Phytoplankton light up the waves at Santa Cruz County beach

Waves filled with bioluminescent phytoplankton put on a blue light show at Seacliff State Beach shortly after midnight on Monday.

Phytoplankton, also known as microalgae, are similar to terrestrial plants in that they contain chlorophyll and require sunlight in order to live and grow. Most phytoplankton are buoyant and float in the upper part of the ocean, where sunlight during the day penetrates the water.

On sunny days, the organisms swim toward the surface where they concentrate, resulting in the intensified coloration of the water — and the reason for the term ‘red tide.’ At night, when the phytoplankton are agitated by waves or other movement in the water, they sometimes emit a dazzling neon blue glow.