Milky seas (Somali: Kaluunka iftiima; English: Milky seas), sometimes confused with mareel, are a luminous phenomenon in the ocean in which large areas of seawater (up to 100,000 km2 or 39,000 sq mi[1]) appear to glow diffusely and continuously (in varying shades of blue). Such occurrences glow brightly enough at night to be visible from satellitesorbitingEarth. Unlike flashing waves or red-tide luminescence caused by "algae" such as dinoflagellates, milky seas are originate from luminous bacteria[2][3].
Mariners and other seafarers have reported that the ocean often emits a visible glow which extends for miles at night. In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow.[4][5] In a follow-up study, they observed a glow that persisted for over 40 days[1].