This phenomenon of bluish luminosity sometimes observed at sea in Tunisia is explained by a natural process called bioluminescence. It is caused by the presence of marine microorganisms, particularly certain types of plankton, capable of emitting a faint blue light when disturbed by waves or water movements.
According to experts, this glow typically appears under specific environmental conditions, particularly when water temperature and ocean currents favor the proliferation of these organisms. Contrary to what one might think, this phenomenon is not linked to pollution, but rather reflects certain biological and ecological dynamics of the marine environment. It thus offers an impressive natural spectacle, giving the sea a luminous glow that is particularly visible at night.
Source : Directinfo
