Lake Kivu 511846 222967058 2008-07-01T23:27:17Z Blofeld of SPECTRE 1616157 /* Methane extraction */ {{Infobox_lake |lake_name = Lake Kivu |image_lake = LakeKivu satellite.jpg |caption_lake = Satellite image of Lake Kivu courtesy of NASA. |coords = {{coor at dm|2|0|S|29|0|E|type:waterbody}} |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}}<ref name=Columbia>[http://www.bartleby.com/65/ki/KivuLak.html Kivu, lake, Congo and Rwanda], [[Columbia Encyclopedia]] , Sixth Edition. 2001-05.</ref> |width = {{convert|48|km|abbr=on}}<ref name=Columbia/> |area = {{convert|2700|km2|sqmi|-1|abbr=on}}<ref name=Columbia/> |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]], Congo<br>[[Bukavu]], Congo<br>[[Kibuye]], Rwanda<br>[[Cyangugu]], Rwanda }} '''Lake Kivu''' is one of the [[Great Lakes (Africa)|Great Lakes]] of [[Africa]]. It lies on the border between the [[Democratic Republic of the Congo]] and [[Rwanda]], and is in the Albertine (western) Rift, a part of the [[Great Rift Valley]]. Lake Kivu empties into the [[Ruzizi River]], which flows southwards into [[Lake 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 [[List of islands in lakes|inland island]], [[Idjwi]], lies in Lake Kivu, while settlements on its shore include [[Bukavu]], [[Kabare]], [[Kalehe]], [[Sake, DRC|Sake]] and [[Goma]] in Congo and [[Gisenyi]], [[Kibuye]] and [[Cyangugu]] in Rwanda. Native fish include species of ''[[Barbus]]'', ''[[Clarias]]'', and ''[[Haplochromis]]'', as well as [[Oreochromis niloticus|Nile Tilapia]]. ''[[Limnothrissa miodon]]'', one of two species known as the [[Kapenta|Tanganyika sardine]], was introduced in 1959 and formed the basis of a new [[pelagic 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.<ref name=FAO>[http://www.fao.org/fi/fcp/en/COD/BODY.HTM Information on Fisheries Management in the Democratic Republic of the Congo], United Nations [[Food and Agriculture Organization]], December 2001</ref> ==Chemistry== [[Image:Lake Kivu shore at Gisenyi.jpg|thumb|left|Shore at [[Gisenyi]], Rwanda]] Lake Kivu is one of three known [[limnic eruption|exploding lakes]], along with Cameroonian [[Lake Nyos]] and [[Lake Monoun]], that experience [[limnic eruption|violent lake overturn]]s. 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 2 million people live in the lake basin. Cores from the Bukavu Bay area of the lake, reveal the bottom has layered deposits of the "rare" mineral [[monohydrocalcite]] interlain with [[diatoms]], on top of [[sapropel]]ic sediments with high [[pyrite]] 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.<ref>"Stoffers, P., and Fischbeck, R. (1974) Monohydrocalcite in the sediments of Lake Kivu (East Africa) Sedimentology, 21, 163-170.</ref> 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.<ref>[http://www.volcanolive.com/news16.html Archived Volcano Eruption News: Nyiragongo Volcano Situation Report], volcanolive.com, January 22-25, 2002</ref><ref name=solidarites>{{PDF|[http://www.eawag.ch/research_e/apec/Scripts/Lorke_publication_lake_kivu_2002.pdf 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]}} by Halbwachs, et al., SOLIDARITES, [[March 9]], [[2002]]</ref>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 lake [[tsunami]]s as gas explodes out of it.<ref name=killer>[http://www.bbc.co.uk/science/horizon/2001/killerlakestrans.shtml "Killer Lakes"], ''BBC'', [[4 April]] [[2002]]</ref><ref>[http://walrusmagazine.ca/articles/2006.05-field-notes-in-the-shadow-of-doom/ "In the Shadow of Doom"], ''The Walrus'', May 2006</ref> 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 only originally thought to be a cheap natural resource for export and the generation of cheap power. Once the mechanisms that caused lake overturns began to be understood, so did the risk the lake posed to the local population. An experimental vent pipe was installed at Lake Nyos in 2001 to degas the deep water, but such a solution for the much larger Lake Kivu would be extremely expensive, running into millions of dollars. No plan has been initiated to reduce the risk posed by Lake Kivu. === Methane extraction === [[Image:GisenyiBeach.jpg|right|300px]] 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 a [[brewery]], the [[Bralirwa brewery]] in [[Gisenyi]].<ref>[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, accessed [[4 May]] [[2007]]</ref><ref name=powerhouse>{{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}}</ref> 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 sell [[electricity]] to neighboring African countries.<ref name=powerhouse /> == Human history == [[Image:Lake Kivu shoreline at Gisenyi.jpg|right|thumb|250px|People on the shore at Gisenyi]] The first [[Europe]]an to visit the lake was [[Germany|German]] [[Gustav Adolf von Götzen|Count Adolf von Götzen]] in 1894. Since then it has been caught up in the conflict between [[Hutu]] and [[Tutsi]] people in Rwanda, and their allies in DR Congo, which led to the 1994 [[Rwandan Genocide]] and the [[First Congo War|First]] and [[Second Congo War]]s. Lake Kivu gained notoriety as a place where many of the victims of the genocide were dumped. ==See also== *[[Limnic eruption]] *[[Mazuku]] *[[Meromictic Lakes]] *[[Methane]] *[[Haroun Tazieff]] *[[Henry's Law]] *[[Raoult's Law]] *[[Lake Nyos]] *[[Lake Monoun]] *[[Disasters]] == Notes and references == <!-- This article uses [[Wikipedia:Footnotes]]. Please use this format when adding references to material in the article. External links added directly to this section will be swiftly deleted without notice. --> <div class="references-small"> <references /> </div> '''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] {{DEFAULTSORT:Kivu}} [[Category:African Great Lakes]] [[Category:Lakes of the Great Rift Valley]] [[Category:Lake Kivu]] [[Category:Lakes of the Democratic Republic of the Congo]] [[Category:Lakes of Rwanda]] [[Category:Meromictic lakes]] [[Category:Natural gas]] [[Category:International lakes]] <!-- The below are interlanguage links. --> [[ca:Llac Kivu]] [[cs:Kivu]] [[da:Kivusøen]] [[de:Kiwusee]] [[et:Kivu järv]] [[es:Lago Kivu]] [[eo:Kivu]] [[eu:Kivu lakua]] [[fr:Lac Kivu]] [[gl:Lago Kivu]] [[id:Danau Kivu]] [[it:Lago Kivu]] [[lv:Kivu ezers]] [[lt:Kivu ežeras]] [[ln:Kivu (etímá)]] [[hu:Kivu-tó]] [[nl:Kivumeer]] [[ja:キブ湖]] [[pl:Kiwu]] [[pt:Lago Kivu]] [[ru:Киву (озеро)]] [[sk:Kivu (jazero)]] [[sr:Језеро Киву]] [[sv:Kivusjön]] [[uk:Ківу]] [[vec:Lago Kivu]] [[wuu:基呒湖]] [[zh:基伏湖]]