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Roanoke Logperch
The Roanoke logperch (''Percina rex'') is a 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 found in the Roanoke and Chowan drainages in Virginia and North Carolina in the United States. They inhabit low and moderate-gradient streams and rivers in warm, clear water in mostly unsilted gravel and rubble in runs, pools, and riffles. They are primarily insectivorous. This fish is a federally listed endangered species. Description Adults Roanoke logperches are between 80 and 115 mm SL. The light-colored body is somewhat stocky and elongated. There are dark, rounded, and vertically elongated blotches on the side. The fish have a long, cone-shaped snout with a bulbous or blunt tip. There are two dorsal fins, which are both very tall on adult males. The first dorsal fin has an orange band bordered on both sides by black bands. The end of the tail fin is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
David Starr Jordan
David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford University, he had served as president of Indiana University from 1884 to 1891. Starr was also a strong supporter of eugenics, and his published views expressed a fear of "race-degeneration" and asserted that cattle and human beings are "governed by the same laws of selection". He was an antimilitarist since he believed that war killed off the best members of the gene pool, and he initially opposed American involvement in World War I. Early life and career Jordan was born in Gainesville, New York, and grew up on a farm in upstate New York. His parents made the unorthodox decision to educate him at a local girls' high school. His middle name, Starr, does not appear in early census records, and was apparently self-selected; he had begun using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dan River
The Dan River flows in the U.S. states of North Carolina and Virginia. It rises in Patrick County, Virginia, and crosses the state border into Stokes County, North Carolina. It then flows into Rockingham County. From there it flows back into Virginia through Pittsylvania County before reentering North Carolina near the border between Caswell County and Rockingham County. It flows into northern Caswell County and then back into southern Virginia (briefly Pittsylvania County, then into Halifax County) and finally into Kerr Reservoir on the Roanoke River. The name of the river was first recorded by William Byrd II in 1728, during an expedition to survey the Virginia border, though Byrd did not explain the reason for the name. A variant name is "South Branch Roanoke River". In 2014, a large amount of coal ash, a byproduct of coal combustion, spilled into the river, prompting a cleanup process costing an estimated $300 million. Dan River is also the name of the southeastern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percina
''Percina'' is a genus of small freshwater ray-finned fish, classified within the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches from North America. Like the similar fishes in the genus ''Etheostoma'', they are some species called "darters". More specifically, the genus as a whole is known as roughbelly darters, while certain species of ''Percina'' with a pattern of vertical bars on the flanks are called logperches. Species There are currently 49 recognized species in this genus: * '' Percina antesella'' J. D. Williams & Etnier, 1978 (Amber darter) * ''Percina apristis'' C. L. Hubbs & Hubbs, 1954 (Guadalupe darter) * '' Percina aurantiaca'' Cope, 1868 (Tangerine darter) * '' Percina aurolineata'' Suttkus & Ramsey, 1967 (Goldline darter) * '' Percina aurora'' Suttkus & B. A. Thompson, 1994 (Pearl darter) * '' Percina austroperca'' B. A. Thompson, 1995 (Southern logperch) * '' Percina bimaculata'' Haldeman, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pigg River
The Pigg River is a river in south-west Virginia in the United States. It is a tributary of the Roanoke River, which flows to the Atlantic Ocean via Albemarle Sound. The Pigg River rises on Fivemile Mountain in western Franklin County and flows generally eastwardly through Franklin and Pittsylvania Counties, past the town of Rocky Mount. It joins the Roanoke River from the south (along a section of the Roanoke often known locally as the Staunton River) as part of the Leesville Reservoir, which is formed by a dam on the Roanoke. Recently, several dams across the Pigg River have been removed. In 2017, the 100 year old power dam at Rocky Mount was breached to restore the historic flow and to improve the habitat of the Roanoke logperch, an endangered species. Other dams removed recently include the dam near the Rocky Mount Veterans Memorial Park in 2013, and the Wasena dam in 2009. The river is named for John Pigg, an early settler from Amelia County, Virginia, who in 1741 acqui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agricultural Pollution
Agricultural pollution refers to biotic and abiotic byproducts of farming practices that result in contamination or degradation of the environment and surrounding ecosystems, and/or cause injury to humans and their economic interests. The pollution may come from a variety of sources, ranging from point source water pollution (from a single discharge point) to more diffuse, landscape-level causes, also known as non-point source pollution and air pollution. Once in the environment these pollutants can have both direct effects in surrounding ecosystems, i.e. killing local wildlife or contaminating drinking water, and downstream effects such as dead zones caused by agricultural runoff is concentrated in large water bodies. Management practices, or ignorance of them, play a crucial role in the amount and impact of these pollutants. Management techniques range from animal management and housing to the spread of pesticides and fertilizers in global agricultural practices. Bad man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urbanization
Urbanization (or urbanisation) refers to the population shift from rural to urban areas, the corresponding decrease in the proportion of people living in rural areas, and the ways in which societies adapt to this change. It is predominantly the process by which towns and cities are formed and become larger as more people begin living and working in central areas. Although the two concepts are sometimes used interchangeably, urbanization should be distinguished from urban growth. Urbanization refers to the ''proportion'' of the total national population living in areas classified as urban, whereas urban growth strictly refers to the ''absolute'' number of people living in those areas. It is predicted that by 2050 about 64% of the developing world and 86% of the developed world will be urbanized. That is equivalent to approximately 3 billion urbanites by 2050, much of which will occur in Africa and Asia. Notably, the United Nations has also recently projected that nearly all gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...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] |
Turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can contain suspended solid matter consisting of particles of many different sizes. While some suspended material will be large enough and heavy enough to settle rapidly to the bottom of the container if a liquid sample is left to stand (the settable solids), very small particles will settle only very slowly or not at all if the sample is regularly agitated or the particles are colloidal. These small solid particles cause the liquid to appear turbid. Turbidity (or haze) is also applied to transparent solids such as glass or plastic. In plastic production, haze is defined as the percentage of light that is deflected more than 2.5° from the incoming light direction. Causes and effects Turbidity in open water may be caused by growth of phyto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger oceans, they do form part of the Earth's water cycle. Lakes are distinct from lagoons, which are generally coastal parts of the ocean. Lakes are typically larger and deeper than ponds, which also lie on land, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which usually flow in a channel on land. Most lakes are fed and drained by rivers and streams. Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, where a river channel has widened into a basin. Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as Stream#Creek, creek, Stream#Brook, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to Geographical feature, geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "Burn (landform), burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague. Rivers are part of the water cycle. Water generally collects in a river from Precipitation (meteorology), precipitation through a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on one another, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and microbes. Ecosystems are controlled by external and internal factors. External factors such as climate, parent material which forms the soil and topography, control the overall structure of an ecosystem but are not themselves influenced by the ecosystem. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
