A captivating light show has unfolded along the coastlines of San Diego County, drawing the gaze of locals and tourists to its shimmering beaches. This natural spectacle, known as bioluminescence, transformed ocean waves into a glowing canvas of neon blue, creating a mesmerizing scene under the cover of night.

The resurgence of these luminous waves has caught the attention of San Diego’s own Vishwas Lokesh, a hobbyist photographer with a knack for capturing nature’s wonders. Lokesh’s recent exploits at Torrey Pines State Beach, North Ponto Beach, and Carlsbad State Beach have yielded stunning photos and videos showcasing the electric blue waves in all their glory. Since last Saturday, his visual documentation on Instagram has become a beacon for those eager to witness this phenomenon firsthand.

But what exactly triggers this ethereal glow? Bioluminescence occurs due to Lingulodinium polyedra, tiny motile dinoflagellates that inhabit the ocean. These organisms, capable of photosynthesis, possess the unique ability to move, earning them the moniker “the Michael Phelps of the plankton world” from Dr. Drew Lucas, an associate professor at Scripps Institution of Oceanography at UC San Diego. Lucas, who has extensively studied these plankton, explains their movement is so effective they can dominate coastal ecosystems, coloring the water red by day (a phenomenon known as red tide) and illuminating it at night.

Their magical glow comes to life when they are disturbed. Be it a breaking wave, a passing boat, or a playful dolphin, any disruption can trigger a dazzling light show. “That flash of light for each individual cell is not very bright, but when there’s a lot of them in the water, that’s when they really can light the waves up and lead to quite bright glowing,” Lucas shares.

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The visibility of bioluminescence varies, sometimes concentrated in specific areas unless during significant events like the one in 2020, where it was widespread. According to Lucas, tracking the red tide movement is best done through social media updates.

Darkness is key for those hoping to witness this natural marvel, as the organisms do not glow under light. While bioluminescence can occur anytime, Lucas has observed more activity from spring to early fall. For beachgoers unable to stay until dusk, Lucas suggests an intriguing method: collect red tide water in a jar, store it in a dark environment like a fridge for an hour, then shake it to observe a miniature light display.

The duration of these red tides—and consequently, the bioluminescence—can last from a few days to several weeks. “In 2020, the red tide was around for almost two months,” Lucas recalls. “Sometimes, it’s only a night or two that is really bioluminescing at the beach.”

Regarding safety, swimming in bioluminescent waters is generally considered harmless. Lucas, who has personal experience swimming and surfing in such conditions, affirms, “In a typical scenario, the bioluminescent red tide is not harmful to human health or even the ecosystem.” However, the decomposing process of these organisms’ post-bloom can deplete oxygen levels in the water, potentially harming marine life and causing discomfort from smells and aerosols.

San Diego’s beaches, adorned by this natural luminescence, offer a mesmerizing experience for those fortunate enough to witness it. For those interested in diving deeper into the science behind this glowing spectacle, Dr. Drew Lucas’s research provides a wealth of information and can be a fantastic resource.