Lake Hillier

Lake Hillier is a salt lake on Middle Island, part of the Recherche Archipelago off the south coast of Western Australia. It is famous because its water is a bright, bubble-gum pink. The lake is about 600 metres long and 250 metres wide.

Only a thin strip of sand dunes and trees separates the pink water from the deep blue Southern Ocean, which makes it look amazing from the air. The pink colour is permanent and does not fade when the water is put in a glass. Scientists think it comes from tiny salt-loving organisms. The lake is about 600 metres long, so it is small but easy to spot from the sky.

Why is it pink?

The colour is believed to come from an alga called Dunaliella salina, which turns pink in very salty water. Researchers who studied the lake's microbes also found a salt-loving bacterium named Salinibacter ruber and some archaea, another kind of tiny life. The colour stays when the water is scooped into a container. In recent years it has faded a bit because heavy rain diluted the salt, but scientists expect the pink to return as the water level drops.

Matthew Flinders and the rose-coloured lake

The first written record of the lake comes from the explorer Matthew Flinders, who visited Middle Island on 15 January 1802. After climbing the island's highest peak, now called Flinders Peak, he described a small lake of a rose colour. His crew told him the water was so full of salt that it crystallised along the shore, enough to load a ship.

On the globe

The toy globe shows Lake Hillier on Middle Island off Western Australia's south coast. Zoom in to see the pink lake beside the blue sea.