During daylight hours Southern California beaches have a red-brown tint to them at the moment, due to microscopic phytoplankton called ‘Lingulodinium polyedra’ causing the red-brown patches. The L. poly has increased significantly in the last couple of weeks.
At night, however, waves disturbing the phytoplankton generate a pulse of blue light using luciferin, a light-emitting molecule. Scientists believe the magical blue glow is a defense mechanism against organisms trying to consume the phytoplankton.
This event only happens once every several years. This current one stretches from Baja California, Mexico up to Los Angeles. The best time to see the glowing waves are a couple of hours after sunset on a sunny day.