Red Tides in Southern California

Southern California’s Neon Waves


Ilya Sviridenko

Bioluminescent plankton. Glowing wave with long exposure.

I started to notice the reddish color to the ocean along with the funny smell. I soon learned that the sight and smell of the ocean were side effects of a mass reproduction of phytoplankton—a single-cell, microscopic plant, that can reproduce rapidly. When these phytoplankton are agitated by movement around them, they light up as a defense mechanism. At night people could go to the beach and see the ocean waves light up as they crash on shore. I immediately wanted to see this phenomenon for myself.

According to research done by UC San Diego, this phytoplankton causes a Red Tide—an algae bloom that comes from a “particular group of phytoplankton called dinoflagellates, which seem to prefer warmer and calmer waters.” The small but socially distanced crowds on the beaches after sunset are in awe at the sight of the blueish greenish glow that appears when the ocean waves crash. Some people have gone out on boats to play with the glowing water by throwing objects into the water, or simply even making a spray with their hand.

What many people do not yet know about the algae blooms is that many scientists are beginning to question the impact they have on sea life and if humans are to blame. There have been more

Bioluminescent Tide in San Diego in April and May of 2020 make the water and rocks glow blue at night. (Kevin Key)

frequent blooms in the past years. In Florida, there is now a yearly algae bloom expected. There have been large numbers of deaths of fish and other sea creatures, that come with a grueling smell, along Florida’s Gulf coast. In 2018, National Geographic said that the “cause of both the deaths and toxic, stinging fumes is a bloom of harmful algae that scientists say is the region’s worst in over a decade.” The dinoflagellate that appears in the Florida Gulf is called Karenia Brevis. Karenia Brevis is one of the handful of dinoflagellates that is poisonous to humans. It is a very common type and produces the neurotoxin Brevetoxin. When the algae blooms wash onto shore in Florida it becomes aerosolized and can cause respiratory issues for humans. If this toxin is ingested through breathing, a person may notice asthma like symptoms. In other areas, such as Maine, the Red Tides make sea life poisonous for humans to ingest. Shellfish are usually some of the more dangerous sea foods to eat during a Red Tide.

Luckily for California and other parts of the Eastern Pacific Ocean, the types of dinoflagellates have not been known to produce such neurotoxins as in the Gulf Coast of Florida. The dinoflagellate that is most likely being viewed down the Southern California coast currently is lingulodinium polyedra. Although this type of dinoflagellate is not known to produce a harmful toxin, there have been reported cases of irritation to the eyes, nose, and throat as well as flu-like symptoms.

Red Tides have been documented since the 1900s in California but are unpredictable and not consistent. In other places around the world Red Tides have been documented from a much earlier time period, although they occurred so infrequently that not much research could be done. Now that some parts of the world, like Florida and Maine, find themselves looking at red water more often, scientists started researching the cause of red tides and although there has not been any proof that humans have caused these increased algae blooms, research is still being conducted.

As I strain my eyes to see the waves light up, I decide I must go onto the beach in order to fully experience the bioluminescence. I feel the cold sand under my feet and look up to see other dark figures walking down to the water’s shoreline. Then I see something light up. It was incredible! The small whitewash waves were bright neon blues and light greens. I could even drag my foot through the wet sand to see my drawing light up for just a second before fading away. This truly is a sight I am going to remember.