The mysterious and elusive Milky Seas phenomenon has been captured on camera for the first time by a yacht sailing in the East Indian Ocean.
Crew members aboard the superyacht, Ganesha, were circumnavigating the globe in 2019 when they noticed the sea all around them had turned white and it was as if they were “sailing on snow.”
The astonished crew naturally attempted to photograph the sensation using a GoPro and a Samsung Galaxy S9+ smartphone. The GoPro camera recorded an extremely noisy image, but with the impression of a snowy field leading to the horizon. The Galaxy S9+ seemed to yield a better result, with a distinct green luminescence emanating from the water. A crying shame that a handy photographer was not on board.
The crew describes the mind-boggling event as “akin to glow-in-thed ark stars or stickers…A very soft glow that was gentle on the eyes,” reports PNAS.
Perception of color varied slightly between the witnesses, attributable, perhaps, to the varying responses of the eye on the fringes between scotopic and photopic vision under low-light conditions. Two unedited images from the two cameras were released, but also a modified photo to approximate human perception.
The skipper, Captain Lemmens, reckons the glow originated from below the surface, while others on the ship described the event as a “watch that has glowing parts on the hands.”
The crew members aboard Ganesha were backed up with satellite observations from a team at Colorado State University led by Stephen Miller, who has been scouring satellite data for evidence of milky seas for years.
A Rare Phenomenon
Milky Seas only appear twice a year, and sometimes not at all. Until now the rare event has only been described by word of mouth from marine voyagers.
“I’d say there’s only a handful of people currently alive who have seen one. They’re just not very common — maybe up to one or two per year globally — and they’re not typically close to shore, so you have to be in the right place at the right time,” Steven Miller, a professor of atmospheric science at Colorado State University and the report’s author, tells The Guardian.
Superyacht Ganesha, which was sailing close to Indonesia at the time, is believed to have sailed through a milky sea that spanned over 39,000 square miles, according to the satellite data.
What Exactly Are Milky Seas?
Milky seas are caused by rare bioluminescent bacteria, which instead of glowing blue or green, glow white. Current theories predict that this rare glow might be due to a saprophytic relationship (feeding on decaying organic matter) between luminous bacteria and a species of microalgae expressing on a large scale.
Strangely, according to the documentation of events published in PNAS, when the Ganesha crew took a bucket sample of the milky sea water and stirred it, the glow got darker. With other bioluminescence, the glow usually gets brighter when disrupted.
The mystery of what causes the white glow that seemingly behaves in the opposite manner to other bioluminescence is yet to be solved. However, some explanations include a prediction that the species of phytoplankton may have a calcium cell wall, meaning that the glow appears paler.
Either way, this confirmation that milky seas can indeed be picked up by satellite imagery means that studying them and unraveling their mysteries will be easier in the future.
Image credits:Photos courtesy of PNAS.