Lake Natron in Arusha, Northern Tanzania is a salt lake i.e water goes in but never comes out except through evaporation. Harsh condition surround this water body: its high alkalinity between pH 9 and pH 10.5, and its temperature which can reach almost 60 ºC. The Lake is home to only few creatures: a single fish species (Alcolapia latilabris), some algae and a colony of flamingos that feeds on the algae and breeds on the shore.
The Lake takes its name from natron, a naturally occurring compound made mainly of sodium carbonate, with a bit of baking soda (sodium bicarbonate) thrown in. Here, this has come from volcanic ash, accumulated from the Great Rift valley. It is so caustic it can burn the skin and eyes of animals that aren’t adapted to it. And deposits of sodium carbonate — which was once used in Egyptian mummification — also acts as a fantastic type of preservative for those animals unlucky enough to die in the waters of Lake Natron.
Animals that become immersed in the water die and are calcified. That explains the whole process as to how the animals became stones instead of decaying into organic matter.
Photographer Nick Brandt, who has a long association with East Africa – he directed the video for Michael Jackson’s Earth Song there in 1995 – took a detour from his usual work when he discovered perfectly preserved birds and bats on the shoreline. “I could not help but photograph them,” he says. “No one knows for certain exactly how they die, but it appears that the extreme reflective nature of the lake’s surface confuses them, and like birds crashing into plate glass windows, they crash into the lake.”
Over the course of about three weeks, Brandt worked with locals to collect some of the most finely-preserved specimens. “They thought I was absolutely insane—some crazy white guy, coming along offering money for people to basically go on a treasure hunt around the lake for dead birds,” he says. “When, one time, someone showed up with an entire, well-preserved fish eagle, it was extraordinary.”
Just coming into contact with the water was dangerous. “It’s so caustic, that even if you’ve got the tiniest cut, it’s very painful,” he says. “Nobody would ever swim in this—it’d be complete madness.”
For the series of photos, titled “The Calcified” and featured in September 2013’s issue of New Scientist, Brandt posed the carcasses in life-like positions. “But the bodies themselves are exactly the way the birds were found,” he insists. “All I did was position them on the branches, feeding them through their stiff talons.”