Masses of glittering eyelashes have returned to the coast of Tasmania in a spectacular bloom of bioluminescence, which experts say is the biggest in years.
Known as “sea sparkles” or “red tides,” the phenomenon was caused by masses of noctiluca scintillans, a pink-colored algae that experts say is beautiful to look at but is considered bad news for the environment.
Dr Lisa-ann Gershwin, scientist and writer who organizes tours of Tasmania’s naturally glowing flora and fauna, said the current algal bloom across Storm Bay, south-east of Hobart, was on a “truly epic” scale.
The algae “put on one heck of a light show,” she said. What appeared to be a “pink blob” during the day gave off a “mesmerizing sparkle” after dark, turning the arc of each ripple into a brilliant blue that stretched as far as the eye could see.
“It’s quite an amazing sight. It’s a really emotional experience, a very spiritual experience, to see something so amazingly inspiring,” she said.
Dr Jen Matthews, a marine biologist from the Future Reefs Research Group at the University of Technology Sydney, said the balloon shape of the organism allows it to float on the surface.
“They exist in small amounts and you might not see them, but when you get a huge amount of them, that’s when you start seeing these red tides,” she said.
The bluish glow was caused by a chemical reaction in a structure called a scintillion that was triggered by movement, such as the action of waves.
“This chemical reaction produces light and it can be really spectacular,” she said. “In the Northern Hemisphere they make snow angels, but you can go into the water and make algae bloom angels out of them if you wave your hands around.”
If there were no waves, Gershwin recommended spraying the surface with water from a sprayer to stimulate sparking and to prevent rocks from being thrown that could pose a hazard.
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While the bioluminescent light show was natural, its scale and density was a sign that something was wrong in the environment, she said. “It’s beauty and the beast.
Gershwin said it’s alarming that algal blooms follow a pulse of salps and that jellyfish blooms begin to appear as the noctiluca die off. These organisms in abundance were usually symptoms of a severely disturbed ecosystem, she said.
Noctiluca scintillans was the first documented in Australia in 1860but was considered a rare sight until the 1990s, when the algae’s range expanded and blooms became more common.
Matthews said large nightshade blooms were usually a sign of poor ecosystem health, which usually meant higher nutrient levels.
Its presence could also be harmful to marine life and aquaculture, she said, because it was a type of algae that fed on plankton in the water, sometimes even eating fish larvae and eggs.