Local Beaches Are Glowing Blue Again

The bioluminescent blue waves are back, with social media posts confirming they have been sighted in Huntington Beach, Newport Beach, Seal Beach and Long Beach.

The iridescent blue is caused by a planktonic organism — dinoflagellates — that are invisible to the eye, said David Caron, a professor of biological sciences at the University of Southern California. When agitated, they flash light through a chemical reaction.

Caron said they do that protectively as the light “shocks or startles” predators, allowing the plankton to move away.

Phytoplankton, zooplankton and even deep sea fish, he said, have bioluminescent organs to “startle predators, maybe to attract prey.”

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Peter Nguyen, a resident of Costa Mesa, has been monitoring the bioluminescence on Facebook, where people share their blue wave sightings. On Tuesday night, in Huntington Beach just off of 17th Street and Pacific Coast Highway, he spotted a faint glow on the beach.

He said he ran down to the shoreline where he watched the bioluminescence in the distance where the waves were just disrupting it.

"And then also a couple times it came up close and as the waves were breaking, it was causing it to light up as well and it was just all over the shoreline,” he said.

Why are we seeing the blue waves more frequently

The last time the blue waves made an appearance was in September. Caron said these plankton blooms wax and wane with the seasons.

“They're documented in the literature as early as the early 1900s," he said. "There were lots of these blooms in the 1970s, then they kind of disappeared for a while. They came back after that prevalent in maybe the early 2000s, and then they weren't that prevalent again, and now they seem to be back again.”

Clarissa Anderson, a biological oceanographer at Scripps Institution of Oceanography at UC San Diego, added that bioluminescence is not something out of the ordinary.

“We don't really see a climate connection, considering the fact that these plankton that caused the bioluminescence have been here for so long,” she said. “We have no reason to make a connection scientifically that global warming is going to cause more of these blooms. But in general, when you have warmer water, you can get more plankton and algae blooms.”

Monitoring

The dinoflagellates are decomposed by bacteria and for that to happen, the bacteria use oxygen from the water, Caron said.

“In doing that, they can actually drive the oxygen concentration in the water down to very low levels,” he added. “They can eliminate the oxygen in the water if they are dense enough and their bloom dies kind of en masse all at once. If that happens, of course, if there's no oxygen in the water, then it does cause detrimental effects for things like fish and other organisms.”

Because of this, the Harmful Algal Bloom Monitoring Program monitors the microscopic algae at several piers in Southern California every week. The information they collect goes into a website managed by the Southern California Coastal Ocean Observing System run out of the Scripps Institution of Oceanography.