The Derwent River has come alive, well at least parts of it, with the shoreline lighting up like a blue neon light. What is causing this to happen is a bloom of Noctiluca scintillans, which is a type of bioluminescent plankton; it is also known as “sea sparkle.”
Lisa-Ann Gershwin from Australian Marine Stinger Advisory Services in Launceston, Australia said: “It was the most wondrous sight imaginable. I’ve seen a lot of bioluminescence in the past 25 years, and this is the best I’ve ever seen.”
Scientists don’t know why the tiny single-cell organisms flash when disturbed, which illuminates the water around them. Dr Gershwin said that while bioluminescence is common, the concentration of the blooms she witnessed were very rare.
When it’s disturbed, the organism produces light in its cytoplasm, the gel-like substance inside its single cell.
As news of the bloom spread, hundreds of people came to see the spectacle.
“People turned out in droves, rolled up their pant legs, and danced, ran, splashed, stomped, tiptoed, you name it, people played! It was incredible!” wrote NewScientist.
Anthony Richardson from the CSIRO, Australia’s national science agency in Brisbane, said to NewScientist: “The displays are a sign of climate change.”
Amazing bioluminescent phytoplankton in Tasmania:
Noctiluca was not seen around the Tasmania waters until 1994. It is believed that due to global warming, the East Australian current has strengthened and it’s because of this that the waters around Tasmania have been getting warmer. “As the Southern Ocean warms, it will be warm enough for Noctiluca to survive,” says Richardson.
This particular plankton has an even more direct impact: “Noctiluca is a voracious feeder on diatoms, which is the food for krill in the Southern Ocean,” Gustaaf Hallegraeff, from the University of Tasmania in Hobart, told NewScientist.
“As wondrous and entertaining as Noctiluca is, it is also a species infamous for causing fish kills,” says Gershwin.
But what the outcome will be from this particular bloom remains an unresolved question, adds Hallegraeff. “Blooms can disappear within days, leaving essentially no trace.”
It is an amazing site to see, but with other impacts to consider, it won’t be a bad thing to see it leave.