Beachgoers walking along Tasmania's shore on Monday night, March 13, were welcomed by a magical sight: the island's northwestern coast sparkled in neon bright light, courtesy of bioluminescent algae.
People taking in the sights on the Australian beach captured this exquisite phenomenon on camera, to the delight of the entire world. Leanne Marshall, a photographer for the Australian Marine Stinger Advisory Services in Launceston, shared fascinating images on social media depicting the area near Rocky Cape National Park.
The other-worldly scenery was also spotted 50 km to the east, at Preservation Bay. Passers-by could observe the aquatic "light show" whenever waves or currents disturbed the plankton.
Scientists explain the iridescent event is the work of Noctiluca scintillans, also called "sea sparkle" — single-celled bioluminescent plankton. During the day, this type of algae colors the water in deep red, brown, or orange hues, a phenomenon described as "red tide," which switches to a blue glow at night time.
According to Gustaaf Hallegraeff, aquatic botany professor at the University of Tasmania, the algae employ this captivating flashing mechanism when feeling threatened, in an attempt to ward off predators.
"Imagine there's a little animal that wants to eat this plankton and suddenly it flashes at you," he told ABC News.
The University of Tasmania explains the blue luminous appearance poses no toxic danger to human viewers, but notes however that Noctiluca's high ammonia content might be irritant for fish species, generally reported to avoid the areas where the algae bloom.
Evidence Of Climate Change
These iridescent algae are no strangers to Tasmania's shores. Their luminous bloom has been spotted on numerous occasions during the last two decades, and studies suggest their numbers are steadily increasing, possibly due to global warming.
"We have some evidence that ocean currents and the warming of the oceans have contributed to it — it's definitely a species that is showing a spectacular range expansion in the last 20 years," Hallegraeff notes.
Noctiluca algae belong to a type of plankton called dinoflagellates, which thrive in temperate weather conditions. The algae require warmer water and a stable water column to bloom, "both of which happen with climate change," as pointed out in a statement by Anthony Richardson, from Australia's Commonwealth Scientific and Industrial Research Organization.
In his opinion, the high prevalence of Noctiluca blooms indicates a clear sign of climate change, responsible for the algae's expansion from the Southern Ocean to the Australian coastline.
The same type of bioluminescent plankton is also present near Chinese shores, in the Gulf of Mexico, as well as near Seattle, and can even be seen in the Arabian Sea, says marine biologist Joaquim Goes, from Columbia University.
As he explains, the sudden algae blooms all around the world are triggered by "by the warming trend and increased stratification of the upper oceans," and pose a problem for local ecosystems. Large bodies of plankton strip the water of oxygen as they decompose, endangering marine wildlife.
