Australia has a lake that is bubblegum pink!

Australia, known for its unique geological wonders, boasts a series of pink lakes that, despite their inviting appearance, are among the saltiest bodies of water globally. One such renowned lake is Lake Hillier, situated off the southern coast of Western Australia on Middle Island, discovered by British explorer Matthew Flinders in 1802.

The Discovery and Salty Secrets

Flinders, while climbing the island’s highest peak, stumbled upon a “rose-coloured” lake, later identified as saline as the Dead Sea. In a surprising turn, Flinders utilised this opportunity to replenish his ship’s salt stores.

The Puzzling Pink Phenomenon

The mysterious pink colour of Lake Hillier has long intrigued scientists. A team from the eXtreme Microbiome Project (XMP) delved into the enigma in 2015. Genetic information collected from sediment and water samples hinted at extremophiles, organisms thriving in solid salt environments, as potential culprits.

Unveiling the Culprits

The analysis revealed around 10 species of salt-loving bacteria, archaea, and various Dunaliella algae. Notably, these organisms exhibited shades of pink, red, or salmon, implicating them in the lake’s unusual coloration. Surprisingly, 33 per cent of the DNA sequencing reads matched a single bacterium species — Salinibacter ruber.

The True Artist: Bacterioruberin

Contrary to the assumption that micro algae caused the colour, the dominant bacterium, Salinibacter ruber, produces a pigment called bacterioruberin. This pigment, spread across the entire bacterial cell, facilitates light harvesting for energy. Consequently, when beholding the lake, the predominant pink hue is attributed to these bacteria rather than algae.

Beyond Lake Hillier

Australia boasts more pink wonders, with four pink lakes in Victoria’s Murray-Sunset National Park and Hutt Lagoon between Geraldton and Kalbarri in Western Australia. This natural spectacle isn’t confined to Australia, extending to Lake Retba in Senegal and Dusty Rose Lake in Canada.

The Shifting Palette

The vibrant pink of these lakes isn’t constant; it fluctuates with seasons, cloud cover, and time of day. Overcast days, post-rain nutrient influx, and mid-morning to sundown periods enhance the lakes’ colour spectrum, ranging from bubblegum pink to lilac purple.

The Unfolding Mystery

The XMP study’s upcoming publication promises deeper insights into the microbial intricacies of Lake Hillier. Will this captivating pink phenomenon endure, or could it evolve into a different palette in the future? The mystery continues, inviting curious minds to delve into the kaleidoscopic world of Australia’s captivating pink lakes.