...The Nitrogen Cycle: Processes, Players, and Human Impact Nitrogen is one of the primary nutrients critical for the survival of all living organisms. Although nitrogen is very abundant in the atmosphere, it is largely inaccessible in this form to most organisms. This article explores how nitrogen becomes available to organisms and what changes in nitrogen levels as a result of human activity means to local and global ecosystems. Introduction Nitrogen is one of the primary nutrients critical for the survival of all living organisms. It is a necessary component of many biomolecules, including proteins, DNA, and chlorophyll. Although nitrogen is very abundant in the atmosphere as dinitrogen gas (N2), it is largely inaccessible in this form to most organisms, making nitrogen a scarce resource and often limiting primary productivity in many ecosystems. Only when nitrogen is converted from dinitrogen gas into ammonia (NH3) does it become available to primary producers, such as plants. In addition to N2 and NH3, nitrogen exists in many different forms, including both inorganic (e.g., ammonia, nitrate) and organic (e.g., amino and nucleic acids) forms. Thus, nitrogen undergoes many different transformations in the ecosystem, changing from one form to another as organisms use it for growth and, in some cases, energy. The major transformations of nitrogen are nitrogen fixation, nitrification, denitrification, anammox, and ammonification (Figure 1). The transformation of nitrogen into...
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...SC4730 Environmental Science Analysis 2 Nitrogen cycle Nitrogen exists in nature in many different forms, from molecular nitrogen in gaseous to the complex organic compounds in the body of plants, animals and humans. In an organism, Nitrogen exists in the form of organic compounds such as proteins, amino acids. When the microorganisms die, the amount of nitrogen exists in soil. Under the action of the group saprophytic microorganisms, proteins are degraded to amino acids. The amino acid to be a group of other microorganisms into NH3 or NH4+ called ammonium group of bacteria. This process called mineralization of organic matter such as through organic nitrogen is converted into nitrogen mineralization types. NH4 + form will be converted into the form of NO3- by nitrifying bacteria. (Wikipedia, Nitrogen cycle) Of the nitrate compounds are converted into nitrogen molecules, this process is called nitrification reaction was carried out by reaction of nitrate bacteria. N2 gas will be fixed in bacterial cells and plant cells are then transformed into organic forms of nitrogen by microorganisms group of fixed nitrogen. (Wikipedia, Nitrogen cycle) Thus nitrogen cycle is closed in most phases of the cycle metabolism and involvement of different groups of microorganisms. If the activities of a group are stopped the whole metabolism of the cycle will be seriously affected. The process of ammonium The organic forms of nitrogen converted to NH3 or NH4 +. a / The chemical urea ammonium:...
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...Nitrogen fixing bacteria refers to any bacteria that combine nitrogen with oxygen or hydrogen to create compounds that are usable by plants (for instance ammonia, nitrates). This bacteria that fixes nitrogen is called diazotroph. Nitrogen fixation Is a process by which nitrogen (N2) in the atmosphere is converted into ammonium (NH4). Atmospheric nitrogen or molecular nitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds. The fixation process frees up the nitrogen atoms from their diatomic form (N2) to be used in other ways. Nitrogen fixation, natural and synthetic, is essential for all forms of life because nitrogen is required to biosynthesize basic building blocks of plants, animals and other life forms, e.g., nucleotides for DNA and RNA and amino acids for proteins. Therefore nitrogen fixation is essential for agriculture and the manufacture of fertilizer. It is also an important process in the manufacture of explosives (e.g. gunpowder, dynamite, TNT, etc.). Nitrogen fixation occurs naturally in the air by means of lightning. Nitrogen fixation also refers to other biological conversions of nitrogen, such as its conversion to nitrogen dioxide. Microorganisms that can fix nitrogen are prokaryotes (both bacteria and archaea, distributed throughout their respective kingdoms) called diazotrophs. Some higher plants, and some animals (termites), have formed associations (symbiosis) with diazotrophs. Where do Nitrogen fixing bacteria...
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...Module title/Code: Precision Agriculture Level and semester: Level 2, Semester 3, Autumn 2012 Research Project (100% of final grade-max words=3000) - Word count: 2644 Title: Developing Management Zones to Target Nitrogen Applications [pic] Table of Contents SUMMARY____________________________________________5 INTRODUCTION ____________________________________________6 WHAT IS PRECISION AGRICULTURE (PA)?____________6 PROJECT OBJECTIVE_________________________________7 PRECISION AGRICULTURE AND VARIATION IN THE SOIL________7 WHERE DOES THE NITROGEN COMES FROM___________________________8 MINERAL SOURCES OF NITROGEN____________________________9 MINERAL FERTILIZERS _____________________________________11 WHAT IS SENSOR-BASED, VARIABLE RATE NITROGEN MANAGEMENT__________11 ENSURING SPREADING PRECISION__________________________________12 REDUCING FERTILIZERS INPUT BY SENSOR CONTROLLED SPREADING___________13 REDUCING SOIL ACIDIFICATION__________________________________15 CONCLUSIONS__________________________________15 REFERENCES_______________________________________________16 APPENDICES ________________________________________________18 SUMMARY To determine soil nitrogen (N) or the potential soil yield, management’s zones for N fertilizer management nowadays offers a large gamma of possibilities using different tools such as topography, satellite imagery, aerial photographs, soil electrical...
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...The experiment was done in the open air, where oxygen and Nitrogen gas are in it. When the Magnesium ribbon was heated in air, the magnesium was reacted with the compounds of the air which has nitrogen and oxygen. The Mg became active and reacted with N to form Magnesium Nitride. However, the Oxygen was much active than Nitrogen and this led it form Magnesium oxide that appears as white powder in the crucible. Mg(s) + N2(g) + O2(g) → MgO(s) + Mg3N2(s) We removed the nitride that was formed by adding drops of water to the crucible to form magnesium hydroxide. The nitride combined with hydrogen to form ammonia gas MgO(s) + Mg3N2(s) + H2O(l) → MgO(s) + Mg(OH)2(s) + NH3(g) Finally, during the heating process, the...
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...Prof. Shakhashiri www.scifun.org Chemistry 103-1 AGRICULTURAL FERTILIZERS: NITROGEN, POTASSIUM, AND PHOSPHORUS Anyone who has grown a garden, maintained a lawn, or kept house plants knows that it is necessary to apply a fertilizer to the soil to keep cultivated plants healthy. As they grow, plants extract nutrients they need from the soil. Unless these nutrients are replenished, plants will eventually cease to grow. In nature, nutrients are returned to the soil when plants die and decay. However, this does not occur with cultivated plants. Humans cultivate plants mainly for food, either for themselves or for livestock. When cultivated plants are harvested, the nutrients that the plants extracted from the soil are taken away. To keep the soil productive, it is necessary to replace these nutrients artificially. The kinds and amounts of nutrients that plants need have been determined and can be supplied by applying to the soil substances that contain these nutrients. A plant contains a great number of chemical compounds. The major compound in all plants is water. The percent of the plant's weight that is water varies greatly from one kind of plant to another, from less than 20% to more than 90%. After the water is removed, the bulk of the dry plant material consists of carbohydrate compounds containing the elements carbon, hydrogen, and oxygen. Using the energy of sunlight in a process called photosynthesis, plants make carbohydrates in their leaves. The carbon and oxygen in carbohydrates...
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...equipment used to produce, store, and transport oil and gas can reduce many of the leaks that contribute to CH4 emissions. Methane from coal mines can also be captured and used for energy Agriculture Cautions: Methane can be reduced and captured by altering manure management strategies at livestock operations or animal feeding practices Waste from Home and Businesses: Because CH4 emissions from landfill gas are a major source of CH4 emissions in the United States, emission controls that capture landfill CH4 are an effective reduction strategy. Nitrous Oxide: nitrous oxide (N2O) accounted for about 6% of all U.S. greenhouse gas emissions from human activities. Nitrous oxide is naturally present in the atmosphere as part of the Earth's nitrogen cycle, and has a variety of natural sources. However, human activities such as agriculture, fossil fuel combustion, wastewater management, and industrial processes are increasing the amount of N2O in the atmosphere. Nitrous oxide...
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...The catalyst The catalyst is actually slightly more complicated than pure iron. It has potassium hydroxide added to it as a promoter - a substance that increases its efficiency. The pressure The pressure varies from one manufacturing plant to another, but is always high. You can't go far wrong in an exam quoting 200 atmospheres. Recycling At each pass of the gases through the reactor, only about 15% of the nitrogen and hydrogen converts to ammonia. (This figure also varies from plant to plant.) By continual recycling of the unreacted nitrogen and hydrogen, the overall conversion is about 98%. Explaining the conditions The proportions of nitrogen and hydrogen The mixture of nitrogen and hydrogen going into the reactor is in the ratio of 1 volume of nitrogen to 3 volumes of hydrogen. Avogadro's Law says that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. That means that the gases are going into the reactor in the ratio of 1 molecule of nitrogen to 3 of hydrogen. That is the proportion demanded by the equation. In some reactions you might choose to use an excess of one of the reactants. You would do this if it is particularly important to use up as much as possible of the other reactant - if, for example, it was much more expensive. That doesn't apply in this case. There is always a down-side to using anything other than the equation proportions. If you have an excess of one reactant there will...
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...volumetric load of 680 g H2 S mÀ3 empty bed dayÀ1 and 85 g NH3 mÀ3 empty bed dayÀ1 was applied for eight weeks to a unit called BGSn (column packed with granulated sludge and mainly supplied with hydrogen sulfide); a volumetric load of 170 g H2 S mÀ3 empty bed dayÀ1 and 340 g NH3 mÀ3 empty bed dayÀ1 was applied for eight weeks to the other called BGNs (column packed with granulated sludge and mainly supplied with ammonia). Ammonia and hydrogen sulfide elimination occur in the biofilters simultaneously. The hydrogen sulphide and ammonia removal efficiencies reached are very high: 100% and 80% for BGSn; 100% and 80% for BGNs respectively. Hydrogen sulfide is oxidized into sulphate and sulfur. The ammonia oxidation products are nitrite and nitrate. The nitrogen error mass balance is high for BGSn (60%) and BGNs (36%). This result could be explained by the denitrification process which would...
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...Question 1 Most insects use external sources of heat to achieve their operative temperature range. Heinrich's research on the sphinx moth (Manduca sexta) indicates that some insects can thermoregulate by using their flight muscles and: A. using their blood as a coolant. B. decreasing their metabolic rate. C. possessing an internal respiratory system. D. using a countercurrent heat exchange mechanism. Question 2 The thermal stability of aquatic environments is a result of the: A. high specific heat of water. B. low latent heat of vaporization of water. C. low latent heat of fusion of water. D. All of the choices are correct. Question 3 Animals that rely mainly on external sources of energy for regulating body temperature are called: A. epitherms. B. endotherms. C. ectotherms. D. peritherms. Question 4 In general, reptiles are considered to be a/an: A. poikilotherm. B. homeotherm. C. endotherm. D. heterotherm. Question 5 Mammalian and avian aquatic endotherms use all of the following mechanisms to thermoregulate EXCEPT: A. fat. B. internal respiratory systems. C. fur or feathers. D. concurrent heat exchange. Question 6 The water availability for organisms is determined by: A. internal dissolved ion concentrations. B. external dissolved ion concentrations. C. movement of water down its concentration gradient. D. movement of water...
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...Chemical Monitoring and Management Part 1 - Chemical Occupations a) Analytical Chemist – uses a various methods to investigate the chemical nature of substances. Their aim is to identify and understand the substance and how it behaves in different conditions. b) Clinical Biochemist – analyses and interprets data relating to patients’ samples to assist with the investigation, diagnosis and treatment of diseases. c) Forensic Scientist – provides impartial scientific evidence for use in courts of law to support the prosecution or defence in criminal and civil investigations. d) Toxicologist - plans and carries out laboratory and field studies to identify, monitor and evaluate the impact of toxic materials and radiation on human and animal health, the environment, and the impact of future technology. e) Process engineer – develops economical industrial processes to make the huge range of products on which modern society depends, including food and drink, fuel , artificial fibres, pharmaceuticals, chemicals, plastics, toiletries, energy and clean water. * Calorimetry * Chromatography * Spectroscopy Analytical Chemist – uses a various methods to investigate the chemical nature of substances. Their aim is to identify and understand the substance and how it behaves in different conditions. They use different types of analysis including: * Gravimetric analysis * Qualitative analysis * Thermal analysis * Volumetric analysis ...
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...limestone. Properties can be changed by adding or replacing certain components. 8. Cement & Concrete: Cement: complex mixture of calcium & aluminum silicates (limestone & clay are mixed together to create clinker, then ground to a fine powder & mixed w/ gypsum, resulting cement is mixed w/ sand & gravel & water, hardens to become concrete. 9. Production (extraction) of iron, aluminum, & copper: Valuable material: extracted from the ores ) 10. Soaring prices on scrap metal. One metal is the cost of energy needed to extract a metal from its ore. The greater the cost of energy, the more it costs to convert ore to metal. Chap. 13 1. Nitrogen cycle: is completed by the action of other types of microbes, which can use nitrate ions as their oxygen source fro the decomposition of organic matter and release Nitrogen gas back to the atmosphere....
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...Theory Chemical oxygen demand (COD) is the measure of wastewater and water quality. This test is focused on the fact that a strong oxidizing agent, under acidic conditions can fully oxidize almost any organic compound to carbon dioxide. COD is equal to the equivalent amount of oxygen required to chemically oxidize substrate materials in water. The COD is often measured using a strong oxidant (e.g. potassium dichromate, potassium iodate, potassium permanganate) under acidic conditions. A known excess amount of the oxidant is added to the sample. Once oxidation is complete, the concentration of organics in the sample is calculated by measuring the amount of oxidant remaining in the solution. COD is expressed in mg/L, which indicates the mass of oxygen consumed per liter of solution. Biological Oxygen Demand (BOD) is a measure of the oxygen used by microorganisms to decompose organic matter under aerobic conditions. Microorganisms such as bacteria are responsible for decomposing organic waste. When organic matter such as dead plants, leaves, grass clippings, manure, sewage, or even food waste is present in a water supply, the bacteria will begin the process of breaking down this waste. When this happens, much of the available dissolved oxygen is consumed by aerobic bacteria, robbing other aquatic organisms of the oxygen they need to live. BOD also includes oxygen used to oxidize inorganic material such as sulfides and ferrous iron. Coliform bacteria are found in the intestines...
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...ABSTRACT Nylons comes in many types but the most common and widely used in textile and plastic industries are Nylon 6 and Nylon 6,6. Nylon 6,6 is made up of two monomers each containing 6 carbon atoms. One of them is Adipic Acid which is a dicarboxylic acid. It is manufactured by oxidation of Cyclohexanol which is produced by oxidative cleavage of cyclohexane or by hydrogenation of phenol. Commercially Cyclohexane is preferred as raw material because of its lower cost and a two-step mechanism involving Nitric acid is used to produce Adipic Acid. This process has higher selectivity and yield than other processes. The only concern with this process is the emission of nitrogen oxides in the gas effluents which is a major environmental concern. 1. Introduction Adipic acid is an organic compound, with formula HOOC (CH2)4COOH, which is a white crystalline solid and one of the most important Dicarboxylic acid. It is Odorless, Colorless and freely soluble in Ethanol, Methanol and Acetone. Other Important properties of Adipic acid is shown in Table 1.From Industrial perspective it is used mainly in Nylon-6, 6 production. About 2.5 billion kilograms of this white crystalline powder are produced annually. In US it is mainly produced by three companies at four manufacturing plants, with nearly two-thirds of the total production, 860,000 tons capacity occurring at DuPont's two Texas facilities. The use of adipic acid in food items have started in recent times and this has created a demand...
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...Name: Date: March 29 2013 Instructor’s Name: Assignment: SCIE207 Phase 1 Lab Report Title: Using Scientific Method Table 1: Maize Yield From Arable Soil |Amount of Mineral Nitrogen Fertilization (kg per 100 acres) |Yield of Maize (mg of dry mass per 100 acres per year) in | | |Arable Soil | |40 |13 | | | | | | | | | | | | | | | | | | | | | | | ...
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