Lake Hillier, located off the coast of Western Australia on Middle Island, is globally renowned for its striking pink color. This unusual hue creates a captivating contrast against the surrounding blue ocean and green foliage.
The Science of Its Pink Hue
The pink color of Lake Hillier is primarily attributed to specific microorganisms thriving in its highly saline environment. The microalga Dunaliella salina is a contributor, producing carotenoid pigments like beta-carotene as protection against intense sunlight and high salt concentrations.
Halophilic bacteria also play a role in the lake’s color. Salinibacter ruber, a dominant salt-loving extremophile, produces red pigments called bacterioruberin. These bacteria are found in the salt crusts and contribute to the water’s pink appearance.
The lake’s extremely high salinity, comparable to the Dead Sea, creates an ideal habitat for these specialized microorganisms. This saline environment limits other organisms, allowing pigment-producing algae and bacteria to flourish. Recent findings suggest bacteria might be the more dominant factor influencing the lake’s permanent pink hue.
Unique Characteristics and Safety
Lake Hillier’s most notable characteristic is the permanence of its pink color, which does not fade even when collected in a container. This distinguishes it from many other pink lakes, which exhibit varying shades based on environmental conditions.
Despite its appearance, the lake’s waters are considered safe for humans. The high salt content, while creating an extreme environment for most aquatic life, poses no adverse effects to human skin. Access to Lake Hillier is restricted due to its protected status as an A-class nature reserve.
These restrictions primarily preserve the lake’s ecosystem. Most visitors observe Lake Hillier from a distance, typically from aerial views. Its safety for human interaction, combined with its protected status, ensures its continued preservation.
Geographical Context and Accessibility
Lake Hillier is situated on Middle Island, the largest island in the Recherche Archipelago. This archipelago lies off Western Australia’s south coast, approximately 150 kilometers offshore from Esperance. The lake measures about 600 meters in length and 250 meters in width.
Due to Middle Island’s remote location, Lake Hillier is not easily accessible by road. Visitors typically view the lake through scenic flights departing from Esperance Airport. These aerial tours offer comprehensive views, showcasing the lake’s pink waters against surrounding eucalyptus and paperbark woodlands and the deep blue Southern Ocean. Boat tours also provide an alternative viewing option.
Other Pink Lakes Worldwide
Lake Hillier is not the only pink lake globally. Many others exist, each with specific contributing factors to its coloration. Lake Retba, also known as Lac Rose, in Senegal, is one example. Its pink hue is largely due to Dunaliella salina algae thriving in high salt content, with color particularly intense during the dry season.
Las Coloradas in Mexico’s Yucatan Peninsula includes pink lagoons within a salt production area. Their vibrant pink is caused by red algae, brine shrimp, and halophilic bacteria flourishing in highly saline, shallow waters. The concentration of these organisms intensifies as water evaporates.
Australia also hosts several other pink lakes, such as Hutt Lagoon and the Pink Lake near Esperance. Hutt Lagoon’s color is attributed to Dunaliella salina producing beta-carotene. However, the Pink Lake near Esperance has not been consistently pink recently due to salinity changes. These examples show that while high salinity and microorganisms are common, exact conditions vary, leading to diverse expressions of pink in these unique aquatic environments.