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Lake Ejagham
Lake Ejagham is a small lake near Eyumodjock in the Southwest Region, Cameroon, Southwest Region of Cameroon. Unlike many other lakes in the region, it is not a volcanic lake, but is likely a solution basin formed by groundwater during the last glacial period, last Ice Age. This highly isolated lake is roughly oval in shape, lacks an inflow, but has an outflow into the Munaya River (part of the Cross River (Nigeria), Cross River system).Schliewen, U.K., Tautz, D., and Pääbo, S. (1994). ''Sympatric speciation suggested by monophyly of crater lake cichlids.'' Nature (journal), Nature 368(6472): 629-632. The outflow is impassable to most fishes because of a waterfall. Biology Despite its very small size, it supports 7 Endemism, endemic species of coptodonine and oreochromine cichlid fishes (''Coptodon deckerti'', ''Coptodon ejagham, C. ejagham'', ''Coptodon fusiforme, C. fusiforme'', ''Coptodon nigrans, C. nigrans'', ''Sarotherodon lamprechti'', and ''Sarotherodon knauerae, S. knaue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solution Basin
A panhole is a depression or basin eroded into flat or gently sloping cohesive rock.Twidale, C.R., and Bourne, J.A., 2018''Rock basins (gnammas) revisited. ''Géomorphologie: Relief, Processus, Environnement, Articles sous presse, Varia, mis en ligne le 08 janvier 2018, consulté le 01 juillet 2018. Similar terms for this feature are gnamma or rock holes (Australia), armchair hollows, weathering pans (or pits) and solution pans (or pits).Hughes, Kebbi A., 2012''Bacterial Communities and their Influence on the Formation and Development of Potholes in Sandstone Surfaces of the Semi-Arid Colorado Plateau''University of Western Ontario - Electronic Thesis and Dissertation Repository. Paper 543. Some authors refer to panholes also as potholes, which is a term typically used for similarly shaped riverine landforms. In fluvial geomorphology, the term ''pothole'' is typically used for a smooth, bowl-shaped or cylindrical hollow, generally deeper than wide, found developed in the rocky be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coptodon Fusiforme
''Coptodon fusiforme'' is a species of fish in the cichlid family, endemic to Lake Ejagham in western Cameroon. It was only scientifically described in 2010, so has not been rated by the IUCN, but it likely faces the same risks as the critically endangered '' C. deckerti'', which is threatened by pollution and sedimentation from human activities, a catfish from the genus ''Parauchenoglanis'' that has been introduced to the lake, and potentially also by large emissions of carbon dioxide (CO2) from the lake's bottom (compare Lake Nyos),Dunz, A. R., & Schliewen, U. K. (2010). ''Description of a Tilapia (Coptodon) species flock of Lake Ejagham (Cameroon), including a redescription of Tilapia deckerti Thys van den Audenaerde, 1967.'' Spixiana, 33(2): 251-280 although Ejagham is too shallow to contain very high amounts of this gas. It reaches up to in length, and mainly feeds on plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric Speciation
Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species), such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived from the Greek roots ("together") and ("homeland"). The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation.Futuyma, D. J. 2009. ''Evolution'' (2nd edition). Sinauer Associates, Inc. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case, divergence is facilitated by the absence of gene flow. Parapatric speciation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introduced Species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, directly or indirectly, and either deliberately or accidentally. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are considered naturalized. The process of human-caused introduction is distinguished from biological colonization, in which species spread to new areas through "natural" (non-human) means such as storms and rafting. The Latin expression neobiota captures the characteristic that these species are ''new'' biota to their environment in terms of established biological network (e.g. food web) relationships. Neobiota can further be divided into neozoa (also: neozoons, sing. neozoon, i.e. animals) and neophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parauchenoglanis
''Parauchenoglanis'' is a genus of claroteid catfishes native to Africa. The range of the genus ''Parauchenoglanis'' stretches from the coastal lowlands of Benin and Nigeria to the Okavango and upper Zambezi River systems in Botswana and Zambia. Species ''Parauchenoglanis'' currently contains the following nine recognized species: * '' Parauchenoglanis ahli'' (Holly, 1930) * '' Parauchenoglanis altipinnis'' (Boulenger, 1911) * '' Parauchenoglanis balayi'' ( Sauvage, 1879) * '' Parauchenoglanis buettikoferi'' ( Popta, 1913) * '' Parauchenoglanis longiceps'' (Boulenger, 1913) * '' Parauchenoglanis monkei'' ( Keilhack, 1910) (Dotted catfish) * '' Parauchenoglanis ngamensis'' (Boulenger, 1911) (Zambezi grunter) * '' Parauchenoglanis pantherinus'' ( Pellegrin, 1929) * '' Parauchenoglanis punctatus'' (Boulenger Boulenger is a surname. Notable people with the surname include: * Benjamin Boulenger (born 1990), French footballer * Edward George Boulenger (1888–1946), British zoologis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Nyos
Lake Nyos ( ) is a crater lake in the Region of Cameroon, located about northwest of Yaoundé, the capital. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcanic activity. A volcanic dam impounds the lake waters. A pocket of magma lies beneath the lake and leaks carbon dioxide () into the water, changing it into carbonic acid. Nyos is one of only three lakes known to be saturated with carbon dioxide in this way, and therefore prone to limnic eruptions (the others being Lake Monoun, also in Cameroon, and Lake Kivu in the Democratic Republic of Congo and Rwanda). In 1986, possibly as the result of a landslide, Lake Nyos suddenly emitted a large cloud of , which suffocated 1,746 people and 3,500 livestock in nearby towns and villages, the most notable one being Chah, which was abandoned after the incident. Though not completely unprecedented, it was the first known large-scale asphyxiation caused b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siltation
Siltation, is water pollution caused by particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the increased accumulation (temporary or permanent) of fine sediments on bottoms where they are undesirable. Siltation is most often caused by soil erosion or sediment spill. It is sometimes referred to by the ambiguous term "sediment pollution", which can also refer to a chemical contamination of sediments accumulated on the bottom, or to pollutants bound to sediment particles. Although "siltation" is not perfectly stringent, since it also includes particle sizes other than silt, it is preferred for its lack of ambiguity. Causes The origin of the increased sediment transport into an area may be erosion on land or activities in the water. In rural areas, the erosion source is typically soil degradation by intensive or inadequate agricultural practices, leading to soil eros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Although environmental pollution can be caused by natural events, the word pollution generally implies that the contaminants have an anthropogenic source – that is, a source created by human activities. Pollution is often classed as point source or nonpoint source pollution. In 2015, pollution killed nine million people worldwide (one in six deaths). This remained unchanged in 2019, with little real progress against pollution being identifiable. Air pollution accounted for of these earlier deaths. Major forms of pollution include air pollution, light pollution, litter, noise pollution, plastic pollution, soil contamination, radioactiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binomial Nomenclature
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name (which may be shortened to just "binomial"), a binomen, name or a scientific name; more informally it is also historically called a Latin name. The first part of the name – the '' generic name'' – identifies the genus to which the species belongs, whereas the second part – the specific name or specific epithet – distinguishes the species within the genus. For example, modern humans belong to the genus ''Homo'' and within this genus to the species ''Homo sapiens''. ''Tyrannosaurus rex'' is likely the most widely known binomial. The ''formal'' introduction of this system of naming species is credit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
