بحيرات وادي الفالق

Coordinates: 3°00′N 36°20′E / 3.000°N 36.333°E / 3.000; 36.333
(تم التحويل من Rift Valley lakes)
"Rift Lake" redirects here. For rift lakes formed by faults within a rift zone, see rift lake.
Rift Valley lakes
Rift Valley lakes
Lake Nakuru flamingos.jpg
Greater and lesser flamingos flock to Lake Nakuru in Kenya
الموقعEast Africa
الإحداثيات3°00′N 36°20′E / 3.000°N 36.333°E / 3.000; 36.333
النوعSeries of lakes
Map of larger region that the lakes are in, including the so-called Great Rift Valley.
View over Lake Turkana

The Rift Valley lakes are a series of lakes in the East African Rift valley that runs through eastern Africa from Ethiopia in the north to Malawi in the south, and includes the African Great Lakes in the south. These include some of the world's oldest lakes, deepest lakes, largest lakes by area, and largest lakes by volume. Many are freshwater ecoregions of great biodiversity, while others are alkaline "soda lakes" supporting highly specialised organisms.

The Rift Valley lakes are well known for the evolution of at least 800 cichlid fish species that live in their waters. More species are expected to be discovered.[1]

The World Wide Fund for Nature has designated these lakes as one of its Global 200 priority ecoregions for conservation.[بحاجة لمصدر]

الجيولوجيا

Lake Malawi and Lake Tanganyika have formed in the various valleys of the East African Rift zone. Lake Kivu's "still waters ... hide another face: dissolved within are billions of cubic meters of flammable methane and more still of carbon dioxide, the result of volcanic gases seeping in."[2]

المنتزه الوطني لبحيرات وادي الفالق الإثيوپية

Ethiopia central lakes.jpg

The Ethiopian Rift Valley lakes are the northernmost of the African Rift Valley lakes. In central Ethiopia, the Main Ethiopian Rift, also known as the Great Rift Valley, splits the Ethiopian highlands into northern and southern halves, and the Ethiopian Rift Valley lakes occupy the floor of the rift valley between the two highlands. Most of the Ethiopian Rift Valley lakes do not have an outlet, and most are alkaline. Although the Ethiopian Rift Valley lakes are of great importance to Ethiopia's economy, as well as being essential to the survival of the local people, there were no intensive and extensive limnological studies undertaken of these lakes until recently.[3]

البحيرات الكبيرة هي

  • Lake Abaya (areal extent 1،162 متر كيلومربع (449 sq mi), elevation 1،285 متر (4،216 ft), maximum depth 13.1 متر (43 ft)), the largest Ethiopian Rift Valley lake by surface area
  • Lake Chamo (areal extent 551 متر كيلومربع (213 sq mi), elevation 1،235 متر (4،052 ft), maximum depth 14 متر (46 ft))
  • Lake Zway or Dambal (areal extent 485 متر كيلومربع (187 sq mi), elevation 1،636 متر (5،367 ft), maximum depth 8.9 متر (29 ft))
  • Lake Shala (areal extent 329 متر كيلومربع (127 sq mi), elevation 1،558 متر (5،112 ft), maximum depth 266 متر (873 ft)), the deepest Ethiopian Rift Valley lake and the largest by water volume
  • Koka Reservoir (areal extent 250 متر كيلومربع (97 sq mi), elevation 1،590 متر (5،220 ft), maximum depth not listed)
  • Lake Langano (areal extent 230 متر كيلومربع (89 sq mi), elevation 1،585 متر (5،200 ft), maximum depth 46 متر (151 ft))
  • Lake Abijatta (areal extent 205 متر كيلومربع (79 sq mi), elevation 1،573 متر (5،161 ft), maximum depth 14 متر (46 ft))
  • Lake Awasa (areal extent 129 متر كيلومربع (50 sq mi), elevation 1،708 متر (5،604 ft), maximum depth 10 متر (33 ft))

Lake Tana, the source of the Blue Nile, lies in the Ethiopian highlands north of the Rift Valley; however, it is not a Rift Valley lake.[4]

بحيرات وادي الفالق الشرقية

بحيرة ناترون

South of the Ethiopian highlands, the rift valley splits into two major troughs. The Eastern Rift is home to the Kenyan Rift Valley lakes, while most of the Central African Rift Valley lakes lie in the Western Rift. This area includes the Gregory Rift in Kenya and Tanzania.

كينيا

The Kenyan section of the Rift Valley is home to eight lakes, of which three are freshwater and the rest alkaline. Of the latter, the shallow soda lakes of the Eastern Rift Valley have crystallised salt turning the shores white and are famous for the large flocks of flamingo that feed on crustaceans.

  • Lake Baringo: second largest of the Kenyan Rift Valley lakes.
    • 130 متر كيلومربع (50 sq mi), elevation 970 متر (3،180 ft), freshwater
  • Lake Bogoria: shallow soda lake, a national preserve.
    • 34 متر كيلومربع (13 sq mi), elevation 990 متر (3،250 ft)
  • Lake Elmenteita: shallow soda lake.
  • Lake Logipi: a shallow hot-spring fed soda lake in the Suguta Valley just south of Lake Turkana. Formerly Lake Suguta
  • Lake Magadi: shallow soda lake near the southern border with Tanzania.
  • Lake Naivasha:
    • 160 متر كيلومربع (62 sq mi) although it varies somewhat with rainfall, elevation 1،890 متر (6،200 ft), freshwater
  • Lake Nakuru: shallow soda lake, has been a national park since 1968.
    • 40 متر كيلومربع (15 sq mi), elevation 1،759 متر (5،771 ft)
  • Lake Turkana: the largest of the Kenyan lakes, on the border of Kenya and Ethiopia.
    • 6،405 متر كيلومربع (2،473 sq mi), elevation 360 متر (1،180 ft), freshwater

تنزانيا

All the lakes in the Tanzanian section of this group are alkaline:

بحيرات وادي الفالق الغربية أو الألبرتية

Map of Great Rift Valley.svg
Some of the Rift Valley lakes. From left to right they are Lake Upemba, Lake Mweru, Lake Tanganyika (largest), and Lake Rukwa. This image spans the SE corner of the Democratic Republic of the Congo, NE Zambia, and southern Tanzania.

The lakes of the Western or Albertine Rift, with Lake Victoria, include the largest, deepest, and oldest of the Rift Valley Lakes. They are also referred to as the Central African lakes. Lakes Albert, Victoria, and Edward are part of the Nile River basin.

Lake Victoria (elevation 1،134 متر (3،720 ft)), with an area of 68،800 متر كيلومربع (26،600 sq mi), is the largest lake in Africa. It is not in the Rift Valley, instead occupying a depression between the eastern and western rifts formed by the uplift of the rifts to either side. Lakes Victoria, Tanganyika, and Malawi are sometimes collectively known as the African Great Lakes.

The Western Rift Valley lakes are fresh water and home to an extraordinary number of species. Approximately 1,500 cichlid fish (Cichlidae) species live in the lakes. In addition to the cichlids, populations of Clariidae, Claroteidae, Mochokidae, Poeciliidae, Mastacembelidae, Centropomidae, Cyprinidae, Clupeidae and other fish families are found in these lakes. They are also important habitats for a number of amphibian species, including Amietophrynus kisoloensis, Bufo keringyagae, Cardioglossa cyaneospila, and Nectophryne batesii.

  • Lake Albert (5،300 متر كيلومربع (2،000 sq mi), elevation 615 متر (2،018 ft)) is the northernmost lake in the western rift.
  • Lake Edward (2،325 متر كيلومربع (898 sq mi), elevation 912 متر (2،992 ft)) drains north into Lake Albert
  • Lake Kivu (2،220 متر كيلومربع (860 sq mi), elevation 1،460 متر (4،790 ft)) empties into Lake Tanganyika via the Ruzizi River.
  • Lake Tanganyika (32،900 متر كيلومربع (12،700 sq mi), elevation 773 متر (2،536 ft)) is the largest and deepest of the Rift Valley lakes (more than 1،400 متر (4،600 ft)), and is the second deepest fresh water lake on the planet (after Lake Baikal).[1] Below roughly 200 meters depth, its water is anoxic and devoid of life besides anoxic bacteria.[4] It is very sensitive to climate.[5] It is part of the Congo River basin, feeding into the River Congo via the Lukuga River.

بحيرات وادي الفالق الجنوبية (تنزانيا وملاوي)

The Southern Rift Valley lakes are like the Western Rift Valley lakes in that, with one exception, they are freshwater lakes.

  • Lake Rukwa (about 5،670 متر كيلومربع (2،190 sq mi) but quite variable) in Tanzania is the alkaline exception, lying south-east of Tanganyika, and has no outlet.
  • Lake Malawi (30،000 متر كيلومربع (12،000 sq mi), elevation 500 متر (1،600 ft)), the second largest and second deepest of the Rift Valley lakes at over 700 متر (2،300 ft), is drained by the Shire River, a tributary of the Zambezi River. Also known as Lake Nyasa.
  • Lake Malombe (450 متر كيلومربع (170 sq mi)) is on the Shire River.
  • Lake Chilwa (1،750 متر كيلومربع (680 sq mi), elevation 622 متر (2،041 ft)) has no outlet but extensive wetlands. It is the southernmost of the Rift Valley lakes.

البحيرات الأخرى في الوادي المتصدع الأكبر

  • Lake Mweru (5،120 متر كيلومربع (1،980 sq mi)[6] elevation 922 m) lies in the Lake Mweru-Luapula graben, which is a branch off the Albertine rift.
  • Lake Mweru Wantipa (1،500 متر كيلومربع (580 sq mi), elevation 930 متر (3،050 ft)) is a marshy lake between lakes Tanganyika and Mweru, and is endorheic but may overflow into Lake Mweru at times of very high flood.

المراجع

  1. ^ أ ب "WWF Global 200 Ecoregions – Rift Valley Lakes (182)". worldwildlife.org. Archived from the original on December 22, 2004. Retrieved 16 March 2008.
  2. ^ "What Lies Beneath". The Economist. 2016-03-12.
  3. ^ Hynes, H. B. N. "Tudorancea, C. & Taylor W.D. (Eds) Ethiopian Rift Valley Lakes". euronet.nl. Retrieved 16 March 2008.
  4. ^ أ ب Smith, Anthony (1988). The Great Rift: Africa's Changing Valley. London: BBC Books. ISBN 978-0-8069-6906-0.
  5. ^ Plisnier P.-D., Chitamwebwa D., Mwape L., Tshibangu K., Langenberg V., Coenen E. (1999). "Limnological annual cycle inferred from physical-chemical fluctuations at three stations of Lake Tanganyika". Hydrobiologia. 407: 45–58. doi:10.1023/A:1003762119873. hdl:2268/294749. S2CID 24637697.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ Bos AR, CK Kapasa and PAM van Zwieten (2006). "Update on the bathymetry of Lake Mweru (Zambia), with notes on water level fluctuations". African Journal of Aquatic Science. 31 (1): 145–150. Bibcode:2006AfJAS..31..145B. doi:10.2989/16085910609503882. S2CID 86387950.

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