Footage has emerged of glowing blue algae putting on a stunning underwater light show, leaving beachgoers amazed .
The video , shot earlier this month in the port town of Qinhuangdao in north-eastern China, shows the living creatures giving off an ethereal blue glow .
The effect is caused by bioluminescence - the production and emission of light by living organisms.
The phenomenon is found widely in marine animals, especially in the open sea, with about three-quarters of all deep-sea animals producing some form of light.
But it is much less common to find light-emitting creatures so close to the shore.
Even some land-dwelling creatures, such as fireflies, are bioluminescent.