from the Ministry of Earth Sciences confirms a recent spike in chlorophyll levels along the South Andaman coast—an early sign of plankton blooms. INCOIS’s 2023 bulletin had anticipated this rise, noting that the Bay of Bengal often experiences such activity before the monsoon. But scientists admit they hadn’t expected this level of visibility or duration.
For residents, the phenomenon is a source of awe and pride. “I’ve lived here my whole life,” said 62-year-old Anjali Das, who brought her grandchildren to see the glow. “We’ve heard about these things in other countries, but to see it here in our backyard, it feels magical.”
Events like this are not unheard of in India. Brief flashes of bioluminescence have been reported along Juhu Beach in Mumbai, Bheemili in Andhra Pradesh, and Lakshadweep’s Bangaram Atoll. But these were fleeting, often undocumented, and rarely accessible to the public in such a consistent way.
A 2021 paper in Current Science highlighted how underreporting and lack of local ecological tracking have kept these occurrences under the radar. The study called for deeper monitoring in biodiversity-rich regions like the Andaman Sea, where climate change and human activity are rapidly reshaping marine systems.
While the glow is captivating, scientists caution that not all is as it seems. Prolonged or dense blooms of Noctiluca have been linked to hypoxia—a condition in which oxygen levels in the water fall dangerously low, threatening marine life. A 2020 UNESCO report documented similar blooms in Southeast Asia and urged heightened surveillance of sensitive marine zones like the Andaman.
The National Institute of Oceanography (NIO) categorizes Noctiluca scintillans as a bio-indicator species, one that may hint at larger, less visible shifts beneath the surface.
“Sometimes the ocean sends signals before we’re ready to hear them,” said a senior marine ecologist at NIO. “Bioluminescence is beautiful, yes, but it can also be a warning.”
In the meantime, visitors continue to arrive at Chouldari after dark, some from as far as Mayabunder or Wandoor, hoping to witness the glow. With the new moon approaching and minimal natural light, conditions are ideal for the spectacle to continue for a few more nights.
Environmentalists are urging care. Posters placed along the Marine Drive request visitors not to wade into glowing patches, use artificial light, or leave trash behind. “This is not an amusement park,” said Arif Khan, a local marine guide. “It’s a delicate process happening right in front of us—and we need to respect it.”
For now, the shoreline glows on, quietly and steadily. Whether it lasts days or weeks, the light is already leaving an impression, not just on the water, but on those who come to see it.
