La Jolla beach-goers, be on the lookout for colorful bioluminescence in local waters

A plankton bloom produced bioluminescent light along the La Jolla coast in spring 2020.
(UC San Diego )

Beach-goers in La Jolla and elsewhere in San Diego County should be on the lookout for bioluminescence, a harmless phenomenon that causes ocean waters to sparkle at night with enchanting neon blue light.

Bioluminescence has been seen in recent days in Dana Point, Newport Beach and Laguna Beach in Orange County.

There was a little of it in the La Jolla area about three weeks ago, and it could return and possibly spread, which is not unusual in the spring.

“We are seeing good numbers of the organisms that cause bioluminescence, but they aren’t as dense in the surf zone as they were last year,” said Clarissa Anderson, executive director of UC San Diego’s Southern California Coastal Ocean Observing System.

San Diego County experienced widespread bioluminescence last year, drawing crowds to local beaches.

The blue glow lighting up the nighttime surf recently in the Scripps Pier area of La Jolla and other spots along the San Diego County coast is bioluminescence, a natural light show produced by tiny organisms.

The phenomenon is caused by single-cell organisms in plankton blooms that produce a chemical reaction that generates flashes of light, especially in breaking surf. ◆