In spring 2020, everyone in San Diego was buzzing about the major red tide off our coast — you remember, the phenomenon that created neon bioluminescence at local beaches at night.

Turns out, the unforgettable glow can be attributed to Lingulodinium polyedra, dinoflagellates described by Scripps Institution of Oceanography as “the Michael Phelps of the plankton world.”

The plankton, up close. | Photo via Scripps Institution of Oceanography

Scripps scientists released a new study showing the plankton species created the “dense blooms” (aka the growth of phytoplankton biomass) because they’re remarkably speedy swimmers, traveling vertically up to 10 body lengths per second for nearly 24 hours.

That glow, though. | Photo via Philipp Arndt/UC San Diego

Researchers deployed instruments into local waters to capture the planktons’ speeds. They swam up during the day to photosynthesize and down at night to replenish their nutrients.

The vertical migration pattern fueled the 2020 event — and while it was a lovely visual — Scripps says it was a “harmful algal bloom” that led to fish dying — a speedy-plankton-causes-bloom hypothesis presented by Scripps oceanographer Richard “Dick” Eppley 50 years ago, now validated through modern science.