"The red tide is due to aggregations of dinoflagellates including Ceratium falcatiforme and Lingulodinium polyedra, the latter of which is well known for its bioluminescent displays, with waves or movement in the water causing the phytoplankton to glow neon blue at night".
Red tide last occurred in San Diego in September 2013 and lasted a week; the previous red tide, in October 2011, lasted a month.
The San Diego coast is hosting a red tide, which is a bloom involving these single-cell organisms that can make the water appear red.More news: Embiid assures 76ers have 'a bright future'
A red tide is sparking a light show on some California beaches.
Photographer Stephen Bay, who captured images of the waves earlier this week and said the color reminded him of a Star Wars light saber, likened the bioluminescence display to another natural phenomenon.
Bio luminescence Expert Michael Latz says that hasn't happened there in almost five years.More news: Mass. Gas Nearly 50 Cents Above Last Year's Price
The dinoflagellates are a type of marine phytoplankton.
According to the Scripps Institution, the phenomenon in San Diego is not known to be toxic, though very little is known about it. "Red tides are unpredictable and not all of them produce bioluminescence", Scripps notes, saying scientists don't know how long this particular event will last.
The current red tide is "quite patchy" and the bioluminescence can be seen only when the algae bloom gets close to shore, Latz said.More news: Judge powers Yankees past Red Sox with late home run
"These are unusual and rare events and they should be enjoyed".