of white-boxed area (43 Kb)
mosaic image (772 Kb)
images of Lake Natron|
STS-41B in 1984|
STS-29 in 1989|
STS-93 in 1999|
If Lake Natron
in Africa's Great Rift Valley had a color theme, it would be pink.
The alkali salt crust on the surface of the lake is often colored
red or pink by the salt-loving microorganisms that live there. The
lake is the only breeding area for the 2.5 million lesser
flamingoes that live in the valley. These flamingoes flock along
saline lakes in the region, where they feed on Spirulina platensis,
a blue-green alga with red pigments. Lake Natron is the only breeding
location for lesser flamingoes because its caustic environment is
a barrier against predators trying to reach their nests. The temperatures
in the mud can reach 50 degrees Celsius (122 degrees Fahrenheit),
and depending on recent rainfall, the alkalinity can reach a pH
between 9 and 10.5, which is almost as alkaline as straight ammonia.
Even more amazing than the ability of the flamingoes to live in
these conditions is the fact that an endemic species of fish --
the alkaline tilapia -- thrives in the waters at the edges of the
hot spring inlets. The unique biodiversity of Lake Natron Basin
led Tanzania to name it to the Ramsar List of Wetlands of International
Importance on July 4, 2001.
of photographs of the southern portion of Lake Natron shows the
largest open lagoon area, an island mud flat and a large area of
pink salt crust. The images were taken by astronauts from the International
Space Station on Nov. 11, 2002, using a digital camera with a 400-mm
lens and 2X extender in order to capture the details of the salt
crust structures. The image shows the actual colors viewed by the
astronauts. Each time the lake is photographed, there are differences
in the pattern of its salt crust and the red colors of the blue-green
algae and bacteria on the surface of the crust.
and the mosaic were provided by the Earth Sciences and Image Analysis
Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway
to Astronaut Photography of Earth.