1.
Potomac River
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The Potomac River /pəˈtoʊmək/ is located along the mid-Atlantic Ocean coast of the United States and flows into the Chesapeake Bay. The river is approximately 405 miles long, with an area of about 14,700 square miles. In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States, over 5 million people live within the Potomac watershed. The river forms part of the borders between Maryland and Washington, D. C. on the left descending bank and West Virginia and Virginia on the right descending bank. The majority of the lower Potomac River is part of the State of Maryland, exceptions include a small tidal portion within the District of Columbia, and the border with Virginia being delineated from point to point. Except for a portion of its headwaters in West Virginia. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, the Potomac River runs 405 miles from the Fairfax Stone in West Virginia on the Allegheny Plateau to Point Lookout, Maryland, and drains 14,679 square miles. The length of the river from the junction of its North and South Branches to Point Lookout is 302 miles, the average flow is 10,800 ft³/s. The largest flow recorded on the Potomac at Washington, D. C. was in March 1936 when it reached 425,000 ft³/s. The lowest flow recorded at the same location was 600 ft³/s in September,1966. The source of the North Branch is at the Fairfax Stone located at the junction of Grant, Tucker, the source of the South Branch is located near Hightown in northern Highland County, Virginia. The rivers two branches converge just east of Green Spring in Hampshire County, West Virginia, to form the Potomac. Once the Potomac drops from the Piedmont to the Coastal Plain at Little Falls, tides further influence the river as it passes through Washington, D. C. salinity in the Potomac River Estuary increases thereafter with distance downstream. The estuary also widens, reaching 11 statute miles wide at its mouth, Potomac is a European spelling of Patowmeck, the Algonquian name of a Native American village, perhaps meaning something brought. Native Americans had different names for different parts of the river, calling the river above Great Falls Cohongarooton, meaning honking geese and Patawomke below the fall, meaning river of swans. The spelling of the name has many forms over the years from Patawomeke to Patawomeck, Patowmack. The rivers name was decided upon as Potomac by the Board on Geographic Names in 1931. The river itself is at least two years old, likely extending back ten to twenty million years before present when the Atlantic Ocean lowered and exposed coastal sediments along the fall line
2.
Cyanobacteria
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The name cyanobacteria comes from the color of the bacteria. Sometimes, they are called blue-green algae, and incorrectly so, because cyanobacteria are prokaryotes, like other prokaryotes, cyanobacteria have no membrane-sheathed organelles. Photosynthesis is performed in distinctive folds in the membrane of the cell. Biologists commonly agree that chloroplasts found in eukaryotes have their ancestry in cyanobacteria, via a process called endosymbiosis, Cyanobacteria are a group of photosynthetic, nitrogen fixing bacteria that live in a wide variety of habitats such as moist soils and in water. They may be free-living or form relationships with plants or with lichen-forming fungi as in the lichen genus Peltigera. They range from unicellular to filamentous and include colonial species, colonies may form filaments, sheets, or even hollow balls. Cyanobacteria can fix nitrogen in anaerobic conditions by means of specialized cells called heterocysts. Heterocysts may also form under the environmental conditions when fixed nitrogen is scarce. Free-living cyanobacteria are present in the column in rice paddies, and cyanobacteria can be found growing as epiphytes on the surfaces of the green alga, Chara. Cyanobacteria such as, can provide rice plantations with biofertilizer, many cyanobacteria form motile filaments of cells, called hormogonia, that travel away from the main biomass to bud and form new colonies elsewhere. The cells in a hormogonium are often thinner than in the state. To break away from the parent colony, a hormogonium often must tear apart a weaker cell in a filament, each individual cell of a cyanobacterium typically has a thick, gelatinous cell wall. They lack flagella, but hormogonia of some species can move about by gliding along surfaces, many of the multicellular filamentous forms of Oscillatoria are capable of a waving motion, the filament oscillates back and forth. In water columns, some cyanobacteria float by forming gas vesicles and these vesicles are not organelles as such. They are not bounded by membranes, but by a protein sheath. Cyanobacteria can be found in almost every terrestrial and aquatic habitat—oceans, fresh water, damp soil, temporarily moistened rocks in deserts, bare rock and soil and they can occur as planktonic cells or form phototrophic biofilms. They are found in almost every endolithic ecosystem, a few are endosymbionts in lichens, plants, various protists, or sponges and provide energy for the host. Some live in the fur of sloths, providing a form of camouflage, aquatic cyanobacteria are known for their extensive and highly visible blooms that can form in both freshwater and marine environments
3.
Phytoplankton
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Phytoplankton /ˌfaɪtoʊˈplæŋktən/ are the autotrophic components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. The name comes from the Greek words φυτόν, meaning plant, most phytoplankton are too small to be individually seen with the unaided eye. Phytoplankton are photosynthesizing microscopic organisms that inhabit the upper layer of almost all oceans. They are agents for primary production, the creation of organic compounds from carbon dioxide dissolved in the water, Phytoplankton obtain energy through the process of photosynthesis and must therefore live in the well-lit surface layer of an ocean, sea, lake, or other body of water. Phytoplankton account for half of all activity on Earth. Their cumulative energy fixation in carbon compounds is the basis for the vast majority of oceanic, the effects of anthropogenic warming on the global population of phytoplankton is an area of active research. Additionally, changes in the mortality of phytoplankton due to rates of zooplankton grazing may be significant, as a side note, one of the more remarkable food chains in the ocean – remarkable because of the small number of links – is that of phytoplankton-feeding krill feeding baleen whales. Phytoplankton are also dependent on minerals. However, across large regions of the World Ocean such as the Southern Ocean and this has led to some scientists advocating iron fertilization as a means to counteract the accumulation of human-produced carbon dioxide in the atmosphere. Large-scale experiments have added iron to the oceans to promote phytoplankton growth, however, controversy about manipulating the ecosystem and the efficiency of iron fertilization has slowed such experiments. Phytoplankton depend on other substances to survive as well, in particular, Vitamin B is crucial. Areas in the ocean have been identified as having a lack of Vitamin B. While almost all species are obligate photoautotrophs, there are some that are mixotrophic and other. Of these, the best known are dinoflagellate genera such as Noctiluca and Dinophysis, the term phytoplankton encompasses all photoautotrophic microorganisms in aquatic food webs. Phytoplankton serve as the base of the food web, providing an essential ecological function for all aquatic life. However, unlike terrestrial communities, where most autotrophs are plants, phytoplankton are a group, incorporating protistan eukaryotes. There are about 5,000 known species of marine phytoplankton, how such diversity evolved despite scarce resources is unclear. In terms of numbers, the most important groups of phytoplankton include the diatoms, cyanobacteria and dinoflagellates, one group, the coccolithophorids, is responsible for the release of significant amounts of dimethyl sulfide into the atmosphere
4.
Detergent
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A detergent is a surfactant or a mixture of surfactants with cleaning properties in dilute solutions. In most household contexts, the term detergent by itself refers specifically to laundry detergent or dish detergent, detergents are commonly available as powders or concentrated solutions. Detergents, like soaps, work because they are amphiphilic, partly hydrophilic and their dual nature facilitates the mixture of hydrophobic compounds with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees, detergents are classified into three broad groupings, depending on the electrical charge of the surfactants. The alkylbenzene portion of these anions is lipophilic and the sulfonate is hydrophilic, two different varieties have been popularized, those with branched alkyl groups and those with linear alkyl groups. The former were phased out in economically advanced societies because they are poorly biodegradable. An estimated 6 billion kilograms of detergents are produced annually for domestic markets. Bile acids, such as acid, are anionic detergents produced by the liver to aid in digestion and absorption of fats. The ammonium center is positively charged, non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside, common examples of the former include Tween, Triton, and the Brij series. These materials are known as ethoxylates or PEGlyates and their metabolites. Glycosides have a sugar as their uncharged hydrophilic headgroup, examples include octyl thioglucoside and maltosides. HEGA and MEGA series detergents are similar, possessing an alcohol as headgroup. Zwitterionic detergents possess a net zero charge arising from the presence of numbers of +1. In World War I, there was a shortage of oils, synthetic detergents were first made in Germany. One of the largest applications of detergents is for household cleaning including dish washing and washing laundry, the formulations are complex, reflecting the diverse demands of the application and the highly competitive consumer market. Both carburetors and fuel injector components of Otto engines benefit from detergents in the fuels to prevent fouling, typical detergents are long-chain amines and amides such as polyisobuteneamine and polyisobuteneamide/succinimide. Reagent grade detergents are employed for the isolation and purification of integral membrane proteins found in biological cells, solubilization of cell membrane bilayers requires a detergent that can enter the inner membrane monolayer
5.
Fertilizer
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A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Fertilizers enhance the growth of plants and this goal is met in two ways, the traditional one being additives that provide nutrients. The second mode by which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration and this article, like many on fertilizers, emphasises the nutritional aspect. The nutrients required for plant life are classified according to the elements. Instead compounds containing these elements are the basis of fertilizers, the macronutrients are consumed in larger quantities and are present in plant tissue in quantities from 0. 15% to 6. 0% on a dry matter basis. Plants are made up of four elements, hydrogen, oxygen, carbon. Carbon, hydrogen and oxygen are widely available as water and carbon dioxide, although nitrogen makes up most of the atmosphere, it is in a form that is unavailable to plants. Nitrogen is the most important fertilizer since nitrogen is present in proteins, DNA, to be nutritious to plants, nitrogen must be made available in a fixed form. Only some bacteria and their host plants can fix atmospheric nitrogen by converting it to ammonia, phosphate is required for the production of DNA and ATP, the main energy carrier in cells, as well as certain lipids. Micronutrients are consumed in quantities and are present in plant tissue on the order of parts-per-million, ranging from 0.15 to 400 ppm DM. These elements are present at the active sites of enzymes that carry out the plants metabolism. Because these elements enable catalysts their impact far exceeds their weight percentage, Fertilizers are classified in several ways. They are classified according to whether they provide a single nutrient, multinutrient fertilizers provide two or more nutrients, for example N and P. Fertilizers are also sometimes classified as inorganic versus organic. Inorganic fertilizers exclude carbon-containing materials except ureas, organic fertilizers are usually plant- or animal-derived matter. Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture, the main nitrogen-based straight fertilizer is ammonia or its solutions. Ammonium nitrate is widely used. Urea is another source of nitrogen, having the advantage that it is solid and non-explosive, unlike ammonia and ammonium nitrate. A few percent of the fertilizer market has been met by calcium ammonium nitrate
6.
Sewage
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Sewage is a water-carried waste, in solution or suspension, that is intended to be removed from a community. Also known as domestic or municipal wastewater, it is characterized by volume or rate of flow, physical condition, chemical and toxic constituents and it consists mostly of greywater, blackwater, soaps and detergents, and toilet paper. Whether it also contains surface runoff depends on the design of sewer system, all sewage ends up back in the environment, by any of several routes. A basic distinction in its route is whether it undergoes sewage treatment to mitigate its effect on the environment before arriving there, Sewage usually travels from a buildings plumbing either into a sewer, which will carry it elsewhere, or into an onsite sewage facility. Whether it is combined with surface runoff in the sewer depends on the sewer design, before the 20th century, sewers usually discharged into a body of water such as a stream, river, lake, bay, or ocean. There was no treatment, so the breakdown of the waste was left to the ecosystem. Today, the goal is that sewers route their contents to a treatment plant rather than directly to a body of water. In many countries, this is the norm, in developing countries. Thus other goals of modern sewage routing include handling surface runoff separately from sewage, handling greywater separately from toilet waste, proper collection and safe, nuisance-free disposal of the liquid wastes of a community are legally recognized as a necessity in an urbanized, industrialized society. In many developing countries the bulk of domestic and industrial wastewater is discharged without any treatment or after primary treatment only, the term sewage is nowadays regarded as an older term and is being more and more replaced by wastewater. In general American English usage, the sewage and sewerage mean the same thing. Both words are descended from Old French assewer, derived from the Latin exaquare, in American technical and professional English usage, sewerage refers to the infrastructure that conveys sewage. Wastes that result from an industrial processes such as the production or manufacture of goods are classed as industrial wastewater, surface runoff, also known as storm flow or overland flow, is that portion of precipitation that runs rapidly over the ground surface to a defined channel. Sewage is a mixture of chemicals, with many distinctive chemical characteristics. These include high concentrations of ammonium, nitrate, phosphorus, high conductivity, high alkalinity, the organic matter of sewage is measured by determining its biological oxygen demand or the chemical oxygen demand. Sewage also contains the nutrients nitrogen and phosphorus, Sewage can be monitored for both disease-causing and benign organisms with a variety of techniques. Traditional techniques involve filtering, staining, and examining samples under a microscope, sequencing DNA from an environmental sample is known as metagenomics. Sewage has also analyzed to determine relative rates of use of prescription
7.
Hypoxia (environmental)
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Hypoxia refers to low oxygen conditions. Normally,20. 9% of the gas in the atmosphere is oxygen, the partial pressure of oxygen in the atmosphere is 20. 9% of the total barometric pressure. In water however, oxygen levels are lower, approximately 1%. Atmospheric hypoxia occurs naturally at high altitudes, total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen which is defined as hypobaric hypoxia. Oxygen remains at 20. 9% of the gas mixture, differing from hypoxic hypoxia. This is common, for example, in the burrows of some subterranean animals. Atmospheric hypoxia is also the basis of training which is a standard part of training for elite athletes. Several companies mimic hypoxia using normobaric artificial atmosphere, dissolved oxygen is typically expressed as a percentage of the oxygen that would dissolve in the water at the prevailing temperature and salinity. An aquatic system lacking dissolved oxygen is termed anaerobic, reducing, or anoxic, most fish cannot live below 30% saturation. A healthy aquatic environment should seldom experience less than 80%, the exaerobic zone is found at the boundary of anoxic and hypoxic zones. Hypoxia can occur throughout the column and also at high altitudes as well as near sediments on the bottom. It usually extends throughout 20-50% of the column, but depending on the water depth. It can occur in 10-80% of the water column, for example, in a 10-meter water column, it can reach up to 2 meters below the surface. In a 20-meter water column, it can extend up to 8 meters below the surface, while phytoplankton, through photosynthesis, will raise DO saturation during daylight hours, the dense population of a bloom reduces DO saturation during the night by respiration. When phytoplankton cells die, they sink towards the bottom and are decomposed by bacteria, if oxygen depletion progresses to hypoxia, fish kills can occur and invertebrates like worms and clams on the bottom may be killed as well. Hypoxia may also occur in the absence of pollutants, in estuaries, for example, because freshwater flowing from a river into the sea is less dense than salt water, stratification in the water column can result. Vertical mixing between the bodies is therefore reduced, restricting the supply of oxygen from the surface waters to the more saline bottom waters. The oxygen concentration in the layer may then become low enough for hypoxia to occur
8.
Sodium triphosphate
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Sodium triphosphate, also sodium tripolyphosphate, or tripolyphosphate, ) is an inorganic compound with formula Na5P3O10. It is the salt of the polyphosphate penta-anion, which is the conjugate base of triphosphoric acid. It is produced on a scale as a component of many domestic and industrial products. Environmental problems associated with eutrophication are attributed to its widespread use, sodium tripolyphosphate is produced by heating a stoichiometric mixture of disodium phosphate, Na2HPO4, and monosodium phosphate, NaH2PO4, under carefully controlled conditions. 2 Na2HPO4 + NaH2PO4 → Na5P3O10 +2 H2O In this way, STPP is a colourless salt, which exists both in anhydrous form and as the hexahydrate. The anion can be described as the pentanionic chain 5−, many related di-, tri-, and polyphosphates are known including the cyclic triphosphate P3O93−. It binds strongly to metal cations as both a bidentate and tridentate chelating agent, the majority of STPP is consumed as a component of commercial detergents. It serves as a builder, industrial jargon for a water softener, in hard water, detergents are deactivated. Being a highly charged chelating agent, TPP5− binds to dications tightly, STPP is a preservative for seafood, meats, poultry, and animal feeds. It is common in food production as E number E451, in foods, STPP is used as an emulsifier and to retain moisture. Many governments regulate the quantities allowed in foods, as it can increase the sale weight of seafood in particular. The United States Food and Drug Administration lists STPP as generally recognized as safe, other uses include ceramics, leather tanning, anticaking, setting retarders, flame retardants, paper, anticorrosion pigments, textiles, rubber manufacture, fermentation, antifreeze. TPP is used as a crosslinker in polysaccharide based drug delivery. Polyphosphates are hydrolyzed into simpler phosphates, which in moderate amounts are nutritious, for example, ATP, a related derivative of triphosphate, is essential for life. Thus, the toxicity of polyphosphates is low, as the lowest LD50 after oral administration is >1,000 mg/kg body weight, similarly, no mutagenic, carcinogenic, or reproductive effects have been noted. Salts of polyphosphate anions are moderately irritating to skin and mucous membranes because they are mildly alkaline, in 2000, the worldwide consumption of STPP was estimated to be approximately 2,000,000 tonnes. Because it is very water-soluble, it is not significantly transferred to sewage sludge, no environmental risk related to STPP use in detergents is indicated in soil or air. As STPP is a substance, biodegradation studies are not applicable
9.
Cultural eutrophication
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Cultural eutrophication is the process that speeds up natural eutrophication because of human activity. Extra nutrients are supplied by treatment plants, golf courses, fertilizers. These nutrients result in a growth of plant life known as an algal bloom. This can change a natural food web, and also reduce the amount of dissolved oxygen in the water for organisms to breathe. Both these things cause animal and plant death rates to increase as the plants take in water while the animals drink the poisoned water. This contaminates water, making it undrinkable, and sediment quickly fills the lake, cultural eutrophication is a form of water pollution. Cultural eutrophication also occurs when excessive fertilizers run into lakes and rivers and this encourages the growth of algae and other aquatic plants. Following this, overcrowding occurs and plants compete for sunlight, space, overgrowth of water plants also blocks sunlight and oxygen for aquatic life in the water, which in turn threatens their survival. Algae also grows easily, thus threatening other water plants no matter whether they are floating, half-submerged, not only does this cause algal blooming, it can cause an array of more long-term effects on the water such as damage to coral reefs and deep sea animal life. It also speeds up the damage of marine and also affects humans if the effects of algal blooming is too drastic. Fish will die and there will be lack of food in the area, nutrient pollution is a major cause of algal blooming, and should be minimized. This is a widespread and highly publicized issue ranging from west coast Victoria, British Columbia, to east coast Nova Scotia
10.
Surface runoff
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Surface runoff is the flow of water that occurs when excess stormwater, meltwater, or other sources flows over the Earths surface. Surface runoff is a component of the water cycle. It is the agent in soil erosion by water. Runoff that occurs on the surface before reaching a channel is also called a nonpoint source. If a nonpoint source contains man-made contaminants, or natural forms of pollution the runoff is called nonpoint source pollution, a land area which produces runoff that drains to a common point is called a drainage basin. When runoff flows along the ground, it can pick up soil contaminants including petroleum, pesticides, surface runoff can be generated either by rainfall, snowfall or by the melting of snow, or glaciers. Snow and glacier melt occur only in areas cold enough for these to form permanently, typically snowmelt will peak in the spring and glacier melt in the summer, leading to pronounced flow maxima in rivers affected by them. The determining factor of the rate of melting of snow or glaciers is both air temperature and the duration of sunlight, in high mountain regions, streams frequently rise on sunny days and fall on cloudy ones for this reason. In areas where there is no snow, runoff will come from rainfall, however, not all rainfall will produce runoff because storage from soils can absorb light showers. This occurs when the rate of rainfall on a surface exceeds the rate at which water can infiltrate the ground and this is called flooding excess overland flow, Hortonian overland flow, or unsaturated overland flow. This more commonly occurs in arid and semi-arid regions, where rainfall intensities are high and this occurs largely in city areas where pavements prevent water from flooding. When the soil is saturated and the depression storage filled, and rain continues to fall, the level of antecedent soil moisture is one factor affecting the time until soil becomes saturated. This runoff is called saturation excess overland flow or saturated overland flow, soil retains a degree of moisture after a rainfall. This residual water moisture affects the soils infiltration capacity, during the next rainfall event, the infiltration capacity will cause the soil to be saturated at a different rate. The higher the level of antecedent soil moisture, the more quickly the soil becomes saturated, once the soil is saturated, runoff occurs. After water infiltrates the soil on a portion of a hill, the water may flow laterally through the soil. This is called subsurface return flow or throughflow, any remaining surface water eventually flows into a receiving water body such as a river, lake, estuary or ocean. Urbanization increases surface runoff by creating more impervious surfaces such as pavement and it is instead forced directly into streams or storm water runoff drains, where erosion and siltation can be major problems, even when flooding is not
11.
Nitrate
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Nitrate is a polyatomic ion with the molecular formula NO−3 and a molecular mass of 62.0049 g/mol. Nitrates also describe the functional group RONO2. These nitrate esters are a class of explosives. The anion is the base of nitric acid, consisting of one central nitrogen atom surrounded by three identically bonded oxygen atoms in a trigonal planar arrangement. The nitrate ion carries a charge of −1. This arrangement is used as an example of resonance. Like the isoelectronic carbonate ion, the ion can be represented by resonance structures. A common example of a nitrate salt is potassium nitrate. A rich source of nitrate in the human body comes from diets rich in leafy green foods, such as spinach. NO3- is the active component within beetroot juice and other vegetables. Nitrite and water are converted in the body to nitric oxide, nitrate salts are found naturally on earth as large deposits, particularly of nitratine, a major source of sodium nitrate. Nitrates are found in man-made fertilizers, as a byproduct of lightning strikes in earths nitrogen-oxygen rich atmosphere, nitric acid is produced when nitrogen dioxide reacts with water vapor. Nitrates are mainly produced for use as fertilizers in agriculture because of their solubility and biodegradability. The main nitrate fertilizers are ammonium, sodium, potassium, several million kilograms are produced annually for this purpose. The second major application of nitrates is as oxidizing agents, most notably in explosives where the oxidation of carbon compounds liberates large volumes of gases. Sodium nitrate is used to air bubbles from molten glass. Mixtures of the salt are used to harden some metals. Explosives and table tennis balls are made from celluloid, although nitrites are the nitrogen compound chiefly used in meat curing, nitrates are used in certain specialty curing processes where a long release of nitrite from parent nitrate stores is needed
12.
Estuary
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An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a zone between river environments and maritime environments. They are subject both to marine influences—such as tides, waves, and the influx of saline water—and to riverine influences—such as flows of fresh water and sediment. The inflows of sea water and fresh water provide high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea began to rise about 10. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns, the banks of many estuaries are amongst the most heavily populated areas of the world, with about 60% of the worlds population living along estuaries and the coast. The word estuary is derived from the Latin word aestuarium meaning tidal inlet of the sea, there have been many definitions proposed to describe an estuary. However, this definition excludes a number of water bodies such as coastal lagoons. This broad definition also includes fjords, lagoons, river mouths, an estuary is a dynamic ecosystem having a connection to the open sea through which the sea water enters with the rhythm of the tides. The sea water entering the estuary is diluted by the water flowing from rivers. The pattern of dilution varies between different estuaries and depends on the volume of water, the tidal range. Drowned river valleys are known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and this is the most common type of estuary in temperate climates. Well-studied estuaries include the Severn Estuary in the United Kingdom and the Ems Dollard along the Dutch-German border, the width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped in the inner part and broadening and deepening seaward. Water depths rarely exceed 30 m, examples of this type of estuary in the U. S. are the Hudson River, Chesapeake Bay, and Delaware Bay along the Mid-Atlantic coast, and Galveston Bay and Tampa Bay along the Gulf Coast. They are relatively common in tropical and subtropical locations and these estuaries are semi-isolated from ocean waters by barrier beaches. Formation of barrier beaches partially encloses the estuary, with only narrow inlets allowing contact with the ocean waters, bar-built estuaries typically develop on gently sloping plains located along tectonically stable edges of continents and marginal sea coasts. They are extensive along the Atlantic and Gulf coasts of the U. S. in areas with active coastal deposition of sediments, barrier beaches form in shallow water and are generally parallel to the shoreline, resulting in long, narrow estuaries
13.
Fish kill
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The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life. The most common cause is reduced oxygen in the water, which in turn may be due to such as drought, algae bloom, overpopulation. Infectious diseases and parasites can also lead to fish kill, toxicity is a real but far less common cause of fish kill. Fish kills are often the first visible signs of stress and are usually investigated as a matter of urgency by environmental agencies to determine the cause of the kill. Pollution events may affect fish species and fish age classes in different ways, if it is a cold-related fish kill, juvenile fish or species that are not cold-tolerant may be selectively affected. If toxicity is the cause, species are more generally affected, a reduction in dissolved oxygen may affect larger specimens more than smaller fish as these may be able to access oxygen richer water at the surface, at least for a short time. Fish kills may result from a variety of causes, of known causes, fish kills are most frequently caused by pollution from agricultural runoff or biotoxins. Ecological hypoxia is one of the most common causes of fish kills. The hypoxic event may be brought on by such as algae blooms, droughts, high temperatures. Because of the difficulty and lack of standard protocol to investigate fish kills, oxygen enters the water through diffusion. The amount of oxygen that can be dissolved in water depends on the atmospheric pressure, the water temperature and whether the water is salty. For example, at 20 °C and one atmosphere of pressure, the amount of oxygen that can be dissolved in the water decreases by about 1 mg/l for each 10 °C increase in water temperature above 20 °C. Many cold water fish live in clean cold waters become stressed when oxygen concentrations fall below 8 mg/l while warm water fish generally need at least 5 ppm of dissolved oxygen. Fish can endure periods of reduced oxygen. Depleted oxygen levels are the most common cause of fish kills, associated with these photosynthetic rhythms there is a matching pH rhythm as bicarbonate ion is metabolised by plant cells. This can lead to pH stress even when oxygen levels are high and these are naturally occurring in many bodies of water, and fish that are stressed for other reasons, such as spawning or suboptimal water quality, are more susceptible. For example, since 2004 fish kills have been observed in the Shenandoah River basin in the spring, so far, investigators suspect certain bacteria, along with environmental and contaminant factors that may cause immune suppression. In fish farming, where populations are optimized for the resources, parasites or disease can spread quickly
14.
Algal bloom
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An algal bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems, and is recognized by the discoloration in the water from their pigments. Cyanobacteria were mistaken for algae in the past, so cyanobacterial blooms are also called algal blooms. Blooms which can injure animals or the ecology are called harmful algal blooms, since algae is a broad term including organisms of widely varying sizes, growth rates and nutrient requirements, there is no officially recognized threshold level as to what is defined as a bloom. For some species, algae can be considered to be blooming at concentrations reaching millions of cells per milliliter, bright green blooms in freshwater systems are frequently a result of cyanobacteria such as Microcystis. Blooms may also consist of macroalgal species and these blooms are recognizable by large blades of algae that may wash up onto the shoreline. Such blooms often take on a red or brown hue and are known colloquially as red tides, freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. The excess of nutrients may originate from fertilizers that are applied to land for agricultural or recreational purposes and they may also originate from household cleaning products containing phosphorus. These nutrients can then enter watersheds through water runoff, excess carbon and nitrogen have also been suspected as causes. Presence of residual sodium carbonate acts as catalyst for the algae to bloom by providing dissolved carbon dioxide for enhanced photosynthesis in the presence of nutrients, when phosphates are introduced into water systems, higher concentrations cause increased growth of algae and plants. Algae tend to very quickly under high nutrient availability, but each alga is short-lived. The decay process consumes dissolved oxygen in the water, resulting in hypoxic conditions, without sufficient dissolved oxygen in the water, animals and plants may die off in large numbers. Use of an Olszewski tube can help combat problems with hypolimnetic withdrawal. Blooms may be observed in freshwater aquariums when fish are overfed and these are generally harmful for fish, and the situation can be corrected by changing the water in the tank and then reducing the amount of food given. A harmful algal bloom is a bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms. HABs are often associated with large-scale marine mortality events and have associated with various types of shellfish poisonings. In studies at the population level bloom coverage has been related to the risk of non-alcoholic liver disease death. In the marine environment, single-celled, microscopic, plant-like organisms naturally occur in the surface layer of any body of water. These organisms, referred to as phytoplankton or microalgae, form the base of the food web upon which all other marine organisms depend
15.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
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Shellfish
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Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found in freshwater, in addition, a few species of land crabs are eaten, for example Cardisoma guanhumi in the Caribbean. Despite the name, shellfish are not a kind of fish, many varieties of shellfish are actually closely related to insects and arachnids, making up one of the main classes of the phylum Arthropoda. Cephalopods and bivalves are molluscs, as are snails and slugs, familiar marine molluscs used as a food source by humans include many species of clams, mussels, oysters, winkles, and scallops. Some crustaceans commonly eaten are shrimp, lobsters, crayfish, echinoderms are not as frequently harvested for food as molluscs and crustaceans, however, sea urchin roe is quite popular in many parts of the world. Most shellfish eat a diet composed primarily of phytoplankton and zooplankton, Shellfish are among the most common food allergens. The term shellfish is used broadly and specifically. In common parlance, as in having shellfish for dinner, it can refer to anything from clams and oysters to lobster, for regulatory purposes it is often narrowly defined as filter-feeding molluscs such as clams, mussels, and oyster to the exclusion of crustaceans and all else. Although the term is applied to marine species, edible freshwater invertebrates such as crayfish. Although their shells may differ, all shellfish are invertebrates, the word shellfish is both singular and plural, the rarely used shellfishes is sometimes employed to distinguish among various types of shellfish. Archaeological finds have shown that humans have been making use of shellfish as an item for hundreds of thousands of years. In the Japanese cuisine, chefs often use shellfish and their roe in different dishes, sushi features both raw and cooked shellfish. Sashimi primarily consists of fresh raw seafood, sliced into thin pieces. Both sushi and sashimi are served with soy sauce and wasabi paste, thinly sliced pickled ginger root, and a simple garnish such as shiso or finely shredded daikon radish, or both. Lobster in particular is a delicacy in the United States. Lobsters are eaten on much of the East Coast, the American lobster ranges from Newfoundland down to about the Carolinas, a typical meal involves boiling the lobster with some slight seasoning and then serving it with drawn butter, baked potato, and corn on the cob. Clamming is done both commercially and recreationally along the Northeast coastline of the US, various type of clams are incorporated into the cuisine of New England. The soft-shelled clam is eaten fried or steamed
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Eutrophic
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The quantities of nitrogen, phosphorus, and other biologically useful nutrients are the primary determinants of a body of waters trophic state index. Consequently, a body of waters trophic index may sometimes be used to make an estimate of its biological condition. Although the term trophic index is commonly applied to lakes, any water body may be indexed. Carlsons index is one of the commonly used trophic indices and is the trophic index used by the United States Environmental Protection Agency. The trophic state is defined as the weight of biomass in a given water body at the time of measurement. Because they are of concern, the Carlson index uses the algal biomass as an objective classifier of a lake or other water bodys trophic status. According to the US EPA, the Carlson Index should only be used with lakes that have relatively few rooted plants, because they tend to correlate, three independent variables can be used to calculate the Carlson Index, chlorophyll pigments, total phosphorus and Secchi depth. Of these three, chlorophyll will probably yield the most accurate measures, as it is the most accurate predictor of biomass, phosphorus may be a more accurate estimation of a water bodys summer trophic status than chlorophyll if the measurements are made during the winter. Finally, the Secchi depth is probably the least accurate measure, consequently, citizen monitoring programs and other volunteer or large-scale surveys will often use the Secchi depth. By translating the Secchi transparency values to a log base 2 scale, the Secchi depth, which measures water transparency, indicates the concentration of dissolved and particulate material in the water, which in turn can be used to derive the biomass. A lake is classified as being in one of three possible classes, oligotrophic, mesotrophic or eutrophic. Lakes with extreme trophic indices may also be considered hyperoligotrophic or hypereutrophic, the table below demonstrates how the index values translate into trophic classes. Each trophic class supports different types of fish and other organisms, if the algal biomass in a lake or other water body reaches too high a concentration, massive fish die-offs may occur as decomposing biomass deoxygenates the water. An oligotrophic lake is a lake with low productivity, as a result of low nutrient content. These lakes have low production, and consequently, often have very clear waters. The bottom waters of such lakes typically have ample oxygen, thus, such lakes often support many species, like lake trout. The oxygen content is likely to be higher in deep lakes, ecologists use the term oligotrophic to distinguish unproductive lakes, characterised by nutrient deficiency, from productive, eutrophic lakes, with an ample or excessive nutrient supply. Oligotrophic lakes are most common in cold regions underlain by resistant igneous rocks, mesotrophic lakes are lakes with an intermediate level of productivity
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Water treatment
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Water treatment is any process that makes water more acceptable for a specific end-use. The end use may be drinking, industrial supply, irrigation, river flow maintenance, water recreation or many other uses. Water treatment removes contaminants and undesirable components, or reduces their concentration so that the water becomes fit for its desired end-use. Substances that are removed during the process of drinking water treatment include suspended solids, bacteria, algae, viruses, fungi, measures taken to ensure water quality not only relate to the treatment of the water, but to its conveyance and distribution after treatment. It is therefore common practice to keep residual disinfectants in the water to kill bacteriological contamination during distribution. World Health Organization guidelines are a set of standards intended to apply where better local standards are not implemeted. More rigorous standards apply across Europe, the USA and in most other developed countries, followed throughout the world for drinking water quality requirements. Disinfection for killing bacteria viruses and other pathogens, technologies for potable water and other uses are well developed, and generalized designs are available from which treatment processes can be selected for pilot testing on the specific source water. In addition, a number of companies provide patented technological solutions for treatment of specific contaminants. Automation of water and waste-water treatment is common in the developed world, source water quality through the seasons, scale and environmental impact can dictate capital costs and operating costs. End use of the treated water dictates the necessary quality monitoring technologies, biological processes can be employed in the treatment of wastewater and these processes may include, for example, aerated lagoons, activated sludge or slow sand filters. To be effective, sewage must be conveyed to a treatment plant by appropriate pipes and infrastructure, some wastewaters require different and sometimes specialized treatment methods. At the simplest level, treatment of sewage and most wastewaters is carried out through separation of solids from liquids, by progressively converting dissolved material into solids, usually a biological floc, which is then settled out, an effluent stream of increasing purity is produced. Two of the processes of industrial water treatment are boiler water treatment. A lack of water treatment can lead to the reaction of solids and bacteria within pipe work. Steam boilers can suffer from scale or corrosion when left untreated, scale deposits can lead to weak and dangerous machinery, while additional fuel is required to heat the same level of water because of the rise in thermal resistance. Poor quality dirty water can become a ground for bacteria such as Legionella causing a risk to public health. With the proper treatment, a significant proportion of industrial on-site wastewater might be reusable, corrosion in low pressure boilers can be caused by dissolved oxygen, acidity and excessive alkalinity
19.
Ecosystem
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An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are regarded as linked together through nutrient cycles, as ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can be of any size but usually encompass specific, limited spaces. Energy, water, nitrogen and soil minerals are other essential components of an ecosystem. The energy that flows through ecosystems is obtained primarily from the sun and it generally enters the system through photosynthesis, a process that also captures carbon from the atmosphere. By feeding on plants and on one another, animals play an important role in the movement of matter and they also influence the quantity of plant and microbial biomass present. Ecosystems are controlled both by external and internal factors, other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can have different characteristics simply because they contain different species. The introduction of species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are controlled by them and are often subject to feedback loops. Other internal factors include disturbance, succession and the types of species present, although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Biodiversity affects ecosystem function, as do the processes of disturbance, classifying ecosystems into ecologically homogeneous units is an important step towards effective ecosystem management, but there is no single, agreed-upon way to do this. The term ecosystem was first used in 1935 in a publication by British ecologist Arthur Tansley, Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as The whole system, including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment. Tansley regarded ecosystems not simply as natural units, but as mental isolates, Tansley later defined the spatial extent of ecosystems using the term ecotope. G. Raymond Lindeman took these ideas one step further to suggest that the flow of energy through a lake was the driver of the ecosystem. Most mineral nutrients, on the hand, are recycled within ecosystems. Ecosystems are controlled both by external and internal factors, external factors, also called state factors, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem
20.
Agriculture
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Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
21.
Sanitary sewer
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A sanitary sewer or foul sewer is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment or disposal. Sanitary sewers are part of a system called sewerage or sewage system. Sewage may be treated to water pollution before discharge to surface waters. Sanitary sewers serving industrial areas also carry industrial wastewater, separate sanitary sewer systems are designed to transport sewage alone. In municipalities served by sewers, separate storm drains may be constructed to convey surface runoff directly to surface waters. Sanitary sewers are distinguished from combined sewers, which combine sewage with stormwater runoff in the same pipe, sanitary sewer systems are considered beneficial because they avoid combined sewer overflows. To overcome these disadvantages, some cities built separate sanitary sewers to collect only municipal wastewater, the decision between a combined sewer system or two separate systems is mainly based on need for sewage treatment and cost of providing treatment during heavy rain events. Many cities with combined sewer systems built prior to sewage treatment have not replaced those sewer systems, in the developed world, sewers are pipes from buildings to one or more levels of larger underground trunk mains, which transport the sewage to sewage treatment facilities. Vertical pipes, usually made of precast concrete, called manholes, depending upon site application and use, these vertical pipes can be cylindrical, eccentric or concentric. The manholes are used for access to the pipes for inspection and maintenance. They also facilitate vertical and horizontal angles in otherwise straight pipelines, pipes conveying sewage from an individual building to a common gravity sewer line are called laterals. Branch sewers typically run under streets receiving laterals from buildings along that street, larger cities may have sewers called interceptors receiving flow from multiple trunk sewers. Design and sizing of sanitary sewers considers the population to be served over the life of the sewer, per capita wastewater production. Commercial and industrial flows are considered, but diversion of surface runoff to storm drains eliminates wet weather flow peaks of inefficient combined sewers. Pumps may be necessary where gravity sewers serve areas at lower elevations than the treatment plant. A lift station is a gravity sewer sump with a pump to lift accumulated sewage to a higher elevation, the pump may discharge to another gravity sewer at that location or may discharge through a pressurized force main to some distant location. Most of the solids are removed by the tanks, so the treatment plant can be much smaller than a typical plant. In addition, because of the vast reduction in solid waste, because the wastestream is pressurized, they can be laid just below the ground surface along the lands contour
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Sewage sludge
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Sewage sludge refers to the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. The term septage is also referring to sludge from wastewater treatment but is connected to simple on-site sanitation systems. When fresh sewage or wastewater enters a primary settling tank, approximately 50% of the solid matter will settle out in an hour. This collection of solids is known as raw sludge or primary solids and is said to be fresh before anaerobic processes become active, the sludge will become putrescent in a short time once anaerobic bacteria take over, and must be removed from the sedimentation tank before this happens. This is accomplished in one of two ways, after digesting for an extended period, the result is called digested sludge and may be disposed of by drying and then landfilling. Biosolids is an often used in conjunction with reuse of sewage sludge after sewage sludge treatment. Biosolids can be defined as organic wastewater solids that can be reused after stabilization processes such as anaerobic digestion, opponents of sewage sludge reuse reject this term as a public relations term. Class A sludge is typically dried and pasteurized, and is known as exceptional quality. Class B includes all sludge not classified as Class A, Class B sludge is typically undigested and is volatile. Both classes of sludge may still contain radioactive or pharmaceutical wastes, the amount of sewage sludge produced is proportional to the amount and concentration of wastewater treated, and it also depends on the type of wastewater treatment process used. It can be expressed as kg dry solids per cubic metre of wastewater treated, the total sludge production from a wastewater treatment process is the sum of sludge from primary settling tanks plus excess sludge from the biological treatment step. For example, primary sedimentation produces about 110–170 kg/ML of so-called primary sludge, the sludge production is expressed as kg of dry solids produced per ML of wastewater treated, one mega litre is 103 m3. United States municipal wastewater treatment plants in 1997 produced about 7.7 million dry tons of sewage sludge, as of 2002, about 60% of all sewage sludge was applied to land as a soil amendment and fertilizer for growing crops. Bacteria in Class A sludge products can actually regrow under certain environmental conditions, Pathogens could easily remain undetected in untreated sewage sludge. Pathogens are not a significant health issue if sewage sludge is properly treated, micro-pollutants can become concentrated in sewage sludge. Each of these disposal options comes with a myriad of potential — and in some cases proven — human health, high levels of sterols and other hormones have been detected, with averages in the range of up to 1,000,000 µg/kg sludge. One of the concerns in the treated sludge is the concentrated metals content. Leaching methods can be used to reduce the content and meet the regulatory limit
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Nitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
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Phosphorus
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Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but because it is reactive, phosphorus is never found as a free element on Earth. At 0. 099%, phosphorus is the most abundant pnictogen in the Earths crust, with few exceptions, minerals containing phosphorus are in the maximally oxidised state as inorganic phosphate rocks. The glow of phosphorus itself originates from oxidation of the white phosphorus — a process now termed chemiluminescence, together with nitrogen, arsenic, antimony, and bismuth, phosphorus is classified as a pnictogen. Phosphates are a component of DNA, RNA, ATP, and the phospholipids, demonstrating the link between phosphorus and life, elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate mines contain fossils, especially marine fossils, because phosphate is present in the deposits of animal remains. Low phosphate levels are an important limit to growth in aquatic systems. The vast majority of compounds produced are consumed as fertilisers. Phosphate is needed to replace the phosphorus that plants remove from the soil, other applications include the role of organophosphorus compounds in detergents, pesticides, and nerve agents. Phosphorus exists as several forms that exhibit different properties. The two most common allotropes are white phosphorus and red phosphorus, from the perspective of applications and chemical literature, the most important form of elemental phosphorus is white phosphorus, often abbreviated as WP. It is a soft and waxy solid consists of tetrahedral P4 molecules. This P4 tetrahedron is also present in liquid and gaseous phosphorus up to the temperature of 800 °C when it starts decomposing to P2 molecules, White phosphorus exists in two crystalline forms, α and β. At room temperature, the α-form is stable, which is common and it has cubic crystal structure and at 195.2 K, it transforms into β-form. These forms differ in terms of the orientations of the constituent P4 tetrahedra. White phosphorus is the least stable, the most reactive, the most volatile, the least dense, White phosphorus gradually changes to red phosphorus. This transformation is accelerated by light and heat, and samples of white phosphorus almost always some red phosphorus. For this reason, white phosphorus that is aged or otherwise impure is also called yellow phosphorus, when exposed to oxygen, white phosphorus glows in the dark with a very faint tinge of green and blue
25.
Phosphorus cycle
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The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. The production of gas occurs in only specialized, local conditions. On the land, phosphorus gradually becomes less available to plants over thousands of years, low concentration of P in soils reduces plant growth, and slows soil microbial growth - as shown in studies of soil microbial biomass. Soil microorganisms act as sinks and sources of available P in the biogeochemical cycle. Locally, transformations of P are chemical, biological and microbiological, humans have caused major changes to the global P cycle through shipping of P minerals, and use of P fertilizer, and also the shipping of food from farms to cities, where it is lost as effluent. Phosphorus is a nutrient for plants and animals. Phosphorus is a nutrient for aquatic organisms. Phosphorus forms parts of important life-sustaining molecules that are common in the biosphere. Phosphorus does not enter the atmosphere, remaining mostly on land and in rock, eighty percent of the mined phosphorus is used to make fertilizers. Phosphates from fertilizers, sewage and detergents can cause pollution in lakes, overenrichment of phosphate in both fresh and inshore marine waters can lead to massive algae blooms which, when they die and decay, leads to eutrophication of fresh waters only. An example of this is the Canadian Experimental Lakes Area and these freshwater algal blooms should not be confused with those in saltwater environments. Recent research suggests that the predominant pollutant responsible for algal blooms in salt water estuaries, Phosphorus occurs most abundantly in nature as part of the orthophosphate ion 3−, consisting of a P atom and 4 oxygen atoms. On land most phosphorus is found in rocks and minerals, Phosphorus rich deposits have generally formed in the ocean or from guano, and over time, geologic processes bring ocean sediments to land. Weathering of rocks and minerals release phosphorus in a form where it is taken up by plants. The plants may then be consumed by herbivores and the phosphorus is either incorporated into their tissues or excreted, after death, the animal or plant decays, and phosphorus is returned to the soil where a large part of the phosphorus is transformed into insoluble compounds. Runoff may carry a small part of the back to the ocean. Generally with time soils become deficient in phosphorus leading to ecosystem retrogression, the primary biological importance of phosphates is as a component of nucleotides, which serve as energy storage within cells or when linked together, form the nucleic acids DNA and RNA. The double helix of our DNA is only possible because of the phosphate ester bridge that binds the helix, besides making biomolecules, phosphorus is also found in bone and the enamel of mammalian teeth, whose strength is derived from calcium phosphate in the form of Hydroxylapatite
26.
Tonne
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The SI symbol for the tonne is t, adopted at the same time as the unit itself in 1879. Its use is also official, for the metric ton, within the United States, having been adopted by the US National Institute of Standards and it is a symbol, not an abbreviation, and should not be followed by a period. Informal and non-approved symbols or abbreviations include T, mT, MT, in French and all English-speaking countries that are predominantly metric, tonne is the correct spelling. Before metrication in the UK the unit used for most purposes was the Imperial ton of 2,240 pounds avoirdupois, equivalent to 1,016 kg, differing by just 1. 6% from the tonne. Ton and tonne are both derived from a Germanic word in use in the North Sea area since the Middle Ages to designate a large cask. A full tun, standing about a high, could easily weigh a tonne. An English tun of wine weighs roughly a tonne,954 kg if full of water, in the United States, the unit was originally referred to using the French words millier or tonneau, but these terms are now obsolete. The Imperial and US customary units comparable to the tonne are both spelled ton in English, though they differ in mass, one tonne is equivalent to, Metric/SI,1 megagram. Equal to 1000000 grams or 1000 kilograms, megagram, Mg, is the official SI unit. Mg is distinct from mg, milligram, pounds, Exactly 1000/0. 453 592 37 lb, or approximately 2204.622622 lb. US/Short tons, Exactly 1/0. 907 184 74 short tons, or approximately 1.102311311 ST. One short ton is exactly 0.90718474 t, imperial/Long tons, Exactly 1/1. 016 046 9088 long tons, or approximately 0.9842065276 LT. One long ton is exactly 1.0160469088 t, for multiples of the tonne, it is more usual to speak of thousands or millions of tonnes. Kilotonne, megatonne, and gigatonne are more used for the energy of nuclear explosions and other events. When used in context, there is little need to distinguish between metric and other tons, and the unit is spelt either as ton or tonne with the relevant prefix attached. *The equivalent units columns use the short scale large-number naming system used in most English-language countries. †Values in the equivalent short and long tons columns are rounded to five significant figures, ǂThough non-standard, the symbol kt is also sometimes used for knot, a unit of speed for sea-going vessels, and should not be confused with kilotonne. A metric ton unit can mean 10 kilograms within metal trading and it traditionally referred to a metric ton of ore containing 1% of metal. In the case of uranium, the acronym MTU is sometimes considered to be metric ton of uranium, in the petroleum industry the tonne of oil equivalent is a unit of energy, the amount of energy released by burning one tonne of crude oil, approximately 42 GJ
27.
Algae
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Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata, xylem, and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria, diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae exhibit a range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, and the roots, leaves, and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy. Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely source is alliga, binding, entwining. The Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it, the Latinization, fūcus, meant primarily the cosmetic rouge. It could be any color, black, red, green, accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used. The name Fucus appears in a number of taxa, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent reduced endosymbiotic cyanobacteria, however, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events. The table below describes the composition of the three groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
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World Resources Institute
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The World Resources Institute is an independent, non-governmental global research organization which seeks to create equity and prosperity through sustainable natural resource management. It was established in 1982 with funding from the John D. WRIs activities are focused on six areas, climate, clean energy, food, forests, water, and sustainable cities. In 2014, Stephen M. Ross, an American real estate developer, the world’s energy systems need a change, they have proved ineffective as well as posing a great threat to the entire population. With climate change due to pollution and activity, as well as more than 1.3 billion people still lacking access to electricity. While subsidies still continue to support fossil fuel investment, there has been a shift in more sustainable energy systems. World Resource works with the policymakers of the society to transform. We focus on reducing greenhouse gas pollution while still providing energy to those in the most poverty-stricken situations. Society, human activity, and the economy are all linked to forests. Forest ecosystems play critical roles in stabilizing the climate, and providing food, water, wood products, World Resource aims at curbing deforestation worldwide while helping to restore already-cleared land. The impacts of a global climate are being felt all around the world. Heat waves and extreme weather effects devastate many countries by, destroying agriculture increasing wildfires and we are working on the national and international level to identify cost-effective solutions that reduce emissions in the short and long-term. The world’s water system face great threats more than 1 billion people live in water scarce regions with it reaching as many as 3.5 billion in nine years, with problems like increasing pollution and climate change, the amount of water available is exponentially decreasing. Our Aqueduct Project uses the most updated data to produce global risk maps, the world is projected to have 9.6 billion people by 2050 and in order to sustain it the meeting of three great needs. We have to reduce agriculture’s impact, ecosystems, and water, at World Resource Institute we are developing solutions to meet these needs by first identifying and then advancing methods, such as climate-smart agriculture to solve them. Traditional models of city development constrict us into congestion, sprawl and we aim at creating a compact, connected, and a more efficient city, As it can provide a better quality of life for the citizens. We accomplish this by collaborating with national decision-makers to implement our projects that overcome all of the challenges presented with urbanization. Some of the initiatives of WRI include, ACT2015 is a relatively new project, designed as an international climate change agreement towards a low-carbon. EMBARQ is part of WRI Ross Center for Sustainable Cities, Aqueduct, an initiative to measure, map and understand water risks around the globe
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Nitrogen fixation
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Nitrogen fixation is a process by which nitrogen in the Earths atmosphere is converted into ammonia or other molecules available to living organisms. Atmospheric nitrogen or molecular dinitrogen is relatively inert, it does not easily react with chemicals to form new compounds. The fixation process frees nitrogen atoms from their triply bonded diatomic form, N≡N, therefore, as part of the nitrogen cycle, it is essential for agriculture and the manufacture of fertilizer. It is also, indirectly, relevant to the manufacture of all compounds that contain nitrogen. Nitrogen fixation occurs naturally in the soil by nitrogen fixing bacteria, some nitrogen-fixing bacteria have very close relationships with plants, referred to as symbiotic nitrogen fixation. Looser relationships between nitrogen-fixing bacteria and plants are referred to as associative or non-symbiotic, as seen in nitrogen fixation occurring on rice roots. It also occurs naturally in the air by means of lightning, all biological nitrogen fixation is done by way of metalloenzymes called nitrogenases. These enzymes contain iron, often with a metal, usually molybdenum. Microorganisms that can fix nitrogen are prokaryotes called diazotrophs, some higher plants, and some animals, have formed associations with diazotrophs. Nitrogen can be fixed by lightning converting nitrogen and oxygen into NOx, NOx may react with water to make nitric acid, which may end up in the soil, where it makes nitrate, which is of use to growing plants. Biological nitrogen fixation was discovered by the German agronomist Hermann Hellriegel, biological nitrogen fixation occurs when atmospheric nitrogen is converted to ammonia by an enzyme called a nitrogenase. The overall reaction for BNF is, N2 +8 H+ +8 e− →2 NH3 + H2 The process is coupled to the hydrolysis of 16 equivalents of ATP and is accompanied by the co-formation of one molecule of H2. The conversion of N2 into ammonia occurs at a cluster called FeMoco, the mechanism proceeds via a series of protonation and reduction steps wherein the FeMoco active site hydrogenates the N2 substrate. In free-living diazotrophs, the ammonium is assimilated into glutamate through the glutamine synthetase/glutamate synthase pathway. The microbial genes required for nitrogen fixation are widely distributed in diverse environments, enzymes responsible for nitrogenase action are very susceptible to destruction by oxygen. For this reason, many bacteria cease production of the enzyme in the presence of oxygen, many nitrogen-fixing organisms exist only in anaerobic conditions, respiring to draw down oxygen levels, or binding the oxygen with a protein such as leghemoglobin. Diazotrophs are a group of prokaryotes that includes cyanobacteria, green sulfur bacteria, along with Azotobacteraceae. Cyanobacteria inhabit nearly all illuminated environments on Earth and play key roles in the carbon, in general, cyanobacteria are able to utilize a variety of inorganic and organic sources of combined nitrogen, like nitrate, nitrite, ammonium, urea, or some amino acids
30.
Orchidaceae
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The Orchidaceae are a diverse and widespread family of flowering plants, with blooms that are often colourful and often fragrant, commonly known as the orchid family. Along with the Asteraceae, they are one of the two largest families of flowering plants, the Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. The determination of which family is larger is still under debate, regardless, the number of orchid species nearly equals the number of bony fishes and is more than twice the number of bird species, and about four times the number of mammal species. The family also encompasses about 6–11% of all seed plants, the largest genera are Bulbophyllum, Epidendrum, Dendrobium and Pleurothallis. The family also includes Vanilla, Orchis, and many cultivated plants such as Phalaenopsis. Moreover, since the introduction of species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids. Orchids are easily distinguished from plants, as they share some very evident, shared derived characteristics. Among these are, bilateral symmetry of the flower, many flowers, a nearly always highly modified petal, fused stamens and carpels. All orchids are perennial herbs that lack any permanent woody structure and they can grow according to two patterns, Monopodial, The stem grows from a single bud, leaves are added from the apex each year and the stem grows longer accordingly. The stem of orchids with a monopodial growth can reach several metres in length, as in Vanda, Sympodial, Sympodial orchids have a front and a back. The plant produces a series of adjacent shoots which grow to a size, bloom. Sympodial orchids grow laterally rather than vertically, following the surface of their support, the growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. While a new lead is developing, the rhizome may start its growth again from a so-called eye, Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil. Terrestrial orchids may be rhizomatous or form corms or tubers, the root caps of terrestrial orchids are smooth and white. Some sympodial terrestrial orchids, such as Orchis and Ophrys, have two subterranean tuberous roots, one is used as a food reserve for wintry periods, and provides for the development of the other one, from which visible growth develops. In warm and constantly humid climates, many terrestrial orchids do not need pseudobulbs, epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis and it is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, the cells of the root epidermis grow at a right angle to the axis of the root to allow them to get a firm grasp on their support
31.
Bog
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A bog is a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a majority of cases, sphagnum moss. It is one of the four types of wetlands. Other names for bogs include mire, quagmire, and muskeg and they are frequently covered in ericaceous shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink, Bogs occur where the water at the ground surface is acidic and low in nutrients. In some cases, the water is derived entirely from precipitation, water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate results in relatively slow plant growth, large areas of landscape can be covered many metres deep in peat. Bogs have distinctive assemblages of animal, fungal and plant species, Bogs are widely distributed in cold, temperate climes, mostly in boreal ecosystems in the Northern Hemisphere. The worlds largest wetland is the bogs of the Western Siberian Lowlands in Russia. Large peat bogs also occur in North America, particularly the Hudson Bay Lowland and they are less common in the Southern Hemisphere, with the largest being the Magellanic moorland, comprising some 44,000 square kilometres. Sphagnum bogs were widespread in northern Europe but have often been cleared and drained for agriculture, a 2014 expedition leaving from Itanga village, Republic of the Congo discovered a peat bog as big as England which stretches into neighboring Democratic Republic of Congo. There are many highly specialised animals, fungi and plants associated with bog habitat, most are capable of tolerating the combination of low nutrient levels and waterlogging. Sphagnum moss is generally abundant, along with ericaceous shrubs, the shrubs are often evergreen, which is understood to assist in conservation of nutrients. In drier locations, evergreen trees can occur, in case the bog blends into the surrounding expanses of boreal evergreen forest. Sedges are one of the more common herbaceous species, carnivorous plants such as sundews and pitcher plants have adapted to the low-nutrient conditions by using invertebrates as a nutrient source. Orchids have adapted to these conditions through the use of fungi to extract nutrients. Some shrubs such as Myrica gale have root nodules in which nitrogen fixation occurs, Bogs are recognized as a significant/specific habitat type by a number of governmental and conservation agencies. They can provide habitat for mammals, such as caribou, moose, the United Kingdom in its Biodiversity Action Plan establishes bog habitats as a priority for conservation. Russia has a reserve system in the West Siberian Lowland
32.
Fen
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A fen is one of the main types of wetland, the others being grassy marshes, forested swamps, and peaty bogs. Along with bogs, fens are a kind of mire, Fens are minerotrophic peatlands, usually fed by mineral-rich surface water or groundwater. They are characterised by their chemistry, which is pH neutral or alkaline, with relatively high dissolved mineral levels. They are usually dominated by grasses and sedges, and typically have brown mosses in general including Scorpidium or Drepanocladus, Fens frequently have a high diversity of other plant species including carnivorous plants such as Pinguicula. They may also occur along lakes and rivers where seasonal changes in water level maintain wet soils with few woody plants. The distribution of species of fen plants is often closely connected to water regimes. Fens have a set of plant species, which sometimes provide the best indicators of environmental conditions. For example, fen indicator species in New York State include Carex flava, Cladium mariscoides, Potentilla fruticosa, Pogonia ophioglossoides and Parnassia glauca. Fens are distinguished from bogs, which are acidic, low in minerals, Fens have been damaged in the past by land drainage, and also by peat cutting. Some are now being restored with modern management methods. The principal challenges are to restore natural water regimes, to maintain the quality of water. Carr is the northern European equivalent of the swamp of the southeastern United States. It is a fen overgrown with small trees of species such as willow or alder. In general, fens may change in composition as peat accumulates, a list of species found in a fen can therefore cover a range of species from those remaining from the earlier stage in the successional development to the pioneers of the succeeding stage. Where streams of water run through bog, these are often lined by strips of fen. Temporary flooding by beavers can have effects on fens. Shakespeare used the term fen-sucked to describe the fog in King Lear, media related to Fens at Wikimedia Commons
33.
Reed (plant)
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Reed is a common name for several tall, grass-like plants of wetlands. Thatching reed, another restio species originating from the geographic region. Phragmites australis, the reed, is used in many areas for thatching roofs. In the United Kingdom, common reed used for purpose is known as Norfolk reed or water reed. However, wheat reed and Devon reed are not in fact reed at all, constructed wetland Reed bed Reed boat Reed fields Thatching
34.
Bramble
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In British English, a bramble is any rough tangled prickly shrub—specifically the blackberry bush —or any hybrid of similar appearance, with thorny stems. Bramble or brambleberry may also refer to the fruit or products of its fruit. The shrub grows abundantly in all parts of the British Isles and harvesting the fruits in late summer and it can also become a nuisance in gardens, sending down its strong suckering roots amongst hedges and shrubs. Many consider it a weed due its tendency to grow in neglected areas and its sharp, tough thorns which can be hazardous to children and pets. Elsewhere, such as in the United States, the term also refers to other members of the Rubus genus. Bramble comes from Germanic bram-bezi, whence come also German Brombeere, Dutch Braambes and it originated before the year 1000, Middle English, Old English bræmbel, variant of brǣmel, equivalent to brǣm-. Bramble bushes have long, thorny, arching shoots and root easily and they send up long, arching canes that do not flower or set fruit until the second year of growth. Brambles usually have trifoliate or palmately-compound leaves, each small unit is called a drupelet. In some, such as the blackberry, the receptacle is elongated and part of the ripe fruit. Many species are grown and bred for their fruit, ornamental species can be grown for flowers, for their ornamental stems and some as ground cover. Members of the Rubus genus tend to have a brittle, porous core, the thorny varieties are sometimes grown for game cover and occasionally for protection. Most species are important for their conservation and wildlife value in their native range, the flowers attract nectar-feeding butterflies and hoverflies, and are a particular favourite of Volucella pellucens. Brambles are important food plants for the larvae of species of Lepidoptera—see list of Lepidoptera that feed on Rubus. The leaves of brambles are often used as a food source for captive stick insects. Many birds, such as the common blackbird, and some mammals will feed on the fruits in autumn. Bramble leaves can be used to feed most Phasmatodea, young leaves contain a toxin that can be harmful to many species of Phasmatodea, however this only occurs up until their third instar, by which time they have developed an immunity to it. There are many different systems developed for the culture of blackberries and raspberries. Bramble cultivars are separated into categories based on their growth habit
35.
Microorganism
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A microorganism or microbe is a microscopic organism, which may be single-celled or multicellular. The study of microorganisms is called microbiology, a subject that began with the discovery of microorganisms in 1674 by Antonie van Leeuwenhoek, microorganisms are very diverse and include all bacteria, archaea and most protozoa. This group also contains some fungi, algae, and some such as rotifers. Many macroscopic animals and plants have microscopic juvenile stages, some microbiologists classify viruses and viroids as microorganisms, but others consider these as nonliving. In July 2016, scientists identified a set of 355 genes from the last universal ancestor of all life, including microorganisms. Microorganisms, under certain test conditions, have observed to thrive in the vacuum of outer space. Microorganisms likely far outweigh all other living things combined, the mass of prokaryote microorganisms including the bacteria and archaea may be as much as 0.8 trillion tons of carbon, out of the total biomass of between 1 and 4 trillion tons. Microorganisms appear to thrive in the Mariana Trench, the deepest spot in the Earths oceans, in August 2014, scientists confirmed the existence of microorganisms living 800 m below the ice of Antarctica. According to one researcher, You can find microbes everywhere — theyre extremely adaptable to conditions, microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. As some microorganisms can fix nitrogen, they are a part of the nitrogen cycle. Microorganisms are also exploited in biotechnology, both in food and beverage preparation, and in modern technologies based on genetic engineering. A small proportion of microorganisms are pathogenic, causing disease and even death in plants, Robert Hooke coined the term cell after viewing plant cells under his microscope. Antonie Van Leeuwenhoek was one of the first people to observe microorganisms in 1673, later, in the 19th century, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In 1876 Robert Koch discovered that microorganisms cause diseases, single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, so, for most of the history of life on Earth, the only forms of life were microorganisms. Bacteria, algae and fungi have been identified in amber that is 220 million years old, microorganisms tend to have a relatively fast rate of evolution. Most microorganisms can reproduce rapidly, and bacteria are able to freely exchange genes through conjugation, transformation and transduction. This rapid evolution is important in medicine, as it has led to the development of multidrug resistant pathogenic bacteria, superbugs, the possible existence of microorganisms was discussed for many centuries before their discovery in the 17th century
36.
Solubility
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Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. The solubility of a substance depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure. The solubility of a substance is a different property from the rate of solution. Most often, the solvent is a liquid, which can be a substance or a mixture. One may also speak of solid solution, but rarely of solution in a gas, the extent of solubility ranges widely, from infinitely soluble such as ethanol in water, to poorly soluble, such as silver chloride in water. The term insoluble is often applied to poorly or very poorly soluble compounds, a common threshold to describe something as insoluble is less than 0.1 g per 100 mL of solvent. Under certain conditions, the solubility can be exceeded to give a so-called supersaturated solution. Metastability of crystals can also lead to apparent differences in the amount of a chemical that dissolves depending on its form or particle size. A supersaturated solution generally crystallises when seed crystals are introduced and rapid equilibration occurs, phenylsalicylate is one such simple observable substance when fully melted and then cooled below its fusion point. Solubility is not to be confused with the ability to dissolve a substance, for example, zinc dissolves in hydrochloric acid as a result of a chemical reaction releasing hydrogen gas in a displacement reaction. The zinc ions are soluble in the acid, the smaller a particle is, the faster it dissolves although there are many factors to add to this generalization. Crucially solubility applies to all areas of chemistry, geochemistry, inorganic, physical, organic, in all cases it will depend on the physical conditions and the enthalpy and entropy directly relating to the solvents and solutes concerned. By far the most common solvent in chemistry is water which is a solvent for most ionic compounds as well as a range of organic substances. This is a factor in acidity/alkalinity and much environmental and geochemical work. According to the IUPAC definition, solubility is the composition of a saturated solution expressed as a proportion of a designated solute in a designated solvent. Solubility may be stated in units of concentration such as molarity, molality, mole fraction, mole ratio, mass per volume. Solubility occurs under dynamic equilibrium, which means that solubility results from the simultaneous and opposing processes of dissolution, the solubility equilibrium occurs when the two processes proceed at a constant rate. The term solubility is used in some fields where the solute is altered by solvolysis
37.
Leaching (agriculture)
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In agriculture, leaching refers to the loss of water-soluble plant nutrients from the soil, due to rain and irrigation. Soil structure, crop planting, type and application rates of fertilizers, Leaching may also refer to the practice of applying a small amount of excess irrigation where the water has a high salt content to avoid salts from building up in the soil. Where this is practiced, drainage must also usually be employed, Leaching is an environmental concern when it contributes to groundwater contamination. As water from rain, flooding, or other sources seeps into the ground, it can dissolve chemicals, of particular concern are hazardous waste dumps and landfills, and, in agriculture, excess fertilizer, improperly stored animal manure, and biocides. Nitrogen is an element in nature and an essential plant nutrient. Approximately 78% of Earths atmosphere is nitrogen, the strong bond between the atoms of N2 makes this gas quite inert and not directly usable by plants and animals. As nitrogen naturally cycles through the air, water and soil it undergoes various chemical and biological transformations, livestock then eat the crops producing manure, which is returned to the soil, adding organic and mineral forms of nitrogen. The cycle is complete when the next crop uses the amended soil, to increase food production, fertilizers, such as nitrate and ammonium, which are easily absorbed by plants, are introduced to the plant root zone. However, soils do not absorb the excess NO3 ions, which then move freely with drainage water. The degree of leaching is affected by, soil type and structure, for example, sandy soil holds little water while clay soils have high water-retention rates, the amount of water used by the plants/crops, how much nitrate is already present in the soil. The level of nitrous oxide in the Earths atmosphere is increasing at a rate of 0.2 to 0. 3% annually, anthropogenic sources of nitrogen are 50% greater than from natural sources, such as, soils and oceans. Leached agricultural inputs, i. e. fertilizers and manures, the Food and Agriculture Organization of the United Nations estimates world demand for nitrogen fertilizers will increase by 1. 7% annually between 2011 and 2015. An increase of 7.5 million tonnes, regional increases of nitrogen fertilizer use are expected to be 67% by Asia, 18% by the Americas, 10% by Europe, 3% by Africa, and 1% by Oceania. High levels of NO3 in water can adversely affect oxygen levels for humans and aquatic systems. Human health issues include methemoglobinemia and anoxia, commonly referred to as blue baby syndrome, as a result of these toxic effects, regulatory agencies limit the amount of NO3 permissible in drinking water to 45–50 mg1-1. Eutrophication, a decline in oxygen content of water, of systems can cause the death of fish. Finally, leaching of NO3 from acidic sources can increase the loss of calcium and other soil nutrients, Leaching Leaching model Soil salinity control SahysMod International Panel on Climate Change On line, R. J. Oosterbaan, Water and salt balances in agricultural hydrology. Lecture notes, International Course on Land Drainage, ILRI, Wageningen, saltMod, A tool for interweaving of irrigation and drainage for salinity control
38.
Turbidity
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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. These small solid particles cause the liquid to appear turbid, Turbidity 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 light direction. Turbidity in open water may be caused by growth of phytoplankton, human activities that disturb land, such as construction, mining and agriculture, can lead to high sediment levels entering water bodies during rain storms due to storm water runoff. Certain industries such as quarrying, mining and coal recovery can generate high levels of turbidity from colloidal rock particles. In drinking water, the higher the turbidity level, the higher the risk that people may develop gastrointestinal diseases and this is especially problematic for immunocompromised people, because contaminants like viruses or bacteria can become attached to the suspended solids. The suspended solids interfere with water disinfection with chlorine because the act as shields for the virus. Similarly, suspended solids can protect bacteria from ultraviolet sterilization of water, high turbidity levels can also affect the ability of fish gills to absorb dissolved oxygen. This phenomenon has been observed throughout the Chesapeake Bay in the eastern United States. For many mangrove areas, high turbidity is needed to support certain species, for most mangroves along the eastern coast of Australia, in particular Moreton Bay, turbidity levels as high as 600 Nephelometric Turbidity Units are needed for proper ecosystem health. The most widely used measurement unit for turbidity is the Formazin Turbidity Unit, ISO refers to its units as FNU. ISO7027 provides the method in water quality for the determination of turbidity and it is used to determine the concentration of suspended particles in a sample of water by measuring the incident light scattered at right angles from the sample. The scattered light is captured by a photodiode, which produces a signal that is converted to a turbidity. Open source hardware has been developed following the ISO7027 method to measure turbidity reliably using an Arduino microcontroller, there are several practical ways of checking water quality, the most direct being some measure of attenuation of light as it passes through a sample column of water. The alternatively used Jackson Candle method is essentially the inverse measure of the length of a column of water needed to completely obscure a candle flame viewed through it, the more water needed, the clearer the water. Of course water alone produces some attenuation, and any substances dissolved in the water that produce color can attenuate some wavelengths, modern instruments do not use candles, but this approach of attenuation of a light beam through a column of water should be calibrated and reported in JTUs. The propensity of particles to scatter a light focused on them is now considered a more meaningful measure of turbidity in water
39.
Caspian Sea
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The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the worlds largest lake or a full-fledged sea. It is in a basin located between Europe and Asia. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, the Caspian Sea lies to the east of the Caucasus Mountains and to the west of the vast steppe of Central Asia. In its northern part, the Caspian Depression lies 28 to 130 m below sea level, the sea bed in the southern part reaches as low as 1023 m below sea level, which is the second lowest natural depression on earth after Lake Baikal. The ancient inhabitants of its coast perceived the Caspian Sea as an ocean, probably because of its saltiness, the sea has a surface area of 371,000 km2 and a volume of 78,200 km3. It has a salinity of approximately 1. 2%, about a third of the salinity of most seawater, the word Caspian is derived from the name of the Caspi, an ancient people who lived to the southwest of the sea in Transcaucasia. Strabo wrote that to the country of the Albanians belongs also the territory called Caspiane, which was named after the Caspian tribe, as was also the sea, but the tribe has now disappeared. Moreover, the Caspian Gates, which is the name of a region in Irans Tehran province, the Iranian city of Qazvin shares the root of its name with that of the sea. In fact, the traditional Arabic name for the sea itself is Bahr al-Qazwin, in classical antiquity among Greeks and Persians it was called the Hyrcanian Ocean. In Persian antiquity, as well as in modern Iran, it is known as the دریای خزر, Daryā-e Khazar, ancient Arabic sources refer to it as Baḥr Gīlān meaning the Gilan Sea. Turkic languages refer to the lake as Khazar Sea, in Turkmen, the name is Hazar deňizi, in Azeri, it is Xəzər dənizi, and in modern Turkish, it is Hazar denizi. An exception is Kazakh, where it is called Каспий теңізі, old Russian sources call it the Khvalyn or Khvalis Sea after the name of Khwarezmia. In modern Russian, it is called Каспи́йское мо́ре, Kaspiyskoye more, the Caspian Sea, like the Black Sea, Namak Lake, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level. Due to the current inflow of water, the Caspian Sea is a freshwater lake in its northern portions, and is most saline on the Iranian shore. Currently, the salinity of the Caspian is one third that of Earths oceans. The Caspian Sea is the largest inland body of water in the world, the coastlines of the Caspian are shared by Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The Caspian is divided into three distinct regions, the Northern, Middle, and Southern Caspian
40.
Water pollution
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Water pollution is the contamination of water bodies. This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds, Water pollution affects the entire biosphere – plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population, Water pollution is a major global problem which requires ongoing evaluation and revision of water resource policy at all levels. It has been suggested that pollution is the leading worldwide cause of deaths and diseases. An estimated 580 people in India die of water related illness every day. About 90 percent of the water in the cities of China is polluted, as of 2007, half a billion Chinese had no access to safe drinking water. In addition to the problems of water pollution in developing countries. The head of Chinas national development agency said in 2007 that one quarter the length of Chinas seven main rivers were so poisoned the water harmed the skin. Natural phenomena such as volcanoes, algae blooms, storms, and earthquakes also cause changes in water quality. Although interrelated, surface water and groundwater have often studied and managed as separate resources. Surface water seeps through the soil and becomes groundwater, conversely, groundwater can also feed surface water sources. Sources of surface water pollution are generally grouped into two based on their origin. Point source water pollution refers to contaminants that enter a waterway from a single, identifiable source, examples of sources in this category include discharges from a sewage treatment plant, a factory, or a city storm drain. The U. S. Clean Water Act defines point source for regulatory enforcement purposes, the CWA definition of point source was amended in 1987 to include municipal storm sewer systems, as well as industrial storm water, such as from construction sites. Nonpoint source pollution refers to contamination that does not originate from a single discrete source. NPS pollution is often the cumulative effect of small amounts of contaminants gathered from a large area, a common example is the leaching out of nitrogen compounds from fertilized agricultural lands. Nutrient runoff in storm water from sheet flow over a field or a forest are also cited as examples of NPS pollution. Contaminated storm water washed off of parking lots, roads and highways, however, because this runoff is typically channeled into storm drain systems and discharged through pipes to local surface waters, it becomes a point source
41.
Asia
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Asia covers an area of 44,579,000 square kilometres, about 30% of Earths total land area and 8. 7% of the Earths total surface area. The continent, which has long been home to the majority of the population, was the site of many of the first civilizations. Asia is notable for not only its large size and population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, the western boundary with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. The most commonly accepted boundaries place Asia to the east of the Suez Canal, the Ural River, and the Ural Mountains, and south of the Caucasus Mountains, China and India alternated in being the largest economies in the world from 1 to 1800 A. D. The accidental discovery of America by Columbus in search for India demonstrates this deep fascination, the Silk Road became the main East-West trading route in the Asian hitherland while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties, the boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Canal. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia, the border between Asia and Europe was historically defined by European academics. In Sweden, five years after Peters death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia, the Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography. Tatishchev announced that he had proposed the idea to von Strahlenberg, the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century, the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, the border between Asia and the loosely defined region of Oceania is usually placed somewhere in the Malay Archipelago. The terms Southeast Asia and Oceania, devised in the 19th century, have had several different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the possessions of the various empires there. Lewis and Wigen assert, The narrowing of Southeast Asia to its present boundaries was thus a gradual process, Asia is larger and more culturally diverse than Europe. It does not exactly correspond to the borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds there is no or is no substantial physical separation between them
42.
Europe
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Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary. Europe covers about 10,180,000 square kilometres, or 2% of the Earths surface, politically, Europe is divided into about fifty sovereign states of which the Russian Federation is the largest and most populous, spanning 39% of the continent and comprising 15% of its population. Europe had a population of about 740 million as of 2015. Further from the sea, seasonal differences are more noticeable than close to the coast, Europe, in particular ancient Greece, was the birthplace of Western civilization. The fall of the Western Roman Empire, during the period, marked the end of ancient history. Renaissance humanism, exploration, art, and science led to the modern era, from the Age of Discovery onwards, Europe played a predominant role in global affairs. Between the 16th and 20th centuries, European powers controlled at times the Americas, most of Africa, Oceania. The Industrial Revolution, which began in Great Britain at the end of the 18th century, gave rise to economic, cultural, and social change in Western Europe. During the Cold War, Europe was divided along the Iron Curtain between NATO in the west and the Warsaw Pact in the east, until the revolutions of 1989 and fall of the Berlin Wall. In 1955, the Council of Europe was formed following a speech by Sir Winston Churchill and it includes all states except for Belarus, Kazakhstan and Vatican City. Further European integration by some states led to the formation of the European Union, the EU originated in Western Europe but has been expanding eastward since the fall of the Soviet Union in 1991. The European Anthem is Ode to Joy and states celebrate peace, in classical Greek mythology, Europa is the name of either a Phoenician princess or of a queen of Crete. The name contains the elements εὐρύς, wide, broad and ὤψ eye, broad has been an epithet of Earth herself in the reconstructed Proto-Indo-European religion and the poetry devoted to it. For the second part also the divine attributes of grey-eyed Athena or ox-eyed Hera. The same naming motive according to cartographic convention appears in Greek Ανατολή, Martin Litchfield West stated that phonologically, the match between Europas name and any form of the Semitic word is very poor. Next to these there is also a Proto-Indo-European root *h1regʷos, meaning darkness. Most major world languages use words derived from Eurṓpē or Europa to refer to the continent, in some Turkic languages the originally Persian name Frangistan is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa
. PMID 12003747.
