Over the past few days, a red tide appeared off the coast of San Diego. The red tide is caused by an algae bloom in the water near the area where salty sea water meets with freshwater. The tide contains large concentrations of aquatic microorganisms.
Some of the microorganisms are bioluminescent phytoplankton. Bioluminescence is the production and emission of light by a living organism. If you ever came across fireflies, lightening bugs or glowworms, you will know what bioluminescence looks like. The light results from a chemical reaction between a light emitting molecule and an enzyme.
During daylight, the affect water appears to be discolored varying in color from a rust to blood red. But during the night, the tide takes on a different hue due to the phytoplankton. As you can see in the photo, the color is an eerie bluish glow. The glowing light is reminiscent of the glow emitted from the auroras.