Videographers recently captured an amazing sight off the coast of San Diego, where one of the largest tidal blooms of glowing algae was seen in Southern California. This stunning ocean light show was featured in an episode of “San Diego: America’s Wildest City,” a PBS series that has won Emmy and Peabody awards. The glowing effect seen in the ocean is caused by single-cell organisms called dinoflagellates, which emit a bright blue light when agitated.
The dinoflagellates create this ethereal glow through a chemical reaction within their cells. When the ocean waves crash, billions of these cells bioluminesce simultaneously, turning the water a mesmerizing blue color. This natural phenomenon of bioluminescence transforms the waters of San Diego into a breathtaking light display, attracting the attention of many.
In the spring of 2020, San Diego experienced heavy rainfall, leading to a significant algal bloom. The rainwater settled on the ocean’s surface, creating separate layers that trapped nutrients near the surface. This provided the perfect conditions for phytoplankton, such as Lingulodinium polyedram, to thrive. Researchers recorded a high concentration of these cells at Scripps Pier in California, turning the sea a reddish brown during the day, also known as a “red tide.”
Satellite images showed that the phytoplankton bloom stretched from Los Angeles to Baja California, Mexico. However, the brightness of the phytoplanktons’ glow depended largely on calm sea conditions, making it challenging to predict the ideal viewing times. The team of filmmakers behind the episode worked tirelessly to capture the bioluminescent algae under a microscope, facing challenges due to the small scale of the organisms.
The episode also features rare footage of San Diego’s unique wildlife, including orcas hunting dolphins and a new population of crows in the area. The team made many unexpected discoveries while filming, adding to the richness of the episode. “San Diego: America’s Wildest City” will air on PBS on Wednesday, Nov. 6, with select episodes available for streaming on the Nature YouTube channel.
The episode showcases the beauty and diversity of San Diego’s marine life, highlighting the incredible natural wonders that can be found just off the coast. The collaboration between the filmmakers and researchers resulted in a visually stunning portrayal of bioluminescent algae and other wildlife in their natural habitat, offering viewers a rare glimpse into the wonders of the underwater world.