It’s a Bioluminescent Red Tide!

Blue-white waves at night near Scripps Pier.

April 29, 2020: We are experiencing a red tide, a massive bloom of the dinoflagellate Lingulodinium polyedra, which is a common member of the local plankton community. Sometimes it gets so abundant that it discolors the water reddish/brown, hence the name red tide. And this is big one, stretching from Baja California to Los Angeles. It was first detected at a mooring offshore of the Scripps Pier on March 25, and seen from shore on April 4. So as of this writing it has already persisted for a month.

L. polyedra is bioluminescent, resulting in some spectacular light displays at night as seen in these videos:



For scientific information about the red tide, visit:

Red Tide Bulletin, by the Southern California Coastal Ocean Observing System

Dr. Latz interviews:


ABC 10News San Diego, April 29, 2020


What Is That Terrible Smell?

Glowing Waves Could be Crashing to an End Soon

NBC7 San Diego, May 5, 2020

‘Greater LA’ radio show KCRW, May 7, 2020

San Diego Union Tribune, May 7, 2020

San Diego Union Tribune, May 21, 2020

Update Friday May 1, 2020: The red tide continues. The water near the shore is dark brown in color. There is a pungent smell, indicating the breakdown of organic material. So perhaps the red tide will degrade soon?


Update Monday May 4, 2020: The water is still brown in color, but now the sulfury odor is intense; we smelled it 1 1/2 miles inland. There is also foam, indicating the breakdown of protein and other organic material. There are also reports of fish kills along beaches and in lagoons and harbors. The breakdown of the red tide by microbes results in low oxygen conditions (hypoxia/anoxia) that are deleterious to some animals.

Foam by the Scripps Pier in the morning (top), with more at night (bottom) due to breakdown of the red tide

The end is near! Nighttime bioluminescence on May 4 (top) was much reduced compared to about one week prior on April 24 (bottom), as the health of the red tide organisms degrades. Despite large crowds, there wasn’t much bioluminescence to see.

Update Friday May 22, 2020: The foam has mostly disappeared and the nasty smell is gone. The water is still murky but it appears that the bulk of the red tide has dissipated. Bioluminescence on the night of May 18 was dim but still noticeable. There was considerable foam on the beach on May 19.