Why Australia’s famous pink lake lost its colour

For years, one image sold a whole corner of Australia: a bubble-gum pink lake in the middle of a green island, ringed by blue sea. It looked fake, but it wasn’t. According to a researcher who studied it, it had looked like that for centuries.

Fly over the island today and you’ll see something else. After a massive rainstorm in April 2022, the water turned the colour of tea. Western Australia’s own tourism site now warns that Lake Hillier “is no longer the bubble pink it used to be” and that its colour can’t be guaranteed. Even the photo on this post isn’t of Hillier: it’s Hutt Lagoon, another pink lake on the state’s west coast.

What made the lake pink

Lake Hillier sits on Middle Island, the largest island in the Recherche Archipelago, about 130 kilometres east of the town of Esperance on Western Australia’s south coast. It’s around 600 metres wide and shaped like a footprint. Its water is ten times saltier than the sea.

For a long time, the colour was put down to an alga, Dunaliella salina, which lives in very salty water and produces beta carotene, the same pigment found in carrots. In 2015, though, molecular biologist Ken McGrath took part in a project that sequenced the DNA of everything living in the lake, and found a different answer. The alga was there, but only just: less than 0.1% of the DNA recovered. More than 20% came from a bacterium, Salinibacter ruber, which produces a pigment called bacterioruberin, much pinker than beta carotene.

McGrath brought a bottle of lake water home and left it on his desk by a window. The algae, which swim toward light, gathered on the sunny side of the bottle. The rest of the water stayed pink. It was proof, right there on his desk, that the colour came from the bacterium.

The storm that diluted the salt

The colour depends on one extreme condition: a lot of salt. In April 2022, a huge storm off the coast dumped water on the area. According to Esperance-based environmental scientist Tilo Massenbauer, nutrients from rotting vegetation washed into the lake, and the salt was diluted below the level the pink microbes need to bloom.

Massenbauer believes climate change played a part. In his view, the island is a pristine environment, and what affects it most are extreme events, heat, downpours and floods, which are becoming more common.

Hillier isn’t the first pink lake in the area to lose its colour. Near Esperance there’s one literally called Pink Lake. In the 1980s it was so famous that the town had a Pink Lake drive-in, a Pink Lake Road and a Pink Lake butcher. Since the late 1990s it hasn’t been pink at all, after years of salt harvesting. And it’s not just Western Australia: a salt lake near the centre of Melbourne that used to turn pink in hot, dry spells has been dark green since 2019, according to Parks Victoria.

Australia has hundreds of pink lakes because of its geology. According to Massenbauer, saline water tables sit beneath them, and a drying climate and millions of years of stable hydrology created the conditions for these microbes to evolve. McGrath suspects Salinibacter ruber is behind all pink lakes, not just Hillier, but notes that bacteria are harder to detect than algae.

Will the pink come back?

For Hillier, scientists are hopeful. As the water evaporates and the level drops, the salt should climb back to ten times seawater, and the bacterium should bloom again. “The tea colours will disperse and be overtaken by the bubble-gum pink,” Massenbauer said in 2025. “But when is anyone’s guess.”

For Pink Lake, there’s a project to restore the colour by pumping salt brine from another nearby lake. With funding, Massenbauer estimates the change could happen within about five years.

Planning a visit

• Check the colour before booking a scenic flight. Western Australia’s tourism site warns the pink isn’t guaranteed.
• Hillier has always been seen from the air, on flights from Esperance, and at least one local operator has stopped offering them.
• If a pink lake is the goal, look at others in Western Australia, such as Hutt Lagoon in the photo, and check recent photos before you go.

A pink lake depends on a delicate balance of salt, sun and rain. In Iceland, a similar shift in climate brought the country’s first-ever mosquitoes. In Australia, it washed away a colour.

Sources

• Lake Hillier, Tourism Western Australia: location, size, shape and the warning that the colour isn’t guaranteed.
• Why Australia has so many pink lakes — and why some of them are losing their colour, ABC News, 2022: salinity, Ken McGrath’s study, Salinibacter ruber, the bottle experiment and Esperance’s Pink Lake.
• WA’s Lake Hillier loses iconic pink colour, but there is strong hope for its recovery, ABC News, 2025: the 2022 storm, Tilo Massenbauer’s explanation, the outlook for recovery and the end of one scenic flight.