If fireflies were aquatic, they’d probably be something like bioluminescent plankton.
In bays around the world, water will sometimes glow up with a constellation of shimmering blue light. The magical marine light show is known as “bioluminescence,” caused by multitudes of phytoplankton.
Photographer Eric Nathan captured awe-inspiring images of the glowing phenomenon at the Kogelberg Biosphere Reserve on Cape Town’s False Bay earlier this month.
“Each time a wave broke the disturbance caused the plankton to fluoresce and an extraordinary sparkling of light was emitted along the entire length of each wave,” Nathan told Travel + Leisure. “Yet the drivers of countless passing cars were oblivious because their eyes were affected by their own headlights and so were not adjusted to the dark.”
Nathan also captured a time-lapse video showing the glowing waves over the course of 90 minutes.
The phenomenon is also sometimes known as red tide/blue tide. During the day, the harmful algae blooms (HABs) will make the water appear red. At night, they glow their famous blue. Biologists believe that the glowing is the planktons’ defense against predators.
Travelers who visit a bioluminescent bay will notice the display is at its most fantastic when actually in the water. Because the glowing is a natural response to predators, the plankton tend to light up when a boat or person is passing through.
Cape Town is not the only place in the world where you can see this phenomenon. Glowing phytoplankton have been spotted on the shores of many tropical environments, including the Maldives, Hawaii, and the Caribbean. The displays depend on many conditions, including temperature, algae blooms and currents.