[Australia] On the largest island in Western Australia’s Recherche Archipelago sits a picture of the surreal.
A bright pink lake called Lake Hillier has entranced both tourists and scientists for years, with the latter speculating that its bubble-gum hue is likely the result of salt-loving algae.
In recent video, SciShow host Hank Green describes extremophiles as ‘some of the weirdest, coolest members of ecosystems here on Earth with adaptations that allow them to live where very few things can.’
These organisms can thrive in extreme environments, including high-salinity lakes like Lake Hillier of Middle Island, Australia.
The pink lake was first covered by SciShow in 2013, spurring the interest of researchers at the eXtreme Microbiome Project.
The scientists launched an investigation to identify the source of Lake Hillier’s rosy colour.
Researchers collected sediment and water from all over the lake to ascertain the algae, archaea, and bacteria that live within.
Among the many microbes collected in the Lake Hillier samples, the researchers found, the algae long thought to be the culprit behind the pink waters.
This algae can also be found in another pink lake, Senegal’s Lake Retba.
D. salina produces pigment compounds called carotenoids, Green explains in the video, helping it to absorb sunlight.
These compounds also give the algae a reddish-pink colouring.
But, D. salina alone isn’t the sole contributor to Lake Hillier’s unique pigmentation, the researchers found.
Scientists with the XMP found other red-coloured microbes, including a few species of archaea, along with a type of bacteria called Salinibacter ruber.
Lake Hillier’s microbiome also revealed some insight on its history, stretching back to the beginning of the 20th century.
Many countries from around the world have pink lakes, including Senegal, Canada, Spain, Australia and Azerbaijan.
Pink lakes are natural phenomena that draw visitors from far and wide, and provide livelihoods to local people.
These natural marvels tend to have a striking colour due to the presence of algae that produces carotenoids, such as Dunaliella salina, a type of halophile green micro-algae especially found in sea salt fields.
In Senegal, Lake Retba, in the Cap Vert peninsula of the country, has such a high concentration of salt – 40 per cent – that is harvested by local people.
The lake is dotted with salt collectors working up to seven hours a day, using long shovels to pile boats high with the mineral.
To protect their skin from the water they rub their skin with Shea butter.
Canada’s Dusty Rose Lake, in British Columbia is pink due to the particulate in the glacial melt waters feeding it.
The surrounding rock is purple/pink in colour; the water feeding the lake is said to have a lavender hue.
In south west Spain, two large salt-water lakes sit adjacent to the city of Torrevieja.
The Salinas de Torrevieja (meaning Salt Pans of Torrevieja) turn pink when sunlight falls on the algae-rich waters.
The lakes are now protected national parks and are a haven for migratory birds, diverse flora and fauna.
Photo: On the largest island in Western Australia’s Recherche Archipelago sits a picture of the surreal. A bright pink lake called Lake Hillier has entranced both tourists and scientists for years, with the latter speculating that its bubble-gum hue is likely the result of salt-loving algae