photo by msauder (Flickr CC)

Late summer algae blooms along the San Diego, California coastline have turned the ocean red during the day and a bioluminescent blue at night.

The fluorescent blue waves have attracted spectators to the shores around San Diego, offering rare photo and video opportunities.

It is interesting to note that the water is not constantly glowing, but only gives off a blue light when agitated, so the waves flash blue when crashing and then grow dark again.

From the Los Angeles Times:

The blue glow is caused by an algae bloom commonly referred to as a red tide. The organisms, phytoplankton called Lingulodinium polyedrum, have bloomed since late August, turning the water brownish-red in the daytime, according to UC San Diego scientists.

Check out this video of bioluminescent blue waves at San Diego’s La Jolla neighborhood.