When the Boondall Wetlands in the Moreton Bay region north of Brisbane mysteriously turned a bubblegum shade of pink in October, scientists were stumped. Now, the mystery has been solved.

 

The water in the Boondall Wetlands is normally green, however for the past month it’s more closely resembled a strawberry milkshake. This has drawn crowds eager to catch the rare phenomenon and share it on social media.

Initial theories about why the water had changed colour ranged from pollution to bacteria. But, the speculation is now over with scientists identifying that Rhodovulum microbes are the culprit.

The Department of Environment and Science has never observed this microbe in south-east Queensland before.

 

Unusual pink hues at Boondall Wetlands, Queensland | Photo supplied by the Department of Environment and Science

Rhodo-what?

‘Rhodovulum is associated with pink coastal waters and sulfide-rich environments such as blooming seawater pools and mudflats,’ explains Dr Chris Rinke from the University of Queensland.

‘These bacteria utilise sulfide as an electron donor for growth which helps them survive in these in sulfide-rich environments.’

 

Similar pink hues at Westgate Lake in Melbourne | @a.canvas.of.light

But why did the lake turn pink?

As far as we know, Boondalll Wetlands haven’t turned pink before. So why now?

‘Due to the lack of winter rain, the Boondall Wetlands became saline, which created the perfect environment for Rhodovulum microbes that require hyper-saline conditions,’ Rinke continued.

Essentially, the Rhodovulum microbes reproduce like mad, cause a population boom, and the water turns pink because the microbes are pink in colour. The more microbes there are, the pinker it gets.

 

Want to see a pink lake for yourself?

Pink blooms like this one at Boondall Wetlands actually occur quite commonly in coastal locations around Australia when the right conditions are met. But there are also some lakes that present this colour so often that they’re known for it.

Check out Lake Hillier and Hutt Lagoon in WA, Lake Eyre and Lake Bumbunga in SA, or the Westgate Lake in Melbourne to see some beautifully vibrant hues. Just like the Boondall Wetlands, the salty secret behind the gorgeous colours of these lakes is the high salinity of the water.

 

Header photo by the Department of Environment and Science

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