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Freshwater Environmental Quality Parameters
Freshwater environmental quality parameters are those chemical, physical or biological parameters that can be used to characterise a freshwater body. Because almost all water bodies are dynamic in their composition, the relevant quality parameters are typically expressed as a range of expected concentrations. They include the natural and man-made chemical, biological and microbiological characteristics of rivers, lakes and ground-waters, the ways they are measured and the ways that they change. The values or concentrations attributed to such parameters can be used to describe the pollution status of an environment, its biotic status or to predict the likelihood or otherwise of a particular organisms being present. Monitoring of environmental quality parameters is a key activity in managing the environment, restoring polluted environments and anticipating the effects of man-made changes on the environment. Characterisation The first step in understanding the chemistry of freshwat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Cycle
The water cycle, also known as the hydrologic cycle or the hydrological cycle, is a biogeochemical cycle that describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water (salt water) and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, transpiration, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor. The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation. The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. It improves strength, workability, and resistance to wear. Manganese oxide is used as an oxidising agent; as a rubber additive; and in glass making, fertilisers, and ceramics. Manganese sulfate can be used as a fungicide. Manganese is also an essential human dietary element, important in macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. It is found mostly in the bones, but also the liver, kidneys, and brain. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes. Manganese was first isolated in 1774. It is familiar in the laboratory in the form of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate group C(=O)(O–)2. The term is also used as a verb, to describe carbonation: the process of raising the concentrations of carbonate and bicarbonate ions in water to produce carbonated water and other carbonated beverageseither by the addition of carbon dioxide gas under pressure or by dissolving carbonate or bicarbonate salts into the water. In geology and mineralogy, the term "carbonate" can refer both to carbonate minerals and carbonate rock (which is made of chiefly carbonate minerals), and both are dominated by the carbonate ion, . Carbonate minerals are extremely varied and ubiquitous in chemically precipitated sedimentary rock. The most common are calcite or calcium carbonate, CaCO3, the chief constituent of limestone (as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Chalk is common throughout Western Europe, where deposits underlie parts of France, and steep cliffs are often seen where they meet the sea in places such as the Dover cliffs on the Kent coast of the English Channel. Chalk is mined for use in industry, such as for quicklime, bricks and builder's putty, and in agriculture, for raising pH in soils with high acidity. It is also used for " blackboard chalk" for writing and drawing on various types of surfaces, although these can also be manufactured from other carbonate-based minerals, or gypsum. Description Chalk is a fine-textured, earthy type of limestone distinguished by its light color, softness, and high porosity. It is composed mostly of tiny fragments of the calcite shells or skeletons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schists
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes or plates. This texture reflects a high content of platy minerals, such as micas, talc, chlorite, or graphite. These are often interleaved with more granular minerals, such as feldspar or quartz. Schist typically forms during regional metamorphism accompanying the process of mountain building (orogeny) and usually reflects a medium grade of metamorphism. Schist can form from many different kinds of rocks, including sedimentary rocks such as mudstones and igneous rocks such as tuffs. Schist metamorphosed from mudstone is particularly common and is often very rich in mica (a ''mica schist''). Where the type of the original rock (the protolith) is discernible, the schist is usually given a name reflecting its protolith, such as ''schistose met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precambrian
The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the Latinised name for Wales, where rocks from this age were first studied. The Precambrian accounts for 88% of the Earth's geologic time. The Precambrian is an informal unit of geologic time, subdivided into three eons ( Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga) to the beginning of the Cambrian Period, about million years ago ( Ma), when hard-shelled creatures first appeared in abundance. Overview Relatively little is known about the Precambrian, despite it making up roughly seven-eighths of the Earth's history, and what is known has largely been discovered from the 1960s onwards. The Precambrian fossil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyporheic
The hyporheic zone is the region of sediment and porous space beneath and alongside a stream bed, where there is mixing of shallow groundwater and surface water. The flow dynamics and behavior in this zone (termed hyporheic flow or underflow) is recognized to be important for surface water/groundwater interactions, as well as fish spawning, among other processes. As an innovative urban water management practice, the hyporheic zone can be designed by engineers and actively managed for improvements in both water quality and riparian habitat. The assemblages of organisms that inhabits this zone are called . The term hyporheic was originally coined by Traian Orghidan in 1959 by combining two Greek words: (below) and (flow). Hyporheic zone and hydrology The hyporheic zone is the area of rapid exchange, where water is moved into and out of the stream bed and carries dissolved gas and solutes, contaminants, microorganisms and particles with it. Depending on the underlying geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Wales
, area_land_km2 = 6,172 , postal_code_type = Postcode , postal_code = LL, CH, SY , image_map1 = Wales North Wales locator map.svg , map_caption1 = Six principal areas of Wales commonly defined to be North Wales, for policing, fire and rescue, health and regional economy. North Wales ( cy, Gogledd Cymru) is a region of Wales, encompassing its northernmost areas. It borders Mid Wales to the south, England to the east, and the Irish Sea to the north and west. The area is highly mountainous and rural, with Snowdonia National Park ( and the Clwydian Range and Dee Valley (), known for its mountains, waterfalls and trails, wholly within the region. Its population is concentrated in the north-east and northern coastal areas, with significant Welsh-speaking populations in its western and rural areas. North Wales is imprecisely defined, lacking any exact definition or administrative structure. It is commonly defined adminis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Elwy
The River Elwy (''Afon Elwy'' in Welsh) is a river in Wales forming a tributary to the River Clwyd. The source of the river is sometimes said to be on the northern flank of Moel Seisiog, south-east of Llanrwst, at Ordnance Survey grid reference SH 853593. However the river only receives the name Elwy at the village of Llangernyw, where three rivers, Afon Cledwen, Afon Collen and Afon Gallen, meet to form the Elwy. It flows eastwards through Llanfair Talhaiarn and a few miles downstream from this village it is joined by a tributary, the River Aled (''Afon Aled'') which has its source in Llyn Aled. After passing through Bont-newydd, the river turns northwards again and flows through St. Asaph (''Llanelwy'' or "the church enclosure on the Elwy" in Welsh). It joins the River Clwyd about half way between St. Asaph and Rhuddlan, and the waters of the two rivers can often be seen flowing side by side for several miles. A number of caves along the lower valley of the Elwy are of great a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Clwyd
The River Clwyd (Welsh: ''Afon Clwyd'') is a river in Wales that rises in the Clocaenog Forest () northwest of Corwen. Its total length is . It flows due south until, at Melin-y-wig, it veers north-eastwards, tracking the A494 and passing through Derwen, Llanelidan, Pwllglas and Llanfair Dyffryn Clwyd to Ruthin. Here it leaves the relatively narrow valley and enters a broad agricultural vale, the Vale of Clwyd (Welsh: ''Dyffryn Clwyd''). Just south of Denbigh, it is joined by the River Clywedog. This substantial tributary also has its source in the Clocaenog Forest but drains out to the east and north of the forest and passes through Cyffylliog, Bontuchel and Rhewl before its confluence with the main river. Then the Clwyd meanders northwards through the fertile Clwyd valley to St Asaph. Around north of St Asaph, the river is joined by a tributary as large as the main river, the River Elwy. In normal flows at low tide, the waters of these two rivers can be seen flowing sid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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