|
Brack Water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root '' brak''. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it can be damaging to the environment (see article on shrimp farms). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (‰), which is a specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to per mille, ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a state function, thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water. A contour line of constant salinity is called an ''isohaline'', or sometimes ''isohale''. Definitions Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Thames
The River Thames ( ), known alternatively in parts as the The Isis, River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the Longest rivers of the United Kingdom, second-longest in the United Kingdom, after the River Severn. The river rises at Thames Head in Gloucestershire and flows into the North Sea near Tilbury, Essex and Gravesend, Kent, via the Thames Estuary. From the west, it flows through Oxford (where it is sometimes called the Isis), Reading, Berkshire, Reading, Henley-on-Thames and Windsor, Berkshire, Windsor. The Thames also drains the whole of Greater London. The lower Reach (geography), reaches of the river are called the Tideway, derived from its long Tidal river, tidal reach up to Teddington Lock. Its tidal section includes most of its London stretch and has a rise and fall of . From Oxford to the estuary, the Thames drops by . Running through some of the drier parts of mainland Bri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flounder
Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuary, estuaries. Taxonomy The name "flounder" is used for several only distantly related species, though all are in the suborder Pleuronectoidei (families Achiropsettidae, Bothidae, Pleuronectidae, Paralichthyidae, and Samaridae). Some of the better known species that are important in fisheries are: * Western Atlantic ** Gulf flounder – ''Paralichthys albigutta'' ** Paralichthys lethostigma, Southern flounder – ''Paralichthys lethostigma'' ** Summer flounder (also known as ''fluke'') – ''Paralichthys dentatus'' ** Winter flounder – ''Pseudopleuronectes americanus'' * European waters **European flounder – ''Platichthys flesus'' **Witch (righteye flounder), Witch flounder – ''Glyptocephalus cynoglossus'' * North Pacific ** Halibut – ''Hippoglossus stenolepis'' ** Olive flounder – ''Paralichthys olivaceus'' Eye migrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus maenas'') is an example of a euryhaline invertebrate that can live in salt and brackish water. Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly. However, some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments, as is the case with salmon and eels. The opposite of euryhaline organisms are stenohaline ones, which can only survive within a narrow range of salinities. Most freshwater organisms are stenohaline, and will die in seawater, and similarly most marine organisms are stenohaline, and cannot live in fresh water. Osmoregulation Osmoregulation is the active process by which an organism maintains its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravesend
Gravesend is a town in northwest Kent, England, situated 21 miles (35 km) east-southeast of Charing Cross (central London) on the Bank (geography), south bank of the River Thames, opposite Tilbury in Essex. Located in the diocese of Rochester, it is the administrative centre of the borough of Gravesham. Gravesend marks the eastern limit of the Greater London Built-up Area, as defined by the UK Office for National Statistics. It had a population of 58,102 in 2021. Its geographical situation has given Gravesend strategic importance throughout the maritime history, maritime and History of communication, communications history of South East England. A Thames Gateway commuter town, it retains strong links with the River Thames, not least through the Port of London Authority Pilot Station, and has witnessed rejuvenation since the advent of High Speed 1 rail services via Gravesend railway station. The station was recently refurbished and has a new bridge. Name Recorded as Graves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thames Estuary
The Thames Estuary is where the River Thames meets the waters of the North Sea, in the south-east of Great Britain. Limits An estuary can be defined according to different criteria (e.g. tidal, geographical, navigational or in terms of salinity). For this reason the limits of the Thames Estuary have been defined differently at different times and for different purposes. Western This limit of the estuary has been defined in two main ways: * The narrow estuary is strongly tidal and is known as the Tideway. It starts in south-west London at Teddington Lock and weir, Teddington/Ham, London, Ham. This point is also mid-way between Richmond Lock which only keeps back a few miles of human-made head (hydrology), head (stasis) of water during low tide and the extreme modern-era head at Thames Ditton Island on Kingston upon Thames, Kingston reach where slack water occurs at maximal high tide in times of rainfall-caused flooded banks. In terms of salinity the transition from freshwater t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pike (fish)
''Esox'' is a genus of freshwater fish commonly known as pike or pickerel. It is the type genus of the family Esocidae. The type species of the genus is '' Esox lucius'', the northern pike. ''Esox'' have a fossil record extending back to the Paleocene. Modern large pike species are native to the Palearctic and Nearctic realms, ranging across Northern America and from Western Europe to Siberia in North Asia. Pike have the elongated, torpedo-like shape typical of predatory fishes, with sharply pointed heads and sharp teeth. Their coloration is typically grey-green with a mottled or spotted appearance with stripes along their backs, providing camouflage among underwater weeds, and each individual pike marking patterns are unique like fingerprints. Pikes can grow to a maximum recorded length of , reaching a maximum recorded weight of 67lb 8oz. Etymology The generic name ''Esox'' (pike fish) derives from the Greek ἴσοξ (''ee-soks'', a large fish) and appears to be cognate wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perch
Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis''). Many species of freshwater game fish more or less resemble perch, but belong to different genera. In fact, the exclusively saltwater-dwelling red drum (which belong to a different order Acanthuriformes) is often referred to as a "red perch", though by definition perch are freshwater species. Though many fish are referred to as perch as a common name, to be considered a true perch, the fish must be of the family Percidae. Species Most authorities recognize three species within the perch genus: * The European perch (''P. fluviatilis'') is primarily found in Europe, but a few can also be found in South Africa, and even as far east on the Southern hemisphere as Australia. This species is typically greenish in color with dark vertical ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carp
The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and are valued (even pisciculture, commercially cultivated) as both food fish, food and ornamental fish in many parts of the Old World, they are considered trash fish and invasive species, invasive pest (organism), pests in many parts of Africa, Australia and most of the United States. Biology The cypriniformes (family Cyprinidae) are traditionally grouped with the Characiformes, Siluriformes, and Gymnotiformes to create the superorder Ostariophysi, since these groups share some common features. These features include being found predominantly in fresh water and possessing Weberian ossicles, an anatomical structure derived from the first five anterior-most vertebrae, and their corresponding ribs and neural crests. The third anterior-most pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Dace
The common dace (''Leuciscus leuciscus'') is a species of freshwater and brackish water ray-finned fish from the family Leuciscidae which is native to Europe but which has been introduced to other parts of the world. It is a quarry species for coarse anglers. Description The common dace differs from other members in the genus ''Leuciscus'' found in Europe by its inferior mouth, slightly longer upper jaw which has the tip of the upper lip level with the centre line of the eye and the lack of an obvious snout. It has a yellowish iris and a body which is covered in large silvery scales, the lateral line having 49–52 scales. The anal fin has a concave margin and the caudal fin is forked. The dorsal fin has 2–3 spines and 7–9 soft rays while the anal fin has 3 spines and 8–9 soft rays. The maximum size attained is a total length of . Distribution The common dace is native to Europe and northern Asia where its occurs in the basins of the North Sea, Baltic Sea, White Sea and Bar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutilus
''Rutilus'', commonly known as roaches, is a genus of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related fishes. This genus is a widely distributed lineage of leuciscids and ranges from West Europe to East Siberia. Taxonomy ''Rutilus'' was first proposed as a genus in 1820 by the French polymath Constantine Samuel Rafinesque with ''Cyprinus rutilus'' designated as the type species but also the type species by absolute tautonymy. ''Cyprinus rutilus'' was first formally described in the 10th edition of ''Systema Naturae'' by Carl Linnaeus with "European lakes" given as the type locality. In a phylogeographic study, Levin et al. (2017) argue that the Ponto-Caspian taxa including ''R. caspicus'', ''R. heckelii'' and ''R. stoumboudae'' could represent a single widespread species whose range extends to Siberia, to be named ''Rutilus lacustris'', whereas ''R. kutum'' is included in ''R. frisii''. Levin, B.A. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battersea
Battersea is a large district in southwest London, part of the London Borough of Wandsworth, England. It is centred southwest of Charing Cross and also extends along the south bank of the Thames Tideway. It includes the Battersea Park. History Battersea is mentioned in the few surviving Anglo-Saxon geographical accounts as and later . As with many former parishes beside tidal flood plains the lowest land was reclaimed for agriculture by draining marshland and building culverts for streams. By the side of this was the River Heathwall, Heathwall tide mill in the north-east with a very long mill pond regularly draining and filling to the south. Battersea () appears in the Domesday Book of 1086 in Surrey within the Hundred (county division), hundred of Hundred_of_Brixton, Brixton () as a vast manor held by St Peter's Abbey, Westminster. Its ''Domesday'' assets were: 18 hide (unit), hides and 17 ploughlands of cultivated land; 7 gristmill, mills worth £42 9s 8d per year, of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
