Lake Tanganyika

Lake Tanganyika is a long, thin lake in Africa.

It is very, very deep. Steep hills rise up from the water. Four countries share it. Fishers go out in boats, and hippos and crocodiles live along the shores.

Lake Tanganyika stretches like a long blue ribbon through the middle of Africa. Britannica measures it at about 660 kilometers long, which makes it the longest freshwater lake in the world, but only 16 to 72 kilometers wide. Its deepest point is 1,436 meters down. Only Lake Baikal, in Russia, is deeper.

Four countries share the lake: Tanzania, the Democratic Republic of the Congo, Burundi and Zambia. The lake itself forms the border between Tanzania and the Democratic Republic of the Congo. For most of its length, steep land rises straight up from the shore. Many rivers flow in, but only one river, the Lukuga, carries water out, and it joins the great Congo River on its way to the Atlantic Ocean.

Britannica gives Lake Tanganyika a length of 660 km, widths of 16 to 72 km, an area of about 32,900 km² and a maximum depth of 1,436 m, second only to Lake Baikal; the European Space Agency gives 676 km and 1,470 m, and a volume of 18,880 km³, which it ranks third in the world after the Caspian and Baikal. Its deepest point lies more than 730 m below sea level, Britannica notes.

The lake forms the boundary between Tanzania and the Democratic Republic of the Congo and parts of the boundaries of Burundi and Zambia with their neighbors. The largest inflows are the Malagarasi, the Ruzizi, which drains Lake Kivu, and the Kalambo, whose Kalambo Falls drop about 215 m over the escarpment near the Zambian frontier. Despite these rivers, the lake is not the center of an extensive drainage area. Its outlet, the Lukuga River on the western shore, flows to the Lualaba and so into the Congo system; Britannica notes that silt and swamp plants sometimes block it.

Lake Tanganyika is full of fish.

About 250 kinds of cichlid fish live here and nowhere else. Small fish called dagaa live there too. Hippos and crocodiles live by the shore. Chimpanzees live in a park beside the lake.

Scientists say about 250 kinds of cichlid fish live in Lake Tanganyika and nowhere else. Many of them are mouthbrooders, carrying their young in their mouths. The European Space Agency, quoting the conservation group IUCN, says the lake holds more than 2,000 species of plants and animals, and over half are found nowhere else.

There are also small, sardine-like fish called dagaa. Britannica says hippos and crocodiles are common along the shores, and that oil palms, trees more typical of West Africa, grow there too. Beside the lake is Gombe Stream National Park, where the scientist Jane Goodall spent many years studying chimpanzees.

Weiss and colleagues (2015, PLoS ONE) describe roughly 250 endemic cichlid species in Lake Tanganyika, which hosts more endemic cichlid genera and more ancient lineages than any other African great lake; they propose a 'melting pot' origin in which several older lineages diversified in ancient rivers and lakes before coming together in today's basin. The European Space Agency, citing IUCN, gives more than 2,000 species in the lake, over half of them endemic. Britannica lists the mouthbrooding Tilapia and the small sardinelike Stolothrissa tanganicae (dagaa) among East African lake fishes.

Life is concentrated in the upper waters, because three-fourths of the volume below is without oxygen. The lake lies on the line dividing the floral regions of eastern and western Africa, so West African oil palms grow on its shores; Britannica adds that hippos and crocodiles abound and bird life is varied. Four protected areas border the lake, ESA notes: Gombe Stream and Mahale Mountains national parks in Tanzania, Nsumbu National Park in Zambia and the Rusizi Natural Reserve in Burundi.

Many people live around the lake.

They catch fish and grow rice by the water. Ships carry people and things from port to port. Long ago, explorers came here looking for the start of the Nile.

Many different peoples live around Lake Tanganyika. Britannica says farmers grow rice and other crops along the shores, and fishing is important. Important ports include Bujumbura in Burundi, Kalemie in the Democratic Republic of the Congo, Mpulungu in Zambia, and Kigoma and Ujiji in Tanzania.

In 1858 two British explorers, Richard Burton and John Hanning Speke, reached Ujiji on the eastern shore while searching for the source of the Nile. They were the first Europeans to visit the lake. In 1871, also at Ujiji, Henry Morton Stanley found the explorer David Livingstone.

Britannica describes the peoples of the eastern shore as predominantly Bantu-speaking, many tracing their origins to the Congo basin, and notes rice and subsistence crops along the shores and a fishery of some significance. The principal ports are Bujumbura (Burundi), Kalemie (Democratic Republic of the Congo), Mpulungu (Zambia), and Ujiji and Kigoma (Tanzania).

The first Europeans to visit the lake were Sir Richard Burton and John Hanning Speke, who reached Ujiji in 1858 during their search for the Nile's source; Speke went on that year to sight Lake Victoria. In 1871 Henry Morton Stanley met David Livingstone at Ujiji. The lake is also studied from space: in September 2006 the European Space Agency's Envisat satellite imaged it at 300 m resolution, and scientists examine its sediments to reconstruct Africa's climatic and environmental history.