7/21/11
Lake Tanganyika and the Tanganyika cichlids
Lake Tanganyika was formed by volcanic activity and shifting of the earth's surface roughly 20 million years ago and is one of the oldest lakes in Africa. It is also the second largest freshwater lake in the world by volume as well as the second deepest, since the lake proceeds down to a depth of 1,470 meters. (The record holder for both volume and dept is Lake Baikal in northern Russia.) If you were to use water from the North Sea to fill up Lake Tanganyika, you would have to use up 50% of the North Sea before you were finished. Its vast water mass has created a stable environment for its inhabitants.
The surface area of Lake Tanganyika is however comparatively small and the lake is only the 7th biggest freshwater lake in the world when it comes to surface area. Lake Tanganyika is a very narrow lake, over 640 km long but with a maximal width of less than 81 km. This doesn’t mean that it is a small lake; it has a surface area of 34,000 square kilometres which is more than the entire country of Belgium.
Lake Tanganyika is one of the African Rift Valley lakes and its territory is shared by three different countries: Burundi, Congo (formerly known as Zaire, Tanzania and Zambia. A long stretch of the lake’s shoreline is quite inaccessible by land since you have to travel over the high mountains to get there. This is a problem when it comes to environmental efforts and conservational projects, since four different governments have to agree and work together if environmental legislation is to be efficient. Roughly 45% of the lake is Congolese territory, while 41% belongs to Tanzania. The water from Lake Tanganyika flows into the Congo River system in central Africa and will ultimately empty into the Atlantic Ocean on the African west coast.
As mentioned above, the immense water mass of Lake Tanganyika has created a very stable environment for its inhabitants. Temperature changes, organic waste, softer rain water etcetera will rapidly be buffered by this enormous lake. This is important to keep in mind when keeping fish from Lake Tanganyika. In certain aspects, they are almost like sea dwelling fish.
Temperature wise, it is not only the large water mass, but another factor that makes Lake Tanganyika so stable - even more stable and homogenous than the ocean in most places. This factor is volcanic activity near the bottom of the lake. The temperature at the bottom of Lake Tanganyika has been measured and turned out to differ no more than 5 degrees F from the surface temperature. The stable temperature has however created sharp changes in oxygen content as you proceed down into the lake. Since there are virtually no temperature changes in Lake Tanganyika, there are no driving forces for vertical currents. Without any vertical currents and water exchange with the surface, the deep soon becomes oxygen depleted. Animals that need oxygen to survive, including of course all the Tanganyika cichlids, can therefore only be found at the top 300 meters of the lake.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment