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Lac Marville
Lac Marville is a lagoon in the Kerguelen islands, part of the French Southern and Antarctic Lands. Extending over approximately ,All measurements were made on Google maps' with ACME planimeter' and checked on Géoportail' and its own tools. it is the largest lake in the archipelago and one of the largest in France. Its drainage basin covers about . Location Lac Marville is located on Grande-Terre, the archipelago's main island, along the northeastern shore of the Courbet Peninsula, between Cape Sandwich to the south and Cape Digby to the north.Topographic descriptions based on the general reconnaissance map at the scale of 1: 200,000: It was patently known to whalers as early as the 19th century, for Captain Joseph J. Fuller in his memoirs described a large lake, at the back of the Royal Bay, the circumference of which was about 15 miles. However, no mention of the lake appeared on charts until the 1930s. Toponymy This great lake was first officially mentioned by Edgar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courbet Peninsula
The Courbet Peninsula (french: Péninsule Courbet) is a peninsula in northeastern Grande Terre Island, the main island of the subantarctic Kerguelen Archipelago, Southern Indian Ocean. In the south of the peninsula is Port-aux-Français, the principal station of the archipelago. Geography On the south coast of the peninsula is the French research station of Port-aux-Français, the only permanent settlement in the archipelago. Molloy, 10 km to the west of Port-aux-Francais along the north shore of the Gulf of Morbihan, is the site of a former observatory, established on 7 September 1874, by an American expedition led by G. P. Ryan, to observe the 1874 Transit of Venus. The Courbet Peninsula occupies the northeastern portion of the main island. The eastern portion of the peninsula is relatively flat, with the surface composed mainly of alluvial deposits of glacial origin, and altitudes not exceeding 200 m. However, the western part is hillier and reaches 900 m at M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edgar Aubert De La Rüe
Edgar Aubert de la Rüe (1901–1991) was a French geographer, geologist, traveller and photographer who was primarily devoted to the islands of Saint Pierre and Miquelon, Kerguelen, and Vanuatu. Mount Aubert de la Rue on Heard Island is named after him. Biography Edgar Aubert de la Rüe was born on 7 October 1901 in Geneva (Switzerland) and died on 24 February 1991 in Lausanne. He took on the duties of an engineer-geologist from the University of Nancy and a scientific adviser for the French Southern and Antarctic Lands. He was also a Doctor of Natural Science from the University of Paris. He dedicated himself to the islands of Saint Pierre and Miquelon (1932, 1935, 1937, 1941 to 1943, 1948, and 1970), Kerguelen (1928, 1929, 1931, and from 1949 to 1953), and Vanuatu, and from November 1937 to May 1938 he stayed in French Somaliland. As an Associate of the National Museum of Natural History in Paris, his geological activities led him to difficult surveys all around the Frenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediastrum
''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial (fixed number of cells) green algae that inhabits freshwater environments. Morphology ''Pediastrum'' is a genus usually look like a green star in the pond or lake. They are coenobial green algae composed of 22 to 27 cells, which are orderly arranged in a circular, flat disk. The diameter of a single coenobium can range from 20 to 80 μm, so they belong to the group of microalgae. Cells in ''Pediastrum'' can be divided into interior cells and peripheral cells by position in the coenobium or their shapes. Some of the species have intracellular cell spaces between interior cells, while some would closely aggregate together. The peripheral cells surround outside the interior cells, and they usually possess bristles, V-liked cutting edges, or wavy projections. Phylogeny The genus of ''Pediastrum'' belongs to the Hydrodictyaceae family, along with '' Psuedopediast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drainage System (geomorphology)
In geomorphology, drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of land, whether a particular region is dominated by hard or soft rocks, and the gradient of the land. Geomorphologists and hydrologists often view streams as part of drainage basins (and sub-basins). This is the topographic region from which a stream receives runoff, throughflow, and its saturated equivalent, groundwater flow. The number, size, and shape of the drainage basins varies and the larger and more detailed the topographic map, the more information is available. Drainage patterns Per the lie of channels, drainage systems can fall into one of several categories, known as drainage patterns. These depend on the topography and geology of the land. All forms of transitions can occur between parallel, dendritic, and trellis patterns. Accordant versus discordant drainage patterns A drai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Trout
The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morpha ''fario'', a lacustrine ecotype, ''S. trutta'' morpha ''lacustris'', also called the lake trout, and anadromous forms known as the sea trout, ''S. trutta'' morpha ''trutta''. The latter migrates to the oceans for much of its life and returns to fresh water only to spawn. Sea trout in Ireland and Britain have many regional names: sewin in Wales, finnock in Scotland, peal in the West Country, mort in North West England, and white trout in Ireland. The lacustrine morph of brown trout is most usually potamodromous, migrating from lakes into rivers or streams to spawn, although evidence indicates some stocks spawn on wind-swept shorelines of lakes. ''S. trutta'' morpha ''fario'' forms stream-resident populations, typically in alpine stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonidae
Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefishes, graylings, taimens and lenoks, which are collectively known as the salmonids ("salmon-like fish"). The Atlantic salmon (''Salmo salar''), whose Latin name became that of its genus ''Salmo'', is also the source of the family and order names. Salmonids have a relatively primitive appearance among the teleost fish, with the pelvic fins being placed far back, and an adipose fin towards the rear of the back. They have slender bodies, with rounded scales and forked tails, and their mouths contain a single row of sharp teeth. Although the smallest species is just long as an adult, most are much larger, with the largest reaching . All salmonids spawn in fresh water of upper reaches of rivers and creeks, but in many cases, the fish spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloride
The chloride ion is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water.Green, John, and Sadru Damji. "Chapter 3." ''Chemistry''. Camberwell, Vic.: IBID, 2001. Print. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating liquid flow in and out of cells. Less frequently, the word ''chloride'' may also form part of the "common" name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane (see IUPAC books) is an organic compound with a covalent C−Cl bond in which the chlorine is not an anion. Electronic properties A chloride ion (diameter 167 pm) is much larger tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of 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 ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a 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 sodium bicarbonate which dissolve into ions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stream Bed
A stream bed or streambed is the bottom of a stream or river (bathymetry) or the physical confine of the normal water flow (Channel (geography), channel). The lateral confines or channel margins are known as the stream Bank (geography), banks or river banks, during all but flood stage. Under certain conditions a river can branch from one stream bed to multiple stream beds. A flood occurs when a stream overflows its banks and flows onto its flood plain. As a general rule, the bed is the part of the stream channel, channel up to the normal water line, and the banks are that part above the normal water line. However, because water flow varies, this differentiation is subject to local interpretation. Usually, the bed is kept clear of terrestrial vegetation, whereas the banks are subjected to water flow only during unusual or perhaps infrequent high water stages and therefore might support vegetation some or much of the time. The nature of any stream bed is always a function of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Challenger Expedition
The ''Challenger'' expedition of 1872–1876 was a scientific program that made many discoveries to lay the foundation of oceanography. The expedition was named after the naval vessel that undertook the trip, . The expedition, initiated by William Benjamin Carpenter, was placed under the scientific supervision of Sir Charles Wyville Thomson—of the University of Edinburgh and Merchiston Castle School—assisted by five other scientists, including Sir John Murray, a secretary-artist and a photographer. The Royal Society of London obtained the use of ''Challenger'' from the Royal Navy and in 1872 modified the ship for scientific tasks, equipping it with separate laboratories for natural history and chemistry. The expedition, led by Captain George Nares, sailed from Portsmouth, England, on 21 December 1872. Other naval officers included Commander John Maclear. – pages 19 and 20 list the civilian staff and naval officers and crew, along with changes that took place during the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigator
A navigator is the person on board a ship or aircraft responsible for its navigation.Grierson, MikeAviation History—Demise of the Flight Navigator FrancoFlyers.org website, October 14, 2008. Retrieved August 31, 2014. The navigator's primary responsibility is to be aware of ship or aircraft position at all times. Responsibilities include planning the journey, advising the ship's captain or aircraft commander of estimated timing to destinations while en route, and ensuring hazards are avoided. The navigator is in charge of maintaining the aircraft or ship's nautical charts, nautical publications, and navigational equipment, and they generally have responsibility for meteorological equipment and communications. With the advent of satellite navigation, the effort required to accurately determine one's position has decreased by orders of magnitude, so the entire field has experienced a revolutionary transition since the 1990s with traditional navigation tasks, like performing c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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