Milky Sea Effect

Milky Sea Effect

Part of: Prelims and GS – III – SCI and tech

Context New satellite technology Day/Night Band is being used by scientists to find glow-in-the-dark milky seas of marine lore.

About  Milky Sea effect

• The Milky Sea effect refers to an unusual marine phenomenon in the ocean in which a large amount of sea water appears to glow brightly (eerie blue glow)at night.
• Also called mareel, the milky sea is caused by bioluminescent bacteria, billions of trillions of them, that live throughout the water column from the surface to the sea floor.
• Some point out that Mareel is typically caused by Noctiluca scintillans (popularly known as “sea sparkle”), a dinoflagellate that glows when disturbed and is found in oceans throughout much of the world.
• Bioluminescent bacteria are light-producing bacteria that are predominantly present in sea water, marine sediments, the surface of decomposing fish and in the gut of marine animals.
• Stress, caused by the movement of the sea and waves, leads the plankton to emit light, or bioluminescence as a defence mechanism in a similar way to some fireflies.
• Such occurrences glow brightly enough at night to be visible from satellites orbiting Earth.
• In 2005, scientists announced that for the first time, they had obtained photographic evidence of this glow.
• Between 1915 and 1993, 235 sightings of milky seas were documented, most of which are concentrated in the northwestern Indian Ocean and near Indonesia.
• The luminescent glow is concentrated on the surface of the ocean and does not mix evenly throughout the water column.