Scripps study highlights what fueled historic ‘red tide’ of spring 2020 in San Diego

The plankton that caused the ocean water to glow are described by scientists as the “Michael Phelps of the plankton world,” aka super swimmers.

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No one can forget the neon hues of the spring 2020 phenomenon at San Diego’s beaches.

Photo via Erik Jepsen/UC San Diego

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.

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 eventand 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.

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Monica is based in San Diego, California. She was previously a senior digital media producer and podcast host at NBC 7 San Diego + The Scene, and has been in the news biz since 2005. She loves hiking, the beach, and family days with her husband and two kids.