The Lights of the Deep Sea
Bioluminescence in the deep sea. Creatures that live beyond the twilight zone spend their lives in a world without sunlight. But many use this to their advantage. These twinkling, flashing, pulsating lights are caused by bioluminescence - the result of a reaction that produces light energy within the body of an organism. It is am adaptation that unifies vastly different creatures, from worms and jellyfish to squid and sharks. This mesmerising display is put on by a swarm of firefly squid, who gather at the surface from March until May to find a mate. But the lights are useful for blending in as well as standing out. Many deep sea creatures can detect the levels of ambient light around them, and adjust the intensity of their bioluminescence to match. As a result, they can hide from predators at both day and night.
