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  Image: Geographic Location Direction Photo #: ISS012-E-20456 Date: Mar. 2006
Geographic Region: TANZANIA

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  View Low-Resolution Image  
  Lake Natron, Tanzania

This image of the southern half of Lake Natron shows the characteristic colors of lakes where very high evaporation occurs. As water evaporates during the dry season, salinity levels increase to the point that salt-loving organisms begin to thrive. Salt-loving organisms include some cyanobacteria, tiny bacteria that grow in water and make their own food with photosynthesis as plants do. The red pigment in the cyanobacteria produce the deep reds of the open water of the lake, and orange colors of the shallow parts of the lake. In the inset, numerous, near-white salt-crust "rafts" pepper the shallowest parts of the lake. Bright white clouds are also visible just right of center and on the top margin. The lake is quite shallow, less than three meters deep, and varies in width depending on its water level. In this image, the lake is about ten kilometers wide. Tan lines run north-south, parallel to the eastern lake shore on the right side of the image. Called fault scarps, these lines are the steep, step-like slopes created when the land was pushed up during earthquakes along faults in the Great Rift Valley system of East Africa. Also part of the rift system is Gelai Volcano, the slopes of which appear in the lower right corner.

The four main environments typical of salt (alkali) lakes in East Africa are illustrated well in the image. The delta of one of two dominant streams that flow into the lake (top left) shows where fresh water enters the basin. Open water, salt flats with salt crusts, and mud flats succeed each other in a west-to-east progression towards the shallow side of the lake. Vast numbers of the pink Lesser Flamingo (2.5 million by one calculation) rely on Lake Natron as their only breeding ground in the Rift Valley. The flamingoes feed on the nutrient-rich cyanobacteria. As salinity increases, so do the number of cyanobacteria, and the lake can support more nests. Threats to the salinity balance from increased fresh water influxes will come from projected logging in Natron watersheds and a planned hydroelectric power plant. Although development plans include construction of a dike at the north end of the lake to contain the fresh water, the threat of dilution to this breeding ground may still be serious. The government of Tanzania recognized both the threat and the uniqueness of the habitat in 2001, when it placed Lake Natron on the list of Wetlands of International Importance as part of the Ramsar Convention, an intergovernmental treaty meant to protect wetlands.

Images of Lake Natron from four other dates can be seen on the Earth Observatory and associated links. The area and shape of the open water and salt-raft zones depend on lake levels, controlled mainly by local rainfall and evaporation. Patterns of these sub-environments therefore appear different across the span of a few years.

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Images: All Available Images Low-Resolution 265k
Mission: ISS012  
Roll - Frame: E - 20456
Geographical Name: TANZANIA  
Center Lat x Lon: 2.4S x 36.0E
Film Exposure:   N=Normal exposure, U=Under exposed, O=Over exposed, F=out of Focus
Percentage of Cloud Cover-CLDP: 10
Camera: E4
Camera Tilt: 32   LO=Low Oblique, HO=High Oblique, NV=Near Vertical
Camera Focal Length: 400  
Nadir to Photo Center Direction: SW   The direction from the nadir to the center point, N=North, S=South, E=East, W=West
Stereo?:   Y=Yes there is an adjacent picture of the same area, N=No there isn't
Orbit Number: 1835  
Date: 20060315   YYYYMMDD
Time: 064117   GMT HHMMSS
Nadir Lat: 0.8S  
Latitude of suborbital point of spacecraft
Nadir Lon: 37.0E  
Longitude of suborbital point of spacecraft
Sun Azimuth: 92   Clockwise angle in degrees from north to the sun measured at the nadir point
Space Craft Altitude: 184   nautical miles
Sun Elevation: 45   Angle in degrees between the horizon and the sun, measured at the nadir point
Water Views: DELTA, LAKE  
Atmosphere Views:  
Man Made Views:  
City Views:  
Photo is not associated with any sequences

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