With a boom in social media attention over the last few years, photographers, swimmers, surfers -- even the occasional dog -- have experienced the splendor of bioluminescence, a phenomenon that turns the ocean off the coast of San Diego a glowing blue.
Bioluminescence has been such a draw for locals that even the Scripps Institution of Oceanography -- the experts on all things sea, including the red tides that create these spectacular sights -- took a chance to capitalize on the intrigue during the latest round, which has been ongoing for nearly a week.
Last Thursday, Scripps researchers hopped on a small boat in the darkness of the night to agitate the waters, in turn creating neon wakes that were captured by a drone. The scientists used the awe-inspiring video -- which can be seen below -- to share more details about red tides, bioluminescence and the minuscule Phytoplankton behind it all.
Get San Diego local news, weather forecasts, sports and lifestyle stories to your inbox. Sign up for NBC San Diego newsletters.
Here's what to know, including how to see the bioluminescence for yourself:
What causes bioluminescence?
Bioluminescence is caused by tiny organisms that drift in the ocean called Lingulodinium polyedra. They are a species of motile photosynthetic dinoflagellates that create an algae bloom or "red tide."
"They're like plants in the sense that they photosynthesize, but they're unlike most plants in the fact that they move around a bunch. They can swim," Dr. Drew Lucas, an associate professor at Scripps Institution of Oceanography at UC San Diego who has researched the plankton species and their bioluminescent blooms, told NBC 7.
In fact, they swim so well for their size that Lucas has referred to them as the Michael Phelps of the plankton world. Their strong swimming abilities are the reason they are able to take over the coastal ecosystem, turning the water red during the day, hence the term red tide, and making it glow at night.
More bioluminescence stories:
During the day, these organisms don't show off their glowing powers. Instead, they turn the water a murky shade of brown, which is where the term "red tide" came from. It's when nighttime rolls around, and they get physically disturbed — like from a breaking wave, a boat, a dolphin or a surfer — that they unleash their glow.
"That flash of light for each individual cell is not very bright, but when there's a lot of them in the water, that's when they really can light the waves up and lead to quite bright glowing," Lucas said.
This round of dinoflagellate is also made up of a second species, Akashiwo sanguinea, which does not glow blue. It has been known to lead to bird deaths in the past, according to Scripps staff scientist Melissa Carter.
When can you see bioluminescence in San Diego?
First things first, it needs to be dark to see bioluminescence. Lucas says the organisms do not glow if they encounter light.
The natural phenomenon can happen at almost any time of the year, Lucas explained. But he's noticed a slight preference for spring to early fall.
If you're at the beach when there's a red tide, and you can't stay until the sun goes down, Lucas shared a tip to see bioluminescence from the comfort of your home. When there's a red tide, fill up a jar with some red water and put it in your fridge for an hour, creating a dark environment. Once you take the jar out, shake it, and it will supposedly light up.
Where can you see bioluminescence in San Diego?
"It is patchy. It does move around unless it's a very strong event like the one in 2020 ... In that case, it was literally everywhere," Lucas said.
That 2020 red tide was so powerful, it produced a potent smell that could be detected miles from the beach.
In this case, because the red tide seems to move around, Lucas says the best way to know where to find the red tide is on social media.
Vishwas Lokesh, an amateur photographer who has been NBC 7 San Diego's "bioluminescence chaser" since we first spoke with him in 2022, is one way to find out.
Lokesh noted the best sightings are between the La Jolla Scripps Pier and Torrey Pines State Beach. But NBC 7 has seen reports as far north as Carlsbad and as far south as Ocean Beach. The phenomenon has also been reported at other Southern California beaches from San Clemente to Santa Barbara.
How long does bioluminescence last?
Red tides are unpredictable and scientists are still trying to understand when it occurs. Lucas says they typically stick around for a couple of weeks.
"In 2020, the red tide was around for almost two months. Sometimes, it's only a night or two that it is really bioluminescing at the beach," Lucas said.
If you plan to view the electric waves from the sand, the red tide must be in the breaking waves. Red tides that are offshore may be viewed from a boat.
Is it safe to swim in bioluminescent waters?
"It is my understanding that, in general, people tolerate swimming in the red tide just fine," said Lucas, who claims he has swam and surfed in it. "In a typical scenario, the bioluminescent red tide is not harmful to human health or even the ecosystem."
Red tides can impact the ecosystem at specific intensities. Interestingly, it doesn't have to do with the bloom but rather when the organisms start to die off.
"They start to decompose in the ocean, and that decomposition uses up all the oxygen, which can really harm marine life," he said. "There have been reports of it creating some amount of discomfort in people in terms of the smell and aerosols that are coming out of the water as the bloom is decaying."
Lucas' research on how Lingulodinium polyedra created a historic red tide and bioluminescence display in 2020 can be found here.
