Tanganyika

Tanganyika: see Tanzania.

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Tanganyika

1. a former state in E Africa: became part of German East Africa in 1884; ceded to Britain as a League of Nations mandate in 1919 and as a UN trust territory in 1946; gained independence in 1961 and united with Zanzibar in 1964 as the United Republic of Tanzania

2. Lake. a lake in central Africa between Tanzania and the Democratic Republic of Congo (formerly Zaïre), bordering also on Burundi and Zambia, in the Great Rift Valley: the longest freshwater lake in the world. Area: 32 893 sq. km (12 700 sq. miles). Length: 676 km (420 miles)

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Tanganyika 

a lake in East Africa, bordering on Zaïre, Tanzania, Zambia, and Burundi. Situated at an elevation of 773 m in a tectonic basin of the Great Rift Valley, Lake Tanganyika is approximately 650 km long and 40 to 80 km wide and occupies an area of 34,000 sq km. It is divided by an underwater sill into two deepwater basins; the maximum depth in the southern part is 1,470 m. Lake Tanganyika is the world’s second deepest lake, after Lake Baikal. The shoreline is predominantly even, with occasional small bays; it is partly elevated and steep and partly low-lying and bordered by a narrow plain.

Lake Tanganyika drains an area of 244,500 sq km. Its main tributaries are the Malagarasi and Ruzizi rivers. Its outlet is through the Lukuga River into the Lualaba River (the name of the upper Congo [Zaïre] River). The average annual influx is 64.8 cu km, including 40.9 cu km (63 percent) from atmospheric precipitation and 23.9 cu km (37 percent) from the rivers. Evaporation accounts for the great majority of water loss (61.2 cu km, or 94.4 percent); only 3.6 cu km, or 5.6 percent of the annual water loss results from water flowing out of the lake.

In the first half of the 19th century, an earthquake or landslide caused the formation of a natural dam in the Lukuga River valley, near the place where the river flowed out of Lake Tanganyika. As a result, Lake Tanganyika became a lake with no outlet, and over the course of several decades its water level gradually rose. In 1878 the dam broke and the water level fell; by the early 20th century the level had become stabilized. During the 20th century there has been a fluctuation of about 4 m in the water level, with an average annual fluctuation of 0.7 m. The lake’s highest levels are recorded in April and May, and the lowest in October and November.

There is turbulence on Lake Tanganyika, caused by the southeasterly trade wind; sometimes seiche is observed. The lake’s water is fresh, but with a high content of magnesium salts. The surface temperature of the water varies during the year from 23.6°-23.8° to 26.5°C; from a depth of 400 m to the bottom there is a constant temperature of approximately 23°C. The stable temperature stratification keeps the water mass from mixing; consequently, only the top layer (to depths of 100–200 m) is oxygen-rich and able to support life.

Approximately 75 percent of Lake Tanganyika’s fauna consists of endemic species, particularly among the fishes, shrimps, ostracods, decapods, copepods, and gastropods. Hippopotamuses, crocodiles, and many types of waterfowl are encountered. There is fishing in the lake; the main commercial fish is the ndagala (dagaa), a member of the family Clupeidae.

Lake Tanganyika is navigable. Ports on the lake include Kigoma, in Tanzania, which is linked by rail with the city of Dar-es-Salaam on the Indian Ocean; Bujumbura, in Burundi; and Kalima, in Zaïre. Lake Tanganyika was discovered in 1858 by the British explorers R. Burton and J. Speke.

REFERENCE

Oleinikov, I. N. “Ozero Tangan’ika: Opyt fiziko-geograficheskoi kharakteristiki.” Strany i narody Vostoka, 1969, fasc. 9. (Contains bibliography.)

I. N. OLEINIKOV