Put it this way, you wouldn’t want to go swimming in Tanzania’s Lake Natron, unless you were an alkaline tilapia fish, which is adapted to its otherwise inhospitable waters, says Helen Pitcher.
Is there really a lake that turns animals into stone?
Lake Natron is a shallow, hot, highly alkaline body of water located in northern Tanzania, near the border with Kenya. It is said to be the Medusa of the natural world. A brief encounter, some believe, is enough to turn a living animal into a statue. Only it’s not quite that simple.
The lake hit the headlines in 2013, when photographer Nick Brandt published a book of photographs of animals that had died on the lake’s shore and then been preserved by its waters. He picked up the carcasses and placed them in life-like poses. A petrified fruit bat clutches a branch. A ghoulish flamingo glides on the glassy water.
But these animals are not made of stone. Feathers and flesh can still be seen. Instead, the carcasses have been desiccated.
The transformation occurs because of the lake’s unusual properties. The water contains high levels of a naturally occurring mineral called natron, which is a mixture of sodium carbonate decahydrate (a type of soda ash) and various other salts.
Situated in a hot, arid part of the world, the lake also has no natural outlet. This means that as the water evaporates, the minerals become more concentrated, making it more and more alkaline. The lake’s pH tends to hover around a value of 10, which is the same as milk of magnesia, but has been known to reach 12, which is the same as household bleach.
For specialist organisms that have evolved to live there, such as the lesser flamingo, a couple of species of tilapia and the salt-loving cyanobacteria that give the water its blood red hue, this presents no problem. But if an animal dies near the lake, and then stews in its waters, the process of mummification begins.
Indeed, the Egyptians used the very same chemical to preserve their dead. Natron absorbs moisture and fat. The animal’s body becomes dehydrated, leaving behind a Tim Burton-caricature of the animal that once was. So, not exactly stone, but a statue, nevertheless.
For non-specialist organisms that have not evolved to live there, like us, a quick dip would not be fatal, but it could cause serious burns. So, follow my advice and stick to your local pool!
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Main image: Lake Natron © Getty
