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Branco River (Rondônia)
The Branco River ( pt, Rio Branco; Engl: ''White River'') is the principal affluent of the Rio Negro from the north. Basin The river drains the Guayanan Highlands moist forests ecoregion. It is enriched by many streams from the Tepui highlands which separate Venezuela and Guyana from Brazil. Its two upper main tributaries are the Uraricoera and the Takutu. The latter almost links its sources with those of the Essequibo; during floods headwaters of the Branco and those of the Essequibo are connected, allowing a level of exchange in the aquatic fauna (such as fish) between the two systems. The Branco flows nearly south, and finds its way into the Negro through several channels and a chain of lagoons similar to those of the latter river. It is long, up to its Uraricoera confluence. It has numerous islands, and, above its mouth, it is broken by a bad series of rapids. Discharge Average, minimum and maximum discharge of the Branco River at near mouth. Period from 1998 to 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boa Vista, Roraima
Boa Vista (, literally ''Good View''; figuratively "Fairview") is the capital of the Brazilian state of Roraima. Situated on the western bank of the Branco River, the city lies from Brazil's border with Venezuela. It is the only Brazilian state capital located entirely north of the equator. Boa Vista is the most populous municipality in the state of Roraima; approximately half of the population of the state lives in the city. Commerce mostly occurs with Manaus, the capital of the State of Amazonas. Business also takes place between Boa Vista and with the cities of Lethem, in Guyana and Santa Elena de Uairén, in Venezuela. These two foreign cities are the only major cities that can be accessed from Boa Vista by road, although roads connect other smaller state municipalities with the capital city. Travel by airplane is the only means of transportation with other regions of the country. As a modern city, Boa Vista stands out among the other capitals of the North Region of Bra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xeruini River
The Xeriuini River is a river located in the Roraima state in northern Brazil. See also *List of rivers of Roraima List of rivers in Roraima (Brazilian State). The list is arranged by drainage basin, with respective tributaries indented under each larger stream's name and ordered from downstream to upstream. Roraima is located entirely within the Amazon Bas ... ReferencesBrazilian Ministry of Transport Rivers of Roraima {{Roraima-river-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dissolved Organic Carbon
Dissolved organic carbon (DOC) is the fraction of organic carbon operationally defined as that which can pass through a filter with a pore size typically between 0.22 and 0.7 micrometers. The fraction remaining on the filter is called particulate organic carbon (POC). Dissolved organic matter (DOM) is a closely related term often used interchangeably with DOC. While DOC refers specifically to the mass of carbon in the dissolved organic material, DOM refers to the total mass of the dissolved organic matter. So DOM also includes the mass of other elements present in the organic material, such as nitrogen, oxygen and hydrogen. DOC is a component of DOM and there is typically about twice as much DOM as DOC. Many statements that can be made about DOC apply equally to DOM, and ''vice versa''. DOC is abundant in marine and freshwater systems and is one of the greatest cycled reservoirs of organic matter on Earth, accounting for the same amount of carbon as in the atmosphere and up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amazon Basin
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 , 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. Most of the basin is covered by the Amazon rainforest, also known as Amazonia. With a area of dense tropical forest, this is the largest rainforest in the world. Geography The Amazon River begins in the Andes Mountains at the west of the basin with its main tributary the Marañón River and Apurimac River in Peru. The highest point in the watershed of the Amazon is the second biggest peak of Yerupajá at . With a length of about before it drains into the Atlantic Ocean, it is one of the two longest rivers in the world. A team of scientists has claimed that the Amazon is longer than the Nile, but debate about its exact length continues. The Amazon system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Headwaters
The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The United States Geological Survey (USGS) states that a river's "length may be considered to be the distance from the mouth to the most distant headwater source (irrespective of stream name), or from the mouth to the headwaters of the stream commonly known as the source stream". As an example of the second definition above, the USGS at times considers the Missouri River as a tributary of the Mississippi River. But it also follows the first definition above (along with virtually all other geographic authorities and publications) in using the combined Missouri—lower Mississippi length figure in lists of lengths of rivers around the world. Most rivers have numerous tributaries and change names often; it is customary to regard the longest t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clearwater River (river Type)
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. The main clearwater rivers are South American and have their source in the Brazilian Plateau or the Guiana Shield. Outside South America the classification is not commonly used, but rivers with clearwater characteristics are found elsewhere. Amazonian rivers fall into three main categories: clearwater, blackwater and whitewater. This classification system was first proposed by Alfred Russel Wallace in 1853 based on water colour, but the types were more clearly defined according to chemistry and physics by from the 1950s to the 1980s. Although many Amazonian rivers fall clearly into one of these categories, others show a mix of characteristics and may vary depending on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater River (river Type)
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, coffee and cream-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. The best-known whitewater rivers are Amazonian and have their source in the Andes, but there are also whitewater rivers elsewhere in South America and in other continents. Amazonian rivers fall into three main categories: whitewater, blackwater and clearwater. This classification system was first proposed by Alfred Russel Wallace in 1853 based on water colour, but the types were more clearly defined according to chemistry and physics by from the 1950s to the 1980s. Although many Amazonian rivers fall clearly into one of these categori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Island
An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. Sedimentary islands in the Ganges delta are called chars. A grouping of geographically or geologically related islands, such as the Philippines, is referred to as an archipelago. There are two main types of islands in the sea: continental and oceanic. There are also artificial islands, which are man-made. Etymology The word ''island'' derives from Middle English ''iland'', from Old English ''igland'' (from ''ig'' or ''ieg'', similarly meaning 'island' when used independently, and -land carrying its contemporary meaning; cf. Dutch ''eiland'' ("island"), German ''Eiland'' ("small island")). However, the spelling of the word ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confluence
In geography, a confluence (also: ''conflux'') occurs where two or more flowing bodies of water join to form a single channel. A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); or where two streams meet to become the source of a river of a new name (such as the confluence of the Monongahela and Allegheny rivers at Pittsburgh, forming the Ohio); or where two separated channels of a river (forming a river island) rejoin at the downstream end. Scientific study of confluences Confluences are studied in a variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion, bars, and scour pools. The water flows and their consequences are often studied with mathematical models. Confluences are relevant to the distribution of living organisms (i.e., ecology) as well; "the general pattern ownstream of confluencesof increasing stream flow and decreasing s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') and ''atoll lagoons''. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world. Definition and terminology Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal, coral reef, or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restrict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essequibo River
The Essequibo River (Spanish: ''Río Esequibo'' originally called by Alonso de Ojeda ''Río Dulce'') is the largest river in Guyana, and the largest river between the Orinoco and Amazon. Rising in the Acarai Mountains near the Brazil–Guyana border, the Essequibo flows to the north for through forest and savanna into the Atlantic Ocean. With a total drainage basin of and an average discharge of . Territory near the river is argued over by Venezuela and Guyana. Venezuela considers that the natural border according to the divortium aquarum that delimits the eastern margin of that country with the Cooperative Republic of Guyana is "by law", although due to the territorial dispute between the two countries for the sovereignty of Guayana Esequiba, it is "De facto administered and occupied for the most part by the former English colony of British Guiana, present-day Guyana. Geography The river runs through the Guianan moist forests ecoregion. The average annual rainfall in the catc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
