Lake Malawi (also known as Lake Nyasa in most countries, or Lake Nyassa, Lake Niassa, or Lago Niassa in Mozambique), is an African Great Lake and the southmost lake in the Great Rift Valley system of East Africa. This lake, the third largest in Africa and the eighth largest lake in the world, is located between Malawi, Mozambique, and Tanzania. It is the second deepest lake in Africa, though its placid northern shore gives no hint of its depth. This great lake's tropical waters reportedly are the habitat of more species of fish than that of any other body of water on the Earth.

Geography

Lake Malawi or Lake Nyaza is between 560 and 580 kilometres long, and about 75 kilometres wide at its widest point. The total surface area of this lake is about 29,600 square kilometres (11,429 square miles). This lake has shorelines on western Mozambique, eastern Malawi, and southern Tanzania. The largest river flowing into this lake is the Ruhuhu River. This large freshwater lake has an outlet, which is the Shire River, a tributary that flows into the very large Zambezi River.

Lake Malawi lies in the Great Rift Valley that was formed by the opening of the East African Rift, where the African tectonic plate is being split into two pieces. This is called a divergent plate tectonics boundary. Lake Malawi or Nyaza itself is variously estimated at about 40,000 years old or about one to two million years.

In addition, Lake Malawi or Nyaza is located about 350 kilometers southeast of Lake Tanganyika, another of the huge lakes of the Great Rift Valley.

Wildlife

Lake Malawi or Nyasa has for millennia provided a major food source to the residents of its shores since its waters are rich in fish such as the chambo, consisting of any one of four species of the cichlid genus Nyasalapia, and the kampango, a large catfish (Bagrus meridionalis). Some of the fish that are caught are exported from Malawi, but the wild population of fish is increasingly threatened by overfishing and water pollution.

The painted hunting dog is believed to be extinct in Malawi, with its last remaining population being spotted in the eastern Miombo woodlands just east of the lake.[9] Other wildlife that is found in and around Lake Malawi or Nyasa include crocodiles, hippopotamus, monkeys, and a significant population of African fish eagles that feed off fish from the lake.

Water chemistry

The water in Lake Malawi or Nyasa is typically slightly alkaline with a pH ranging from 7.7 to 8.6, a carbonate hardness of 107 to 142 mg L−1, and a conductivity of 210 to 285 µS cm−1. Given its tropical latitude, the water of this lake is generally warm, having a surface temperature that ranges from 24 to 29 degrees celsius (75 to 84 degrees fahrenheit), with a deep water temperature of about 22 celsius (72 °F), year round.

credited to wikipedia

Lake Victoria or Victoria Nyanza (also known as Ukerewe, Nalubaale, Sango, or Lolwe) is one of the African Great Lakes. The lake was named after the United Kingdom's Queen Victoria, by John Hanning Speke, the first European to see the lake.

With a surface area of 68,800 square kilometres (26,600 sq mi), Lake Victoria is Africa’s largest lake, and the largest tropical lake in the world, and is Earth's second largest freshwater lake - Only North America's Lake Superior is larger. In terms of volume, it is the world’s eighth largest continental lake, containing 2,750 cubic kilometres (2.2 billion acre-feet) of water.

The lake receives most of its water from direct precipitation. Its largest influent is the Kagera River, the mouth of which lies on the lake's western shore. The only river to leave the lake, the White Nile (known as the "Victoria Nile" as it leaves the lake), leaves at Jinja, Uganda, on the lake’s north shore.

Lake Victoria occupies a shallow depression in the East African Plateau, and has a maximum depth of 84 metres (276 ft) and an average depth of 20 metres (66 ft). Its catchment area covers 184,000 square kilometres (71,040 sq mi). The lake has a shoreline of some 4,828 kilometres (3,000 mi), with islands constituting some 3.7% of this length, and is divided between three countries: Kenya (6% or 4,100 km2/1,600 sq mi), Uganda (45% or 31,000 km2/12,000 sq mi) and Tanzania (49% or 33,700 km2/13,000 sq mi).

Lake Victoria supports Africa's largest inland fishery.

Geology

Lake Victoria has, during its geological history, gone through successive changes ranging from its present shallow depression, through to what may have been a series of much smaller lakes. Cores taken from its bottom show that Lake Victoria has dried up completely three times since it formed. These drying cycles are probably related to past ice ages, which are times when precipitation declined globally. The lake last dried out 17,300 years ago, and filled again beginning 14,700 years ago. Geologically, the lake is relatively young - about 400,000 years old - and formed when westward-flowing rivers were dammed by an upthrown crustal block.

This geological history probably contributed to the dramatic Cichlid speciation that characterises its ecology, as well as that of other African Great Lakes, although there are researchers who refute this, arguing that while Lake Victoria was at its lowest between 18,000 and 14,000 calendar years ago, and it dried out at least once during that time, there is no evidence of remnant ponds or marshes persisting within the desiccated basin. If such features existed, then they would have been small, shallow, turbid, and/or saline, and therefore markedly different from the lake to which today’s species are adapted.

The lake's shallowness, limited river inflow, and large surface area relative to its volume make it vulnerable to the effects of climate changes.

Hydrology and limnology

Lake Victoria receives almost all (80%) of its water from direct precipitation. Average evaporation on the lake is between 2,000–2,200 millimetres (79–87 in) per annum, almost double the precipitation of riparian areas. In the Kenya Sector, the main influent rivers are the Sio, Nzoia, Yala, Nyando, Sondu Miriu, Mogusi and the Migori. Combined, these rivers contribute far more water to the lake than does the largest single in-flowing river, the Kagera, which enters the lake from the west. The only river flowing out of the lake is the White Nile.

The lake exhibits eutrophic conditions. In 1990-1991, oxygen concentrations in the mixed layer were higher than in 1960-61, with nearly continuous oxygen supersaturation in surface waters. Oxygen concentrations in hypolimnetic waters (i.e. the layer of water that lies below the thermocline, is noncirculating, and remains perpetually cold) were lower in 1990-1991 for a longer period than in 1960-1961, with values of less than 1 mg per litre (<>

Other thinkers on the subject blame the lake's eutrophication on the mass extinction of the Haplochromis species 'flock'. The fertility of tropical waters depends on the rate at which nutrients can be brought into solution. The influent rivers of Lake Victoria provide few nutrients to the lake in relation to its size. Because of this, it is thought that most of Lake Victoria’s nutrients are locked up in lake-bottom deposits. By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, and therefore the fertility of the lake is dependent on the rate at which these nutrients can be eaten up by fish and other organisms. There is little doubt that Haplochromis played an important role in returning detritus and plankton back into solution. With some 80% of Haplochromis species feeding off detritus, and equally capable of feeding off one another, they represented a tight, internal recycling system, moving nutrients and biomass both vertically and horizontally through the water column, and even out of the lake via predation by humans and terrestrial animals and humans. The removal of Haplochromis, however, may have contributed to the increasing frequency of algal blooms, which may in turn be responsible for mass fish kills.

credited to wikipedia

Lake Tanganyika is an African Great Lake. It is estimated to be the second largest freshwater lake in the world by volume, and the second deepest, after Lake Baikal in Siberia; it is also the world's longest lake. The lake is divided between four countries – Burundi, Democratic Republic of the Congo (DRC), Tanzania and Zambia, with the DRC (45%) and Tanzania (41%) possessing the majority of the lake. The water flows into the Congo River system and ultimately into the Atlantic Ocean.

Geography

The lake is situated within the Western Rift of the geographic feature known as the Great Rift Valley formed by the tectonic East African Rift, and is confined by the mountainous walls of the valley. It is the largest rift lake in Africa and the second largest lake by surface area on the continent. It is the deepest lake in Africa and holds the greatest volume of fresh water. It extends for 673 km in a general north-south direction and averages 50 km in width. The lake covers 32,900 km², with a shoreline of 1,828 km and a mean depth of 570 metres (1,870 ft) and a maximum depth of 1,470 metres (4,820 ft) (in the northern basin) it holds an estimated 18,900 km³ (4500 cubic miles). It has an average surface temperature of 25 °C and a pH averaging 8.4. Additionally, beneath the 500 m of water there are about 4,500 metres of sediment lying over the rock floor.

The enormous depth and tropical location of the lake prevent 'turnover' of water masses, which means that much of the lower depths of the lake is so-called 'fossil water' and is anoxic (lacking oxygen). The catchment area of the lake covers 231,000 km², with two main rivers flowing into the lake, numerous smaller rivers and streams (due to the steep mountains that keep drainage areas small), and one major outflow, the Lukuga River, which empties into the Congo River drainage.

The major inflow beginning 10.6 ka is the Ruzizi River, entering the north of the lake from Lake Kivu. The Malagarasi River, which is Tanzania's second largest river, enters the east side of Lake Tanganyika. The Malagarasi predates Lake Tanganyika and was formerly continuous with the Congo river. Lake Tanganyika is presently the second largest freshwater lake in the world by volume. Around 106 ka the lake level was reduced by 435 m. During LGM (34-14) ka dropped 261 m below present lake level. The lake is 9-12 Ma old.

Biology

The lake holds at least 250 species of cichlid fish and 150 non-cichlid species, most of which live along the shoreline down to a depth of approximately 180 metres (590 ft). Many species of cichlids from Lake Tanganyika are popular fish among aquarium owners due to their bright colors. Recreating a Lake Tanganyika biotope to host those cichlids in an habitat similar to their natural environment is also popular in the aquarium hobby.

Lake Tanganyika is thus an important biological resource for the study of speciation in evolution. The largest biomass of fish, however, is in the pelagic zone (open waters) and is dominated by six species: two species of "Tanganyika sardine" and four species of predatory lates (related to, but not the same as, the Nile perch that has devastated Lake Victoria cichlids). Almost all (98%) of the Tanganyikan cichlid species are endemic to the lake and many, such as fish from the brightly coloured Tropheus genus, are prized within the aquarium trade. This kind of elevated endemism also occurs among the numerous invertebrates in the lake, most especially the molluscs (which possess forms similar to those of many marine molluscs), crabs, shrimps, copepods, jellyfishes, leeches, etc.

credited to wikipedia and fickr: Fishwhisperer

Lake Tana is the source of the Blue Nile and is the largest lake in Ethiopia. Located in the north-western Ethiopian highlands, according to the Statistical Abstract of Ethiopia for 1967/68, the lake is approximately 84 kilometers long and 66 kilometers wide, with a maximum depth of 15 meters, and an elevation of 1,840 meters. Lake Tana is fed by the Lesser Abay, Reb and Gumara Rivers and its surface area ranges from 3,000 to 3,500 km² depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile, which regulates the flow to the Tis Abbai falls and hydro-power station.

Overview

The lake has a number of islands, whose numbers vary depending on the level of the lake; it has fallen about 6 feet in the last 400 years. According to Manoel de Almeida (who was a Portuguese missionary in the early 17th century), there were 21 islands, seven to eight of which had monasteries on them "formerly large, but now much diminished." When James Bruce visited the area in the later 18th century, he noted that the locals counted 45 inhabited islands, but stated he believed that "the number may be about eleven." A more modern geographer named 37 islands, of which he believed 19 have or had monasteries or churches on them.

Remains of ancient Ethiopian emperors and treasures of the Ethiopian Church are kept in the isolated island monasteries (including Kebran Gabriel, Ura Kidane Mehret, Narga Selassie, Daga Estifanos, Medhane Alem of Rema, Kota Maryam and Mertola Maryam). On the island of Tana Qirqos is a rock shown to Paul B. Henze, on which he was told the Virgin Mary had rested on her journey back from Egypt; he was also told that Frumentius, who introduced Christianity to Ethiopia, is "allegedly buried on Tana Cherqos." The body of Yekuno Amlak is interred in the monastery of St. Stephen on Daga Island; other Emperors whose tombs are on Daga include Dawit I, Zara Yaqob, Za Dengel and Fasilides. Other important islands in Lake Tana include Dek, Mitraha, Gelila Zakarias, Halimun, and Briguida.

The monasteries are believed to rest on earlier religious sites and include the fourteenth century Debre Maryam, the eighteenth century Narga Selassie, Tana Qirqos (said to have housed the Ark of the Covenant before it was moved to Axum), and Ura Kidane Mecet, known for its regalia. A ferry service links Bahir Dar with Gorgora via Dek Island and various lake shore villages.

Lake Tana supports a notable fishing industry; according to the Ethiopian Department of Fisheries and Aquaculture, 1,454 tonnes of fish are landed each year at Bahir Dar, which the department estimates is 15% of its sustainable amount.

credited to wikipedia

Lake Titicaca is a lake located on the border of Peru and Bolivia. It sits 3,812 m (12,500 ft) above sea level, making it one of the highest commercially navigable lakes in the world. By volume of water, it is also the largest lake in South America.

Overview

The lake is located at the northern end of the endorheic Altiplano basin high in the Andes on the border of Peru and Bolivia. The western part of the lake lies within the Puno Region of Peru, and the eastern side is located in the Bolivian La Paz Department.

The lake is composed of two nearly separate sub-basins that are connected by the Strait of Tiquina which is 800 m (2,620 ft) across at the narrowest point. The larger sub-basin, Lago Grande (also called Lago Chucuito) has a mean depth of 135 m (443 ft) and a maximum depth of 284 m (932 ft). The smaller sub-basin, Wiñaymarka (also called Lago Pequeño, "little lake") has a mean depth of 9 m (30 ft) and a maximum depth of 40 m (131 ft). The overall average depth of the lake is 107 m (351 ft).

Lake Titicaca is fed by rainfall and meltwater from glaciers on the sierras that abut the Altiplano. Five major river systems feed into Lake Titicaca. In order of their relative flow volumes these are Ramis, Coata, Ilave, Huancané, and Suchez. More than 20 other smaller streams empty into Titicaca, and the lake has 41 islands, some of which are densely populated.

Having only a single season of free circulation, the lake is monomictic, and water passes through Lago Huiñaimarca and flows out the single outlet at the Rio Desaguadero, which then flows south through Bolivia to Lake Poopó. This only accounts for about 10% of the lake's water balance. Evapotranspiration, caused by strong winds and intense sunlight at altitude, balances the remaining 90% of the water input. It is nearly a closed lake.

Temperature

The cold sources and winds over the lake give it an average surface temperature of 10 to 14 °C (50 to 57 °F). In the winter (June-September), mixing occurs with the deeper waters, which are always between 10 to 11 °C (50 to 52 °F).

Name

The origin of the name Titicaca is unknown. It has been translated as "Rock Puma ", allegedly because of its resemblance to the shape of a puma hunting a rabbit, combining words from the local languages Quechua and Aymara, and as well as translated as "Crag of Lead." Locally, the lake goes by several names. Because the southeast quarter of the lake is separate from the main body (connected only by the Strait of Tiquina), the Bolivians call it Lago Huiñaymarca (Quechua: Wiñay Marka) and the larger part Lago Chucuito. In Peru, these smaller and larger parts are referred to as Lago Pequeño and Lago Grande, respectively.

Islands

*Uros

* Amantaní

*Taquile

*Isla del Sol

*Isla de la Luna

*Suriqui

credited to wikipedia

Lake Inari (Finnish: Inarijärvi/Inarinjärvi, Northern Sami: Anárjávri, Inari Sami: Aanaarjävri, Skolt Sami: Aanarjäuˊrr, Swedish: Enare träsk, Norwegian: Enaresjøen) is the third largest lake in Finland and the largest lake in Sápmi. It is located in the northern part of Lapland, north of the Arctic Circle. The lake is 117–119 meters above sea level and it is regulated at the Kaitakoski power plant in Russia. The freezing period normally extends from November to early June.

The most well known islands of the lake are Hautuumaasaari ("Graveyard Island"), which served as cemetery of ancient Sami people and Ukonkivi ("Ukko's Stone"), a historical sacrifice place of the ancient habitants of the area. There are over 3,000 islands in total. Trout, lake salmon, white fish, perch and pike are found in Lake Inari's waters.

The lake covers 1,040 square kilometres. It empties northwards through the Paatsjoki at the mouth of the Varangerfjord, which is a bay of Barents Sea.

Mentions in media

In 1989, the Lake shortly attracted local attention, after a group of scientists on an expedition gave account to have noticed a blue glow which appeared to have come from within the Lake Inari. Since it was never confirmed and no newspaper articles appeared it is still uncertain whether or not this event actually took place.

Inari village and Lake Inari also feature in the 1998 German movie Zugvögel - ... einmal nach Inari (international English title Trains 'n' Roses) where the protagonist Hannes Weber makes a train journey from Dortmund, Germany to his destination Inari for a train timetable contest.

In Philip Pullman's His Dark Materials trilogy, the lake is renamed Lake Enara, the home to a clan of witches.

credited to wikipedia and flickr: Kanikoski

Wast Water or Wastwater is a lake in the Lake District National Park, England. The lake is approximately 4.6 kilometres (almost 3 miles) long and 600 metres (more than a third of a mile) wide, and is located in the Wasdale valley. It is the deepest lake in England, at 79 metres (258 feet), and is owned by the National Trust.

It is one of the finest examples of a glacially 'over-deepened' valley. The surface of the lake is about 200 feet above sea level, while its bottom is over 50 feet below sea level.

The name of the lake and its valley is pronounced as in was, not with a hard a. The lake is named "Wast Water" on Ordnance Survey maps, but the spelling "Wastwater" is used with roughly equal frequency, including by its owner, the National Trust, along with the Cumbria Tourist Board, and the Lake District National Park Authority.

The steep slopes on the south-eastern side of the lake, leading up to the summits of Whin Rigg and Illgill Head, are known as the "Wastwater Screes" or on some maps as "The Screes". These screes formed as a result of ice and weathering erosion on the rocks of the Borrowdale Volcanic Group, that form the fells to the East of the lake, towards Eskdale. They are approximately 2,000 feet, from top to base, the base being about 200 feet below the surface of the lake.

The head of the Wasdale valley is surrounded by some of the highest mountains in England, including Scafell Pike, Great Gable and Lingmell.

Wast Water is the source of the River Irt which flows into the Irish Sea near Ravenglass.

A popular path runs the length of the lake, through the boulders and scree fall at the base of this craggy fell-side. On the north-western side are the cliffs of Buckbarrow (a part of Seatallan) and the upturned-boat shape of Yewbarrow.

Britain's Favourite View

On September 9, 2007, Wast Water was announced as the winner of a vote to determine "Britain's Favourite View" by viewers of ITV.

Crime

The Wasdale Lady in the Lake, Margaret Hogg, was murdered and her body was disposed of in the lake. She was found after eight years, with her body preserved like wax due to the lack of oxygen in the water.

Underwater gnomes

In February 2005 it was reported that a "gnome garden" complete with picket fence was removed from the bottom of Wastwater after three divers died in the late 1990s. It is thought the divers spent too much time too deep searching for the ornaments. Police divers report there is a rumour that the garden has returned at a depth beyond which they are allowed. PC Kenny McMahon, a member of the North West Police Underwater Search Unit, said "Wastwater is quite clear at the bottom, but there's nothing to see. At a depth of about 48m, divers had taken gnomes down and put a picket fence around them. But several years ago there were a number of fatalities and the Lake District National Park Authority asked us to get rid of them. We went down there, put them in bags and removed the lot. But now there's a rumour about a new garden beyond the 50m depth limit. As police divers we can't legally dive any deeper so, if it exists, the new garden could have been purposefully put out of our reach."

credited to wikipedia and flickr: Nick Landells

The Western Brook Pond is a Canadian fjord or lake located in Gros Morne National Park on the west coast of the island of Newfoundland. It is in the Long Range Mountains, the most northern section of the Appalachian Mountains.

It is surrounded by steep rock walls 600 m (2,000 ft) high., having been carved from the surrounding plateau by glaciers. After the glaciers melted, the land rebounded and the fjord was cut off from the sea. Salty water was eventually flushed from the fjord leaving it fresh. The catchment area is composed of igneous rock with relatively thin soil, so the waters feeding Western Brook Pond are low in nutrients and the lake is classified as ultraoligotrophic. It is fed by Stag Brook at the extreme eastern end of the lake and by numerous waterfalls cascading from the plateau above. One of these, Pissing Mare Falls at 350 m (1,100 ft), is one of the highest in eastern North America.

The lake is accessible by a moderate-easy 3 km (1.9 mi) hiking trail over coastal bogs and low limestone ridges. Two tour boats, one with a capacity of 70 passengers and the other 90 passengers, cruise the lake from June to mid-October. The lake waters are pristine, having had very little impact from human activities. The tour boat operators had to undergo special certification to ensure that their operations would have minimal impact on the environment.

In the early part of the 20th century, a part of the surrounding cliff broke off and fell into the lake, causing a 30 m (98 ft) tsunami.

credited to wikipedia

Lake Turkana , formerly known as Lake Rudolf, is a lake in the Great Rift Valley in Kenya, with its far northern end crossing into Ethiopia. It is the world's largest permanent desert lake and the world's largest alkaline lake. By volume it is the world's fourth largest salt lake after the Caspian Sea, Lake Issyk-Kul and the (shrinking) Aral Sea, and among all lakes it ranks twentieth. The water is potable but not palatable. It supports a rich lacustrine wildlife. The climate is hot and very dry.

The rocks of the surrounding area are predominantly volcanic. Central Island is an active volcano, emitting vapors. Outcrops and rocky shores are found on the East and South shores of the lake, while dunes, spits and flats are on the West and North, at a lower elevation.

On-shore and off-shore winds can be extremely strong as the lake warms and cools more slowly than the land. Sudden, violent storms are frequent. Three rivers (the Omo, Turkwel and Kerio) flow into the lake, but lacking outflow its only water loss is by evaporation. Lake volume and dimensions are variable. For example, its level fell by 10 meters between 1975 and 1993.

Due to temperature, aridity and geographic inaccessibility, the lake retains its wild character. Nile crocodiles are found in great abundance on the flats. The rocky shores are home to scorpions and carpet vipers. Although the lake and its environs have been popular for expeditions of every sort under the tutelage of guides, rangers and experienced persons, they certainly must be considered hazardous for unguided tourists.

Lake Turkana National Parks are now listed as a UNESCO World Heritage Site.Sibiloi National Park lies on the lake's eastern shore, while Central Island National Park and South Island National Park lie in the lake. Both are known for their crocodiles.

Demography

The lake was named Lake Rudolf (in honor of Crown Prince Rudolf of Austria) by Count Sámuel Teleki de Szék and his second-in-command Lieutenant Ludwig Ritter Von Höhnel, a Hungarian and an Austrian, 6 March 1888. They were the first Europeans to have recorded visiting the lake, "finding" it on a large safari across East Africa. Native peoples who live around lake Turkana include the Turkana, Rendille, Gabbra, Daasanach, Hamar Koke, Karo, Nyagatom, Mursi, Surma and Molo. For the location of many of these peoples refer to the dialect map in the article.

J. W. Gregory reported in The Geographical Journal of 1894 that it had been called "'Basso Narok' This means black lake in the samburu language and basso naibor for lake Stefanie meaning white lake in the Samburu language. The Samburu are among the dominant tribes in the lake Turkana region when the explorers came." What the native form of this phrase was, what it might mean and in what language is not clear. The lake kept its European name during the colonial period of British East Africa. After the independence of Kenya, the president, Mzee Jomo Kenyatta, renamed it in 1975 after the Turkana, the predominant tribe there.

At some unknown time the lake became known as the Jade Sea from its turquoise color seen on approaching from a distance. The color comes from algae that rise to the surface in calm weather. This is likely also a European name. The Turkana refer to the lake as anam Ka'alakol, meaning the sea of many fish. It is from the name Ka'alakol that Kalokol, a town on the western shore of Lake Turkana, east of Lodwar, derives its name. The area still sees few Western visitors, being a three-day drive from Nairobi, 400 km to the south.

Biology

Biomes

The major biomes are the lake itself, which is an aquatic biome, and the surrounding region, which is classified as Deserts and xeric shrublands. The desert is the Chalbi desert. During moister times a dry grassland appears, featuring Aristida adcensionis and A. mutabilis. During drier times the grass disappears. The shrublands contain dwarf shrubs, such as Duosperma eremophilum and Indigofera spinosa. Near the lake are doum palms.

Plankton

Both phytoplankton and zooplankton are found in the lake. Of the former the Cyanobacteria are represented by Microcystis aeruginosa; the Microalgae,Botryococcus braunii. Also present are Anabaenopsis arnoldii, Planctonema lauterbornii, Oocystis gigas, Sphaerocystis schroeteri, and some others. The zooplankton include copepods, Cladocera and Protozoa.

Fish

A number of species of native fish abound both in the demersal zone and the pelagic zone of the lake: the Alestiidae, or African tetras, a few genera of Cichlids, such as Tilapia, some species of bichir, an elephantfish (Mormyridae), the African arowana, the African knifefish (Gymnarchus niloticus), Distichodus niloticus of the Distichodontidae, as well as the Nile perch (Lates niloticus) and the Rudolph lates (Longispina), and numerous others. The lake has been heavily fished. During the early Holocene, the water level of lake Turkana was higher, and the lake overflowed into the Nile River, allowing fish and crocodiles access.

Birds

The Lake Turkana region is home to hundreds of species of birds native to Kenya. The East African Rift System also serves as a flyway for migrating birds, bringing in hundreds more. The birds are essentially supported by plankton masses in the lake, which also feed the fish.

Some birds more common to Turkana are the Little Stint, the Wood Sandpiper, and the Common Sandpiper. The African Skimmer (Rhyncops flavirostris) nests in the banks of Central Island. The White-necked Cormorant (Phalacrocorax africanus) ranges over the lake. The Greater Flamingo wades in its shallows. Heuglin's Bustard (Neotis heuglinii) is found in the east of the lake region.

Reptiles

The lake formerly contained Africa's largest population of Nile crocodiles: 14,000, as estimated in a 1968 study by Alistair Graham -- see the book 'Eyelids of Morning' for an account of the Lake and its crocodiles.

Mammals

Over the dry grasslands ranges a frail population of grazing mammals and predators. The grazers are chiefly Grevy's zebra, Burchell's Zebra, the Beisa Oryx, Grant's Gazelle, the topi and the reticulated giraffe. They are hunted by the lion and the cheetah. Elephants and the black rhinoceros are no longer seen, although Teleki reported seeing (and shooting) many. Closer to the dust is the gerbil (Gerbillus pulvinatus).

Geology

Lake Turkana is an East African Rift feature. A rift is a weak place in the Earth's crust due to the separation of two tectonic plates, often accompanied by a graben, or trough, in which lake water can collect. The rift began when East Africa, impelled by currents in the mantle, began separating from the rest of Africa, moving to the northeast. Currently the graben is 320 km wide in the north of the lake, 170 km in the south. This rift is one of two, and is called the Great or Eastern Rift. There is another to the west, the Western Rift.

The basement rocks of the region have been dated by two analytical determinations to 522 and 510 million years ago (ma or mya). No rift was in the offing at that time. A rift is signalled by volcanic activity through the weakened crust. The oldest volcanic activity of the region occurred in the Nabwal Hills northeast of Turkana and is dated to 34.8 mya in the late Eocene.

The visible tectonic features of the region result from extensive extrusions of basalt over the Turkana-Omo basin in the window 4.18-3.99 mya. These are called the Gombe Group Basalts. They are subdivided into the Mursi Basalts and the Gombi Basalts.

The two latter basalts are identified as the outcrops that are the rocky mountains and badlands around the lake. In the Omo portion of the basin, of the Mursi Basalts, the Mursi Formation is on the west side of the Omo, the Nkalabong on the Omo, and the Usno and Shungura east of the Omo. Probably the best known of the formations are the Koobi Fora on the east side of Turkana and the Nachukui on the west.

Short-term fluctuations in lake level combined with periodic volcanic ash spewings over the region have resulted in a fortuitous layering of the ground cover over the basal rocks. These horizons can be dated more precisely by chemical analysis of the tuff. As this region is believed to have been an evolutionary nest of Hominins, the dates are important for generating a diachronic array of fossils, both Hominoid and non-Hominoid. Many thousands have been excavated.

Terraces representing ancient shores are visible in the Turkana basin. The highest is 75 m above the surface of the lake (only approximate, as the lake level fluctuates), which was current about 9500 years ago, at the end of the Pleistocene. It is generally theorized that Turkana was part of the upper Nile system at that time, connecting to Lake Baringo at the southern end and the White Nile in the north, and that volcanic land adjustments severed the connection. Such a hypothesis explains the Nile species in the lake, such as the crocodiles and the Nile Perch.

Anthropology

Around 2 million–3 million years ago, the lake was larger and the area more fertile, making it a centre for early hominins. Richard Leakey has led numerous anthropological digs in the area which have led to many important discoveries of hominin remains. The two-million-year-old Skull 1470 was found in 1972. It was originally thought to be Homo habilis, but the scientific name Homo rudolfensis derived from the old name of the Lake Rudolf, was proposed in 1986 by V. P. Alexeev. In 1984, the Turkana Boy, a nearly complete skeleton of a Homo erectus boy was discovered by Kamoya Kimeu. More recently, Meave Leakey discovered a 3,500,000-year-old skull there, named Kenyanthropus platyops, which means "The Flat-Faced Man of Kenya".

Wind Power

The Lake Turkana Wind Power consortium (LTWP) plans to provide 300 MW of clean power to Kenya's national electricity grid by tapping the unique wind conditions around the lake. The plan calls for 360 wind turbines, each with a capacity of 850 kilowatts. As of March 2010, the project had found financing, and the Kenyan government will take responsibility for the construction of the transmission lines. If completed, it will the largest wind power project in Africa.

credited to wikipedia

Mono Lake is an alkaline and hypersaline lake in Mono County, California that is a critical nesting habitat for several bird species and is an unusually productive ecosystem.

Geology

Mono Lake is believed to have formed at least 760,000 years ago, dating back to the Long Valley eruption. Sediments located below the ash layer hint that Mono Lake could be a remnant of a larger and older lake that once covered a large part of Nevada and Utah, making it among the oldest lakes in North America.

Mono Lake is a terminal lake in a watershed fed from melting runoff with no outlet. Dissolved salts in the runoff thus remain in the lake and raise the pH and the salt concentration.

Mono Lake is in a geologically active area at the north end of the Mono-Inyo Crater volcanic chain of the Long Valley Caldera. The geological activity is caused by faulting at the base of the Sierra Nevada, and is associated with the crustal stretching of the Basin and Range Province.

Volcanic activity continues in the Mono Lake vicinity: the most recent eruption occurred 350 years ago at Paoha Island in Mono Lake. Panum Crater (on the south shore of the lake) is an excellent example of a combined rhyolite dome and cinder cone.

Limnology

The lake contains approximately 280 million tons of dissolved salts, with the salinity varying on the amount of water in the lake at any given time. Before 1941, the salinity was approximately 50 grams per liter (g/l) (compared to a value of 31.5 g/l for the world's oceans). In January 1982, when the lake reached its lowest level of 6,372 feet (1,942 m), the salinity had nearly doubled to 99 g/l. In 2002, it was measured at 78 g/l and is expected to stabilize at an average 69 g/l as the lake replenishes over the next 20 years.

An important aspect of the end of water diversions was an onset of "meromixis" in Mono Lake. Prior to the end of water diversions, Mono Lake was typically "monomictic," which means that at least once each year the deeper waters and the shallower waters of the lake mixed thoroughly, thus bring oxygen and other nutrients to the deeper waters. In meromictic lakes, the deeper waters do not undergo this mixing. In meromictic lakes, the deeper layers are more saline than the water near the surface, and are typically nearly devoid of oxygen. As a result, meromixis greatly changes a lake's ecology.

Mono Lake has undergone meromictic periods prior to the one commencing in 1994, and this most recent meromictic period brought on by the end of water diversions ended by 2004.

Ecology

The hypersalinity and high alkalinity (pH=10 or equivalent to 2.5 grams of NaOH per liter of water) of the lake, means that no fish are native to the lake. An attempt by the California Department of Fish and Game to stock the lake failed. The lake is famous for the Mono Lake brine shrimp, Artemia monica, a tiny species of brine shrimp, no bigger than a thumbnail, that are found nowhere else on earth. During the warmer summer months, an estimated 4-6 trillion brine shrimp inhabit the lake. The brine shrimp feed on microscopic planktonic algae which reproduce rapidly during winter and early spring after winter runoff brings nutrients to the surface layer of water. By March the lake is "as green as pea soup" with photosynthesizing algae. Brine shrimp has no food value for humans, but is a staple for birds of the region. Also an important food source, alkali flies (Ephydra hians) live along the shores of the lake and walk underwater encased in small air bubbles to graze and to lay eggs. The whole food chain of the lake is based on the high population of single-celled algae present in the warm shallow waters.

Mono Lake is a vital resting and eating stop for migratory shorebirds and has been recognized as a site of international importance by the Western Hemisphere Shorebird Reserve Network. Nearly 2,000,000 waterbirds, including 35 species of shorebirds, use Mono Lake to rest and eat for at least part of the year. Some shorebirds that depend on the resources of Mono Lake include American Avocets, Killdeer and sandpipers. Over 1.5 million Eared Grebes and phalaropes use Mono Lake during their long migrations.

Late every summer tens of thousands of Wilson's Phalaropes and Red-necked Phalaropes arrive from their nesting grounds, and feed until they continue their migration to South America or the tropical oceans respectively.

In addition to migratory birds, a few species spend several months to nest at Mono Lake. Mono Lake is the second largest nesting population of California Gulls, second only to the Great Salt Lake in Utah. After abandoning the landbridged Negit Island in the late 1970s, California gulls have moved to some nearby islets and have established new, if less protected nesting sites. Cornell University and Point Reyes Bird Observatory have continued the study of nesting populations on Mono Lake that was begun over 20 years ago. Snowy Plovers also arrive at Mono Lake each spring to nest along the remote eastern shores.

credited to wikipedia and flickr: Bill Wight CA