Phosphorescence

When I lived in Saint Thomas, one of the most magical things I experienced was the phosphorescent plankton that would appear in the secluded bay where we lived. On nights when the waves would crest with pale green light, we would go to the beach and swim surrounded by beads of green-blue light.
It happened on the hottest nights of the year, and when the sea was calm. The plankton gives off light when it's agitated, so it glows just at the edge of the ocean where the waves wash onto the beach. Walk along the wet sand, and your footprints glow. When you swim, the plankton lights up all around you. You can smear the plankton on your body, and leave luminescent tribal tattoos. Once, on a boat at night, the plankton lit up in the boats wake. We leaned over the railing, the starry sky above, the dark water below, and it seemed we were floating along the milky way.
Of course, that's when my glasses dropped off into the ocean, and we couldn't afford to buy new ones. I didn't get another pair of glasses until I'd lived in Paris for a year.