- Lake Kivu
Infobox_lake
lake_name = Lake Kivu
image_lake = LakeKivu satellite.jpg
caption_lake = Satellite image of Lake Kivu courtesy of NASA.
coords = coord|2|0|S|29|0|E|type:waterbody|display=inline,title
type =Rift Valley lakes ,Meromictic
inflow =
outflow =Ruzizi River
catchment = convert|7000|km2|sqmi|-2|abbr=on
basin_countries = Rwanda, Democratic Republic of Congo
length = convert|89|km|abbr=on [http://www.bartleby.com/65/ki/KivuLak.html Kivu, lake, Congo and Rwanda] ,Columbia Encyclopedia , Sixth Edition. 2001-05.]
width = convert|48|km|abbr=on
area = convert|2700|km2|sqmi|-1|abbr=on
depth = convert|240|m|ft|0|abbr=on
max-depth = convert|480|m|ft|0|abbr=on
volume = convert|500|km3|cumi|-1|abbr=on
shore =
elevation = convert|1460|m|ft|0|abbr=on
islands =Idjwi
cities =Goma , CongoBukavu , CongoKibuye , RwandaCyangugu , RwandaLake Kivu is one of the Great Lakes of
Africa . It lies on the border between theDemocratic Republic of the Congo andRwanda , and is in the Albertine (western) Rift, a part of theGreat Rift Valley . Lake Kivu empties into theRuzizi River , which flows southwards intoLake Tanganyika .Geography and fisheries
The
lake covers a total surface area of some convert|2700|km2|sqmi|-1|abbr=on and stands at a height of convert|1460|m|ft|-1 above sea level. The lake bed sits upon a rift valley that is slowly being pulled apart, causing volcanic activity in the area, and making it particularly deep, its maximum depth of convert|480|m|ft|0|abbr=on is ranked fifteenth in the world. The lake is surrounded by majestic mountains.The world's tenth-largest inland island,
Idjwi , lies in Lake Kivu, while settlements on its shore includeBukavu ,Kabare ,Kalehe , Sake andGoma in Congo andGisenyi ,Kibuye andCyangugu in Rwanda.Native fish include species of "
Barbus ", "Clarias ", and "Haplochromis ", as well as Nile Tilapia. "Limnothrissa miodon ", one of two species known as the Tanganyika sardine, was introduced in 1959 and formed the basis of a newpelagic zone fishery. In the early 1990s, the number of fishers on the lake was 6,563, of which 3,027 were associated with the pelagic fishery and 3,536 with the traditional fishery. Widespread armed conflict in the surrounding region from the mid-1990s resulted in a decline in the fisheries harvest. [http://www.fao.org/fi/fcp/en/COD/BODY.HTM Information on Fisheries Management in the Democratic Republic of the Congo] , United NationsFood and Agriculture Organization , December 2001]Chemistry
Lake Kivu is one of three known exploding lakes, along with Cameroonian
Lake Nyos andLake Monoun , that experience violent lake overturns. Analysis of Lake Kivu's geological history indicates a periodic massive biological extinction about every 1,000 years. The trigger for lake overturns in Lake Kivu's case is unknown but periodic volcanic activity is suspected. The gaseous chemical composition of exploding lakes is unique to each lake; in Lake Kivu's case, methane and carbon dioxide due to lake water interaction with a volcano. The risk from a possible Lake Kivu overturn would be catastrophic, dwarfing other documented lake overturns at Lakes Nyos and Monoun, since approximately two million people live in the lake basin.Cores from the Bukavu Bay area of the lake reveal that the bottom has layered deposits of the "rare" mineral
monohydrocalcite interlain withdiatoms , on top ofsapropel ic sediments with highpyrite content. These are found at three different intervals. The sapropelic layers are believed to be related to hydrothermal discharge and the diatoms to a bloom which reduced the carbon dioxide levels low enough to precipitiate monohydrocalcite. ["Stoffers, P., and Fischbeck, R. (1974) Monohydrocalcite in the sediments of Lake Kivu (East Africa) Sedimentology, 21, 163-170.]Scientists hypothesize that sufficient volcanic interaction with the lake's bottom water that has high gas concentrations would heat water, force the methane out of the water, spark a methane explosion, and trigger a nearly simultaneous release of carbon dioxide. [ [http://www.volcanolive.com/news16.html Archived Volcano Eruption News: Nyiragongo Volcano Situation Report] , volcanolive.com, January 22-25, 2002] cite web
url=http://www.eawag.ch/research_e/apec/Scripts/Lorke_publication_lake_kivu_2002.pdf
title=Investigations in Lake Kivu(East Central Africa) after the Nyiragongo Eruption of January 2002: Specific study of the impact of the sub-water lava inflow on the lake stability
publisher=Solidarities
author=Halbwachs, et al.
date=2002-03-09
accessdate=2008-08-17
quote=
format=pdf [http://www.webcitation.org/query?url=http%3A%2F%2Fwww.eawag.ch%2Fresearch_e%2Fapec%2FScripts%2FLorke_publication_lake_kivu_2002.pdf&date=2008-08-17 mirror] ] The carbon dioxide would then suffocate large numbers of people in the lake basin as the gases roll off the lake surface. It is also possible that the lake could spawn laketsunami s as gas explodes out of it. [http://www.bbc.co.uk/science/horizon/2001/killerlakestrans.shtml "Killer Lakes"] , "BBC",4 April 2002 ] [ [http://walrusmagazine.ca/articles/2006.05-field-notes-in-the-shadow-of-doom/ "In the Shadow of Doom"] , "The Walrus", May 2006]The risk posed by Lake Kivu began to be understood during the analysis of more recent events at Lake Nyos. Lake Kivu's methane was originally thought to be merely a cheap natural resource for export, and for the generation of cheap power. Once the mechanisms that caused lake overturns began to be understood, so did awareness of the risk the lake posed to the local population.
An experimental vent pipe was installed at Lake Nyos in 2001 to remove gas from the deep water, but such a solution for the much larger Lake Kivu would be considerably more expensive. No plan has been initiated to reduce the risk posed by Lake Kivu.
Methane extraction
Lake Kivu has recently been found to contain approximately 55 billion cubic metres (72 billion cubic yards) of dissolved
methane gas at a depth of convert|300|m|ft|-2. Until 2004, extraction of the gas was done on a small scale, with the extracted gas being used to run boilers at abrewery , theBralirwa brewery inGisenyi . [ [http://www.avec.co.za/casestudies/cs_08.htm "Case Studies : Recovery of Gas from Lake Kivu - The Goats of Rwanda"] , Added Value Engineering Consultants, accessed4 May 2007 ] cite web |url=http://news.bbc.co.uk/1/hi/world/africa/6624395.stm |title=Rwanda's Underwater Powerhouse |date=May 4, 2007 |accessdate=2008-02-05 |author=Adam Mynott |publisher=BBC News] As far as large-scale exploitation of this resource is concerned, the Rwandan government is in negotiations with a number of parties to produce methane from the lake. Extraction is said to be cost effective and simple because once the gas rich water is pumped up the dissolved gases (primarily carbon dioxide, hydrogen sulphide and methane) begin to bubble out as the water pressure gets lower. This project is expected to increase Rwanda's energy generation capability by as much as 20 times and will enable Rwanda to sellelectricity to neighboring African countries.Human history
The first
Europe an to visit the lake was German Count Adolf von Götzen in 1894. Since then it has been caught up in the conflict betweenHutu andTutsi people in Rwanda, and their allies in DR Congo, which led to the 1994Rwandan Genocide and the First andSecond Congo War s. Lake Kivu gained notoriety as a place where many of the victims of the genocide were dumped.ee also
*
Limnic eruption
*Mazuku
*Meromictic Lakes
*Methane
*Haroun Tazieff
*Henry's Law
*Raoult's Law
*Lake Nyos
*Lake Monoun
*Disasters Notes and references
Biology of lake Kivu:
Phytoplankton [http://edoc.bib.ucl.ac.be:61/ETD-db/collection/available/FUNDPetd-10242006-193024/] , [http://plankt.oxfordjournals.org/cgi/content/abstract/fbl017v1] , [http://www.cryptogamie.com/pagint/recherche/affich_art.php?cid=171]
Zooplankton [http://edoc.bib.ucl.ac.be:61/ETD-db/collection/available/FUNDPetd-10242006-162039/] , [http://plankt.oxfordjournals.org/cgi/content/abstract/28/11/971]
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