Fisheries Conservation photo

Strangely glowing waves on the southern California coast are attracting surfers and kyakers, but what’s causing this seemingly otherworldly phenomenon? It’s actually not an uncommon occurance: a massive red tide.


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It looks like something from the movie “Avatar”: ocean waters that light up like neon glow sticks when they splash. Beaches across southern California have recently been alight with eerie, glowing waves. What could be causing such an otherworldly phenomenon?

_A recent report by Discovery News has provided an answer. According to marine biologist Jorge Ribas, the glowing is caused by a massive red tide, or algal bloom, of bioluminescent phytoplankton called Lingulodinium polyedrum. The microorganisms emit light as a response to stress, such as when a wave crashes into the shore, a surfboard slashes through the surf, or a kayaker’s paddle splashes the water. The result is a wickedly cool glowing ocean.

The phenomenon has actually been observed on a semi-regular basis since at least 1901 along the beaches around San Diego, California. By day the algal blooms give the water a soupy red coloration, which is why they’re often referred to as a red tide. But unlike some forms of red tide which can be toxic to people and marine life, the glowing blooms occurring in San Diego waters are reportedly harmless.

For surfers who don’t mind catching a wave in water teeming with a sludge of microorganisms, the glowing ocean offers the chance of a lifetime. Nightswimmers also often delight in the opportunity to bathe in the bioluminescent sea. The organisms can also be present in wet beach sand, so even beach walkers can watch as the ground sparks with every footstep.