The shores of Tasmania’s Preservation Bay glowed blue last week, but why?
The blue light caused by billions of algae is called Noctiluca scintillans, or sea sparkle. Bioluminescent algae illuminates the water when disturbed by waves and currents.
According to Gustaaf Hallegraeff, an aquatic botany professor at the University of Tasmania, scientists believe the algae’s flashing light is used as a deterrence mechanism against predators.
“Imagine there’s a little animal that wants to eat this plankton and suddenly it flashes at you,” he said.
A deep red or orange color in the daylight, the algae only glows blue at night. The phenomenon was first reported in Sydney Harbour in 1860, but has since expanded to other regions. Hallegraeff attributes this in part to oceanic warming and currents.