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Citico Darter
The Citico darter (''Etheostoma sitikuense'') is a threatened species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to Tennessee. This species was formerly subsumed within '' Etheostoma percnurum'' (duskytail darter). The ''E. percnurum'' group now consists of four distinct species: ''E. percnurum'', '' E. marmorpinnum'' (marbled darter), '' E. lemniscatum'' (tuxedo darter), and ''E. sitikuense''.Blanton, Jenkins 2008. Three new darter species of the ''Etheostoma percnurum'' species complex (Percidae, subgenus ''Catonotus'') from the Tennessee and Cumberland river drainages. Geographic distribution The Citico darter is an endangered species found only in several isolated locations in east Tennessee: Abrams Creek, Citico Creek, and the Tellico River.Johnathan G. Davis, Jason E Miller, M. Shane Billings, W. Keith Gibbs, S. Bradford Cook Captur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebecca E
Rebecca, ; Syriac: , ) from the Hebrew (lit., 'connection'), from Semitic root , 'to tie, couple or join', 'to secure', or 'to snare') () appears in the Hebrew Bible as the wife of Isaac and the mother of Jacob and Esau. According to biblical tradition, Rebecca's father was Bethuel the Aramean from Paddan Aram, also called Aram-Naharaim. Rebecca's brother was Laban the Aramean, and she was the granddaughter of Milcah and Nahor, the brother of Abraham. Rebecca and Isaac were one of the four couples that some believe are buried in the Cave of the Patriarchs, the other three being Adam and Eve, Abraham and Sarah, and Jacob and Leah. Early life After the Binding of Isaac, Sarah died. After taking care of her burial, Abraham went about finding a wife for his son Isaac, who was already 37 years old. He commanded his servant (whom the Torah commentators identify as Eliezer of Damascus) to journey to his birthplace of Aram Naharaim to select a bride from his own f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumberland River
The Cumberland River is a major waterway of the Southern United States. The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed June 8, 2011 river drains almost of southern Kentucky and north-central Tennessee. The river flows generally west from a source in the Appalachian Mountains to its confluence with the Ohio River near Paducah, Kentucky, and the mouth of the Tennessee River. Major tributaries include the Obey, Caney Fork, Stones, and Red rivers. Although the Cumberland River basin is predominantly rural, there are also some large cities on the river, including Nashville and Clarksville, both in Tennessee. Also, the river system has been extensively altered for flood control. Major dams impound areas of both the main stem and many of its important tributaries. Geography Its headwaters are three separate forks that begin in Kentucky and converge in Baxter, KY, located in Harlan County. Martin's Fork starts n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Midges
A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some midges, such as many Phlebotominae (sand fly) and Simuliidae (black fly), are vectors of various diseases. Many others play useful roles as prey for insectivores, such as various frogs and swallows. Others are important as detritivores, and form part of various nutrient cycles. The habits of midges vary greatly from species to species, though within any particular family, midges commonly have similar ecological roles. Examples of families that include species of midges include: * Blephariceridae, net-winged midges * Cecidomyiidae, gall midges * Ceratopogonidae, biting midges (also known as no-see-ums or punkies in North Americabr>BugGuide/ref> and sandflies in Australia) * Chaoboridae, phantom midges * Chironomidae, non-biting midges (also kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (biology)
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. In agriculture and horticulture * Cellulose substrate * Expanded clay aggregate (LECA) * Rock wool * Potting soil * Soil In animal biotechnology Requirements for animal cell and tissue culture Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microscope r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cobble (geology)
A cobble (sometimes a cobblestone) is a clast of rock defined on the Udden–Wentworth scale as having a particle size of , larger than a pebble and smaller than a boulder. Other scales define a cobble's size differently. A rock made predominantly of cobbles is termed a conglomerate. Cobblestone is a building material based on cobbles. Etymology Cobbles, also called cobblestones, derive their name from the word cob, meaning a rounded lump. The term is further related to the German ', meaning ''head''. Chester Wentworth referred to cobbles as ''cobble bowlders'' in his 1922 paper that would become the basis for the Udden–Wentworth scale. Classifications Within the widely used Krumbein phi scale of grain sizes, cobbles are defined as clasts of rock ranging from −6 to −8 φ. This classification corresponds with the Udden–Wentworth size scale which defines cobbles as clasts with diameters from . On this scale, cobbles are larger than pebbles which measure in diameter a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grade (slope)
The grade (also called slope, incline, gradient, mainfall, pitch or rise) of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a special case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of "tilt". Often slope is calculated as a ratio of "rise" to "run", or as a fraction ("rise over run") in which ''run'' is the horizontal distance (not the distance along the slope) and ''rise'' is the vertical distance. Slopes of existing physical features such as canyons and hillsides, stream and river banks and beds are often described as grades, but typically grades are used for human-made surfaces such as roads, landscape grading, roof pitches, railroads, aqueducts, and pedestrian or bicycle routes. The grade may refer to the longitudinal slope or the perpendicular cross slope. Nomenclature There are several ways to express slope: # as an ''angle'' of inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riffle
A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indicators Riffles are almost always found to have a very low discharge compared to the flow that fills the channel (approximately 10–20%), and as a result the water moving over a riffle appears shallow and fast, with a wavy, disturbed water surface. The water's surface over a riffle at low flow also has a much steeper slope than that over other in-channel landforms. Channel sections with a mean water surface slope of roughly 0.1 to 0.5% exhibit riffles, though they can occur in steeper or gentler sloping channels with coarser or finer bed materials, respectively. Except in the period after a flood (when fresh material is deposited on a riffle), the sediment on the riverbed in a riffle is usually much coarser than on that in any other in-chann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellico Reservoir
Tellico Reservoir, also known as Tellico Lake, is a reservoir in Tennessee, created by the Tennessee Valley Authority (TVA) in 1979 upon the completion of Tellico Dam. The dam impounds the Little Tennessee River and the lower Tellico River. While TVA is careful to refer to its artificial lakes as reservoirs (such as "Tellico Reservoir"), common usage tends to refer to the reservoir as "Tellico Lake". The lake is approximately 16,000 acres in surface area and provides 357 miles of shoreline. Tellico Reservoir was to be created as the last major dam and reservoir project of the TVA. Planning had begun for the project in the 1960s, when the agency began acquiring properties that had to be vacated prior to flooding of a large area subject to inundation. The National Environmental Policy Act of 1969 (NEPA) provided for agencies to assess the environmental effects of their projects prior to undertaking them. Opponents of the dam project, who were concerned about its effects on the ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilhowee Dam
Chilhowee Dam is a hydroelectric dam located in Blount and Monroe counties, Tennessee, United States, between river mile 33 and 34 on the Little Tennessee River. Construction began in 1955 and was completed in 1957. The dam's reservoir covers approximately at normal full pool and has a drainage area of . The elevation of Chilhowee Reservoir is above mean sea level (USGS). Chilhowee's powerhouse is equipped with three Kaplan turbines that have a combined generating capacity of 48 megawatts.AlcoaChilhowee, 2010. Retrieved: 5 January 2010. Like Calderwood and Cheoah, Chilhowee is controlled by TVA's Fontana Dam. Fontana Dam is the primary flow control facility for the lower Little Tennessee River. Tapoco built and operates the Chilhowee Development. Chilhowee Dam and its powerhouse are listed on the National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildi ... [...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] |
