Like a lot of my other spur of the moment trips, this started out with a post on Twitter: someone down in San Diego mentioned that the ocean was blue. Granted, the ocean is generally described as being blue, but this was different.
According to The Scripps Institute, this bioluminescent (light produced bu an organism) tide is caused by a bloom of dinoflagellates, a type of plankton that emit a blue glow when bumped into or jostled around. The ocean itself doesn’t constantly glow, but waves do light up with a surprisingly bright blue light when they crash.
The plankton blooms that lead to these glowing tides don’t happen with any kind of regularity and aren’t predictable. Even the folks who study them for a living don’t have a real good way of predicting when they will appear or disappear, or how intense they will be.
As luck would have it, I heard the news a little late and showed up past the peak of the event. The bloom started on Monday, peaked on Tuesday, and was fading by the time I arrived on Thursday. On Friday night, there was nothing left anywhere along the coast.
From Twitter and Reddit, I got the impression that the bloom was moving north, so I got off the freeway at Carlsbad and worked my way south until I saw a shoreline packed with cars. Figuring that there was no other reason so many people would be at the beach at midnight on a Thursday, I parked and walked to the shore.
As hard as it might be to believe, it actually does look like this. The blue is consistently visible to the naked eye, though you may have to spend a minute or two letting your eyes adjust to the darkness.
Unfortunately, there’s no real solid way of knowing when the next plankton bloom that leads to a bioluminescent tide will happen. If you live near the coast, you’ll need to keep your ears and eyes open and head to the shore as soon as you hear about blue waves to have a chance of witnessing one of these relatively rare events. You’ll be sleepy the next morning, but it’s worth it.