An algae bloom in Tasmania’s Preservation Bay recently turned the calm, warm water a glowing electric blue, creating quite the photogenic scene for local shutterbugs.
“The whole bay was iridescent blue,” Brett Chatwin, who photographed the spectacle near his home, told the BBC. “I was gobsmacked. It was just an amazing sight.”
The bioluminescent phytoplankton (Noctiluca scintillans), often called sea sparkle, is a natural phenomenon. When the single-cell, nonparasitic algae is disturbed or threatened, it emits the light as a defense mechanism. As the Australian Broadcasting Corporation (ABC) reports:
Gustaaf Hallegraeff, a professor in aquatic botany at the University of Tasmania, said scientists believe the flashing mechanism is deployed to scare off predators. “Imagine there’s a little animal that wants to eat this plankton and suddenly it flashes at you,” he said. “There’s actually evidence that shows if you offer an animal a choice between a luminescent plankton and a non-luminescent plankton, they avoid the luminescent one.”
Although the algae is nontoxic to humans, this algae species can cause skin irritation in some people.
But just because it’s not toxic doesn’t mean it’s not harmful in other ways. “This is an organism that eats other species and so if there’s a huge amount of it, and basically it behaves like a vacuum cleaner and it eats away all the other plankton,” Hallegraeff told ABC.
Experts say these blooms may not stick around long, and their arrival is unpredictable. Chatwin told The Examiner that in his 10 years of photographing the area, he had never seen sea sparkle before.
There’s some evidence that warming oceans have contributed to a rise in sea sparkle algae blooms, as this species’ range has expanded in recent years, Hallegraeff told ABC.