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69-461: Nostoc , also known as star jelly , troll's butter , spit of moon , fallen star , witch's butter (not to be confused with the fungi commonly known as witches' butter ), and witch's jelly, is the most common genus of cyanobacteria found in a variety of both aquatic and terrestrial environments that may form colonies composed of filaments of moniliform cells in a gelatinous sheath of polysaccharides. It may also grow symbiotically within

138-439: A 6- or 7-fold increase in the flux of NO x to the atmosphere. Its production is a function of combustion temperature - the higher the temperature, the more NO x is produced. Fossil fuel combustion is a primary contributor, but so are biofuels and even the burning of hydrogen. However, the rate that hydrogen is directly injected into the combustion chambers of internal combustion engines can be controlled to prevent

207-609: A connection between star jelly and the Paramount movie The Blob , in which a gelatinous monster slime falls from space. The Blob , which was released in 1958, was supposedly based on the Philadelphia reports from 1950 and specifically a report in The Philadelphia Inquirer called "Flying 'Saucer' Just Dissolves" where four police officers encountered a UFO debris that was described as evaporating with

276-473: A fallen star," said the hermit, "and thou shalt only light on some foul jelly, which, in shooting through the horizon, has assumed for a moment an appearance of splendour." An unidentifiable substance that falls to earth during a meteor-type event forms the background to " The Colour Out of Space ", a 1927 short story by the American horror and science fiction author H. P. Lovecraft . Some observers have made

345-445: A few notable and well-known exceptions that include most Prochlorococcus and some Synechococcus that can only take up nitrogen as ammonium. The nutrients in the ocean are not uniformly distributed. Areas of upwelling provide supplies of nitrogen from below the euphotic zone. Coastal zones provide nitrogen from runoff and upwelling occurs readily along the coast. However, the rate at which nitrogen can be taken up by phytoplankton

414-533: A further build-up of fixed nitrogen in the ocean, with the potential consequence of eutrophication . Gray arrows represent an increase while black arrows represent a decrease in the associated process. As a result of extensive cultivation of legumes (particularly soy , alfalfa , and clover ), growing use of the Haber–Bosch process in the production of chemical fertilizers , and pollution emitted by vehicles and industrial plants, human beings have more than doubled

483-491: A genus of Gram-negative photosynthetic cyanobacteria . Many species of Nostoc possess an outer layer and extensive inner matrix of polysaccharides , giving them their "jelly-like" or gelatinous appearance, and also help to protect them from their environment and can assist in the absorption of moisture. This allows them to survive stressful conditions such as fluctuating temperatures, drought, salt stress, desiccation, UV radiation, and infection by pathogens. Some species within

552-489: A habitat to other freshwater bacteria. Additionally, some species like N. commune and N. flageliforme form relationships with heterotrophic bacteria and actinobacteria present in their environments, likely due to the fact that they are a potential significant player in nitrogen cycling in aquatic ecosystems. Nostoc has been documented to produce many compounds of interest, including those that are antiviral, antitumor, antifungal, and antibacterial. In addition to

621-695: A healthy food and traditional medicine, most notably in Asia Historically, the species N. flagelliforme and N. commune have been consumed in China, where it was used to survive famines and has been used as an ingredient in Chinese medicine since the Eastern Jin Dynasty . Additionally, Nostoc has had documented culinary usage in India, Indonesia, Peru, Bolivia, and Ecuador. Nostoc

690-529: A major proportion of nitrogen conversion in the oceans . The stoichiometrically balanced formula for the ANAMMOX chemical reaction can be written as following, where an ammonium ion includes the ammonia molecule, its conjugated base : This an exergonic process (here also an exothermic reaction ) releasing energy, as indicated by the negative value of Δ G °, the difference in Gibbs free energy between

759-472: A process that leads to high algal population and growth, especially blue-green algal populations. While not directly toxic to fish life, like ammonia, nitrate can have indirect effects on fish if it contributes to this eutrophication. Nitrogen has contributed to severe eutrophication problems in some water bodies. Since 2006, the application of nitrogen fertilizer has been increasingly controlled in Britain and

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828-500: A purple glow leaving nothing. Paramount Pictures was also sued for this movie by the author Joseph Payne Brennan , who had written a short story published in Weird Tales Magazine in 1953 called "Slime" about a similar creature. In a 2019 episode of The Twilight Zone entitled "Not All Men", a virulent star jelly causes the male residents of a town to become psychotic. Nitrogen cycle The nitrogen cycle

897-466: A term for a "falling" or "shooting" star). In Welsh it has been referred to as "pwdre ser" meaning "rot from the stars". The Oxford English Dictionary lists a large number of other names for the substance, with references dating back to the circa-1440 English-Latin dictionary entry mentioned above: star-fallen, star-falling, star-jelly, star-shot, star-slime, star-slough, star-slubber, star-spurt, and star-slutch. The slime mold Enteridium lycoperdon

966-479: A variety of environments, both terrestrial and aquatic, depending on the species. Their polysaccharide outer layer and matrix allows them to survive and thrive in a variety of conditions and habits ranging from deserts, semideserts, grasslands, polar, and tropical regions depending on the particular species of Nostoc . In terms of aquatic environments, Nostoc has been documented to be naturally found in marine water, fresh water, as well as brackish water. Depending on

1035-460: Is a complex two-component enzyme that has multiple metal-containing prosthetic groups. An example of free-living bacteria is Azotobacter . Symbiotic nitrogen-fixing bacteria such as Rhizobium usually live in the root nodules of legumes (such as peas, alfalfa, and locust trees). Here they form a mutualistic relationship with the plant, producing ammonia in exchange for carbohydrates . Because of this relationship, legumes will often increase

1104-414: Is a member of the family Nostocaceae of the order Nostocales . Species include (see collapsed list on the right for full listing) : Star jelly There have been reports of 'star-jelly' for centuries. John of Gaddesden (1280–1361) mentions stella terrae ( Latin for 'star of the earth' or 'earth-star') in his medical writings, describing it as "a certain mucilaginous substance lying upon

1173-428: Is absorbed, it is first reduced to nitrite ions and then ammonium ions for incorporation into amino acids, nucleic acids, and chlorophyll. In plants that have a symbiotic relationship with rhizobia, some nitrogen is assimilated in the form of ammonium ions directly from the nodules. It is now known that there is a more complex cycling of amino acids between Rhizobia bacteroids and plants. The plant provides amino acids to

1242-719: Is also highly nutritious, containing protein and vitamin C , as well as all essential amino acids . It has been suggested to be anti-inflammatory and an antioxidant as well. Because of this, Nostoc has also been considered to be a strong candidate for extraterrestrial agriculture. Because of human foot traffic, and contaminated gardening tools and irrigation systems, Nostoc is usually found outside of its natural habitat in plant nurseries and greenhouses. A number of different control methods can be effective in removing unwanted Nostoc from these environments, including implementing increased drainage in these facilities, physical removal of Nostoc , and flame weeders or solarization. Nostoc

1311-518: Is also known as the ANAMMOX process, an abbreviation coined by joining the first syllables of each of these three words. This biological process is a redox comproportionation reaction, in which ammonia (the reducing agent giving electrons) and nitrite (the oxidizing agent accepting electrons) transfer three electrons and are converted into one molecule of diatomic nitrogen ( N 2 ) gas and two water molecules. This process makes up

1380-496: Is an anaerobic respiration process. Microbes which undertake DNRA oxidise organic matter and use nitrate as an electron acceptor, reducing it to nitrite , then ammonium ( NO − 3 → NO − 2 → NH + 4 ). Both denitrifying and nitrate ammonification bacteria will be competing for nitrate in the environment, although DNRA acts to conserve bioavailable nitrogen as soluble ammonium rather than producing dinitrogen gas. The AN aerobic AMM onia OX idation process

1449-432: Is an important component of the marine environment. One reason is that only continual input of new nitrogen can determine the total capacity of the ocean to produce a sustainable fish harvest. Harvesting fish from regenerated nitrogen areas will lead to a decrease in nitrogen and therefore a decrease in primary production. This will have a negative effect on the system. However, if fish are harvested from areas of new nitrogen

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1518-458: Is an important process in the ocean as well. While the overall cycle is similar, there are different players and modes of transfer for nitrogen in the ocean. Nitrogen enters the water through the precipitation, runoff, or as N 2 from the atmosphere. Nitrogen cannot be utilized by phytoplankton as N 2 so it must undergo nitrogen fixation which is performed predominately by cyanobacteria . Without supplies of fixed nitrogen entering

1587-565: Is atmospheric nitrogen , making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems . The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition . Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered

1656-666: Is called caca de luna ("moon's feces") by the locals in the state of Veracruz in Mexico. Another theory states that star jelly is most likely formed from the glands in the oviducts of frogs and toads . Birds and mammals eat the animals but not the oviducts which, when they come into contact with moisture, swell and distort, leaving a vast pile of jellylike substance sometimes also referred to as otter jelly. In 1910, T. M. Hughes ruminated in Nature as to why poets and ancient writers associated meteors with star jelly, and observed that

1725-444: Is carefully regulated in all organisms. When a plant or animal dies or an animal expels waste, the initial form of nitrogen is organic . Bacteria or fungi convert the organic nitrogen within the remains back into ammonium ( NH + 4 ), a process called ammonification or mineralization . Enzymes involved are: The conversion of ammonium to nitrate is performed primarily by soil-living bacteria and other nitrifying bacteria. In

1794-613: Is decreased in oligotrophic waters year-round and temperate water in the summer resulting in lower primary production. The distribution of the different forms of nitrogen varies throughout the oceans as well. Nitrate is depleted in near-surface water except in upwelling regions. Coastal upwelling regions usually have high nitrate and chlorophyll levels as a result of the increased production. However, there are regions of high surface nitrate but low chlorophyll that are referred to as HNLC (high nitrogen, low chlorophyll) regions. The best explanation for HNLC regions relates to iron scarcity in

1863-417: Is done by free-living or symbiotic bacteria known as diazotrophs . These bacteria have the nitrogenase enzyme that combines gaseous nitrogen with hydrogen to produce ammonia , which is converted by the bacteria into other organic compounds . Most biological nitrogen fixation occurs by the activity of molybdenum (Mo)-nitrogenase, found in a wide variety of bacteria and some Archaea . Mo-nitrogenase

1932-484: Is likely to enhance nitrogen fixation by diazotrophs (gray arrow), which utilize H ions to convert nitrogen into bioavailable forms such as ammonia ( NH 3 ) and ammonium ions ( NH + 4 ). However, as pH decreases, and more ammonia is converted to ammonium ions (gray arrow), there is less oxidation of ammonia to nitrite (NO 2 ), resulting in an overall decrease in nitrification and denitrification (black arrows). This in turn would lead to

2001-412: Is reduced to NO − 2 , N 2 O, N 2 , and NH + 4 depending on the conditions and microbial species involved. The fecal plumes of cetaceans also act as a junction in the marine nitrogen cycle, concentrating nitrogen in the epipelagic zones of ocean environments before its dispersion through various marine layers, ultimately enhancing oceanic primary productivity. The nitrogen cycle

2070-426: Is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric , terrestrial , and marine ecosystems . The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation , ammonification , nitrification , and denitrification . The majority of Earth's atmosphere (78%)

2139-441: Is toxic to plants. Due to their very high solubility and because soils are highly unable to retain anions , nitrates can enter groundwater . Elevated nitrate in groundwater is a concern for drinking water use because nitrate can interfere with blood-oxygen levels in infants and cause methemoglobinemia or blue-baby syndrome. Where groundwater recharges stream flow, nitrate-enriched groundwater can contribute to eutrophication ,

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2208-441: The stratosphere , where it breaks down and acts as a catalyst in the destruction of atmospheric ozone . Nitrous oxide is also a greenhouse gas and is currently the third largest contributor to global warming , after carbon dioxide and methane . While not as abundant in the atmosphere as carbon dioxide, it is, for an equivalent mass, nearly 300 times more potent in its ability to warm the planet. Ammonia ( NH 3 ) in

2277-488: The tissues of plants , providing nitrogen to its host through the action of terminally differentiated cells known as heterocysts . Nostoc is a genus that includes many species that are diverse in morphology, habitat distribution, and ecological function. Nostoc can be found in soil , on moist rocks, at the bottom of lakes and springs, and rarely in marine habitats. It may also be found in terrestrial temperate, desert, tropical, or polar environments. The name Nostoc

2346-499: The United States. This is occurring along the same lines as control of phosphorus fertilizer, restriction of which is normally considered essential to the recovery of eutrophied waterbodies. Denitrification is the reduction of nitrates back into nitrogen gas ( N 2 ), completing the nitrogen cycle. This process is performed by bacterial species such as Pseudomonas and Paracoccus , under anaerobic conditions. They use

2415-688: The aboveground physiology and growth of plants near large point sources of nitrogen pollution. Changes to plant species may also occur as nitrogen compound accumulation increases availability in a given ecosystem, eventually changing the species composition, plant diversity, and nitrogen cycling. Ammonia and ammonium – two reduced forms of nitrogen – can be detrimental over time due to increased toxicity toward sensitive species of plants, particularly those that are accustomed to using nitrate as their source of nitrogen, causing poor development of their roots and shoots. Increased nitrogen deposition also leads to soil acidification, which increases base cation leaching in

2484-514: The annual transfer of nitrogen into biologically available forms. In addition, humans have significantly contributed to the transfer of nitrogen trace gases from Earth to the atmosphere and from the land to aquatic systems. Human alterations to the global nitrogen cycle are most intense in developed countries and in Asia, where vehicle emissions and industrial agriculture are highest. Generation of Nr, reactive nitrogen , has increased over 10 fold in

2553-512: The atmosphere has tripled as the result of human activities. It is a reactant in the atmosphere, where it acts as an aerosol , decreasing air quality and clinging to water droplets, eventually resulting in nitric acid ( H NO 3 ) that produces acid rain . Atmospheric ammonia and nitric acid also damage respiratory systems. The very high temperature of lightning naturally produces small amounts of NO x , NH 3 , and HNO 3 , but high-temperature combustion has contributed to

2622-505: The bacteroids so ammonia assimilation is not required and the bacteroids pass amino acids (with the newly fixed nitrogen) back to the plant, thus forming an interdependent relationship. While many animals, fungi, and other heterotrophic organisms obtain nitrogen by ingestion of amino acids , nucleotides , and other small organic molecules, other heterotrophs (including many bacteria ) are able to utilize inorganic compounds, such as ammonium as sole N sources. Utilization of various N sources

2691-466: The cycle. N 2 can be returned to the atmosphere through denitrification . Ammonium is thought to be the preferred source of fixed nitrogen for phytoplankton because its assimilation does not involve a redox reaction and therefore requires little energy. Nitrate requires a redox reaction for assimilation but is more abundant so most phytoplankton have adapted to have the enzymes necessary to undertake this reduction ( nitrate reductase ). There are

2760-638: The earth in the form of a trembling gelly, are their excrement. John Dryden , in 1679, wrote: When I had taken up what I supposed a fallen star I found I had been cozened with a jelly. William Somervile , in 1740, wrote in The Talisman : Swift as the shooting star, that gilds the night With rapid transient Blaze, she runs, she flies; Sudden she stops nor longer can endure The painful course, but drooping sinks away, And like that falling Meteor, there she lyes A jelly cold on earth. Sir Walter Scott , in his novel The Talisman , wrote: "Seek

2829-508: The earth" and suggesting that it might be used to treat abscesses . A fourteenth-century Latin medical glossary has an entry for uligo , described as "a certain fatty substance emitted from the earth, that is commonly called 'a star which has fallen'". Similarly, an English-Latin dictionary from around 1440 has an entry for "sterre slyme" with the Latin equivalent given as assub (a rendering of Arabic ash-shuhub , also used in medieval Latin as

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2898-503: The emission of NO x , an unintentional waste product. When those reactive nitrogens are released into the lower atmosphere, they can induce the formation of smog, particulate matter , and aerosols, all of which are major contributors to adverse health effects on human health from air pollution. In the atmosphere, NO 2 can be oxidized to nitric acid ( HNO 3 ), and it can further react with NH 3 to form ammonium nitrate ( NH 4 NO 3 ), which facilitates

2967-462: The euphotic zone is referred to as new nitrogen because it is newly arrived from outside the productive layer. The new nitrogen can come from below the euphotic zone or from outside sources. Outside sources are upwelling from deep water and nitrogen fixation. If the organic matter is eaten, respired, delivered to the water as ammonia, and re-incorporated into organic matter by phytoplankton it is considered recycled/regenerated production. New production

3036-467: The euphotic zone. Bacteria are able to convert ammonia to nitrite and nitrate but they are inhibited by light so this must occur below the euphotic zone. Ammonification or Mineralization is performed by bacteria to convert organic nitrogen to ammonia. Nitrification can then occur to convert the ammonium to nitrite and nitrate. Nitrate can be returned to the euphotic zone by vertical mixing and upwelling where it can be taken up by phytoplankton to continue

3105-444: The fact that nitrite and ammonium are intermediate species. They are both rapidly produced and consumed through the water column. The amount of ammonium in the ocean is about 3 orders of magnitude less than nitrate. Between ammonium, nitrite, and nitrate, nitrite has the fastest turnover rate. It can be produced during nitrate assimilation, nitrification, and denitrification; however, it is immediately consumed again. Nitrogen entering

3174-447: The form of a living organism, humus or in the intermediate products of organic matter decomposition. The processes in the nitrogen cycle is to transform nitrogen from one form to another. Many of those processes are carried out by microbes , either in their effort to harvest energy or to accumulate nitrogen in a form needed for their growth. For example, the nitrogenous wastes in animal urine are broken down by nitrifying bacteria in

3243-647: The genus also have nitrogen-fixing heterocyst filaments enclosed in this membrane. Many members of the Nostoc genus form colonies. These colonies can reach several centimeters in diameter. These colonies consist of mats or gelatinous masses created by aggregated trichomes that can appear in a range of colors (depending on the species) such as brown, yellow, or green. Additionally, some species of Nostoc are able to enter quiescent stages, further aiding in their survival of adverse conditions, and allowing them to resume metabolism when re-hydrated. Nostoc can be found in

3312-472: The global nitrogen cycle . Human modification of the global nitrogen cycle can negatively affect the natural environment system and also human health. Nitrogen is present in the environment in a wide variety of chemical forms including organic nitrogen, ammonium ( NH + 4 ), nitrite ( NO − 2 ), nitrate ( NO − 3 ), nitrous oxide ( N 2 O ), nitric oxide (NO) or inorganic nitrogen gas ( N 2 ). Organic nitrogen may be in

3381-458: The health of plants, animals, fish, and humans. Decreases in biodiversity can also result if higher nitrogen availability increases nitrogen-demanding grasses, causing a degradation of nitrogen-poor, species-diverse heathlands . Increasing levels of nitrogen deposition is shown to have several adverse effects on both terrestrial and aquatic ecosystems . Nitrogen gases and aerosols can be directly toxic to certain plant species, affecting

3450-487: The higher combustion temperatures that produce NO x . Ammonia and nitrous oxides actively alter atmospheric chemistry . They are precursors of tropospheric (lower atmosphere) ozone production, which contributes to smog and acid rain , damages plants and increases nitrogen inputs to ecosystems. Ecosystem processes can increase with nitrogen fertilization , but anthropogenic input can also result in nitrogen saturation, which weakens productivity and can damage

3519-760: The human body, nitrate can react with organic compounds through nitrosation reactions in the stomach to form nitrosamines and nitrosamides , which are involved in some types of cancers (e.g., oral cancer and gastric cancer ). Human activities have also dramatically altered the global nitrogen cycle by producing nitrogenous gases associated with global atmospheric nitrogen pollution. There are multiple sources of atmospheric reactive nitrogen (Nr) fluxes. Agricultural sources of reactive nitrogen can produce atmospheric emission of ammonia ( NH 3 ), nitrogen oxides ( NO x ) and nitrous oxide ( N 2 O ). Combustion processes in energy production, transportation, and industry can also form new reactive nitrogen via

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3588-509: The impact of nitric acid rain deposition, resulting in the killing of fish and many other aquatic species. Ammonia ( NH 3 ) is highly toxic to fish, and the level of ammonia discharged from wastewater treatment facilities must be closely monitored. Nitrification via aeration before discharge is often desirable to prevent fish deaths. Land application can be an attractive alternative to aeration. Leakage of Nr (reactive nitrogen) from human activities can cause nitrate accumulation in

3657-469: The jelly seemed to "grow out from among the roots of grass". Sir John Suckling , in 1641, wrote a poem which contained the following lines: As he whose quicker eye doth trace A false star shot to a mark'd place Do's run apace, And, thinking it to catch, A jelly up do snatch Henry More , in 1656 wrote: That the Starres eat...that those falling Starres, as some call them, which are found on

3726-532: The marine cycle, the fixed nitrogen would be used up in about 2000 years. Phytoplankton need nitrogen in biologically available forms for the initial synthesis of organic matter. Ammonia and urea are released into the water by excretion from plankton. Nitrogen sources are removed from the euphotic zone by the downward movement of the organic matter. This can occur from sinking of phytoplankton, vertical mixing, or sinking of waste of vertical migrators. The sinking results in ammonia being introduced at lower depths below

3795-567: The natural water environment, which can create harmful impacts on human health. Excessive use of N-fertilizer in agriculture has been a significant source of nitrate pollution in groundwater and surface water. Due to its high solubility and low retention by soil, nitrate can easily escape from the subsoil layer to the groundwater, causing nitrate pollution. Some other non-point sources for nitrate pollution in groundwater originate from livestock feeding, animal and human contamination, and municipal and industrial waste. Since groundwater often serves as

3864-605: The nitrate as an electron acceptor in the place of oxygen during respiration. These facultatively (meaning optionally) anaerobic bacteria can also live in aerobic conditions. Denitrification happens in anaerobic conditions e.g. waterlogged soils. The denitrifying bacteria use nitrates in the soil to carry out respiration and consequently produce nitrogen gas, which is inert and unavailable to plants. Denitrification occurs in free-living microorganisms as well as obligate symbionts of anaerobic ciliates. Dissimilatory nitrate reduction to ammonium (DNRA), or nitrate/nitrite ammonification,

3933-474: The nitrogen content of nitrogen-poor soils. A few non-legumes can also form such symbioses . Today, about 30% of the total fixed nitrogen is produced industrially using the Haber-Bosch process, which uses high temperatures and pressures to convert nitrogen gas and a hydrogen source (natural gas or petroleum) into ammonia. Plants can absorb nitrate or ammonium from the soil by their root hairs. If nitrate

4002-433: The nitrogen will be replenished. As illustrated by the diagram on the right, additional carbon dioxide (CO 2 ) is absorbed by the ocean and reacts with water, carbonic acid ( H 2 CO 3 ) is formed and broken down into both bicarbonate ( HCO − 3 ) and hydrogen ( H ) ions (gray arrow), which reduces bioavailable carbonate ( CO 2− 3 ) and decreases ocean pH (black arrow). This

4071-487: The ocean, which may play an important part in ocean dynamics and nutrient cycles. The input of iron varies by region and is delivered to the ocean by dust (from dust storms ) and leached out of rocks. Iron is under consideration as the true limiting element to ecosystem productivity in the ocean. Ammonium and nitrite show a maximum concentration at 50–80 m (lower end of the euphotic zone ) with decreasing concentration below that depth. This distribution can be accounted for by

4140-453: The past century due to global industrialisation . This form of nitrogen follows a cascade through the biosphere via a variety of mechanisms, and is accumulating as the rate of its generation is greater than the rate of denitrification . Nitrous oxide ( N 2 O ) has risen in the atmosphere as a result of agricultural fertilization, biomass burning, cattle and feedlots, and industrial sources. N 2 O has deleterious effects in

4209-427: The primary domestic water supply, nitrate pollution can be extended from groundwater to surface and drinking water during potable water production, especially for small community water supplies, where poorly regulated and unsanitary waters are used. The WHO standard for drinking water is 50 mg NO − 3 L for short-term exposure, and for 3 mg NO − 3 L chronic effects. Once it enters

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4278-525: The primary stage of nitrification, the oxidation of ammonium ( NH + 4 ) is performed by bacteria such as the Nitrosomonas species, which converts ammonia to nitrites ( NO − 2 ). Other bacterial species such as Nitrobacter , are responsible for the oxidation of the nitrites ( NO − 2 ) into nitrates ( NO − 3 ). It is important for the ammonia ( NH 3 ) to be converted to nitrates or nitrites because ammonia gas

4347-419: The products of reaction and the reagents. Though nitrogen fixation is the primary source of plant-available nitrogen in most ecosystems , in areas with nitrogen-rich bedrock , the breakdown of this rock also serves as a nitrogen source. Nitrate reduction is also part of the iron cycle , under anoxic conditions Fe(II) can donate an electron to NO − 3 and is oxidized to Fe(III) while NO − 3

4416-748: The soil and amounts of aluminum and other potentially toxic metals, along with decreasing the amount of nitrification occurring and increasing plant-derived litter. Due to the ongoing changes caused by high nitrogen deposition, an environment's susceptibility to ecological stress and disturbance – such as pests and pathogens – may increase, thus making it less resilient to situations that otherwise would have little impact on its long-term vitality. Additional risks posed by increased availability of inorganic nitrogen in aquatic ecosystems include water acidification; eutrophication of fresh and saltwater systems; and toxicity issues for animals, including humans. Eutrophication often leads to lower dissolved oxygen levels in

4485-466: The soil to be used by plants. The diagram alongside shows how these processes fit together to form the nitrogen cycle. The conversion of nitrogen gas ( N 2 ) into nitrates and nitrites through atmospheric, industrial and biological processes is called nitrogen fixation. Atmospheric nitrogen must be processed, or " fixed ", into a usable form to be taken up by plants. Between 5 and 10 billion kg per year are fixed by lightning strikes, but most fixation

4554-709: The species, Nostoc may either be free-living in their environment, or they may form relationships with the other organisms in their environment, such as plants, fungi, or other bacteria. Because Nostoc is able to form colonies on the surface of bare minerals, it is able to provide a more stable environment for higher vegetation in its environment. Some species of Nostoc also form relationships with plants that lack vascular tissue such as Bryophytes because of their ability to fix nitrogen. Nostoc has also been found to form symbiotic associations and other relationships with other bacteria in their environment. Some species of Nostoc that form colonies in freshwater environments provide

4623-554: The suggested pharmaceutical usage, Nostoc has also been a suggested biofertilizer , and source of fatty acids for biofuel production. Nostoc has the unique ability to survive and colonize new and bare mineral surfaces by moss and other higher plants, which then allows for more organic soil and stable vegetation. It has been suggested that Nostoc be used in environments of retreating glaciers in order to establish new and more stable presences of vegetation on newly exposed mineral surfaces. Nostoc has historically been utilized as

4692-635: The water column, including hypoxic and anoxic conditions, which can cause death of aquatic fauna. Relatively sessile benthos, or bottom-dwelling creatures, are particularly vulnerable because of their lack of mobility, though large fish kills are not uncommon. Oceanic dead zones near the mouth of the Mississippi in the Gulf of Mexico are a well-known example of algal bloom -induced hypoxia . The New York Adirondack Lakes , Catskills , Hudson Highlands , Rensselaer Plateau and parts of Long Island display

4761-556: Was coined by Paracelsus and is a combination of the English nost ril and German Nasenloch "nose hole, nostril", likely due to appearance of many species colonies being similar to nasal mucus. When it is on the ground, a Nostoc colony is ordinarily not seen, but after a rain, it swells up into a conspicuous, jellylike mass, which was once thought to have fallen from the sky, hence the popular names, like star jelly , troll's butter , and witch's butter mentioned above. Nostoc are

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