ISSN:
1573-5117
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Lake Tumba is a shallow lake situated in the Congo basin near the Equator. Its area is about 191.250 acres. It gets its waters from different rivers and the surplus is shed into the Congo River, through the Irebu Channel, a little south-west from Coquilhatville. The maximum depth is about 8 meters and the mean depth is 3 to 5 meters (see bathymetric map). The waters are very rich in humic substances, owing to their origin in the forest soils around the lake. Its acid and brown waters are poor in true phyto-and zooplancton. The bottom is hard, made of kaolin and sand, without mud and as a matter of consequence, the bottom fauna is very poor. There is oxygen in the water down to the bottom at any time. The coasts are covered with a thick forest and dead leaves, branches and tree trunks contribute much foodstuff to the waters. This makes it possible for this lake to be rather rich in fish. Sixty six species of fishes are listed for the lake itself and ten species for the swamps or the flooded forest which, at high waters, communicate with the lake. Their food relations are described. As mature fish is very rare in the lake, the hypothesis has been made that, at high waters, the fishes migrate into the flooded forests and swamps around the lake when maturity comes. Breeding would happen in the inundated areas and the fish would return afterwards to the lake. A discussion is given about the origin of lake Tumba. Morphology of the lake, Chemistry of the waters and nearly complete lack of endemic species and of pelagic life point to a recent origin. The hypothesis is advanced that lake Tumba would be the result of the damming of an affluent of the Congo River and not the residue of the slow evaporation of an ancient central african lake.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00142195
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