Lake Natron, located in Tanzania, has gained widespread attention for its supposed ability to “turn animals to stone.” This intriguing phenomenon, often depicted in striking photographs, sparks curiosity about the lake’s unique properties. The reality behind Lake Natron’s effects is a fascinating interplay of extreme chemistry and natural preservation. This distinctive environment, though harsh, reveals remarkable adaptations and provides a glimpse into the raw power of geological processes.
Lake Natron’s Unique Chemistry
Lake Natron is an extreme aquatic environment, characterized by its high alkalinity, significant salt concentration, and elevated temperatures. The lake’s pH levels frequently exceed 10 and can reach values greater than 12, making its water comparable in causticity to ammonia or household bleach. This extreme alkalinity stems from the surrounding volcanic geology, particularly the nearby Ol Doinyo Lengai volcano, which produces rare natrocarbonatite lava rich in sodium and potassium carbonates. These minerals wash into the lake from the surrounding hills and enter through mineral-rich hot springs.
High levels of evaporation, typical of the arid region, further concentrate the salts and minerals, including natron (sodium carbonate decahydrate) and trona (sodium sesquicarbonate dihydrate). The lake’s shallow depth, often less than three meters, contributes to its high temperatures, which can frequently exceed 40 °C (104 °F) and reach as high as 60 °C (140 °F) during warmer periods. This combination of high pH, extreme salinity, and heat creates a caustic brine that is inhospitable to most forms of life.
How Calcification Occurs
The “stone” appearance of animals found at Lake Natron is not true petrification, but a process of calcification and preservation. When animals perish in the lake’s highly alkaline, mineral-rich waters, sodium carbonate and other salts interact with their organic tissues. This deposits minerals onto and into the body, hardening and preserving the remains.
The high sodium carbonate concentration acts as a natural mummifying agent, similar to how ancient Egyptians used natron. The water absorbs moisture and fat from the carcass, preventing decomposition and leaving a desiccated, hardened form. This mineral deposition creates a statue-like or mummified appearance, often with fine details like hair intact.
Wildlife Encounters with Lake Natron
Lake Natron’s unique environment attracts certain wildlife while proving deadly to others. The lake is the primary breeding ground for East Africa’s lesser flamingos, numbering in the millions. These birds have adapted to the harsh conditions, with tough leg skin to withstand caustic water and specialized salt glands to excrete excess salt. They build nests on seasonal islands, where extreme conditions deter most predators, providing a safe haven for their young.
However, other animals, particularly birds, can fall victim to the lake’s deceptive surface. The highly reflective water disorients flying creatures, causing them to crash into the lake. Once in the water, the caustic properties quickly prove fatal. Photographer Nick Brandt highlighted this phenomenon with his images of calcified birds and bats found along the shoreline.
Is Lake Natron Dangerous to Humans?
Lake Natron poses significant risks to humans due to its extreme chemical properties and high temperatures. Direct contact with the water can cause severe skin and eye irritation or chemical burns from its high alkalinity. The water’s temperature, often exceeding 40 °C, further exacerbates these effects, leading to thermal burns or heat-related injuries.
While no human deaths are directly attributed to the lake “turning people to stone,” prolonged exposure or immersion is highly dangerous. If a human body were to drown and remain in the lake, the high salt content and alkalinity could prevent decomposition, leading to preservation similar to mummification. Visitors are advised to observe the lake from a distance, as even the air can contain ammonia, causing irritation to eyes, throat, and lungs.