Jump to content

Lake Malawi

From Wikipedia
Lake Malawi
lake
Part ofLake Malawi National Park, African Great Lakes, Rift Valley lakes Edit
Native labelLake Malawi Edit
OutflowsShire River Edit
Drainage basinZambezi Basin Edit
CountryMalawi, Mozambique, Tanzania Edit
Coordinate location12°11′0″S 34°22′0″E Edit
Dey share bother plusChintheche Edit
Map

Lake Malawi, dem sanso know as Lake Nyasa insyd Tanzania den Lago Niassa insyd Mozambique, (Swahili: Ziwa Nyasa) be an African Great Lake den de southernmost lake insyd de East African Rift system, dey locate between Malawi, Mozambique den Tanzania.

E be de fourth largest freshwater lake insyd de world by volume, de ninth largest lake insyd de world by area den de third largest den second deepest lake insyd Africa. Lake Malawi be home to more species of fish dan any other lake insyd de world,[1] wey dey include at least 700 species of cichlids.[2] Na de Mozambique portion of de lake officially be declared a reserve by de Government of Mozambique on June 10, 2011,[3] while insyd Malawi a portion of de lake be included insyd Lake Malawi National Park.[1]

Lake Malawi be a meromictic lake, wey dey mean say ein water layers no dey mix. De permanent stratification of Lake Malawi ein water den de oxic-anoxic boundary be maintained by moderately small chemical den thermal gradients.[4]

Geography

[edit | edit source]

Lake Malawi be between 560 kilometres (350 mi) den 580 kilometres (360 mi) long,[5] den about 75 kilometres (47 mi) wide at ein widest point. De lake get a total surface area of about 29,600 square kilometres (11,400 sq mi).[5] De lake be 706 m (2,316 ft) at ein deepest point, wey locate insyd a major depression insyd de north-central part.[6] Anoda smaller depression insyd de far north dey reach a depth of 528 m (1,732 ft).[6] De southern half of de lake be shallower; less dan 400 m (1,300 ft) insyd de south-central part den less dan 200 m (660 ft) insyd de far south.[6]

Geological history

[edit | edit source]

Malawi be one of de major Rift Valley lakes den an ancient lake. De lake dey lie insyd a valley wey de opening of de East African Rift form, wer de African tectonic plate be split into two pieces. Dis be called a divergent plate tectonics boundary. Malawi typically be estimated to be 1–2 million years old (mya),[7][8] buh more recent evidence points to a considerably older lake plus a basin wey start to form about 8.6 mya den deep-water condition first appear 4.5 mya.[9][10]

De water levels vary dramatically over time, wey dey range from almost 600 m (2,000 ft) below current level[11] to 10–20 m (33–66 ft) above.[9] During periods de lake dry out almost completely, wey dey leave only one anaa two relatively small, highly alkaline den saline lakes insyd what currently be Malawi ein deepest parts.[9][11] A water chemistry wey dey resemble de current conditions only appear about 60,000 years ago.[11] Major low-water periods be estimated to occur about 1.6 to 1.0–0.57 million years ago (wer e fi dry out completely), 420,000 to 250,000–110,000 years ago,[9] about 25,000 years ago den 18,000–10,700 years ago.[10] During de peak of de low-water period between 1390 den 1860 AD, e fi be 120–150 m (390–490 ft) below current water levels.[8]

References

[edit | edit source]
  1. 1 2 "Protected Areas Programme". United Nations Environment Programme, World Conservation Monitoring Centre, UNESCO. October 1995. Archived from the original on 2008-05-11. Retrieved 2008-06-26.
  2. ↑ Turner, Seehausen, Knight, Allender, and Robinson (2001).
  3. ↑ WWF (10 June 2011).
  4. ↑ Pilskaln, C. H. (2004).
  5. 1 2 "Lake Nyasa". Columbia Encyclopedia Online. Columbia University Press. Retrieved 2011-08-02.
  6. 1 2 3 Konings, Ad (1990).
  7. ↑ Wilson, Ab.; Teugels, Gg.; Meyer, A. (Apr 2008). Moritz, Craig (ed.). "Marine Incursion: The Freshwater Herring of Lake Tanganyika Are the Product of a Marine Invasion into West Africa". PLOS ONE. 3 (4) e1979. Bibcode:2008PLoSO...3.1979W. doi:10.1371/journal.pone.0001979. PMC 2292254. PMID 18431469.
  8. 1 2 Givnish, T.J.; and K.J. Sytsma, editors (1997). Molecular Evolution and Adaptive Radiation, p. 598. ISBN 0-521-57329-7.
  9. 1 2 3 4 Delvaux, D. (1995). Age of Lake Malawi (Nyasa) and water level fluctuations. Mus. roy. Afr. centr., Tervuren (Belg.), Dept. Geol. Min., Rapp. ann. 1993 & 1994: 99–108.
  10. 1 2 Sturmbauer; Baric; Salzburger; Rüber; and Verheyen (2001). Lake Level Fluctuations Synchronize Genetic Divergences of Cichlid Fishes in African Lakes. Mol Biol Evol 18(2): 144–154. doi:10.1093/oxfordjournals.molbev.a003788
  11. 1 2 3 Cohen; Stone; Beuning; Park; Reinthal; Dettman; Scholz; Johnson; King; Talbot; Brown; and Ivory (2007). Ecological consequences of early Late Pleistocene megadroughts in tropical Africas. Proc Natl Acad Sci USA 104(42): 16422-16427. doi:10.1073/pnas.0703873104
[edit | edit source]
Dem retrieve am from "https://gpe.wikipedia.org/w/index.php?title=Lake_Malawi&oldid=100328"