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Gilgai
A gilgai is a small, ephemeral#Geographical examples, ephemeral lake formed from a depression in the soil surface in expanding clay soils. Additionally, the term "gilgai" is used to refer to the overall micro-relief in such areas, consisting of mounds and depressions, not just the lakes themselves. The name comes from an Australian Aboriginal word meaning small water hole. These pools are commonly a few metres across and less than deep, however in some instances they may be several metres deep and up to across. Gilgais are found worldwide wherever Vertisol, cracking clay soils and pronounced wet and dry seasons are present. Gilgais are also called "melonholes, crabholes, hogwallows or puff and shelf formations". Gilgais are thought to form in vertisols through repeated cycles of swelling of the clay when wet and subsequent shrinkage upon drying. This action, known as argillipedoturbation, causes the soil to crack when dry and loose soil material then fills these cracks. When the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mima Mound
Mima mounds are low, flattened, circular to oval, domelike, natural mounds that are composed of loose, unstratified, often gravelly sediment that is an overthickened Soil horizon#A horizon, A horizon. These mounds range in diameter from 3 to more than 50 m; in height 30 cm to greater than 2 m; and in density from several to greater than 50 mounds per hectare, at times forming conspicuous patterns in nature, natural patterns. Mima mounds can be seen at the Mima Mounds Natural Area Preserve in Washington (state), Washington state. "Mima" is a name derived from a Chinook Jargon term meaning "a little further along" or "downstream". Theories for the origin of Mima mounds include burrowing by pocket gophers; accumulation of wind-blown (aeolian processes, aeolian) sediments around vegetation to form coppice dunes or nebkhas; seismic ground shaking by major earthquakes, though none have been observed to form Mima mounds; and shrinking and swelling of clays in hog-wallow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertisol
A vertisol, or vertosol, is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes ''self-ploughing'', where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an ''A/C soil''). This heaving of the underlying material to the surface often creates a microrelief known as '' gilgai''. Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertisol
A vertisol, or vertosol, is a soil type in which there is a high content of expansive clay minerals, many of them known as montmorillonite, that form deep cracks in drier seasons or years. In a phenomenon known as argillipedoturbation, alternate shrinking and swelling causes ''self-ploughing'', where the soil material consistently mixes itself, causing some vertisols to have an extremely deep A horizon and no B horizon. (A soil with no B horizon is called an ''A/C soil''). This heaving of the underlying material to the surface often creates a microrelief known as '' gilgai''. Vertisols typically form from highly basic rocks, such as basalt, in climates that are seasonally humid or subject to erratic droughts and floods, or that impeded drainage. Depending on the parent material and the climate, they can range from grey or red to the more familiar deep black (known as "black earths" in Australia, "black gumbo" in East Texas, "black cotton" soils in East Africa, and "vlei soils" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argillipedoturbation
Argillipedoturbation, sometimes referred to as self-mulching, is a process of soil mixing caused by the shrinking and swelling of the smectite clays contained in the soil. It is an effect specific to soils of the vertisolic variety, and is triggered by the constant cycles of wetting and drying It is characterized by wide (up to ), deep ( or more) vertical cracks in the solum that contain differing materials from the rest of the soil layer they are found in, as well as sloughed-in surface materials. In order for argillipedoturbation to occur, the soil must be at least 30% clay content. The expression of argillipedoturbation depends to a large degree on the exact clay content of the soil, as well as on what other minerals make up the soil composition. Argillipedoturbation can be strong enough that it can affect the soil horizons by combining the different horizons, making them difficult to distinguish. It can also result in a gently-rolling surface referred to as gilgai topography an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ephemeral
Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, from digital media to types of streams. "There is no single definition of ephemerality". With respect to unique performances, for example, it has been noted that " hemerality is a quality caused by the ebb and flow of the crowd's concentration on the performance and a reflection of the nostalgic character of specific performances". Because different people may value the passage of time differently, ephemerality may be a relative, perceptual concept: "In brief, what is short-lived may not be the object itself, but the attention we afford it".Ronald Beiner, ''Political Philosophy: What It Is and Why It Matters'' (2014), p. 10. Ephemerality and nature Geographical features An ephemeral stream is that which only exists following precipitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Well
A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be injected back into the aquifer through the well. Wells were first constructed at least eight thousand years ago and historically vary in construction from a simple scoop in the sediment of a dry watercourse to the qanats of Iran, and the stepwells and sakiehs of India. Placing a lining in the well shaft helps create stability, and linings of wood or wickerwork date back at least as far as the Iron Age. Wells have traditionally been sunk by hand digging, as is still the case in rural areas of the developing world. These wells are inexpensive and low-tech as they use mostly manual labo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lakes
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 last ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian English
Australian English (AusE, AusEng, AuE, AuEng, en-AU) is the set of varieties of the English language native to Australia. It is the country's common language and ''de facto'' national language; while Australia has no official language, English is the first language of the majority of the population, and has been entrenched as the ''de facto'' national language since European settlement, being the only language spoken in the home for 72% of Australians. It is also the main language used in compulsory education, as well as federal, state and territorial legislatures and courts. Australian English began to diverge from British and Irish English after the First Fleet established the Colony of New South Wales in 1788. Australian English arose from a dialectal 'melting pot' created by the intermingling of early settlers who were from a variety of dialectal regions of Great Britain and Ireland, though its most significant influences were the dialects of Southeast England. By ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioturbation
Bioturbation is defined as the reworking of soils and sediments by animals or plants. It includes burrowing, ingestion, and defecation of sediment grains. Bioturbating activities have a profound effect on the environment and are thought to be a primary driver of biodiversity. The formal study of bioturbation began in the 1800s by Charles Darwin experimenting in his garden. The disruption of aquatic sediments and terrestrial soils through bioturbating activities provides significant ecosystem services. These include the alteration of nutrients in aquatic sediment and overlying water, shelter to other species in the form of burrows in terrestrial and water ecosystems, and soil production on land.Shaler, N. S., 1891, The origin and nature of soils, in Powell, J. W., ed., USGS 12th Annual report 1890-1891: Washington, D.C., Government Printing Office, p. 213-45. Bioturbators are deemed ecosystem engineers because they alter resource availability to other species through the physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kangaroo
Kangaroos are four marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern grey kangaroo, and western grey kangaroo. Kangaroos are indigenous to Australia and New Guinea. The Australian government estimates that 42.8 million kangaroos lived within the commercial harvest areas of Australia in 2019, down from 53.2 million in 2013. As with the terms " wallaroo" and " wallaby", "kangaroo" refers to a paraphyletic grouping of species. All three terms refer to members of the same taxonomic family, Macropodidae, and are distinguished according to size. The largest species in the family are called "kangaroos" and the smallest are generally called "wallabies". The term "wallaroos" refers to species of an intermediate size. There are also the tree-kangaroos, another type of macropod, which inhabit the trop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feral
A feral () animal or plant is one that lives in the wild but is descended from domesticated individuals. As with an introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in some cases, contributed to extinction of indigenous species. The removal of feral species is a major focus of island restoration. Animals A feral animal is one that has escaped from a domestic or captive status and is living more or less as a wild animal, or one that is descended from such animals. Other definitions include animals that have changed from being domesticated to being wild, natural, or untamed. Some common examples of animals with feral populations are horses, dogs, goats, cats, rabbits, camels, and pigs. Zoologists generally exclude from the feral category animals that were genuinely wild before they escaped from captivity: neither lions escaped from a zoo nor the white-tailed eagles re-introduced to the UK are regarded a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vermin
Vermin ( colloquially varmint(s) or varmit(s)) are pests or nuisance animals that spread diseases or destroy crops or livestock. Since the term is defined in relation to human activities, which species are included vary by region and enterprise. The term derives from the Latin ''vermis'' (worm), and was originally used for the worm-like larvae of certain insects, many of which infest foodstuffs. The term ''varmint'' (and ''vermint'') has been found in sources from c. 1530–1540s. Definition The term "vermin" is used to refer to a wide scope of organisms, including rodents (such as rats), cockroaches, termites, bed bugs, ferrets, stoats, sables, pigeons, and occasionally foxes. Historically, in the 16th and 17th century, the expression also became used as a derogatory term associated with groups of persons typically plagued by vermin, namely beggars and vagabonds, and more generally the poor. Disease-carrying rodents and insects are the usual case, but the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
