— Anastasiia Sosna

Noctiluca

Since ancient times, people have observed the mysterious glow of the sea at night. In some cases, it appears as an even, milky light spread through the water; in others, as a luminous trail behind a ship’s stern, or as flashes and sparks within the water itself. For a long time, scientists struggled to explain the nature of this phenomenon, proposing various theories. Only in the 18th century was its biological origin finally established, proving that the sea’s mysterious glow is caused by bioluminescence—the ability of living organisms to emit light.

Bioluminescence can be produced both by planktonic organisms of various sizes and by microscopic bacteria. In the Black Sea, the most well-known and thoroughly studied bioluminescent organism is Noctiluca scintillans, commonly known as sea sparkle.

Every summer, one can observe the glowing surf along the Black Sea coast, the luminous wake trailing behind passing boats, and shimmering streaks in the water left by swimming fish. There is an old Crimean legend that tells how the glow of waves, stirred by the oars of ships, prevented the Greek fleet from approaching the shores of Taurica unnoticed. If this legend has a historical basis, it was most likely Noctiluca that saved the Taurians from a sudden attack.