Lake Bogoria
Encyclopedia
Lake Bogoria is a saline
, alkaline lake
that lies in a volcanic region in a half-graben basin south of Lake Baringo
, Kenya
, a little north of the equator
. Lake Bogoria, like Lake Nakuru
, Lake Elmenteita
, and Lake Magadi
further south in the Rift Valley
, and Lake Logipi
to the north, is home at times to one of the world's largest populations of lesser flamingo
es. The lake is a Ramsar
site and has been a protected National Reserve since November 29, 1973. Lake Bogoria is shallow (about 10 m depth), and is about 34 km long by 3.5 km wide, with a drainage basin of 700 km²
.
Local features include the Kesubo Swamp to the north and the Siracho Escarpment to the east, both within the National Reserve. The lake is also famous for geyser
s and hot spring
s along the bank of the lake and in the lake. In four locations around the lake can be observed at least 10 geysers, which erupt up to 5 m high. Geyser activity is affected by the fluctiations of lake level, which may indundate or expose some geysers.
The lake waters contain large concentrations of Na+, HCO3- and CO32- ions. They originate from inflow from the Sandai and Emsos rivers, and from about 200 alkaline hot springs that are present at three onshore sites: Loburu, Chemurkeu, and a southern group (Ng'wasis, Koibobei, Losaramat). Other springs discharge directly from the lake floor. Lake Bogoria also contains the highest concentration of true geysers in Africa (at least 18 are known). The lake waters are alkaline (pH
:10.5) and saline (up to 100 g/L Total Dissolved Salts). The lake has no surface outlet so the water becomes saline mainly through evaporation, which is high in this semi-arid region. The lake itself is meromictic
(stratified) with less dense surface waters lying on a denser more saline bottom waters. Although hypersaline, the lake is highly productive with abundant cyanobacteria (Arthrospira fusiformis) that feed the flamingoes, but few other organisms inhabit the lake e.g. the monogonont rotifer
species Brachionus
sp. Austria (belonging to the Brachionus plicatilis
cryptic species complex) is found in high densities.
The lake has not always been saline. Sediment cores from the lake floor have shown that freshwater conditions existed for several periods during the past 10,000 years, and that lake level was up to about 9 m higher than its present level of about 990 m above sea-level. At times it might have overflowed northward towards Lake Baringo
. At times, during the late Pleistocene
it might have been united with a larger precursor of modern Lake Baringo, but this is still uncertain.
The lake area was the traditional home of the Endorois people, who were forced to leave the area in the 1970s and are now challenging their removal at the African Commission on Human and Peoples' Rights
.
Hotel accommodation is available near Loboi village at the north end of the lake. Camping is permitted at the southern end of the lake (see North Lewis, 1998, for details).
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
, alkaline lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
that lies in a volcanic region in a half-graben basin south of Lake Baringo
Lake Baringo
Lake Baringo is, after Lake Turkana, the most northern of the Great Rift Valley lakes of Kenya, with a surface area of about and an elevation of about . The lake is fed by several rivers, El Molo, Perkerra and Ol Arabel, and has no obvious outlet; the waters are assumed to seep through lake...
, Kenya
Kenya
Kenya , officially known as the Republic of Kenya, is a country in East Africa that lies on the equator, with the Indian Ocean to its south-east...
, a little north of the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
. Lake Bogoria, like Lake Nakuru
Lake Nakuru
Lake Nakuru is one of the Rift Valley soda lakes at an elevation of 1754 m above sea level. It lies to the south of Nakuru, in the rift valley of Kenya and is protected by Lake Nakuru National Park....
, Lake Elmenteita
Lake Elmenteita
Lake Elmenteita, also spelled Elementaita, is a soda lake, in the eastern limb of East Africa's Great Rift Valley, about 120 km northwest of Nairobi, Kenya.- Geography :...
, and Lake Magadi
Lake Magadi
Lake Magadi is the southernmost lake in the Kenya Rift Valley, lying in a catchment of faulted volcanic rocks, north of Tanzania's Lake Natron. During the dry season, it is 80% covered by soda and is well known for its wading birds, including flamingos....
further south in the Rift Valley
Great Rift Valley
The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...
, and Lake Logipi
Lake Logipi
Lake Logipi is a saline, alkaline lake that lies at the northern end of the arid Suguta Valley in the northern Kenya Rift. It is separated from Lake Turkana by the Barrier volcanic complex, a group of young volcanoes that last erupted during the late 19th Century or early 20th Century...
to the north, is home at times to one of the world's largest populations of lesser flamingo
Lesser Flamingo
The Lesser Flamingo is a species in the flamingo family of birds that resides in Africa and in southern Asia...
es. The lake is a Ramsar
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
site and has been a protected National Reserve since November 29, 1973. Lake Bogoria is shallow (about 10 m depth), and is about 34 km long by 3.5 km wide, with a drainage basin of 700 km²
1 E8 m²
To help compare different orders of magnitude and geographical regions, listed below are areas between 100 km2 and 1000 km2. See also areas of other orders of magnitude.* Areas less than 100 km2* 100 km2 is equal to:** 1 E+8 m²...
.
Local features include the Kesubo Swamp to the north and the Siracho Escarpment to the east, both within the National Reserve. The lake is also famous for geyser
Geyser
A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...
s and hot spring
Hot spring
A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...
s along the bank of the lake and in the lake. In four locations around the lake can be observed at least 10 geysers, which erupt up to 5 m high. Geyser activity is affected by the fluctiations of lake level, which may indundate or expose some geysers.
The lake waters contain large concentrations of Na+, HCO3- and CO32- ions. They originate from inflow from the Sandai and Emsos rivers, and from about 200 alkaline hot springs that are present at three onshore sites: Loburu, Chemurkeu, and a southern group (Ng'wasis, Koibobei, Losaramat). Other springs discharge directly from the lake floor. Lake Bogoria also contains the highest concentration of true geysers in Africa (at least 18 are known). The lake waters are alkaline (pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
:10.5) and saline (up to 100 g/L Total Dissolved Salts). The lake has no surface outlet so the water becomes saline mainly through evaporation, which is high in this semi-arid region. The lake itself is meromictic
Meromictic
A meromictic lake has layers of water that do not intermix. In ordinary, "holomictic" lakes, at least once each year there is a physical mixing of the surface and the deep waters...
(stratified) with less dense surface waters lying on a denser more saline bottom waters. Although hypersaline, the lake is highly productive with abundant cyanobacteria (Arthrospira fusiformis) that feed the flamingoes, but few other organisms inhabit the lake e.g. the monogonont rotifer
Rotifer
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703...
species Brachionus
Brachionus
Brachionus is a genus of planktonic rotifers occurring in freshwater, alkaline and brackish water.-Species:e.g. Brachionus calyciflorus,Brachionus plicatilis s.s.,Brachionus ibericus,Brachionus rotundiformis,...
sp. Austria (belonging to the Brachionus plicatilis
Brachionus plicatilis
Brachionus plicatilis is a euryhaline rotifer in the Family Brachionidae, and is possibly the only commercially important rotifer, being raised in the aquaculture industry as food for fish larvae. It has a broad distribution in salt lakes around the world and has become a model system for studies...
cryptic species complex) is found in high densities.
The lake has not always been saline. Sediment cores from the lake floor have shown that freshwater conditions existed for several periods during the past 10,000 years, and that lake level was up to about 9 m higher than its present level of about 990 m above sea-level. At times it might have overflowed northward towards Lake Baringo
Lake Baringo
Lake Baringo is, after Lake Turkana, the most northern of the Great Rift Valley lakes of Kenya, with a surface area of about and an elevation of about . The lake is fed by several rivers, El Molo, Perkerra and Ol Arabel, and has no obvious outlet; the waters are assumed to seep through lake...
. At times, during the late Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
it might have been united with a larger precursor of modern Lake Baringo, but this is still uncertain.
The lake area was the traditional home of the Endorois people, who were forced to leave the area in the 1970s and are now challenging their removal at the African Commission on Human and Peoples' Rights
African Commission on Human and Peoples' Rights
The African Commission on Human and Peoples' Rights is a quasi-judicial body tasked with promoting and protecting human rights and collective rights throughout the African continent as well as interpreting the African Charter on Human and Peoples' Rights and considering individual complaints of...
.
Hotel accommodation is available near Loboi village at the north end of the lake. Camping is permitted at the southern end of the lake (see North Lewis, 1998, for details).