Mysterious Glowing Seas: Mere Bacteria...Or How Our Sci-Fi Horror Begins?

'Milky Seas' Detect from Space

from The BBC

Mariners over the centuries have reported surreal, nocturnal displays of glowing sea surfaces stretching outwards to the horizon. Little is known about these "milky seas" other than that they are probably caused by luminous bacteria.

But the first satellite detection of this strange phenomenon in the Indian Ocean may now aid future research.

The observation is described in the journal Proceedings of the National Academy of Sciences. The glowing sea covered an area about the size of the US state of Connecticut and was observed over three consecutive nights, with the first night corroborated by a ship-based account.

The team was able to estimate of the number of bacteria that the observed area would have contained - an abnormally "giant" population.

"To put it into context, it's about 200 times more than the number of background, free-living bacteria that are spread over the continental shelf waters of all the oceans," said Dr. Steve Miller, from the Naval Research Laboratory in California.

There have been 235 documented sightings of milky seas since 1915 - mainly concentrated in the north-western Indian Ocean and near Java, Indonesia.

Milky seas are distinct from the brief flashes of bioluminescence seen at ships' wakes, or breaking waves, which are caused by microscopic algae called dinoflagellates. Instead, the constant light emitted over a wide area probably comes from the luminous bacteria Vibrio harveyi, living in association with microalgal blooms.