What’s causing California’s ocean waves to glow?

CALIFORNIA (KTLA) — Earlier this week, a photographer and videographer captured boogie boarders surfing some bioluminescent waves in Huntington Beach. The glow from the waves is a result of algae that is disturbed at night and causes bioluminescence. 

Nate Jaros, senior director of fish and invertebrates at the Aquarium of the Pacific told KTLA that the microalgae, called a dinoflagellate, is associated with a red tide and gives the water a red-colored tint during the day while creating a bioluminescent glow when disturbed at night. 

“It's the same type of organism when you have a red tide, which gives the water kind of an orangish brown, red kind of tint when they are in high density during the day,” he said. “But at night when disturbed, they produce bioluminescence. So when there's a lot of agitation in the surf, it can activate that bioluminescence which makes the waves appear to be glowing.”

The microalgae always exists in the water, but during the summer when the water is warmer and contains more nutrients, the algae blooms, their population increases, and they are more dense.

“The growth is associated with increased nutrients in the water, which can be a number of things such as increased runoff after rainstorms, or really anything that's going to build up the nutrients like the nitrogen and the phosphorus," Jaros said. “When those conditions are right, and the water temperature is right, it creates these kinds of scenarios where they're more common, seasonally, like the late summer when the waters are a bit warmer.”

Although this type of dinoflagellate is known for producing toxins, it doesn’t produce as many toxins in Southern California as in other areas like the Mediterranean. Some people, however, can be reactive to it, and can experience skin-related issues and irritation.  

“There's no health advisories that go out when the red tides are present here in Southern California, but some people can be reactive. So it's enter at your own risk,” Jaros said. 

Jaros says the bioluminescent glow in the waves is very faint and is best seen when it’s really dark at night.