Misplaced Pages

#988011

104-841: The Urewe culture developed and spread in and around the Lake Victoria region of Africa during the African Iron Age . The culture's earliest dated artefacts are located in the Kagera Region of Tanzania , and it extended as far west as the Kivu region of the Democratic Republic of the Congo , as far east as the Nyanza and Western provinces of Kenya , and north into Uganda , Rwanda and Burundi . Sites from

208-401: A basin filled with fresh green leafy branches and herbs which served as a filter for the slag deposit at the base. Above the basin was a cone-shaped shaft, not unlike a chimney, made by superimposing rolls of damp clay. The decorated furnace, with its fluted patterns on the upper roll and deeply incised criss-cross or s-shaped patterns on the outer surface, may be reminiscent of the rim or neck of

312-556: A few species are extinct in the wild (only survive in captivity). Before the mass extinction that has occurred among the lake's cichlids in the last 50 years, about 90 percent of the native fish species in the lake were haplochromines. Disregarding the haplochromines, the only native Victoria cichlids are two critically endangered tilapia, the Singida tilapia or ngege ( Oreochromis esculentus ) and Victoria tilapia ( O. variabilis ). In 1927–1928 Michael Graham conducted

416-447: A few types of chemical degradation. Toxins can accumulate in the soil from industrial processes like mining and waste management . Some biological examples include biodiversity loss , emitting greenhouse gasses , reduced carbon content, and a reduced capacity to sequester carbon. One of the most predictable ways to determine whether soil degradation has occurred is to measure its organic carbon content. The soil organic carbon pool

520-459: A great deal of intense debate within the scientific community of the day, but also much interest by other explorers keen to either confirm or refute Speke's discovery. In the late 1860s, the famous Scottish explorer and missionary David Livingstone failed in his attempt to verify Speke's discovery, instead pushing too far west and entering the River Congo system instead. Ultimately,

624-519: A maximum depth of 80–81 m (262–266 ft). Its catchment area covers 169,858 km (65,583 sq mi). The lake has a shoreline of 7,142 km (4,438 mi) when digitized at the 1:25,000 level, with islands constituting 3.7% of this length. The lake's area is divided among three countries: Tanzania occupies 49% (33,700 km (13,000 sq mi)), Uganda 45% (31,000 km (12,000 sq mi)), and Kenya 6% (4,100 km (1,600 sq mi)). The lake

728-797: A result of the spread of the invasive water hyacinth (an optimum snail habitat), and the loss of many snail-eating cichlids in the lake. Evarcha culicivora is a species of jumping spider (family Salticidae ) found only around Lake Victoria in Kenya and Uganda. It feeds primarily on female mosquitos. Lake Victoria supports Africa's largest inland fishery (as of 1997). Initially the fishery involved native species, especially tilapia and haplochromine cichlids, but also catfish ( Bagrus , Clarias , Synodontis and silver butter catfish), elephantfish, ningu ( Labeo victorianus ) and marbled lungfish ( Protopterus aethiopicus ). Some of these, including tilapia and ningu ( Labeo victorianus ), had already declined in

832-399: A ribboned pattern of crafted geometrical designs, and a dimple base finish. The decorative markings are adapted to and emphasise the shape of the vase with its 4 components, often seen on the little vase in simplified form. Conversely, these '4 component' patterns are all stuck on the bowl; regardless of its '3 components' shape. One proposed hypothesis suggests the bowl was developed later than

936-613: A second hydroelectric complex in the area, the Kiira Hydroelectric Power Station , with World Bank assistance. By 2006, the water levels in Lake Victoria had reached an 80-year low, and Daniel Kull, an independent hydrologist living in Nairobi , Kenya, calculated that Uganda was releasing about twice as much water as is allowed under the agreement, and was primarily responsible for recent drops in

1040-491: A sieve. The water is then ready to be chlorinated or treated in another way. The sand filtration helps reduce water-borne diseases and is based on the use of the local environment. The only outflow for Lake Victoria is at Jinja, Uganda, where it forms the Victoria Nile. The water for at least 12,000 years has drained across a natural rock weir. In 1952, engineers acting for the government of Colonial Uganda blasted out

1144-452: A sustainable and resilient ecosystem. This can be accomplished through intentional landscaping to increase the efficiency of capturing rainfall into the system or by placing nitrogen-fixing plants near nitrogen-demanding plants, such as legumes . Utilizing the interconnections of various plants, animals, and processes is a key practice in permaculture. Native plants should be used whenever possible, their roots help water infiltrate deep into

SECTION 10

#1732764749989

1248-486: A variety of activities. The Urewe would have lived a relatively sedentary life as farmers, devoting themselves to agriculture (including cereal growing) and small-scale cattle rearing. They do not appear to have supplemented their diet by hunting and fishing as will be the case in these areas in the late Iron Age, and which occurred in the early Iron Age in those more east-lying Urewe civilisations around Lake Victoria, influenced perhaps by contacts with nomadic communities along

1352-453: A variety of plants, always keeping soil covered, maintaining a living root system, and minimizing soil disturbance. Macro and micro organisms assist with processes such as decomposition , nutrient cycling, disease suppression, and moderating CO 2 in the atmosphere . Plants have a particularly symbiotic relationship with microbes in the rhizosphere of the soil. The rhizosphere is an "area of concentrated microbial activity close to

1456-583: A water and sanitation project that serves Mwanza and the satellite towns of Lamadi, Misungwi, Magu, Bukoba, and Musoma on the bank of Lake Victoria.  European Investment Bank started the project in 2013 with the aim of protecting the environmental health of the lake, through improved water and sanitation to the towns whose pollution is part of the degradation of the lake. The project aims to provide safe drinking water for an estimated one million people and improved sanitation for 100 000 people. Sediment and suspended solids are filtered out using sand, which acts like

1560-436: Is Caridina nilotica , which is common and widespread in Lake Victoria. Lake Victoria is home to 28 species of freshwater snails (e.g., Bellamya , Biomphalaria , Bulinus , Cleopatra , Gabbiella , and Melanoides ), including 12 endemic species/subspecies. There are 17 species of bivalves ( Corbicula , Coelatura , Sphaerium , and Byssanodonta ), including 6 endemic species and subspecies. It

1664-517: Is a lack of pests and diseases. Low biodiversity increases the risk of pests and diseases. Having too much or too little of any of the components of soil can cause soil degradation . For example, having a high clay content reduces aeration and water permeability . Another example is that, though phosphorus and nitrogen are essential for plant growth, they are toxic in high amounts. Soil degradation means that soil quality has diminished, which causes ecosystem functions to decline. One third of

1768-583: Is a part of the same river system known as the White Nile and is occasionally referred to as such, strictly speaking this name does not apply until after the river crosses the Uganda border into South Sudan to the north. The lake exhibits eutrophic conditions . In 1990–1991, oxygen concentrations in the mixed layer were higher than in 1960–1961, with nearly continuous oxygen supersaturation in surface waters. Oxygen concentrations in hypolimnetic waters (i.e.,

1872-465: Is being altered and in some cases, broken by the indiscriminate eating habits of the Nile perch. The subsequent decrease in the number of algae-eating fish allows the algae to grow at an alarming rate, thereby choking the lake. The increasing amounts of algae, in turn, increase the amount of detritus (dead plant material) that falls to the deeper portions of the lake before decomposing. As a by-product of this

1976-404: Is composed of organic matter (decomposing plants, animals, and microbes), biomass (living plants, animals, and microbes), water, air, minerals (sand, silt, and clay), and nutrients (nitrogen, carbon, phosphorus). For optimal plant growth , a proper carbon to nitrogen ratio of 20–30:1 must be maintained. Promoting biodiversity is key to maintaining healthy soil. This can be done by growing

2080-523: Is extremely important for soil fertility . There is a significant connection between the carbon cycle and climate change . Most greenhouse gases are primarily composed of carbon and they produce an effect where warmer air that is heated by the sun is kept from leaving the atmosphere by forming a barrier in the troposphere . According to the Intergovernmental Panel on Climate Change , greenhouse gasses produced by human activity are

2184-460: Is home to many species of fish which live nowhere else, especially cichlids . Invasive fish, such as the Nile perch , have driven many endemic species to extinction . Though having multiple local language names ( Swahili : Ukerewe ; Dholuo : Nam Lolwe ; Luganda : 'Nnalubaale ; Kinyarwanda : Nyanza ), the lake was renamed after Queen Victoria by the explorer John Hanning Speke ,

SECTION 20

#1732764749989

2288-690: Is in remission and this trend could be permanent if control efforts are continued. Pollution of Lake Victoria is mainly due to discharge of raw sewage into the lake, dumping of domestic and industrial waste, and fertiliser and chemicals from farms. The Lake Victoria basin, while generally rural, has many major centres of population. Its shores are dotted with key cities and towns, including Kisumu , Kisii , and Homa Bay in Kenya; Kampala , Jinja and Entebbe in Uganda; and Bukoba, Mwanza , and Musoma in Tanzania. These cities and towns are also home to many factories that discharge some chemicals directly into

2392-453: Is likely that undescribed species of snails remain. Conversely, genetic studies indicate that some morphologically distinctive populations, traditionally regarded as separate species, may only be variants of single species. Two of the snail genera, Biomphalaria and Bulinus , are intermediate hosts of the parasite that causes bilharzia (schistosomiasis). Human infections by this parasite are common at Lake Victoria. This may increase as

2496-479: Is near-endemic. Four species of freshwater crabs are known from Lake Victoria: Potamonautes niloticus is widespread in the lake and P. emini has been recorded from the vicinity of Bukoba in Tanzania, but both are also found elsewhere in Africa. The last were first scientifically described in 2017 and very little is known about them: P. entebbe is only known from near Entebbe (the only known specimen

2600-607: Is ongoing in the Great Lakes region on the initiative of London University in collaboration with the BIEA. 0°02′51″S 34°20′15″E  /  0.04750°S 34.33750°E  / -0.04750; 34.33750 Lake Victoria Lake Victoria is one of the African Great Lakes . With a surface area of approximately 59,947 km (23,146 sq mi), Lake Victoria is Africa's largest lake by area,

2704-511: Is relatively reliable. Environmental studies combine the tree species identification of charcoal collected from iron smelting furnaces and open hearths, palynological analyses of high altitude and valley peat bogs as well as in archaeological structures as well as phyto-sociological and geomorphologic data. The settlement period of the Urewe civilisation should be seen in the context of a cooling and drying out period in about 1000 BC. Those members of

2808-534: Is the continuity of language. This civilisation emerges in the region during the transition from the second to the first millennium B.C. and seems to have thrived in various sites well into the second millennium A.D. It underwent its greatest period of expansion, allied to an important metalworking activity, from the first to the sixth century A.D. and covered the Kivu region (in the Democratic Republic of

2912-485: The African humid period began. Lake Victoria receives 80 percent of its water from direct rainfall. Average evaporation on the lake is between 2.0 and 2.2 metres (6.6 and 7.2 ft) per year, almost double the precipitation of riparian areas. Lake Victoria receives its water additionally from rivers, and thousands of small streams . The Kagera River is the largest river flowing into this lake, with its mouth on

3016-525: The Welsh-American explorer Henry Morton Stanley , on an expedition funded by the New York Herald newspaper, confirmed the truth of Speke's discovery, circumnavigating the lake and reporting the great outflow at Ripon Falls on the lake's northern shore. Many towns and cities are reliant on Lake Victoria for their water supplies, for farming and other uses. The Lamadi water scheme is

3120-443: The hippopotamus , African clawless otter , spotted-necked otter , marsh mongoose , sitatunga , bohor reedbuck , defassa waterbuck , cane rats , and giant otter shrew . Lake Victoria and its wetlands has a large population of Nile crocodiles , as well as African helmeted turtles , variable mud turtles , and Williams' mud turtle . The Williams' mud turtle is restricted to Lake Victoria and other lakes, rivers, and swamps in

3224-452: The lithosphere and biospheres to the atmosphere. By means of fossil fuels and intensive farming , much of the natural carbon in the Earth's pedosphere has been released into the atmosphere, contributing to greenhouse gasses. There are many ways to regenerate soil and improve soil quality, such as land management by conservation agriculture . Agriculture is one of the main factors in

Urewe - Misplaced Pages Continue

3328-729: The pH of the soil, adding nutrients, and promoting the activity of organisms. The current conditions of the soil will determine which type of amendment and how much to use. Inorganic amendments are generally used for things like improving the texture and structure of the soil, balancing the pH, and limiting the bioavailability of heavy metal toxins. There are two types of inorganic amendments: alkaline and mineral. Some examples of inorganic amendments include wood ash, ground limestone, and red mud. Mineral amendments include gypsum and dredged materials. Organic amendments improve biological activity, water permeability, and soil structure. Mulch , for example, reduces erosion and helps to maintain

3432-586: The 7th century, the appearance of simpler, roulette-decorated, ceramic pottery as well as new types of iron furnace, heralded a major change towards the late Iron Age. However, the Urewe civilisation did manage to survive in isolated pockets at least up to the 14th century. The authors and major institutions linked to research into the Urewe civilisation in the Great Lakes region are: Mary Leakey (Owen collection published in 1948), Jean Hiernaux (excavations and publications 1960–70), Merrick Posnansky (excavations and publications 1960–70), David Phillipson (Synthesis of

3536-498: The Congo) to the west up to Uganda, Rwanda, and Burundi in north-west Tanzania and south-west Kenya. Urewe seems to be a fully developed civilisation recognizable through its distinctive, stylish earthenware and highly technical and sophisticated iron working techniques. Their pottery incorporated such distinctive features as dimples and concentric lines. However, minor local variations in the ceramic ware can be observed. The origins of

3640-754: The Early Iron Age in Eastern Africa in 1976), the British Institute in Eastern Africa (BIEA), in Nairobi, under the aegis of J.E.G. Sutton (within the Bantu Studies Project, excavations and publications 1960–70), Peter Schmidt (excavations and publications 1970–80, synthesis 1997), Marie-Claude Van Grunderbeek, Emile Roche and Hugues Doutrelepont (excavations 1978–87, publications up to the present day). New on-site research

3744-606: The Great Lakes. Believing he had found the source of the Nile on seeing this "vast expanse of open water" for the first time, Speke named the lake after Queen Victoria. Burton, who had been recovering from illness at the time and resting further south in Kazeh (near present-day Tabora ), was outraged that Speke claimed to have proved his discovery to have been the true source of the Nile River, which Burton regarded as still unsettled. A very public quarrel ensued, which not only sparked

3848-468: The Nile perch, since that requires a significant amount of capital resources. The water hyacinth has become a major invasive plant species in Lake Victoria. The release of large amounts of untreated wastewater (sewage) and agricultural and industrial runoff directly into Lake Victoria over the past 30 years has greatly increased the nutrient levels of nitrogen and phosphorus in the lake "triggering massive growth of exotic water hyacinth, which colonised

3952-582: The Owen Falls Dam in 1954. This allowed it to spread to Lake Kyoga where additional Nile perch were released in 1955, but not Victoria itself. Scientists argued that further introduction should wait until research showed the effect of the introduction in Kyoga, but by the late 1950s, Nile perch began being caught in Lake Victoria. As the species was already present, there were few objections when more Nile perch were transferred to Victoria to further bolster

4056-450: The Owen Falls Dam when shut down for maintenance, but this is considered highly unlikely by many scientists. The Nile perch had spread throughout the lake by 1970. Initially the population of the Nile perch was relatively low, but a drastic increase happened, peaking in the 1980s, followed by a decline starting in the 1990s. Due to the presence of the Nile perch, the natural balance of the lake's ecosystem has been disrupted. The food chain

4160-557: The Urewe Culture spoke the Proto-Great Lakes Bantu language . Urewe ceramics are modest in size, measuring from 30 cm up to a maximum of 36 cm in height. Three distinct shapes have been observed: vases, small vases, both closed s-shaped pieces, open-bowls on which stereotyped patterns have been crafted: and bevelling on the rim, hatching on the neck surface for ease of handling, the body decorated with

4264-562: The Urewe civilisation who settled in Rwanda and Burundi did so exclusively in the hills region (central plain) in a 1700 and 1300 meters high zone on clay soils on primary substrate which are some of Africa's richest. The undulating countryside, covered with woodland savanna (tree cover vegetation, sparser on the slopes and denser in valleys and on crests) together provided good living conditions (moderate temperatures and average rainfall, protected from carriers of human and animal disease) encouraged

Urewe - Misplaced Pages Continue

4368-685: The Urewe culture are thought to ultimately be in the Bantu expansion originating in Cameroon . Research into early Iron Age civilisations in sub-Saharan Africa has been undertaken concurrently with studies on Niger–Congo linguistics on Bantu expansion. The Urewe culture may correspond to the Eastern subfamily of Bantu languages , spoken by the descendants of the first wave of Bantu peoples to settle East Africa . The inhabitants were likely cattle herders and millet and sorghum farmers. The people of

4472-419: The Urewe culture date from the Early Iron Age, from the 5th century BC to the 6th century AD. The Urewe people certainly did not disappear, and the continuity of institutional life was never completely broken. One of the most striking things about the Early Iron Age pots and smelting furnaces is that some of them were discovered at sites that the local people still associate with royalty, and still more significant

4576-438: The ceramic pottery. Analyses carried out on the ironworking residue have not yet provided data on the efficiency of these furnaces, or whether they were a measure of their technical nature. Iron ore and fuel were readily available. The word "ubutare" meaning "iron" still crops up in many place names. The wooded crown cover was used to produce charcoal. As new wood was always used for this purpose, radiocarbon dating of this material

4680-462: The colonial government. In the following decades, the pressure to introduce the Nile perch continued, as did warnings about the possible effects of doing it. The first introduction of Nile perch to the region, done by the Uganda Game and Fisheries Department (then part of the colonial government) and local African fish guards, happened upstream of Murchison Falls directly after the completion of

4784-575: The complete disappearance of many endemic cichlid species has been called the "most dramatic example of human-caused extinctions within an ecosystem". Starting in the 1950s, many species have been introduced to Lake Victoria where they have become invasive and a prime reason for the extinction of many endemic haplochromine cichlids. Among the introductions are several tilapias : redbreast ( Coptodon rendalli ), redbelly ( C. zillii ), Nile ( Oreochromis niloticus ) and blue-spotted tilapias ( O. leucostictus ). Although these have contributed to

4888-544: The current Lake Victoria basin . During its geological history, Lake Victoria went through changes ranging from its present shallow depression, through to what may have been a series of much smaller lakes. Geological cores taken from its bottom show Lake Victoria has dried up completely at least three times since it formed. These drying cycles are probably related to past ice ages , which were times when precipitation declined globally. Lake Victoria last dried out about 17,300 years ago, and it refilled 14,700 years ago as

4992-416: The depletion of soil richness. As one historical review put it, "Accelerated soil erosion has plagued the earth since the dawn of settled agriculture, and has been a major issue in the rise and fall of early civilization." Certain agricultural practices can deplete the soil of carbon, such as monoculture , where only one type of crop is harvested in a field season after season. This depletes nutrients from

5096-423: The detritivores). The zooplanktivores have been least affected and in the late 1990s had reached densities similar to, or above, the densities before the drastic declines, although consisting of fewer species and often switching their diet towards macroinvertebrates . Some of the threatened Lake Victoria cichlid species have captive "insurance" populations in zoos, public aquaria and among private aquarists, and

5200-413: The east African Rift Valley. Combined human activities, land clearance, ironworking, cereal growing, etc., led to the deforestation of fringes of the great forest which once covered the north–south backbone as well as the forest corridors along the water sources which caused soil erosion on the slopes. This phenomenon led to the extensive erosion of Kabuye hill near Butare as a result of their occupation of

5304-422: The ecosystem, it is estimated that at least 200 species (about 40 percent) of Lake Victoria haplochromines have become extinct, including more than 100 undescribed species. Initially it was feared that this number was even higher, by some estimates 65 percent of the total species, but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990s. Several of

SECTION 50

#1732764749989

5408-480: The end of 2001. Greater growth was observed in the northern part of the lake, in relatively protected areas, which may be linked to current and weather patterns and could also be due to the climate and water conditions, which are more suitable to the plants growth (as there are large urban areas to the north end of the lake, in Uganda). The invasive weed was first attempted to be controlled by hand, removed manually from

5512-418: The extinction of native fish by causing significant changes to the ecosystem , outcompeted natives and (in the case of the Nile tilapia) possibly hybridized with the highly threatened native tilapias, the most infamous introduction was the large and highly predatory Nile perch ( Lates niloticus ). As early as the 1920s, it was proposed to introduce a large pelagic predator such as the Nile perch to improve

5616-450: The feeding apparatus, changes to the eyes (giving them better sight in turbid water) and smaller head/larger caudal peduncle (allowing faster swimming). The piscivorous (affected by both predation and competition from Nile perch ), molluscivorous and insectivorous haplochromines were particularly hard hit with many extinctions. Others have become extinct in their pure form, but survive as hybrids between close relatives (especially among

5720-486: The fertility of the lake is dependent on the rate at which these nutrients can be taken 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 percent 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

5824-487: The first Briton to document it in 1858, while on an expedition with Richard Francis Burton . Geologically, Lake Victoria is relatively young at about 400,000 years old. It was formed when westward-flowing rivers were dammed by an upthrown crustal block. During the Miocene era, what is now the catchment area of the lake was on the western side of an uplifted area that functioned as a continental divide, with streams on

5928-492: The first ever systematic Fisheries Survey of Lake Victoria . In his official report of the expedition, Graham wrote that "The ngege or satu Tilapia esculenta , is the most important food fish of the lake, whether for native or non-native consumption. No other fish equals it in the quality of the flesh. It is convenient size for trade, travels well and is found in much greater numbers than other important fish, such as semutundu (Luganda), Bagrus sp. ". Furthermore, Graham noted that

6032-406: The first half of the 20th century due to overfishing . To boost fishing, several species of non-native tilapia and Nile perch were introduced to the lake in the 1950s. Nevertheless, the natives continued to dominate fisheries until the 1970s where their decline meant that there was a strong shift towards the non-native Nile tilapia (now 7 percent of catches), non-native Nile perch (60 percent) and

6136-514: The first true bathymetric map of the lake. The deepest part of the lake is offset to the east of the lake near Kenya and the lake is generally shallower in the west along the Ugandan shoreline and the south along the Tanzanian shoreline. Many mammal species live in the region of Lake Victoria, and some of these are closely associated with the lake itself and the nearby wetlands. Among these are

6240-401: The fisheries in the lake. At the same time it was warned that this could present a serious danger to the native fish species and required extensive research into possible ecological effects before done. These warnings primarily concerned the native tilapia O. esculentus , as the smaller haplochromine cichlids (despite playing an important role in local fisheries) were regarded as "trash fish" by

6344-422: The globe's land has degraded soil; especially the tropics and subtropics with around 500 million hectares . Soil degradation occurs due to physical, chemical, and biological forces. These forces can be natural and anthropogenic . Tilling is a physical example which causes erosion, compaction , and decreased microbial activity. Erosion is “one of the most serious problems facing urban soil quality", and

SECTION 60

#1732764749989

6448-458: The inland routes in search of gold , ivory , other precious commodities, and slaves . The lake existed and was known to many Africans in the catchment area who left no written records long before it was sighted by a European in 1858 when the British explorer John Hanning Speke reached its southern shore while on his journey with Richard Francis Burton to explore central Africa and locate

6552-521: The intake of water for industries. On the other hand, water hyacinth mats can potentially have a positive effect on fish life in that they create a barrier to overfishing and allow for fish growth, there has even been the reappearance of some fish species thought to have been extinct in recent years. The overall effects of the water hyacinth, however, are still unknown. Growth of the water hyacinth in Lake Victoria has been tracked since 1993, reaching its maxima biomass in 1997 and then declining again by

6656-411: The introduction of MV  Uhuru and MV  Umoja . The ferry MV Bukoba sank in the lake on 21 May 1996 with a loss of between 800 and 1,000 lives, making it one of Africa's worst maritime disasters. Another tragedy occurred recently on 20 September 2018 that involved the passagers ferry MV Nyerere from Tanzania that caused the deaths of over 200 people. On 6 November 2022, Lake Victoria

6760-547: The introduction of Nile perch , the extinction of cichlids in the genus Haplochromis has also been blamed on the lake's eutrophication. 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, most of Lake Victoria's nutrients are thought to be locked up in lake-bottom deposits. By itself, this vegetative matter decays slowly. Animal flesh decays considerably faster, however, so

6864-805: The introduction of the European flax gill net of 5 inch mesh had undoubtedly caused a diminution in the number of ngege in those parts of the Kavirondo Gulf, the northern shore of the lake, the Sesse Islands and Smith's Sound which are conveniently situated close to markets. Survey catches in 1927–28 included several Haplochromis species that are now thought to be extinct, including: Haplochromis flavipinnis , Haplochromis gowersii , Haplochromis longirostris , Haplochromis macrognathus , Haplochromis michaeli , Haplochromis nigrescens , Haplochromis prognathus . As well as being due to

6968-406: The lake for its natural resources. Hundreds of endemic species that evolved under the special conditions offered by the protection of Lake Victoria have been lost due to extinction, and several more are still threatened. Their loss is devastating for the lake, the fields of ecology, genetics and evolution biology, and more evidently, for the local fisheries. Local fisheries once depended on catching

7072-411: The lake in the late 1990s". This invasive weed creates anoxic (total depletion of oxygen levels) conditions in the lake, inhibiting decomposing plant material, raising toxicity and disease levels to both fish and people. At the same time, the plant's mat or "web" creates a barrier for boats and ferries to maneuver, impedes access to the shoreline, interferes with hydroelectric power generation, and blocks

7176-473: The lake or its influent rivers. The set up of small beaches and local authorities around the lake lack proper sewage treatment facilities allowing pollutants to find their way into the water. Large parts of these urban areas also discharge untreated (raw) sewage into the river, increasing its eutrophication that in turn is helping to increase the invasive water hyacinth. Increased logging and act of deforestation has led to environmental degradation around

7280-405: The lake's level. Since the 1900s, Lake Victoria ferries have been an important means of transport between Uganda, Tanzania, and Kenya. The main ports on the lake are Kisumu, Mwanza, Bukoba, Entebbe , Port Bell , and Jinja. Until 1963, the fastest and newest ferry, MV Victoria , was designated a Royal Mail Ship . In 1966, train ferry services between Kenya and Tanzania were established with

7384-515: The lake's western shore. Lake Victoria is drained solely by the Nile River near Jinja, Uganda, on the lake's northern shore. In the Kenya sector, the main influent rivers are the Sio , Nzoia , Yala , Nyando , Sondu Miriu , Mogusi , and Migori . The only outflow from Lake Victoria is the Nile River, which exits the lake near Jinja, Uganda. In terms of contributed water, this makes Lake Victoria

7488-496: The lake's wide area; from increased nutrient inflows via rivers, and from increased pollution associated with settlement along its shores. Between 2010 and 2022 the surface area of Lake Victoria increased by 15% flooding lakeside communities. The lake is considered a shallow lake considering its large geographic area with a maximum depth of approximately 80 metres (260 ft) and an average depth of 40 metres (130 ft). A 2016 project digitized ten-thousand points and created

7592-449: The lake; however, re-growth occurred quickly. Public awareness exercises were also conducted. More recently, measures have been used such as the introduction of natural insect predators, including two different water hyacinth weevils and large harvesting and chopping boats, which seem to be much more effective in eliminating the water hyacinth. A green power plant that uses harvested water hyacinth (but also can use other degradable waste)

7696-634: 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 (< 0.4  gr /cu ft) occurring in water as shallow as 40 metres (130 ft) compared with a shallowest occurrence of greater than 50 metres (160 ft) in 1961. The changes in oxygenation are considered consistent with measurements of higher algal biomass and productivity. These changes have arisen for multiple reasons: successive burning within its basin, soot and ash from which has been deposited over

7800-404: The lungfish, tilapia, carp and catfish that comprise the local diet. Today, the composition and yields of such fish catches are virtually negligible. Extensive fish kills, Nile perch, loss of habitat and overfishing have caused many fisheries to collapse and many protein sources to be unavailable at the market for local consumption. Few fisheries, though, have been able to make the switch to catching

7904-530: The most significant cause of global climate change since the 1950s. Without human interaction, carbon is removed from and reintroduced to soil through a variety of ecosystem processes known as the carbon cycle . Humans have been significantly influencing the global carbon cycle since the Industrial Revolution through various means, such as transportation and agriculture . Through these actions, most of this carbon has moved in one direction, from

8008-459: The native Lake Victoria sardine (30 percent). Because of its small size, the abundant open-water Lake Victoria sardine only supported minor fisheries until the decline of other natives. At the peak in the early 1990s, 500,000 tonnes (490,000 long tons; 550,000 short tons) of Nile perch were landed annually in Lake Victoria, but this has declined significantly in later years. A number of environmental issues are associated with Lake Victoria and

8112-462: The oxygen levels in the deeper layer of water are being depleted. Without oxygen, any aerobic life (such as fish) cannot exist in the deeper parts of the lake, forcing all life to exist within a narrow range of depth. In this way, the Nile perch has degraded the diverse and thriving ecosystem that was once Lake Victoria. The abundance of aquatic life is not the only dependent of the lake: more than thirty million people in Tanzania, Kenya and Uganda rely on

8216-540: The plants. Heavy winds and rains along with their subsequent waves may have also damaged the plants during this same time frame. The plants may not have been destroyed, instead merely moved to another location. Additionally, the water quality, nutrient supply, temperature, and other environmental factors could have played a role. Overall, the timing of the decline could be linked to all of these factors and perhaps together, in combination, they were more effective than any one deterrent would have been by itself. The water hyacinth

8320-570: The principal source of the longest branch of the Nile. However, the most distal source of the Nile Basin, and therefore the ultimate source of the Nile , is more often considered to be one of the tributary rivers of the Kagera River (the exact tributary remains undetermined), and which originates in either Rwanda or Burundi . The uppermost section of the Nile is generally known as the Victoria Nile until it reaches Lake Albert . Although it

8424-499: The problem is exacerbated by uncovered soil. Compaction occurs when soil is pushed together and becomes harder, so the ability to retain air and water is diminished. This increases erosion and flooding, diminishes the ability of plants to grow good root systems, and reduces biological diversity. Overgrazing is another example in which the root system beneath the soil is damaged, reducing water permeability. Acidification , salinization , nutrient leaching , and toxin contamination are

8528-577: The region dried out, as happened to Lake Victoria about 15,000 years ago. In recent history only Lake Kyoga was easily accessible to Victoria cichlids, as further downstream movement by the Victoria Nile (to Lake Albert) is prevented by a series of waterfalls, notably Murchison . In contrast, the Owen Falls (now flooded by a dam ) between Victoria and Kyoga were essentially a series of rapids that did not effectively block fish movements between

8632-403: The region reducing the absorption of polluting chemicals and deteriorating the water quality. As of 2016, an environmental data repository exists for Lake Victoria. The repository contains shoreline, bathymetry, pollution, temperature, wind vector, and other important data for both the lake and the wider Basin. The first recorded information about Lake Victoria comes from Arab traders plying

8736-598: The region, notably Kyoga , Edward – George , Albert, and Kivu . Most of these lakes are relatively shallow (like Victoria) and part of the present-day upper Nile basin. The exception is Lake Kivu, which is part of the present-day Congo River basin , but is believed to have been connected to Lakes Edward and Victoria by rivers until the uplifting of parts of the East African Rift . This deep lake may have functioned as an "evolutionary reservoir" for this haplochromine group in periods where other shallower lakes in

8840-403: The remaining species are seriously threatened and additional extinctions are possible. Some species have survived in nearby small satellite lakes, have survived in refugias among rocks or papyrus sedges (protecting them from the Nile perch), or have adapted to the human-induced changes in the lake itself. Such adaptions include a larger gill area (adaption for oxygen-poor water), changes in

8944-408: The root" and where water and nutrients are readily available. Plants exchange carbohydrates for nutrients excreted by the microbes, different carbohydrates support different microbes. Dead plants and other organic matter also feed the variety of organisms in the soil. Organisms like earthworms and termites are examples of macro organisms in the soil. A good indication that you have quality soil

9048-512: The site for about 500 years. The hilly region of Rwanda and Burundi was probably a well frequented route from the northern to the southern hemisphere in Africa and would therefore have regularly experienced the relative overcrowding of people fleeing the drought-ridden Sahel regions which impeded soil regeneration . On the contrary, the impact of human activity, combined with consecutive periods of hot, dry climatic conditions have only served to aggravate soil degradation up to modern times. Since

9152-731: The soil because each type of plant has a specific set of nutrients that it requires to grow or that it can fix back into the soil. With a lack of plant diversity, only certain nutrients will be absorbed. Over time, these nutrients will be depleted from the soil. Agroecology is an overarching category of approaches to creating a more sustainable agricultural system and increasing soil health. These conservation agricultural practices utilize many techniques and resources to maintain healthy soil. Some examples are cover cropping , crop rotation , reducing soil disturbance, retaining mulch , and integrated nutrient management . These practices have many benefits, including increased carbon sequestration and reducing

9256-416: The soil. holistic management stems from the work of Allan Savory , who observes that planned grazing can improve soil health and reverse the effects of desertification by increasing biomass. Researchers dispute the desertification claim. There are also many kinds of soil amendments , both organic and inorganic. They promote soil quality in a variety of ways, such as sequestering toxins, balancing

9360-422: The spiny eel Mastacembelus frenatus , elephantfish ( Gnathonemus , Hippopotamyrus , Marcusenius , Mormyrus , Petrocephalus , and Pollimyrus ), the climbing gourami Ctenopoma muriei and marbled lungfish ( Protopterus aethiopicus ). At a genus level, most of these are widespread in Africa, but the very rare Xenobarbus and Xenoclarias are endemic to the lake, and the common Rastrineobola

9464-515: The stock in 1962–63. The origin of the first Victoria introductions in the 1950s is not entirely clear and indisputable evidence is lacking. Uganda Game and Fisheries Department (UGFD) officials denied that they were involved, but circumstantial evidence suggests otherwise and local Africans employed by UGFD have said that they introduced the species in 1954–55 under the directive of senior officials. UGFD officials argued that Nile perch must have spread to Lake Victoria by themselves by passing through

9568-415: The temperature of the soil. Compost is rich in organic matter, it is composed of decomposed matter such as food, vegetation, and animal wastes. Adding compost increases the moisture and nutrient content of the soil and promotes biological activity. Creating compost requires careful management of temperature, the carbon to nitrogen ratio, water, and air. Biochar is an amendment that is full of carbon and

9672-411: The two lakes. The Victoria haplochromines are distinctly sexually dimorphic (males relatively brightly colored; females dull), and their ecology is extremely diverse, falling into at least 16 groups, including detritivores , zooplanktivores , insectivores , prawn-eaters, molluscivores and piscivores . As a result of predation by the introduced Nile perch , eutrophication and other changes to

9776-426: The upper Nile basin. Lake Victoria formerly was very rich in fish, including many endemics, but a high percentage of these became extinct since the 1940s. The main group in Lake Victoria is the haplochromine cichlids ( Haplochromis sensu lato ) with more than 500 species, almost all endemic, and including an estimated 300 that still are undescribed . This is far more species of fish than any other lake in

9880-426: The use of fossil fuels. Permaculture (from "permanent" and "agriculture") is a type of conservation agriculture, which is a systems thinking approach that seeks to increase the carbon content of soil by utilizing natural patterns and processes. There is a strong emphasis on knowledge of plants, animals, and natural cycles to promote high-efficiency food production, decrease reliance on human involvement, and create

9984-417: The vase. Support for this comes from the identification, in terms of Bantu linguistics, of a new term first appearing around 1000 B.C. meaning "frying pan" probably serving as a clue to a change in cooking techniques reflecting adaptation to a more sedentary lifestyle when Bantu-speaking people began to settle in the Rwanda and Burundi hills. The ironsmelting furnace associated to these Urewe ceramics comprised

10088-756: The water column, and even out of the lake via predation by humans and terrestrial animals. 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 . The non-cichlid native fish include African tetras ( Brycinus ), cyprinids ( Enteromius , Garra , Labeo , Labeobarbus , Rastrineobola and Xenobarbus ), airbreathing catfish ( Clariallabes , Clarias and Xenoclarias ), bagrid catfish ( Bagrus ), loach catfish ( Amphilius and Zaireichthys ), silver butter catfish ( Schilbe intermedius ), Synodontis squeaker catfish, Nothobranchius killifish, poeciliids ( Aplocheilichthys and Micropanchax ),

10192-403: The weir and reservoir to replace it with an artificial barrage to control the level of the lake and reduce the gradual erosion of the rock weir. A standard for mimicking the old rate of outflow called the "agreed curve" was established, setting the maximum flow rate at 300 to 1,700 cubic metres per second (392–2,224 cu yd /sec) depending on the lake's water level. In 2002, Uganda completed

10296-811: The western side flowing into the Congo River basin and streams on the eastern side flowing to the Indian Ocean. As the East African Rift System formed, the eastern wall of the Albertine Rift (or Western Rift) rose, gradually reversing the drainage towards what is now Lake Victoria. The opening of the main East African Rift and the Albertine Rift downwarped the area between them as the rift walls rose, creating

10400-479: The world's largest tropical lake, and the world's second-largest fresh water lake by surface area after Lake Superior in North America. In terms of volume, Lake Victoria is the world's ninth-largest continental lake , containing about 2,424 km (1.965 × 10  acre⋅ft) of water. Lake Victoria occupies a shallow depression in Africa. The lake has an average depth of 40 m (130 ft) and

10504-431: The world, except Lake Malawi . These are the result of a rapid adaptive radiation in the last circa 15,000 years. Their extraordinary diversity and speed of evolution have been the subjects for many scientists studying the forces that drive the richness of life everywhere. The Victoria haplochromines are part of an older group of more than 700 closely related species, also including those of several smaller lakes in

10608-429: Was collected in 1955 and it is unknown if it was in or near the lake) and P. busungwe only at Busungwe Island in the northwestern part of the lake. The latter likely is the smallest African freshwater crab with a carapace width up to about 1.6 cm (0.6 in), although P. kantsyore of Kagera River , and Platythelphusa maculata and P. polita of Lake Tanganyika are almost as small. The only shrimp/prawn

10712-474: Was constructed in Kisumu County in 2013. In addition to the biogas it produces, its by-product can be used as fertilizer . Other factors which may have contributed to the decline of the water hyacinth in Lake Victoria include varying weather patterns, such as El Niño during the last few months of 1997 and first six months of 1998 bringing with it higher levels of water in the lake and thus dislodging

10816-525: Was the site of a commercial passenger aircraft crash. Precision Air Flight 494 an ATR 42–500 carrying 39 passengers and four crew, crashed while approaching Bukoba Airport , resulting in 19 fatalities. Soil regeneration Soil quality means the ability of the soil to "perform its functions." Soil is integral to a variety of ecosystem services. These services include food, animal feed, and fiber production, climate moderation, waste disposal, water filtration, elemental cycling, and much more. Soil

#988011