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These sparkly sea organisms are an eerie omen of climate change

A bloom of bioluminescent plankton has wowed crowds along a river in Southern Tasmania this week, but it could be a warning sign of climate change
These sparkly sea organisms are an eerie omen of climate change

(Image: Jo Malcomson)

鈥淎ll I can say is wow, just freakin wow!鈥 says from Australian Marine Stinger Advisory Services in Launceston, Australia.

This river in Southern Tasmania seemed to come alive this week as a bloom of Noctiluca scintillans 鈥 a type of bioluminescent plankton, also known as 鈥渟ea sparkle鈥 鈥 washed into the region.

When it鈥檚 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, says Gershwin. 鈥淧eople turned out in droves, rolled up their pant legs and danced, ran, splashed, stomped, tiptoed, you name it, people played! It was incredible!鈥

But there is a dark side to this impromptu festival of light. 鈥淭he displays are a sign of climate change,鈥 says from the CSIRO, Australia鈥檚 national science agency in Brisbane.

Until 1994, Noctiluca had not been seen in Tasmania. But global warming has been strengthening the East Australian current, which pushes warm water south towards Tasmania. 鈥淎s the Southern Ocean warms, it will be warm enough for Noctiluca to survive,鈥 says Richardson.

What鈥檚 more, these particular plankton have more direct impacts too. 鈥Noctiluca is a voracious feeder on diatoms, which is the food for krill in the Southern Ocean,鈥 says from the University of Tasmania in Hobart. Dense blooms like this can therefore starve other organisms, he says. They can also kill fish through oxygen depletion and gill irritation.

鈥淎s wondrous and entertaining as Noctiluca is, it is also a species infamous for causing fish kills,鈥 says Gerhswin. But what the outcome will be from this particular bloom remains an unresolved question, adds Hallegraeff. 鈥淏looms can disappear within days, leaving essentially no trace.鈥

Topics: Climate change / Microbiology