Carlsbad’s surf sparkles with bioluminescence — but you can’t go to the beach

Tiny organisms produce brilliant neon blue flashes on the San Diego coastline in Carlsbad.
Tiny organisms produce brilliant neon blue flashes on the San Diego coastline in Carlsbad.
(Brian A. Witkin)

The historic rains that recently drenched San Diego County have generated a coastal red tide that is producing bright blue bioluminescence, a beloved phenomenon also known as sea sparkle.

But it has appeared in the surf in Carlsbad at the very moment that the public is barred from visiting most beaches due to the novel coronavirus.

The ocean is teeming with Lingulodinium polyedra, a type of single-cell organism that can produce brilliant flickers of light, particularly in breaking surf or the wake of a boat.


The organism also has been found off the Scripps Pier, where UC San Diego’s Scripps Institution of Oceanography manages a program that monitors the coastal waters of Southern California.

Lingulodinium polyedra
The coastal bioluminescence being seen at some San Diego County beaches is produced by Lingulodinium polyedra.
(Southern California Coastal Ocean Observing Systems

So far, the bioluminescence hasn’t appeared in La Jolla. But it showed up earlier in the week in Newport Beach, and in Carlsbad, where it was seen by lawyer and surfer Brian Witkin.

“I took my family for a drive to get out of the house, and we saw bioluminescence off Coast Highway about 9 p.m.,” Witkin said. “It was very bright, very blue and really beautiful.

“It’s too bad that this comes when we can’t go to the beach.”

The location of the bioluminescence isn’t surprising. Carlsbad Airport received just over 6 inches of rain from April 5 to 10. It produced heavy runoff that carried lots of nutrients into the ocean, generating a red tide. That tide contains Lingulodinium polyedra.

Scientists don’t know how long the bioluminescence will last.

Robbins writes for the San Diego Union-Tribune.