Why is Lake Hillier Pink?

Why is Lake Hillier Pink?

Situated off the south coast of Western Australia is a pink-colored lake that’s sure to catch the attention of tourists. Called Lake Hillier, you can find it right on the edge of the continent’s Recherche Archipelago, literally just a couple of steps away from the Southern Ocean’s turquoise waters.

Pink lakes certainly aren’t new. In fact, there is one called Lake Retba or Lac Rose near the capital city of Senegal. Even though people have known about Lake Hillier’s existence since the 19th century, scientists are still not sure why the lake possesses such an unusual, weirdly consistent hue.

Below, we address the most commonly asked questions about this unique and interesting pink lake in Australia.

How was Lake Hillier discovered?

female tourist posing in front of a pink lake

Lake Hillier was first discovered in 1802 by a Royal Navy explorer named Mathew Flinders. That January, he alighted the HMS Investigator to go ashore and climbed the highest peak on the island (now named Flinders Peak). This was where he got a glimpse of the magnificent lake, which he described as “a small lake of rose color” in his log.

Flinders also gave the lake its name, in memory of a crew member named William Hillier who died of dysentery while docked at the island.

Why is Lake Hillier pink?

close-up shot of a pink lake in Australia

Since its discovery, the strawberry milkshake-colored lake has left anyone who’s seen it in awe. But in essence, Lake Hillier is actually a pink salt lake. It has a high level of salinity and the color is suspected to be due to saltwater reacting with sodium bicarbonate (baking soda) or certain microorganisms—particularly salt-loving algae (dunaliella salina) and pink bacteria (halobacteria).

Dunaliella salina can tolerate very high salt concentrations (up to 35%). And when these photosynthetic microorganisms generate energy, they do so by using only orange and red frequencies in the light spectrum, which reportedly causes them to produce carotenoid pigments (the same found in carrots) and give off a bubble gum pink hue.

Lake Hillier is also said to contain large amounts of halophilic bacteria and archaea in its salt crusts. These non-algal microorganisms contribute to the lake’s interesting appearance by also producing similar carotenoid pigments within their cell membranes.

Another mystery that sets Lake Hillier apart from other pink lakes is that it remains pink all year round, while other known pink lakes regularly change colors when their temperatures fluctuate. Lake Retba, for example, is pinker during the dry season between November and June.

When you draw closer to Lake Hillier, the color will look more translucent and watery but still very pink. You can even bottle it and it won’t change its color! If anything, it only adds to the curiosity of anybody who wishes to see it in person.

Is it safe to swim in Lake Hillier?

woman floating on top of a pink lake

Given its unique hue and the mystery surrounding it, a lot of people wonder if it’s safe to swim in Lake Hillier. Although it is very salty, similar to diving in the Dead Sea, swimming in Lake Hillier has not been reported to be any danger to those who wish to wade in.

According to the official site for Australia’s pink lake, the colored water is very safe and will not cause any harm to the swimmer or their skin. However, it’s also not possible to personally confirm this as the island that it’s on is currently being protected as a nature reserve and can only be visited under special circumstances, such as research.

Needless to say, while the water is safe to swim in and the microorganisms are harmless, drinking hypersaline water is highly discouraged.

When is the best time to visit Lake Hillier?

aerial shot of Lake Hillier

As previously mentioned, Lake Hillier doesn’t change its color, so you can catch it in all its glory any time of the year. But given that it is closed off to the public, it can be viewed from the air via helicopter rides between October and April or when you book a private tour the rest of the year. After all, what makes it especially wonderful is its contrasting vivid pink color against the surrounding green forestry and blue oceans.

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