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Climate and Environment

That Magical Glimmering Glow Known As Bioluminescence Is Back Off California Shores

Blue waves glow at night as the tide rolls to shore on a beach with a lifeguard station.
The scene on Manhattan Beach in April 2020. Bioluminescence has been spotted more recently in the waters off California in San Diego and the Bay areas.
(Valerie Macon
AFP via Getty Images)
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The waters off California shores are having a glow up.

After the sun sets, you may able to catch crashing ocean waves that reveal millions of glowing neon blue sparkles. It’s magical, looking like the ocean is sprinkled with glitter. That glitter is actually an algae called dinoflaggetas.

It’s becoming something of a yearly end-of-summer tradition to see the ocean glow, where internet videos show surfers, dolphins, and boaters wade through the glimmering sea.

The naturally occurring phenomenon has been spotted in recent days off the coast of San Diego and in the Bay area.

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Some people even scuba dive in it. Two weeks ago, Kyla Kelley, a Ph.D. candidate in Marine Environmental Biology, descended 40 feet into the ocean at night, and was unexpectedly surrounded by the algae bloom.

“You wave your arms around and it was just this magical explosion of blue that mirrored every movement,” Kelly said. She dived for an hour, and said it was the most dense of any bloom she experienced.

The Science Behind That Glow

The explosion of glowing algae is called an algae bloom, which — depending on the type — can be exacerbated by our climate emergency. For the kind that glows, however, Kelly says that while climate change is likely a contributing factor, the relationship is not well-established.

During a bloom last year our newsroom talked to Clarissa Anderson, who is Executive Director of the Southern California Coastal Ocean Observing System located at Scripps Institution of Oceanography.

She explained that the glow is triggered by something crashing against the algae — whether waves, a person or a boat (you get the idea.)

Anderson said: "The turbulence that's stirring up those cells is what's turning on a chemical reaction that gives you a light show."

"It is thought that it has something to do with scaring off predators like other microscopic organisms that feed on them," she said.

We spoke to Anderson again this week and she said the glowing algae has been off California’s shores since the 19th century. “It is natural and has been happening for a long time."

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How much the blue glowing algae and its toxins affect the ecosystem hasn’t been very well-studied.

The toxins are irritating to human skin after scuba diving, says Kelly. “It made my skin itchy because of the toxin.”

Your Best Bet At Seeing Them IRL

The glowing blooms can last from a couple of weeks to months, and usually happens no further north than Los Angeles.

Around L.A., the glowing algae is best seen while scuba diving, but in San Diego, you may be able to see it from the pier. They’ve been increasing, duration and intensity over the last 10 to 15 years but exactly when they’ll appear is still hard to predict.

What questions do you have about Southern California?