On the shorelines of New Zealand’s north island, shores have been lit up by the glowing “aurora of the sea”: blooms of plankton that glow blue-green after nightfall.
The elusive, beautiful phenomenon that sometimes sweeps into the coasts was witnessed by local “biohunter” enthusiasts who scour the shorelines for bioluminescence.
“It’s also called the aurora of the sea – like the Aurora Australis you see in the sky,” says Sajith Muraleedharan, a photographer who captured the phenomenon in Napier.
The light is activated by movement: cresting waves begin to glow, splashes sparkle, footprints glimmer blue in the wet sand, and swimming fish can leave sparkling trails. “Every time a wave comes in, you can see this beautiful phenomenon. It’s amazing – a lot of people were there, a lot of people with families, some of them were swimming,” Muraleedharan said. “It is indeed a great thing to witness.”
The phenomenon is caused by blooms of plankton and phytoplankton species, some of which use the “luminescence” adaptation to evade or distract predators.
“Dinoflagellates produce this light when disturbed, and will give a light flash lasting a fraction of a second – disturbing the predator trying to consume them,” said Karl Safi, algal ecologist at the National Institute of Water and Atmospheric Research.
The glowing waves are unpredictable, but Safi said they were “common on warm nights and may also occur after days of heavy rain”. The phenomenon only occurs at night, Safi said, as the creatures have an inbuilt biological clock, and do not glow during the daytime – even if put into a dark space or container.
Microbiologist Siouxsie Wiles uses bioluminescence to track the growth of infectious disease in a laboratory setting – but says she is also an enthusiast, and has gone hunting to see the creatures lighting up in the wild.
Around New Zealand’s shorelines, amateur “biohunting” groups have sprung up, where watchers alert one another if they’ve seen the phenomenon occurring, and sometimes travel up the coast to try to witness it. “People post if they’ve seen anything and it’s been quite quiet this year, so it was really great to see that one,” Wiles said of the Napier sighting. She has been “hunting” twice to see the waves lighting up.
“The more people who see it, the better I think,” Wiles says. “It’s just this beautiful – magical really – kind of amazing phenomenon.”
