Chemistry project Natural Resources--Nitrogen Cycle Presented by :- Group 3 Presented by :- Group 3 The Elite members The Elite members  Sahil>>>> Roll Number- 43  Prateek>>>> Roll Number- 28  Akshiv>>>> Roll Number -41  U Moses>>>> Roll Number- 44  Apekshit>>>> Roll Number -46  Gaurav>>>> Roll Number- 18  Imlijungla>>>> Roll Number- 42

N itrogen is a very interesting element, and it is used for many purposes. The word "Nitrogen" means, "giving rise to niter." Niter is a substance rich in Nitrogen, and was discovered before Nitrogen was. Nitrogen is the seventh element on the Periodic Table. Its symbol on the Periodic Table is "N". The atomic weight of Nitrogen is Nitrogen has some of the lowest freezing and melting temperatures. Nitrogen melts at negative degrees Celsius, and boils at negative degrees Celsius. Nitrogen gas makes up 78% of our atmosphere and nitrogen is also a part of many molecules essential to life like proteins, nucleic acids and some vitamins. Nitrogen is found in other biologically important compounds such as alkaloids and urea too. Nitrogen is thus an essential nutrient for all life-forms. Nitrogen has many uses. One of these uses is making light bulbs. Light bulbs are almost always filled with Nitrogen. Another use is explosives. Nitrogen can be used to make four different explosives Ammonium Nitrate Nitroglycerin, Nitrocellulose, and Trinitrotoluene You probably know Trinitrotoluene better by the initials TNT. Yet another use for Nitrogen is that it is used to make Laughing Gas. Nitrogen has been nicknamed The Lifeless Element", because it cannot support life of any kind. Nitrogen makes up more than ¾ of the air around us. thus its an its everlasting existence is an important question to ponder on. The answer Nitrogen Cycle Nitrogen – The wonder element

Nitrogen Cycle N itrogen cycle is the natural cyclic process in the course of which atmospheric nitrogen enters the soil and becomes part of living organisms, before returning to the atmosphere. Five main processes cycle nitrogen through the biosphere, atmosphere, and geosphere: 1.Nitrogen fixation, 2.Nitrogen uptake (organism growth), 3.Nitrogen mineralization (decay), 4.Nitrification,5.Denitrification.

Nitrogen Fixation N itrogen fixation refers to the conversion of atmospheric nitrogen gas (N2) to ammonia (NH3) or nitrate (NO3). A few forms of bacteria, life-forms are not able to convert the comparatively inert nitrogen molecule into forms like nitrates and nitrites which can be taken up and used to make the required molecules. These ‘nitrogen-fixing’ bacteria may be free-living or be associated with some species of dicot plants. Most commonly, the nitrogen-fixing bacteria are found in the roots of legumes in special structures called root nodules. Other than these bacteria, the only other manner in which the nitrogen molecule is converted to nitrates and nitrites is by a physical process. During lightning, the high temperatures and pressures created in the air convert nitrogen into oxides of nitrogen. These oxides dissolve in water to give nitric and nitrous acids and fall on land along with rain. These are then utilized by various life forms. Part of a clover root system bearing naturally occurring nodules of Rhizobium, bacteria that can fix atmospheric nitrogen. Each nodule is about 2-3 mm long. Nitrogen Fixation N 2 NH 4 +

Nitrogen Uptake NH 4 +  Organic N T he ammonia produced by nitrogen fixing bacteria is usually quickly incorporated into protein and other organic nitrogen compounds, either by a host plant, the bacteria itself, or another soil organisms. When organisms nearer the top of the food chain (like us!) eat, we are using nitrogen that has been fixed initially by nitrogen fixing bacteria.

Nitrogen Mineralization Organic N  NH 4 + A fter nitrogen is incorporated into organic matter, it is often converted back into inorganic nitrogen by a process called nitrogen mineralization, otherwise known as decay. When organisms die, decomposers (such as bacteria and fungi) consume the organic matter and lead to the process of decomposition. During this process, a significant amount of the nitrogen contained within the dead organism is converted to ammonium.

Nitrification NH 4 +  NO 3 - N itrification refers to the process by which some of the ammonium produced is converted into Nitrates. The bacteria that carry out this reaction gain energy from it. Nitrification requires the presence of oxygen, so nitrification can happen only in oxygen-rich environments like circulating or flowing waters and the very surface layers of soils and sediments. The primary stage of nitrification, the oxidation of ammonia (NH3) is performed by bacteria such as the Nitrosomonas species, which converts ammonia to nitrites (NO2-). Other bacterial species, such as the Nitrobacter, are responsible for the oxidation of the nitrites into nitrates (NO3-)

Denitrification NO 3 -  N 2 + N 2 O D enitrification is the reduction of nitrates back into the largely inert nitrogen gas (N2), completing the nitrogen cycle. This process is performed by bacterial species such as the Pseudomonas and Clostridium. Through denitrification, oxidized forms of nitrogen such as nitrate and nitrite (NO2-) are converted to dinitrogen (N2). Denitrification is an anaerobic process that is carried out by denitrifying bacteria, which convert nitrate to dinitrogen in the following sequence: NO 3 - NO 2 - NO N 2 O N 2. Pseudomonas Clostridium

Nitrogen Cycle in an aquarium T T he primary source of ammonia (NH3) is created when fish consume food and oxygen (O2) and create waste and carbon dioxide (CO2). The fish waste then decays into ammonia. Other sources include excess food that is not eaten as well as decaying plants and dead fish. The rise in ammonia triggers the growth of Nitrosomonas which produce nitrites (NO2). The nitrites trigger the growth of Nitrospira to produce nitrates (NO3). The nitrates and carbon dioxide are consumed by plant life which produce oxygen through the process of photosynthesis. Excess nitrates are removed by water changes.