Lake Tanganyika

Geography

The lake Tanganyika covers a surface of 32.900 km ² (roughly same surface as the Belgium) and is stretched on 677 km along the border of the Tanzania (in the east) and of the Democratic republic of Congo (in the west); its northern end separates these two countries from the Burundi, its end southern separates them from the Zambia. One finds in the west (Congolese side), the Monts Mitumba.

The lake Tanganyika, in figures:

Length : 677 km; the the longest lake of the world (distance separating Lille from Montélimar)
average Width : 50 km (22 to 80 km)
maximum Depth : 1.433 m (642 m under the sea level), the second deepest lake in the world (after the Lake Baïkal)
Shores : 2.500 km

Water of these areas bordering comes to accumulate there. The lake Tanganyika now forms part of the hydraulic basin of the river Congo. It flows there by its Exutoire, the Lukuga (until in 1878 this river was thrown in the lake, but movements Tectonique S, and especially the rise of the level of water, reversed the direction of them towards the Congo river).

The Bassin draining lake Tanganyika covers a surface of 250.000 km ², that is to say the equivalent of half of the surface of France. The principal rivers which feed it out of water are the Malagarazi, the Rusizi, the Ifume, the Lufubu and the Lunangwa which pour 24 km ³ there water per annum; the rains, as for them, pour 41 km ³ per year of them.

Geology

The lake Tanganyika is located in the East-African Rift. 6000 m of Sédiment S Lac ustres are accumulated at the bottom of the lake.

The composition of the shore is distributed as follows:

Sand: 31%
Rock S: 43% intermediate
(rocks and sands): 21%
Marsh: 5%

Tectonics - Geothermics

The situation of the lake, in fact a Tectonic place of activities S remarkable, first of all total depth of the Fault at this place, which rises to approximately 7000 m; level of water at the sedimentary bottom. the Sédimentation on million years filled an enormous volume, oil research made it possible to discover there a deposit worked by Congo. The Géothermie is visible in the northern part on Congolese bank, on the Péninsule of the Ubwari (course Banza) like in the area of Kalundu/Pemba.

vent S releasing from water charged with minerals and reaching a temperature of 180° C were discovered there, with depths varying from 5 to 40 m (see bond forwarding Tanganydro '96). The activity also lets filter gazs in certain portions of coasts rock with Pemba, in the form of chains of more or less fine and regular bubbles.

December 5th, 2005 a violent one Seism, of a Magnitude of 7.5 on the open scales of Richter, caused damage and makes some victims in Congo. Its epicentre was located under the lake at a 10 km depth (futura-sciences.com source).

Water

The lake is known for the exceptional limpidity of its water, this one allowing a visibility reaching the 25 meters. The water of the lake Tanganyika is of an extreme mineral richness, and its parameters are very particular. Of a conductivity of approximately 609-620µS, its pH is of 9.5 on the surface and 8.6 with - 1300 Mr. TAC is of 12-19 low value taking into consideration proportion of salts:

principal salts according to Dr. Kufferath member of the Belgian hydrobiologic mission of 1946-47: Values in milligram/liter:

Carbonate of sodium: NA₂CO₃ =125 (anhydrous)
Chloride of potassium: KCl = 59
Nitrate of KNO₃ potassium = 0,5
Carbonate of Li₂CO₃ lithium = 4
Carbonate of CaCO₃ calcium = 30
Carbonate of MgCO₃ magnesium = 144
Sulfate of aluminum Al₂ (SO₄) ₃18H₂O = 5
Sulfate of K₂SO₄ potassium = 4
Sulfate of ferric NA₂SO₄ sodium = 1
Chloride FeCl₃6H₂O = 0,5
Phosphate of NA₃PO₄H₂O sodium = 0,4
Silicate of NA₂SiO₃ sodium = 13,5

Beyond the two hundred meters of depth, the life of higher beings is impossible, the absence of oxygen, replaced by hydrogen sulfide, allows maintains it only anaerobic bacteria (sulfato-reducing). The winds prevailing during the southern summer (coming from south-east) causes increase of this anoxyque zone. The alive fish on these sectors have of another choice only to flee, or die per thousands.

Hydrobiologic exploration

During the years 1946 and 1947 Dr. max Poll organizes a forwarding on the lake. Its goal is to collect a maximum of various data. A boat (the Baron Dhanis ) is especially chartered for this purpose. Bathymetric surveys and readings of the funds are taken. Fishings with the Trawl, with the seine, the gill net, with the line are organized of day like night to collect fish. Fluctuations of the level of water, temperature variations, the chemistry of the lake (variation of minerality, pH, Conductivity), invertebrates, insects watery, the plankton (phyto and zoo), batrachians and reptiles: an enormous sum of data is indexed. Specimens are classified and described it-there-have place.

Most of current knowledge on the lake Tanganyika comes us from this titanic work. For example: after sorting on the spot, the collection of the cichlidae, preserved for a systematic study in Belgium (royal Museum of central Africa with Tervuren), included/understood approximately 27.000 specimens, an ichtyologic enrichment some.

IV volumes and not less than 9 booklets are appeared following this forwarding.

the authors are:

E. Leloup: Invertebrate S, Lamellibranche S, Gastropodous S, Jellyfish S.
A. Capart: Surveys and bathymetric chart , geographical environment and Geophysical, Crustacean S, décapode S, Brachyura.
J. Kufferath: The biochemical medium.
L. Van Meel: Vegetable medium, the Phytoplankton.
S. Prudhoue: Trematoda, Gestoda and Acanthocephala.
P. Basilewski: Coleoptera, Garabidae.
A.W. Lacourt: Bryozoaire S.
K. Lindberg: Cyclopide S (shellfish, Copépode S).
G.F. of Witte: Amphibian S and Reptile S.
V. Lallemand: Hemiptera, Homoptera.
H. Synave: Hemyptera, Homoptera.
A. Janssens: Coleoptera, Lamellicorna.
R.D. Wood: Characeae.
G. Vanden Bergen: Hepiticae.
F. Demaret: Pteridophyta.
A. Lawalree: Compositae, Leeaceae, Limnecaea and Viticaeae.

Fauna and flora

Plus of 1200 animal species and vegetable was listed on the lake (Coulter 1991), of the Diatomée to the Hippopotame.

Watery

The lake Tanganyika shelters a particularly rich fauna; the fish are mainly represented by the family of the Cichlidé S ( Neolamprologus, Paleolamprologus, Altolamprologus, Xenotilapia, Julidochromis, Telmatochromis, Tropheus, Petrochromis … For most known), very appreciated aquarist S. One counts more than 300 S pertaining to this family, including one great part is only in this place (endemic species ). Non-cichlidés for their part approximately 150 species count, including two S of an particular importance:

Stolothrissa and Limnothrissa differently called " Ndagala "(vern.) - fish of the family of the Clupeidae (Sardine, Herring, Alose, Tarpon…) -

Besides these Sardine S represents a considerable contribution in Protéine S for the people living on an immense territory around the lake.

the Cobra of water ( Boulengerina annulata stormsi , endemic species) is a Reptile adapted to the subaqueous life, as the sea-snakes of the Récif S coral S. the final part of the body is compressed laterally in order to facilitate the stroke. Young person it nourishes readily alive Neolamprologus in the shells of Neothauma tanganicense (endemic snails of the lake Tanganyika), adult it does not hesitate to attack preys much more imposing…

Richness of its fauna in fact a place of experiments and examinations on the evolution and the Speciation. Scientists of various nationalities (Congo, Tanzania, Burundi, Zambia, Japan, Austria, Switzerland, Belgium…) there work regularly. This lake is an immense alive laboratory on the Biodiversité.

Around the lake

Species living around the lake:

Crocodile S: Crocodilus niloticus and Crocodylus cataphractus
Hippopotamus S
various fishing birds: Héron S, eagle S, Sea eagle S, Anhinga, martins, etc

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