Every Birdy Must Get Stoned
Gizmodo has a fascinating and mildly creepy story about Tanzania’s Lake Natron titled “Any Animal That Touches This Lethal Lake Turns to Stone.” It features the haunting black and white photos of Nick Brandt, who placed the calcified carcasses of dead fauna in “living” poses above the alkaline salt lake that was the likely cause of their demise. The whole gallery’s got a very “Weeping Angels" vibe to it, eh?
There’s just one catch. Lake Natron shouldn’t really be called a “lethal lake”, because not every living thing that touches it turns to stone. But it is one of the most interesting bodies of water on this here planet, and a very important one, if you happen a flamingo.
Lake Natron is fed from underground hot springs, which keep its temperature near 50-60˚C. The shallow lake also has an extremely high pH, approaching that of an ammonia solution (pH 10-11). This is because of the high levels of sodium carbonate and sodium bicarbonate that are dissolved in its sweltering waters, along with a host of other mineral salts.
It’s those mineral salts that give the lake its name (“natron" is another name for a mix of soda ash and other minerals) and its rather lethal reputation. Most animals know that it’s a good idea to avoid Natron’s caustic waters, on account of how bathing in ammonia is discouraged by 10 out of 10 dermatologists. Fail to heed that warning? Brandt’s photos show the consequence.
But as we have seen so many times, no matter how inhospitable a place on Earth may seem, Mother Nature operates strictly under what I call the Ian Malcolm Principle:
Numerous salt-loving algae call Lake Natron home, their pink and red hues staining the serene saline slough a shade of reddish orange:
This color (let’s call it “roseblood”) is common in salt lakes around the world, perhaps most famously in Australia’s Hutt Lagoon, which glows Pepto-Bismol pink thanks to a microbe named Dunaliella salina:
But little pink microbial aliens aren’t the only biology that Lake Natron is host to. They attract a much larger form of life, one that shares the pink hue of its smallest residents: The lesser flamingo (Phoenicopterus minor):
Lesser flamingos feed on salt-loving pink algae, spirulina and other halophiles, filtering food as small as two hundredths of an inch in diameter using its unique filter-like beak. And like Goose (from Top Gun, not the bird), they do it while inverted. The skin on the flamingos’ legs has adapted specially to resist burns from this high pH water. It’s one of the more basic tales of evolution (puns!), if you think about it.
Lake Natron’s waters are so inhospitable to other animals (as Brandt’s photos demonstrate), that lesser flamingos have sort of cornered the real estate market. It’s their primary breeding ground. That means the future of their species literally depends on this place. Good thing they’ve got it all to themselves!
Except that they might not. Not for much longer, anyway. A few members of our own species see money in Lake Natron’s mineral deposits and want to set up industrial plants to extract them from the water. Tanzania’s government is pushing hard to build factories there. And that doesn’t even begin to include the effects that a changing climate could have on Lake Natron, flooding its delicate balance with excess rain, or drying it up completely.
It’s painfully ironic that the very chemistry that makes Lake Natron such a perfect home for the lesser flamingo, those same alkaline salts that have directed their evolution and the history of their whole species, could be the cause of the bird’s demise. If we aren’t careful, Brandt’s photos might foretell the future of one of the one animal that breathes life into this deadly lake.
(painting by C.G. Finch-Davies)