Today's Earth Sci Pic of the Day is a nice one and an interesting one - one that would freak me out to death if I saw it live and wasn't aware of the phenomenon.
In the background is La Jolla cove, California. Apparently a summer of long warm weather and smooth sea encourages the growth of certain algae.
Bioluminescent dinoflagellates, they say, make the water red at day and show flashes of green at night. Just another reason to generally avoid the ocean, because it's scary.