People are being warned to stay away from a popular and vast mangrove area after one stretch of water experienced a radical change in colour.
In a bizarre photo shared to Reddit on Monday, the water near a walkway appeared bright pink.
“Boondall Wetlands looking a little polluted today,” the poster wrote. They went on to explain in a later comment “the water in the rest of the wetlands is a normal colour” and “the pink water is directly beside the Nudgee dump”.
“Crikey, that looks terrible, I hope someone in the relevant government department checks this out and sorts it out,” one user responded, while others debated what could have caused the water to change colour, with someone suggesting it could be algae.
The wetlands are located in the Moreton Bay region, north of Brisbane, and locals joked it was the maroon “tears of 10,000 Lions and Broncos fans” after Queensland’s loss in both the NRL and AFL grand finals on the weekend. “It’s from all the jerseys flushed down the toilets,” another added.
A Brisbane City Council spokesperson said on Tuesday council officers would visit the site to assess the health of the waterway but stressed pink water can occur naturally as a result of environmental factors.
"Warmer weather and low rain fall can lead to less water flow and higher salt levels, causing the algae and bacteria in the water to turn pink," the spokesperson said.
Rivers expert weighs in
Professor Michele Burford from Griffith University’s Australian Rivers Institute agreed it could be an algal bloom, and said there's a particular type of algae that is quite pink.
She told Yahoo News the algae could have been washed in with the tide and come through the mangroves, or it could have risen from below the surface.
“Sometimes, if the weather conditions are right and it's really calm, the algae can sort of swim up to the surface and then get blown in if there’s a little bit of breeze that can just push it into the shore,” she said. “So sometimes you do see that kind of concentration effect happening because of that.”
While Prof Burford did say it could also mean there is a problem, she said it’s unlikely, because the Boondall Wetlands is “a pretty clean area”.
Locals warned to stay away
If the pink colouration is due to algae, Professor Burford said it won’t last long, “usually just a few days”, but she’s warning people to stay away because it could be toxic.
“It’s a good idea for people if they see it not to go wading around in it, just in case,” she urged. “It’s hard to say for sure [if it’s toxic] but it’s always a good precautionary principle. It's like any sort of green, slimy stuff you might say. It's not a good idea to go wading around in it.”
She warned that if it is toxic, it could impact the skin.
“You might get some sort of dermatitis or rash or something like that if it has got some toxins in it,” Prof Burford explained. “So if you do come into contact with it, wash it off as soon as you can so you minimise the effect and definitely do not let animals into it or drink from it. That would not be a good thing.”
Yahoo News Australia had reached out to the Department of Environment and Science but hadn't heard back at the time of publication.
Do you have a story tip? Email: email@example.com.
Love Australia's weird and wonderful environment? Get our new weekly newsletter showcasing the week’s best stories.