Tulka and Port Lincoln residents were treated to a light show in the waters off Proper Bay at the weekend with the presence of bio-luminescent algae.
The algae was first seen in a large quantity by Tulka residents on Sunday evening which attracted many to come to Proper Bay on Monday night.
Tulka resident Therese Pedler said the household first noticed the algae on Sunday night just after dinner.
“Our dog was in the water fishing as he does, and we noticed she was green and the water was green,” she said.
“The whole bay was a luminous green colour.”
The light is caused by noctiluca scintillans, also known as sea sparkle, a phytoplankton that is mostly restricted to coastal waters.
Ms Pedler said the algae was first seen by a local on Saturday night but reached a large amount on Sunday.
“We’ve seen it half a dozen times, but only in small amounts, this was the whole bay,” she said.
“It literally looked like Mother Nature went to all the $2 shops in the world, bought all the glow sticks and emptied them into Proper Bay.”
Ms Pedler said her son Kye Higgins took local filmmaker Mark Thomas out into the bay where he was able to film the algae reacting to human interaction.
The algae brought people out to Proper Bay on Monday night for one more chance to witness its glow.
Ms Pedler said there were only small amounts on Monday night but it was great to see “kids out enjoying Mother Nature”.
“We are so lucky to live in this part of the world,” she said.
Biosecurity SA phycologist Clinton Wilkinson said this phytoplankton can be found worldwide and was non-toxic to humans.
“In SA it is found along the west coast of Eyre Peninsula, (there are) many reports from Ceduna of red tides (algal blooms), I have seen several in Boston Bay,” he said.
He said there had been previous reports of this phytoplankton at Point Bolingbroke, Proper Bay and Kellidie Bay but an event like this did not happen every day.
“Not a very common event and scientists are not sure why,” he said.
“Function is unknown, experiments have shown prey feed lest on bio-luminescence Noctiluca cells, so this may be the reason.”
Mr Wilkinson said the phytoplankton could be seen all year around in South Australia but was more abundant in the summer months due to food availability.
A similar event to this one was seen off the coast of northwest Tasmania in March this year.