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The Amazon River in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile.
The Amazon rainforest, also called Amazon jungle or Amazonia, is a moist broadleaf tropical rainforest in the Amazon biome that covers most of the Amazon basin of South America. This basin encompasses 7,000,000 km2 (2,700,000 sq mi), of which 5,500,000 km2 (2,100,000 sq mi) are covered by the rainforest. This region includes territory belonging to nine nations and 3,344 formally acknowledged indigenous territories.
Symphysodon is a genus of cichlids native to the Amazon river basin in South America. Due to their distinctive shape, calm behavior, many bright colors and patterns, and dedicated parenting techniques, discus are popular as freshwater aquarium fish, and their aquaculture in several countries in Asia is a major industry. They are sometimes referred to as pompadour fish. The discus fish has attracted a cult following of collectors and has created a multimillion dollar international industry complete with shows, competitions, and reputable online breeders.
The Amazon river dolphin, also known as the boto, bufeo or pink river dolphin, is a species of toothed whale which is native to and is exclusively of South America classified in the family Iniidae. Three subspecies are currently recognized: I. g. geoffrensis, I. g. boliviensis and I. g. humboldtiana while position of Araguaian river dolphin within the clade is still unclear. The three subspecies are distributed in the Amazon basin, the upper Madeira River in Bolivia, and the Orinoco basin, respectively.
Symphysodon discus, the red discus or Heckel discus, is a species of cichlid native to the Amazon Basin, where found in the lower Rio Negro, upper Uatumã, Nhamundá, Trombetas and Abacaxis.
The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 7,000,000 km2 (2,700,000 sq mi), or about 35.5 percent of the South American continent. It is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela, as well as the territory of French Guiana.
Corydoras narcissus, commonly known as the long nosed arched cory, is a freshwater fish belonging to the Corydoradinae subfamily of the family Callichthyidae, native to the Madeira and Purus river basins in Amazonian Brazil. It has a longer, more concave ("saddle-shaped") nose, but its color pattern resembles that also seen in a few other Corydoras species from the western Amazon basin, as well as Brachyrhamdia thayeria; they all have spiny fins with a painful but not dangerous venom and their similarity is an example of Müllerian mimicry. C. narcissus generally is an uncommon species in its range.
The tambaqui is a large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere. It is also known by the names black pacu, black-finned pacu, giant pacu, cachama, gamitana, and sometimes as pacu.
Symphysodon aequifasciatus, the blue discus or brown discus, is a species of cichlid native to rivers of the eastern and central Amazon Basin downriver from the Purus Arch. This discus is found in black-, clear- and whitewater, but its preference for lentic habitats such as floodplains and flooded forests means that the whitewater it inhabits contain little suspended material. It is largely restricted to water with a high temperature of 25–32 °C (77–90 °F) and a pH of 5.2–7.7.
The raspy river stingray, mosaic stingray or arraia is a species of freshwater fish in the family Potamotrygonidae. This stingray is endemic to the Amazon basin in Brazil, where known from the Amazon–Pará River, the Madeira River basin, Uatumã River and lower Tocantins River.
Apteronotus is a genus of weakly electric knifefish in the family Apteronotidae, distinguished by the presence of a tiny tail fin. This genus is restricted to tropical and subtropical South America and Panama where found in a wide range of freshwater habitats. They feed on small animals.
The biara is a South American piscivorous fish in the dogtooth characin family. It belongs to the monotypic genus Rhaphiodon, although some minor differences in morphometrics and colour are known from across its large range. It is found in the Amazon, Orinoco, and Río de la Plata Basins, as well as rivers of the Guianas. It occurs in a wide range of freshwater habitats such as main river channels, flooded forests, lakes and reservoirs. Some populations are migratory.
Hypopygus is a genus of South American gymnotiform knifefishes native to the Amazon, Orinoco and upper Paraguay basins, as well as rivers in the Guianas. They are often common, and found near submerged roots, aquatic vegetation and leaf-litter in streams, edges of rivers and floodplains. They are regularly found among vegetation in floating meadows, a habitat that often contains little oxygen, but they are well-adapted to this.
Steatogenys is a genus of gymnotiform knifefishes found in the Amazon, Orinoco and Essequibo river basins in tropical South America. The widespread and common S. elegans is found in a wide range of habitats, from the shallow essentially static waters such as floodplain lakes to fast-flowing rivers as deep as 50 m (160 ft). The two remaining species are less common and widespread, with A. duidae found mainly in small streams running through terra firme forests and S. ocellatus among submerged roots and branches in static or slow-flowing blackwater habitats. All three are regularly found among vegetation in floating meadows, a habitat that often contains little oxygen, but they are well-adapted to this.
Eigenmannia is a genus of fish in the family Sternopygidae native to tropical and subtropical South America, and Panama. They are typically found in slow-flowing streams, along the edge of large rivers, in deep river channels and in floodplains, and the genus also includes E. vicentespelaea, the only cave-adapted knifefish. Eigenmannia are often found near submerged roots, aquatic plants and floating meadows.
A várzea forest is a seasonal floodplain forest inundated by whitewater rivers that occurs in the Amazon biome. Until the late 1970s, the definition was less clear and várzea was often used for all periodically flooded Amazonian forests.
Symphysodon tarzoo, the green discus, is a species of cichlid native to rivers of the western Amazon Basin upriver from the Purus arch, although it occasionally occurs downstream. An introduced population in the Nanay River is based on stock from the Tefé region. The green discus is found in blackwater habitats with a high temperature of 27–30 °C (81–86 °F) and low pH of 4.8–5.9. Although also known from whitewater, its preference for lentic habitats such as floodplains means that the water contain little suspended material.
The Amazon biome contains the Amazon rainforest, an area of tropical rainforest, and other ecoregions that cover most of the Amazon basin and some adjacent areas to the north and east. The biome contains blackwater and whitewater flooded forest, lowland and montane terra firma forest, bamboo and palm forest, savanna, sandy heath and alpine tundra. Some areas of the biome are threatened by deforestation for timber and to make way for pasture or soybean plantations.
A whitewater river is classified based on its chemistry, sediments and water colour. Whitewater rivers have high levels of suspended sediments, giving the water a pH that is near-neutral, a high electric conductivity and a pale muddy, café au lait-like colour. Whitewater rivers are of great ecological importance and are important to local fisheries. The major seasonal Amazonian floodplains known as várzea receive their water from them.
A clearwater river is classified based on its chemistry, sediments and water colour. Clearwater rivers have a low conductivity, relatively low levels of dissolved solids, typically have a neutral to slightly acidic pH and are very clear with a greenish colour. Clearwater rivers often have fast-flowing sections.
References
- ↑ Morales L.G. (1957). "A study of the Upper Amazonas and its oil possibilities". Relatório Interno da Petrobras , Depex 822, 22 p.
- 1 2 Caputo, Mario Vicente; Amaral Soares, Emilio Alberto (2016). "Eustatic and tectonic change effects in the reversion of the transcontinental Amazon River drainage system". Brazilian Journal of Geology . 46 (2): 301–328. doi: 10.1590/2317-4889201620160066 .
- ↑ Ivanyisky III, S.J.; Albert, J.S. (2014). "Systematics and biogeography of Sternarchellini (Gymnotiformes: Apteronotidae): Diversification of electric fishes in large Amazonian rivers". Neotrop. Ichthyol. 12 (3): 565–584. doi: 10.1590/1982-0224-20130159 .
- ↑ Albert, J.S.; Lovejoy, N.R.; Crampton, W.G.R. (2006). "Mioscene tectonism and the separation of cis- and trans-Andean river basins: evidence from Neotropical fishes". Journal of South American Earth Sciences. 21 (1–2): 14–27. doi:10.1016/j.jsames.2005.07.010.
- ↑ Amado, M.V.; Farias, I.P.; Hrbek, T. (2011). "A Molecular Perspective on Systematics, Taxonomy and Classification Amazonian Discus Fishes of the Genus Symphysodon". International Journal of Evolutionary Biology. 2011: 360654. doi: 10.4061/2011/360654 . PMC 3147135 . PMID 21811676.
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