# Lake Kivu

Lake Kivu

meromictic lake, lake| Part of | African Great Lakes  |
| Native label | Lake Kivu  |
| Inflows | Karundura  |
| Outflows | Ruzizi River  |
| Basin country | Rwanda  |
| Continent | Africa  |
| Country | Democratic Republic of the Congo, Rwanda  |
| Coordinate location | 1°51′11″S 29°8′7″E  |

**Lake Kivu** be one of de African Great Lakes. E dey lie for de border between de Democratic Republic of the Congo den Rwanda top, den e dey for de Albertine Rift insyd, de western branch of de East African Rift. Lake Kivu dey empty into de Ruzizi River, wey dey flow southwards into Lake Tanganyika. For 1894 insyd, German officer den colonial ruler Gustav Adolf von Götzen be de first European wey dem record to visit de lake.

Kivu lake shoreline at Gisenyi, RwandaFor de past insyd, Lake Kivu drain toward de north, wey e contribute to de White Nile. About 13,000 to 9,000 years ago, volcanic activity block Lake Kivu ein outlet to de watershed of de Nile. De volcanism produce mountains, wey dey include de Virungas, wey rise between Lake Kivu den Lake Edward, to de north. Dem then force water from Lake Kivu south down de Ruzizi. Dis, for turn insyd, raise de level of Lake Tanganyika, wey ovaflow down de Lukuga River.

Lake Kivu be one of three lakes for de world insyd, along plus Lake Nyos den Lake Monoun, dat dey undergo limnic eruptions (wey ovaturn of deepwater stratified layers dey release dissolved carbon dioxide (CO2)). De lake ein bottom dey sanso contain methane (CH4). If a limnic eruption dey occur, de lives of de two million pippoe wey dey live nearby go be for danger insyd.

## Geography

Lake Kivu dey approximately 42 km (26 mi) long den 50 km (31 mi) at ein widest. Ein irregular shape dey make measuring ein precise surface area difficult; dem estimate am to cover a total surface area of sam 2,700 km2 (1,040 sq mi), wey e make am Africa ein eighth largest lake. De surface of de lake dey sit at a height of 1,460 metres (4,790 ft) above sea level. Dis lake get a chance of suffering a limnic eruption every 1000 years. De lake get a maximum depth of 475 m (1,558 ft) den a mean depth of 220 m (722 ft), wey e make am de world ein twentieth deepest lake by maximum depth, den de thirteenth deepest by mean depth.

De lake bed dey sit upon a rift valley wey dem slowly pull am apart, wey e cause volcanic activity for de area insyd.

De world ein tenth-largest island for a lake insyd, Idjwi, dey lie for Lake Kivu insyd

### Human geography

Sam 1,370 square kilometres (529 sq mi) anaa 58 percent of de lake ein waters dey lie within DRC borders.

Settlements for de lake ein shore top dey include Bukavu, Kabare, Kalehe, Sake den Goma for de Democratic Republic of the Congo insyd, den Gisenyi, Kibuye, den Cyangugu for Rwanda insyd.

For early 2025 insyd, during de M23 campaign, de Rwandan military occupy all settlements for de Congolese side of de lake ein shores insyd den de M23 Movement, plus provincial capital Goma wey dem capture for January insyd den all settlements wey dey under M23 control as of early March. For 12 March insyd, M23 land for Idjwi island top, wey e occupy am without resistance.

## Chemistry

Lake Kivu be a meromictic lake wey dey contain a freshwater surface layer dat dey becam more saline plus depth, plus a salinity wey dey approach 6 g/kg near de bottom. Along plus Cameroonian Lake Nyos den Lake Monoun, Lake Kivu be one of three dat dem know to undergo limnic eruptions (wey ovaturn of deepwater stratified layers dey release dissolved carbon dioxide). Around de lake, researchers find evidence of massive local extinctions about every thousand years, wey outgassing events presumably cause am. De trigger give lake ovaturns for Lake Kivu insyd, dem no know am, but volcanic activity den changes for climate insyd, dem suspect both. De gaseous chemical composition of exploding lakes be unique to each lake. For Lake Kivu ein case, e dey include methane (CH4) den carbon dioxide (CO2), as a result of lake water interaction plus volcanic hot springs.

De amount of methane wey dem contain am at de bottom of de lake, dem estimate am to be 65 cubic kilometres (16 cu mi). If dem burn am for a modern combined-cycle generating plant insyd, dat amount of methane go generate around 40,000 megawatts give an entire year, wey dey equivalent to de power output equivalent to six times dat of de Grand Coulee Dam at peak springtime power. De lake sanso dey hold an estimated 256 cubic kilometres (61 cu mi) of carbon dioxide wey, if dem release am for an eruption event insyd, e fi suffocate all of de inhabitants of de lakeshore. De water temperature be 24 °C (75 °F), den de pH dey about 7 for de anoxic region insyd, den around 9 for de oxygenated waters insyd. Dem report say microbial reduction of de volcanic produce methane (CO2). A future ovaturn den gas release from de deep waters of Lake Kivu go result for catastrophe insyd, wey dey dwarf de historically lake ovaturns dem document at de much smaller Lakes Nyos den Monoun. De lives of de approximately two million pippoe wey live for de lake basin area insyd, dem go threaten am.

Cores from de Bukavu Bay area of de lake reveal dat de bottom get layered deposits of de rare mineral monohydrocalcite wey dem interlay plus diatoms, for top of sapropelic sediments plus high pyrite content. Dem find'em at three different intervals. Dem believe de sapropelic layers to be related to hydrothermal discharge den de diatoms to a bloom wey reduce de carbon dioxide levels low enough to precipitate monohydrocalcite.

Scientists hypothesize dat sufficient volcanic interaction plus de lake ein bottom water dat get high gas concentrations go heat water, force de methane out of de water, spark a methane explosion, den trigger a nearly simultaneous release of carbon dioxide, though de entry of 1 million cubic meters of lava during de January 2002 eruption get no effect. De carbon dioxide go then suffocate large numbers of pippoe for de lake basin insyd as de gases roll off de lake surface. E sanso dey possible say de lake fi spawn lake tsunamis as gas dey explode out of am.

Dem begin to understand de risk wey Lake Kivu pose during de analysis of more recent events at Lake Nyos. Dem originally think Lake Kivu ein methane to be merely a cheap natural resource give export, den give de generation of cheap power. Once de mechanisms wey cause lake ovaturns begin to be understood, so do awareness of de risk de lake pose to de local population.

Dem install an experimental vent pipe at Lake Nyos for 2001 insyd to remove gas from de deep water, but such a solution give de much larger Lake Kivu go dey considerably more expensive. De approximately 510 million metric tons (500×10~~^~~6 long tons) of carbon dioxide for de lake insyd be a little under 2 percent of de amount wey human fossil fuel burning release am annually. Therefore, de process of releasing am fi potentially get costs beyond simply building den operating de system.

Dis problem wey dem associate plus de prevalence of methane be dat of mazuku, de Swahili term "evil wind" give de outgassing of methane den carbon dioxide dat dey kill pippoe den animals, den fi even kill vegetation when for high enough concentration insyd.

### Methane extraction

A methane extraction platform, Gisenyi, Rwanda.Dem recently find Lake Kivu to contain approximately 55 billion m3 (1.9 trillion cu ft) of dissolved biogas at a depth of 300 metres (1,000 ft). Until 2004, dem do extraction of de gas for a small scale top, plus dem use extracted gas to run boilers at de Bralirwa brewery for Gisenyi insyd. As far as large-scale exploitation of dis resource dey concern, de Rwandan government negotiate plus a number of parties to extract methane from de lake.

## Biology den fisheries

Fishing boats for Lake Kivu top, 2009
Paradis Malahide Island within de lake
De sky wey reflect for Lake Kivu topDe fish fauna for Lake Kivu insyd be relatively poor plus 28 described species, wey dey include four introduced species. De natives be de Lake Rukwa minnow (*Raiamas moorii*), four species of barb (ripon barbel, *Barbus altianalis*, East African red-finned barb, *Enteromius apleurogramma*, redspot barb, *E. kerstenii* den Pellegrin's barb, *E. pellegrini*), an *Amphilius* catfish, two *Clarias* catfish (*C. liocephalus* den *C. gariepinus*), Nile tilapia (*Oreochromis niloticus*) den 15 endemic *Haplochromis* cichlids. Another c. 20 possibly undescribed species of cichlids, dem know from de lake. De species dem introduce be three cichlids, de longfin tilapia (*Oreochromis macrochir*), blue-spotted tilapia (*O. leucostictus*) den redbreast tilapia (*Coptodon rendalli*), den a clupeid, de Lake Tanganyika sardine (*Limnothrissa miodon*) Dem refer sardine to locally as 'Ndagala' anaa 'Isambaza'.

De exploitable stock of de Lake Tanganyika sardine, dem estimate am at 2,000–4,000 metric tons (2,000–3,900 long tons) per year. Dem introduce am to Lake Kivu for late 1959 insyd by de Belgian agronomist Alphonse Collart. An attempt to introduce de similar Lake Tanganyika sprat (*Stolothrissa tanganicae*) at de same time be unsuccessful.

At present, Lake Kivu be de sole natural lake for wey *L. miodon*, a sardine dem originally restrict to Lake Tanganyika, dem introduce am initially to fill an empty niche. Prior to de introduction, no planktivorous fish dey present for de pelagic waters of Lake Kivu insyd. For de early 1990s insyd, de number of fishers for de lake top be 6,563, wey 3,027 dey associated plus de pelagic fishery den 3,536 plus de traditional fishery. De widespread armed conflict for de surrounding region insyd from de mid-1990s result for a decline for de fisheries harvest insyd.

Following dis introduction, de sardine gain substantial economic den nutritional importance give de lakeside human population but from an ecosystem standpoint, de introduction of planktivorous fish fi result for important modifications of plankton community structure insyd. Recent observations show de disappearance during de last decades of a large grazer, *Daphnia curvirostris*, den de dominance of mesozooplankton community by three species of cyclopoid copepod: *Thermocyclops consimilis*, *Mesocyclops aequatorialis* den *Tropocyclops confinis*.

Dem release first comprehensive phytoplankton survey for 2006 insyd. Plus an annual average chlorophyll for de mixed layer insyd of 2.2 mg m−3 den low nutrient levels for de euphotic zone insyd, de lake be clearly oligotrophic. Diatoms be de dominant group for de lake insyd, particularly during de dry season episodes of deep mixing. During de rainy season, de stratified water column, plus high light den lower nutrient availability, favour dominance of cyanobacteria plus high numbers of phototrophic picoplankton. De actual primary production be 0.71 g C m−2 d−1 (≈ 260 g C m−2 a−1).

A study of evolutionary genetics show dat de cichlids from lakes for northern Virunga insyd (e.g., Edward, George, Victoria) go fi dey evolve for a "proto-lake Kivu" insyd, much older dan intense volcanic activity (20,000-25,000 years ago) wey cut de connection. De elevation of de mountains west of de lake (wey currently be de Kahuzi-Biega National Park, one of de largest reserves of eastern lowland (anaa Grauer's) gorillas for de world insyd), wey dem combine plus de elevation of de eastern rift (wey dem locate for eastern Rwanda insyd) go dey responsible give de drainage of water from central Rwanda for de actual Lake Kivu insyd. Lack of consistent geological evidence challenge dis concept of "proto-lake Kivu", although de cichlid ein molecular clock dey suggest de existence of a lake much older dan de commonly cited 15,000 years.

Lake Kivu be de home of four species of freshwater crab, wey dey include two non-endemics (*Potamonautes lirrangensis* den *P. mutandensis*) den two endemics (*P. bourgaultae* den *P. idjwiensis*). Among Rift Valley lakes, Lake Tanganyika den Lake Victoria be de only oda plus endemic freshwater crabs.

### Illegal fishing

For 2018 insyd, dem record ova 400 cases of potential illegal fishing for Lake Kivu top. According to de Animal Research den Technology Transfer at de Rwanda Agricultural Board, fish production for Kivu Lake insyd drop from 24,199 tonnes for de 2017–2018 fishing season insyd to 16,194 tonnes for 2019–2020 insyd, wey Deputy Director Solange Uwituze attribute to fishing methods dat dey affect fish reproduction. Between May den July 2020, Rwanda Police Marine Unit operations report 27 cases wey dey include 10 poachers dem arrest give illegal fishing for de lake top.

## Islands

* Idjwi (part of Idjwi Territory, South Kivu Province)
* Nyamunini (dem sanso know am Napoleon Island)
* Amahoro
* Iwawa

## Gallery

* Lake Kivu from Sake, Goma, D R Congo
* Lake Kivu plus Goma for de background insyd, Congo
* Lake Kivu dey separate Bukavu (For de foreground insyd) den Cyangugu (For de background insyd) as dem see from Tumbimbi.