Biogeochemical cycles


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a) Phosphorus
b) Sulfur


a) Carbon
b) Hydrogen
c) Oxygen
d) Nitrogen

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Biogeochemical cycles

  1. 1. BIOGEOCHEMICAL CYCLES   A biogeochemical cycle or cycling of substances is a pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of Earth. A cycle is a series of change which comes back to the starting point and which can be repeated.
  2. 2. TWO CATEGORIES  * GASEOUS CYCLES These involve the transportation of matter through the atmosphere. * SEDIMENTARY CYCLES These cycles involve the transportation of matter through the ground to water; that is to say from the lithosphere to the hydrosphere.
  3. 3. GASEOUS CYCLES  • Carbon • Hydrogen • Oxygen • Nitrogen
  4. 4. CARBON  • Carbon (from Latin: carbo "coal") is the chemical element with symbol C and atomic number 6. • As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds.
  5. 5. CARBON GROUP (GROUP 14)  Z Element No. of electrons/shell 6 Carbon (C) 2, 4 14 Silicon (Si) 2, 8, 4 32 Germanium (Ge) 2, 8, 18, 4 50 Tin (Sn) 2, 8, 18, 18, 4 82 Lead (Pb) 2, 8, 18, 32, 18, 4 114 Flerovium (Fl) 2, 8, 18, 32, 32, 18, 4 (predicted)
  6. 6. NONMETALLIC   In chemistry, a nonmetal or non-metal is a chemical element which mostly lacks metallic attributes. Physically, nonmetals tend to be highly volatile (easily vaporized), have low elasticity, and are good insulators of heat and electricity; chemically, they tend to have high ionization energy and electronegativity values, and gain or share electrons when they react with other elements or compounds. Seventeen elements are generally classified as nonmetals; most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine); and a few are solids (carbon, phosphorus, sulfur, selenium, and iodine).
  7. 7. TETRAVALENT   In chemistry, a tetravalence is the state of an atom with four electrons available for covalent chemical bonding in its valence (outermost electron shell). An example is methane (CH4).
  8. 8. ALLOTROPES OF CARBON   When we say allotropes of Carbon, it means the two or more different physical forms in which the carbon is existing.  EXAMPLES: Graphite, Charcoal and Diamond.
  9. 9.  Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d–f) fullerenes g) amorphous carbon; h) carbon nanotube.
  10. 10. ELECTRON  The electron is a subatomic particle with a negative elementary electric charge.
  11. 11. COVALENT BONDS   Covalent bonding is a common type of bonding, in which the electronegativity difference between the bonded atoms is small or nonexistent. Bonds within most organic compounds are described as covalent.
  12. 12. CARBON   Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known life forms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen.
  13. 13. OCCURENCE   Carbon is the fourth most abundant chemical element in the universe by mass after hydrogen, helium, and oxygen. Carbon is abundant in the Sun, stars, comets, and in the atmospheres of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts.
  14. 14.  Carbon is a major component in very large masses of  carbonate rock (limestone, dolomite, marble and so on). Coal is the largest commercial source of mineral carbon, accounting for 4,000 gigatonnes or 80% of fossil carbon fuel.
  15. 15. ISOTOPES  Isotopes are atoms that have the same number of protons and electrons but different numbers of neutrons and therefore have different physical properties.
  16. 16.  Isotopes of carbon are atomic nuclei that contain six protons plus a number of neutrons. Carbon has two stable, naturally occurring isotopes.
  17. 17. CARBON-12   Carbon-12 is the more abundant of the two stable isotopes of the element carbon, accounting for 98.89% of carbon; it contains six protons, six neutrons and six electrons. Its abundance is due to the Triple-alpha process by which it is created in stars.  The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
  18. 18. CARBON-13  Carbon-13 (13C) is a natural, stable isotope of carbon and one of the environmental isotopes. It makes up about 1.1% of all natural carbon on Earth.
  19. 19. CARBON-14  Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with a nucleus containing 6 protons and 8 neutrons.
  21. 21. ORGANIC COMPOUNDS   Carbon has the ability to form very long chains of interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable. This property allows carbon to form an almost infinite number of compounds.  The simplest form of an organic molecule is the hydrocarbon—a large family of organic molecules that are composed of hydrogen atoms bonded to a chain of carbon atoms.
  22. 22. Carbon occurs in all known organic life and  is the basis of organic chemistry. When united with hydrogen, it forms various hydrocarbons which are important to industry as refrigerants, lubricants, solvents, as chemical feedstock for the manufacture of plastics and petrochemicals and as fossil fuels.
  23. 23. INORGANIC COMPOUNDS   Commonly carbon-containing compounds which are associated with minerals or which do not contain hydrogen or fluorine, are treated separately from classical organic compounds; however the definition is not rigid.  Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide (CO2). This was once the principal constituent of the paleoatmosphere, but is a minor component of the Earth's atmosphere today.
  24. 24.  The other common oxide is carbon monoxide (CO). It is  formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar, resulting in a tendency to bind permanently to hemoglobin molecules, oxygen, which has a lower binding affinity displacing
  25. 25. HISTORY   The English name carbon comes from the Latin carbo for coal and charcoal, whence also comes the French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are Kohlenstoff, koolstof and kulstof respectively, all literally meaning coalsubstance.
  26. 26. HISTORY   Carbon was discovered in prehistory and was known in the forms of soot and charcoal to the earliest human civilizations. Diamonds were known probably as early as 2500 BCE in China, while carbon in the form of charcoal was made around Roman times by the same chemistry as it is today, by heating wood in a pyramid covered with clay to exclude air.
  27. 27. HISTORY   In 1722, René Antoine Ferchault de Réaumur demonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon.  In 1772, Antoine Lavoisier showed that diamonds are a form of carbon; when he burned samples of charcoal and diamond and found that neither produced any water and that both released the same amount of carbon dioxide per gram.
  28. 28. HISTORY   In 1779, Carl Wilhelm Scheele showed that graphite, which had been thought of as a form of lead, was instead identical with charcoal but with a small admixture of iron, and that it gave "aerial acid" (his name for carbon dioxide) when oxidized with nitric acid.  In 1786, the French scientists Claude Louis Berthollet, Gaspard Monge and C. A. Vandermonde confirmed that graphite was mostly carbon by oxidizing it in oxygen in much the same way Lavoisier had done with diamond.
  29. 29. HISTORY  A new allotrope of carbon, fullerene, that was discovered in 1985 includes nanostructured forms such as buckyballs and nanotubes. Their discoverers – Robert Curl, Harold Kroto and Richard Smalley – received the Nobel Prize in Chemistry in 1996.
  30. 30. CARBON CYCLE   The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to making the Earth capable of sustaining life; it describes the movement of carbon as it is recycled and reused throughout the biosphere.
  31. 31. CARBON CYCLE   The carbon cycle was initially discovered by Joseph Priestley and Antoine Lavoisier, and popularized by Humphry Davy.
  32. 32.
  33. 33. GASEOUS CYCLES  • • • • Carbon Hydrogen Oxygen Nitrogen
  34. 34. HYDROGEN  Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element and its monatomic form (H) is the most abundant chemical substance, constituting roughly 75% of the universe's baryonic mass.
  35. 35. HYDROGEN   At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Most of the hydrogen on Earth is in molecules such as water and organic compounds because hydrogen readily forms covalent compounds with most non-metallic elements.
  36. 36. HYDROGEN   The most common isotope of hydrogen is protium (name rarely used, symbol 1H) with a single proton and no neutrons. As the simplest atom known, the hydrogen atom has been of theoretical use.  Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, a property which later gave it its name: in Greek, hydrogen means "water-former".
  37. 37. HYDROGEN  Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks
  38. 38. PROPERTIES   Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume.  Hydrogen gas forms explosive mixtures with air if it is 4– 74% concentrated and with chlorine if it is 5–95% concentrated. The mixtures may be ignited by spark, heat or sunlight.
  39. 39. PROPERTIES   H2 reacts with every oxidizing element. Hydrogen can react spontaneously and violently at room temperature with chlorine and fluorine to form the corresponding hydrogen halides, hydrogen chloride and hydrogen fluoride, which are also potentially dangerous acids.
  40. 40. ELECTRON ENERGY LEVELS   The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies.
  41. 41. BOHR MODEL   In atomic physics, the Bohr model, introduced by Niels Bohr in 1913, depicts the atom as small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus— similar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity.
  42. 42. PHASES  Compressed Hydrogen Liquid Hydrogen Slush Hydrogen Solid Hydrogen Metallic Hydrogen
  43. 43. COMPRESSED HYDROGEN   Compressed hydrogen (CGH2 or CGH2) is the gaseous state of the element hydrogen kept under pressure. Compressed hydrogen in hydrogen tanks is used for mobile hydrogen storage in hydrogen vehicles. It is used as a fuel gas.
  44. 44. LIQUID HYDROGEN   Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. To exist as a liquid, H2 must be cooled below hydrogen's critical point of 33 K. However, for hydrogen to be in a full liquid state without evaporating at atmospheric pressure, it needs to be cooled to 20.28 K (−423.17 °F/−252.87°C). One common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. Liquid hydrogen is typically used as a concentrated form of hydrogen storage. As in any gas, storing it as liquid takes less space than storing it as a gas at normal temperature and pressure. However, the liquid density is very low compared to other common fuels. Once liquefied, it can be maintained as a liquid in pressurized and thermally insulated containers.
  45. 45. SLUSH HYDROGEN   Slush hydrogen is a combination of liquid hydrogen and solid hydrogen with a lower temperature and a higher density than liquid hydrogen. It is formed by bringing liquid hydrogen down to nearly the melting point (14.01 K or −259.14 °C) that increases density by 16–20% as compared to liquid hydrogen. It is proposed as a rocket fuel in place of liquid hydrogen in order to improve tankage and thus reduce the dry weight of the vehicle.
  46. 46. SOLID HYDROGEN   Solid hydrogen is the solid state of the element hydrogen, achieved by decreasing the temperature below hydrogen's melting point of 14.01 K (−259.14 °C). It was collected for the first time by James Dewar in 1899 and published with the title "Sur la solidification de l'hydrogène" in the Annales de Chimie et de Physique, 7th series, vol.18, Oct. 1899. Solid hydrogen has a density of 0.086 g/cm3 making it one of the lowest density solids.
  47. 47. METALLIC HYDROGEN   Metallic hydrogen is a state of hydrogen in which it behaves as an electrical conductor. This state was predicted theoretically in 1935, but has not been reliably produced in laboratory experiments due to the requirement of high pressures, on the order of hundreds of gigapascals. At these pressures, hydrogen might exist as a liquid rather than solid. Liquid metallic hydrogen is thought to be present in large amounts in the gravitationally compressed interiors of Jupiter and Saturn.
  48. 48. COMPOUNDS   While H2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens or oxygen; in these compounds hydrogen takes on a partial positive charge. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of medium-strength noncovalent bonding called hydrogen bonding, which is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as hydrides.
  49. 49. ISOTOPES   H1 is the most common hydrogen isotope with an abundance of more than 99.98%. Because the nucleus of this isotope consists of only a single proton, it is given the descriptive but rarely used formal name protium.
  50. 50. ISOTOPES   H2 the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in its nucleus. Essentially all deuterium in the universe is thought to have been produced at the time of the Big Bang, and has endured since that time. Deuterium is not radioactive, and does not represent a significant toxicity hazard.
  51. 51. ISOTOPES   H3 is known as tritium and contains one proton and two neutrons in its nucleus. It is radioactive, decaying into helium-3 through beta decay with a half-life of 12.32 years. It is so radioactive that it can be used in luminous paint, making it useful in such things as watches. The glass prevents the small amount of radiation from getting out. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases; tritium has also been released during nuclear weapons tests.
  52. 52. HISTORY   In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metal-acid reaction "flammable air". In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek hydro meaning water and genes meaning creator). Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask.
  53. 53. HYDRGOLOGIC CYCLE (WATER CYCLE)  The water cycle, also known as the hydrologic cycle or the H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. In so doing, the water goes through different phases: liquid, solid (ice), and gas (vapor).
  54. 54.
  55. 55. GASEOUS CYCLES  • Carbon • Hydrogen • Oxygen • Nitrogen
  56. 56. OXYGEN   Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetallic element and oxidizing agent that readily forms compounds (notably oxides) with most elements. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium At STP, two atoms of the element bind to form dioxygen, a diatomic gas that is colorless, odorless, and tasteless; with the formula O2.
  57. 57. OXYGEN   Many major classes of organic molecules in living organisms, such as proteins, nucleic acids, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that are constituents of animal shells, teeth, and bone.  Oxygen is an important part of the atmosphere, and is necessary to sustain most terrestrial life as it is used in respiration.
  58. 58. OXYGEN   Atomic Number: 8  Atomic Weight: 15.9994  Melting Point: 54.36 K (-218.79°C or -361.82°F)  Boiling Point: 90.20 K (-182.95°C or -297.31°F)  Density: 0.001429 grams per cubic centimeter  Phase at Room Temperature: Gas  Element Classification: Non-metal  Period Number: 2  Group Number: 16  Group Name: Chalcogen
  59. 59. CHALCOGEN GROUP   The chalcogens are the chemical elements in group 16 of the periodic table. This group is also known as the oxygen family. It consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and the radioactive element polonium (Po). The synthetic element livermorium (Lv) is predicted to be a chalcogen as well. Often, oxygen is treated separately from the other chalcogens, sometimes even excluded from the scope of the term "chalcogen" altogether, due to its very different chemical behavior from sulfur, selenium, tellurium and polonium. The word "chalcogen" is derived from a combination of the Greek word khalkόs principally meaning copper (the term was also used for bronze/brass, any metal in the poetic sense, ore or coin), and the Latinized Greek word genēs, meaning born or produced.
  60. 60. ALLOTROPES OF OXYGEN   The common allotrope of elemental oxygen on Earth is called dioxygen, O2.  Trioxygen (O3) is usually known as ozone and is a very reactive allotrope of oxygen that is damaging to lung tissue. Ozone is produced in the upper atmosphere when O2 combines with atomic oxygen made by the splitting of O2 by ultraviolet (UV) radiation. Since ozone absorbs strongly in the UV region of the spectrum, the ozone layer of the upper atmosphere functions as a protective radiation shield for the planet.
  61. 61. BIOLOGICAL ROLE OF OXYGEN  Photosynthesis splits water to liberate O2 and fixes CO2 into sugar in what is called a Calvin cycle.
  62. 62. BIOLOGICAL ROLE OF OXYGEN   In nature, free oxygen is produced by the light-driven splitting of water during oxygenic photosynthesis. According to some estimates, Green algae and cyanobacteria in marine environments provide about 70% of the free oxygen produced on Earth and the rest is produced by terrestrial plants. Other estimates of the oceanic contribution to atmospheric oxygen are higher, while some estimates are lower, suggesting oceans produce 45% of Earth's atmospheric oxygen each year.
  63. 63. HISTORY  Philo's experiment investigators. inspired later
  64. 64. HISTORY   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 and surrounding the vessel's neck with water resulted in some water rising into the neck. 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 Philo's work by observing that a portion of air is consumed during combustion and respiration.
  65. 65. HISTORY   In the late 17th century, Robert Boyle proved that air is necessary for combustion. English chemist John Mayow (1641–1679) refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus or just nitroaereus.  Oxygen was first discovered by Swedish pharmacist Carl Wilhelm Scheele. He had produced oxygen gas by heating mercuric oxide and various nitrates by about 1772. Scheele called the gas "fire air" because it was the only known supporter of combustion, and wrote an account of this discovery in a manuscript he titled Treatise on Air and Fire, which he sent to his publisher in 1775. However, that document was not published until 1777.
  66. 66. HISTORY   In the meantime, on August 1, 1774, an experiment conducted by the British clergyman Joseph Priestley focused sunlight on mercuric oxide (HgO) inside a glass tube, which liberated a gas he named "dephlogisticated air". He noted that candles burned brighter in the gas and that a mouse was more active and lived longer while breathing it. After breathing the gas himself, he wrote: "The feeling of it to my lungs was not sensibly different from that of common air, but I fancied that my breast felt peculiarly light and easy for some time afterwards." Priestley published his findings in 1775 in a paper titled "An Account of Further Discoveries in Air" which was included in the second volume of his book titled Experiments and Observations on Different Kinds of Air. Because he published his findings first, Priestley is usually given priority in the discovery.
  67. 67. HISTORY   The noted French chemist Antoine Laurent Lavoisier later claimed to have discovered the new substance independently. However, Priestley visited Lavoisier in October 1774 and told him about his experiment and how he liberated the new gas. Scheele also posted a letter to Lavoisier on September 30, 1774 that described his own discovery of the previously unknown substance, but Lavoisier never acknowledged receiving it.
  68. 68. COMPOUNDS OF OXYGEN  Water (H2O) is the most familiar oxygen compound.
  69. 69. INORGANIC COMPOUNDS   Water (H2O) is the oxide of hydrogen and the most familiar oxygen compound. Hydrogen atoms are covalently bonded to oxygen in a water molecule but also have an additional attraction to an adjacent oxygen atom in a separate molecule. These hydrogen bonds between water molecules hold them approximately 15% closer than what would be expected in a simple liquid with just van der Waals forces.
  70. 70. VAN DER WAALS FORCES   In physical chemistry, the van der Waals' force (or van der Waals' interaction), named after Dutch scientist Johannes Diderik van der Waals, is the sum of the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds, the hydrogen bonds, or the electrostatic interaction of ions with one another or with neutral molecules or charged molecules.
  71. 71. INORGANIC COMPOUNDS   Due to its electronegativity, oxygen forms chemical bonds with almost all other elements at elevated temperatures to give corresponding oxides. However, some elements readily form oxides at standard conditions for temperature and pressure; the rusting of iron is an example.
  72. 72. ORGANIC COMPOUNDS  Acetone is an important feeder material in the chemical industry. Oxygen (Red) Carbon (Black) Hydrogen (White)
  73. 73. ORGANIC COMPOUNDS   There are many important organic solvents that contain oxygen, including: acetone, methanol, ethanol, isopropanol, furan, THF, diethyl ether, dioxane, ethyl acetate, DMF, DMSO, acetic acid, and formic acid.  Oxygen reacts spontaneously with many organic compounds at or below room temperature in a process called autoxidation. Most of the organic compounds that contain oxygen are not made by direct action of O2.
  74. 74. ALLOTROPES OF OXYGEN  There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O3). Others include: • Atomic oxygen • Singlet oxygen • Tetraoxygen • Solid oxygen
  75. 75. ATOMIC OXYGEN   Atomic oxygen is very reactive, as the single atoms of oxygen tend to quickly bond with nearby molecules; on Earth's surface it does not exist naturally for very long, though in outer space, the presence of plenty of ultraviolet radiation results in a low-Earth orbit atmosphere of about 96% atomic oxygen.
  76. 76. SINGLET OXYGEN   Singlet oxygen is the common name used for the two metastable states of molecular oxygen (O2) with higher energy than the ground state triplet oxygen. Because of the differences in their electron shells, singlet oxygen has different chemical properties than triplet oxygen, including absorbing and emitting light at different wavelengths.
  77. 77. TETRAOXYGEN  Tetraoxygen had been suspected to exist since the early 1900s, when it was known as oxozone, and was identified in 2001 by a team led by F. Cacace at the University of Rome.
  78. 78. SOLID OXYGEN   Solid oxygen forms at normal atmospheric pressure at a temperature below 54.36 K (−218.79 °C, −361.82 °F). Solid oxygen O2, like liquid oxygen, is a clear substance with a light sky-blue color caused by absorption in the red.
  79. 79. OXYGEN CYCLE   The oxygen cycle is the biogeochemical cycle that describes the movement of oxygen within its three main reservoirs: the atmosphere (air), the total content of biological matter within the biosphere (the global sum of all ecosystems), and the lithosphere (Earth's crust). Failures in the oxygen cycle within the hydrosphere (the combined mass of water found on, under, and over the surface of a planet) can result in the development of hypoxic zones. The main driving factor of the oxygen cycle is photosynthesis, which is responsible for the modern Earth's atmosphere and life on earth .
  80. 80. THE MAIN RESERVOIRS  The reservoirs are the locations in which oxygen is found.  Biosphere (living things)  Lithosphere (Earth’s crust)  Atmosphere (air)  Hydrosphere(water)
  81. 81. STEP ONE  oxygen Plant release oxygen into the atmosphere as a by-product of photosynthesis.
  82. 82. STEP TWO   Animals take in oxygen through the process of respiration.  Animals then break down sugars and food.
  83. 83. STEP THREE   Carbon dioxide is released by animals and used in plants in photosynthesis.  Oxygen is balanced between the atmosphere and the ocean.
  84. 84. GAEOUS CYCLES  • Carbon • Hydrogen • Oxygen • Nitrogen
  85. 85. NITROGEN   Nitrogen, symbol N, is the chemical element of atomic number 7. At room temperature, it is a gas of diatomic molecules and is colorless and odorless. Nitrogen is a common element in the universe, estimated at about seventh in total abundance in our galaxy and the Solar System. On Earth, the element is primarily found as the free element; it forms about 80% of the Earth's atmosphere. The element nitrogen was discovered as a separable component of air, by Scottish physician Daniel Rutherford, in 1772.
  86. 86. Name, symbol, number Pronunciation NITROGEN  nitrogen, N, 7 /ˈ naɪtrədʒən/ NY-trə-jən Element category diatomic nonmetal Group, period, block 15 (pnictogens), 2, p Standard atomic weight Electron configuration 14.007(1) [He] 2s2 2p3 2, 5 History Discovery Daniel Rutherford (1772) Named by Jean-Antoine Chaptal (1790) Physical properties Phase Density Liquid density at b.p. gas (0 °C, 101.325 kPa) 1.251 g/L 0.808 g·cm−3 Melting point 63.15 K, −210.00 °C, −346.00 °F Boiling point 77.355 K, −195.795 °C, −320.431 °F
  87. 87. PNICTOGENS   The pnictogens are the chemical elements in group 15 of the periodic table. This group is also known as the nitrogen family. It consists of the elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and the synthetic element ununpentium (Uup) (unconfirmed).
  88. 88. HISTORY   Nitrogen is formally considered to have been discovered by Scottish physician Daniel Rutherford in 1772, who called it noxious air or fixed air.  The English word nitrogen (1794) entered the language from the French nitrogène, coined in 1790 by French chemist Jean-Antoine Chaptal (1756–1832), from the Greek "nitron" and the French gène (producing).
  89. 89. PRODUCTION   Nitrogen gas is an industrial gas produced by the fractional distillatio of liquid ai, or by mechanical means using gaseous air. Commercial nitrogen is often a byproduct of air-processing for industrial concentration of oxyge for steelmaking and other purposes. When supplied compressed in cylinders it is often called OFN (oxygen-free nitrogen).
  90. 90. PROPERTIES  Nitrogen is a nonmetal, with an electronegativity of 3.04. It has five electrons in its outer shell and is, therefore, trivalent in most compounds. The triple bond in molecular nitrogen (N2) is one of the strongest. The resulting difficulty of converting N2 into other compounds, and the ease (and associated high energy release) of converting nitrogen compounds into elemental N2, have dominated the role of nitrogen in both nature and human economic activities.
  91. 91. ISOTOPES   There are two stable isotopes of nitrogen: 15N. 14N and By far the most common is 14N (99.634%), which is produced in the CNO cycle in stars. Of the ten isotopes produced synthetically, 13N has a half-life of ten minutes and the remaining isotopes have halflives on the order of seconds or less.
  92. 92. ELECTROMAGNETIC SPECTRUM  Nitrogen tube. discharge (spectrum)
  93. 93. ELECTROMAGNETIC SPECTRUM   Molecular nitrogen (14N2) is largely transparent to infrared and visible radiation because it is a homonuclear molecule and, thus, has no dipole moment to couple to electromagnetic radiation at these wavelengths. Significant absorption occurs at extreme ultraviolet wavelengths, beginning around 100 nanometers. This is associated with electronic transitions in the molecule to states in which charge is not distributed evenly between nitrogen atoms. Nitrogen absorption leads to significant absorption of ultraviolet radiation in the Earth's upper atmosphere and the atmospheres of other planetary bodies. For similar reasons, pure molecular nitrogen lasers typically emit light in the ultraviolet range.
  94. 94. ELECTROMAGNETIC SPECTRUM   Nitrogen also makes a contribution to visible air glow from the Earth's upper atmosphere, through electron impact excitation followed by emission. This visible blue air glow (seen in the polar aurora and in the re-entry glow of returning spacecraft) typically results not from molecular nitrogen but rather from free nitrogen atoms combining with oxygen to form nitric oxide (NO).
  95. 95. NITROGEN CYCLE   The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms. This transformation 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%) is nitrogen, making it the largest pool 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 the global nitrogen cycle.
  96. 96. NITROGEN CYCLE 
  97. 97. NITROGEN FIXATION & THE NITROGEN CYCLE   In a symbiotic relationship with the soil bacteria known as 'rhizobia', legumes form nodules on their roots (or stems, see figure below) to 'fix' nitrogen into a form usable by plants (and animals). The process of biological nitrogen fixation was discovered by the Dutch microbiologist Martinus Beijerinck. Rhizobia (e.g., Rhizobium, Mesorhizobium, Sinorhizobium) fix atmospheric nitrogen or dinitrogen, N2, into inorganic nitrogen compounds, such as ammonium, NH4+, which is then incorporated into amino acids, which can be utilized by the plant. Plants cannot fix nitrogen on their own, but need it in one form or another to make amino acids and proteins. Because legumes form nodules with rhizobia, they have high levels of nitrogen available to them.
  98. 98. NITROGEN FIXATION & THE NITROGEN CYCLE   Their abundance of nitrogen is beneficial not only to the legumes themselves, but also to the plants around them. There are other sources of nitrogen in the soil, but are not always provided at the levels required by plants, making the symbiotic relationship between legumes and rhizobia highly beneficial. In return for the fixed nitrogen that they provide, the rhizobia are provided shelter inside of the plant's nodules and some of the carbon substrates and micronutrients that they need to generate energy and key metabolites for the cellular processes that sustain life (Sprent, 2001). Nodulation and nitrogen fixation by rhizobia is not exclusive to legumes; rhizobia form root nodules on Parasponis Miq., a genus of five species in the Ulmaceae.
  99. 99. NITROGEN FIXATION & THE NITROGEN CYCLE   The nitrogen cycle describes the series of processes by which the element nitrogen, which makes up about 78% of the Earth’s atmosphere, cycles between the atmosphere and the biosphere. Plants, bacteria, animals, and manmade and natural phenomena all play a role in the nitrogen cycle. The fixation of nitrogen, in which the gaseous form dinitrogen, N2) is converted into forms usable by living organisms, occurs as a consequence of atmospheric processes such as lightning, but most fixation is carried out by free-living and symbiotic bacteria. Plants and bacteria participate in symbiosis such as the one between legumes and rhizobia or contribute through decomposition and other soil reactions. Bacteria like Rhizobium, or the actinomycete Frankia which nodulates members of the plant families Rosaceae and Betulaceae, utilize atmospheric nitrogen and convert it to an inorganic form (usually ammonium, NH4+) that plants can use.
  100. 100. NITROGEN FIXATION & THE NITROGEN CYCLE   The plants then use the fixed nitrogen to produce vital cellular products such as proteins. The plants are then eaten by animals, which also need nitrogen to make amino acids and proteins. Decomposers acting on plant and animal materials and waste return nitrogen back to the soil. Human-produced fertilizers are another source of nitrogen in the soil along with pollution and volcanic emissions, which release nitrogen into the air in the form of ammonium and nitrate gases. The gases react with the water in the atmosphere and are absorbed by the soil with rain water. Other bacteria in the soil are key components in this cycle converting nitrogen containing compounds to ammonia, NH3, nitrates, NO3-, and nitrites, NO2-. Nitrogen is returned back to the atmosphere by denitrifying bacteria, which convert nitrates to dinitrogen gas.
  101. 101. NITRIFICATION  oxidation of ammonia  Nitrification is the biological with oxygen, then into ammonium, then into nitrite followed by the oxidation of these nitrites into nitrates. Degradation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil. This process was discovered by the Russian microbiologist, Sergei Winogradsky.
  102. 102. NITRIFICATION   The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). AOB can be found among the β-proteobacteria and gammaproteobacteria. Currently, only one AOA, Nitrosopumilus maritimus, has been isolated and described. In soils the most studied AOB belong to the genera Nitrosomonas and Nitrosococcus. Although in soils ammonia oxidation occurs by both AOB and AOA, AOA dominate in both soils and marine environments, suggesting that Thaumarchaeota may be greater contributors to ammonia oxidation in these environments.
  103. 103. NITRIFICATION   The second step (oxidation of nitrite into nitrate) is done (mainly) by bacteria of the genus Nitrobacter. Both steps are producing energy to be coupled to ATP synthesis. Nitrifying organisms are chemoautotrophs, and use carbon dioxide as their carbon source for growth.
  104. 104. ASSIMILATION   Plants take nitrogen from the soil, by absorption through their roots in the form of either nitrate ions or ammonium ions. All nitrogen obtained by animals can be traced back to the eating of plants at some stage of the food chain.
  105. 105. ASSIMILATION   Plants can absorb nitrate or ammonium ions from the soil via their root hairs. If nitrate 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 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 is carefully regulated in all organisms.
  106. 106. AMMONIFICATION   The term ammonification can be defined as impregnation with ammonia or a compound of ammonia. It is the process in which pure forms of nitrogen are converted to ammonium by decomposers or bacteria. When a plant or animal dies, or an animal expels waste, the initial form of nitrogen is organic. Bacteria, or fungi in some cases, convert the organic nitrogen within the remains back into ammonium (NH4+), a process called ammonification or mineralization.
  107. 107. DENITRIFICATION   Denitrification is a microbially facilitated process of nitrate reduction that may ultimately produce molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products.  This respiratory process reduces oxidized forms of nitrogen in response to the oxidation of an electron donor such as organic matter. The preferred nitrogen electron acceptors in order of most to least thermodynamically favorable include nitrate (NO3−), nitrite (NO2−), nitric oxide (NO), nitrous oxide (N2O) finally resulting in the production of dinitrogen (N2) completing the nitrogen cycle.
  108. 108. DENITRIFICATION   The process is performed primarily by heterotrophic bacteria (such as Paracoccus denitrificans and various pseudomonads), although autotrophic denitrifiers have also been identified (e.g., Thiobacillus denitrificans). Denitrifiers are represented in all main phylogenetic groups. Generally several species of bacteria are involved in the complete reduction of nitrate to molecular nitrogen, and more than one enzymatic pathway have been identified in the reduction process.
  109. 109. SEDIMENTARY CYCLES  • Phosphorus • Sulfur
  110. 110. PHOSPHORUS  Appearance colourless, waxy white, yellow, scarlet, red, violet, black waxy white (yellow cut), red (granules centre left, chunk centre right), and violet phosphorus General properties Name, symbol, number Pronunciation Element category Group, period, block Standard atomic weight Electron configuration phosphorus, P, 15 /ˈf sfərəs/ FOS-fər-əs ɒ polyatomic nonmetal sometimes considered a metalloid 15 (pnictogens), 3, p 30.973761998(5) [Ne] 3s2 3p3 2, 8, 5 History Discovery Recognized as an element by Hennig Brand (1669) Antoine Lavoisier (1777) Physical properties Phase Density (near r.t.) Melting point Sublimation point Boiling point solid (white) 1.823, (red) ≈ 2.2 – 2.34, (violet) 2.36, (black) 2.69 g·cm−3 (white) 44.2 °C, (black) 610 °C (red) ≈ 416 – 590 °C, (violet) 620 °C (white) 280.5 °C
  111. 111. PHOSPHORUS   Phosphorus is a nonmetallic chemical element with symbol P and atomic number 15. A multivalent pnictogen, phosphorus as a mineral is almost always present in its maximally oxidised state, as inorganic phosphate rocks. Elemental phosphorus exists in two major forms—white phosphorus and red phosphorus— but due to its high reactivity, phosphorus is never found as a free element on Earth.
  112. 112. PHOSPHORUS   The first form of elemental phosphorus to be produced (white phosphorus, in 1669) emits a faint glow upon exposure to oxygen – hence its name given from Greek mythology, meaning "lightbearer" (Latin Lucifer), referring to the "Morning Star", the planet Venus. The term "phosphorescence", meaning glow after illumination, originally derives from this property of phosphorus, although this word has since been used for a different physical process that produces a glow. The glow of phosphorus itself originates from oxidation of the white (but not red) phosphorus— a process now termed chemiluminescence.
  113. 113. PHOSPHORUS   The vast majority of phosphorus compounds are consumed as fertilizers. Other applications include the role detergents, of organophosphorus pesticides and compounds nerve agents, in and matches.  Phosphorus is essential for life. As phosphate, it is a component of DNA, RNA, ATP, and also the phospholipids that form all cell membranes.
  114. 114. DNA   Deoxyribonucleic acid (DNA) is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. DNA is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. Most DNA molecules are double-stranded helices, consisting of two long biopolymers made of simpler units called nucleotides—each nucleotide is composed of a nucleobase (guanine, adenine, thymine, and cytosine), recorded using the letters G, A, T, and C, as well as a backbone made of alternating sugars (deoxyribose) and phosphate groups (related to phosphoric acid), with the nucleobases (G, A, T, C) attached to the sugars.
  115. 115. RNA   Ribonucleic acid (RNA) is a ubiquitous family of large biological molecules that perform multiple vital roles in the coding, decoding, regulation, and expression of genes. Together with DNA, RNA comprises the nucleic acids, which, along with proteins, constitute the three major macromolecules essential for all known forms of life. Like DNA, RNA is assembled as a chain of nucleotides, but is usually singlestranded. Cellular organisms use messenger RNA (mRNA) to convey genetic information (often notated using the letters G, A, U, and C for the nucleotides guanine, adenine, uracil and cytosine) that directs synthesis of specific proteins, while many viruses encode their genetic information using an RNA genome.
  116. 116. ATP   Adenosine triphosphate (ATP) is a nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism. It is one photophosphorylation, of the cellular end products respiration, of and fermentation and used by enzymes and structural proteins in many cellular processes, including biosynthetic reactions, motility, and cell division.
  117. 117. WHITE PHOSPHORUS   The most important form of elemental phosphorus from the perspective of applications and the chemical literature is white phosphorus.  White phosphorus is the least stable, the most reactive, the most volatile, the least dense, and the most toxic of the allotropes. White phosphorus gradually changes to red phosphorus. This transformation is accelerated by light and heat, and samples of white phosphorus almost always contain some red phosphorus and accordingly appear yellow. For this reason it is also called yellow phosphorus. It glows in the dark (when exposed to oxygen) with a very faint tinge of green and blue, is highly flammable and pyrophoric (self-igniting) upon contact with air and is toxic (causing severe liver damage on ingestion).
  118. 118. RED PHOSPHORUS   Red phosphorus is polymeric in structure. It can be viewed as a derivative of P4 wherein one P-P bond is broken, and one additional bond is formed with the neighboring tetrahedron resulting in a chain-like structure. Red phosphorus may be formed by heating white phosphorus to 250 °C (482 °F) or by exposing white phosphorus to sunlight. Phosphorus after this treatment is amorphous.
  119. 119. VIOLET PHOSPHORUS   Violet phosphorus is a form of phosphorus that can be produced phosphorus by above day-long 550 °C. annealing In 1865, of red Hittorf discovered that when phosphorus was recrystallized from molten lead, a red/purple form is obtained. Therefore this form is sometimes known as "Hittorf's phosphorus" (or violet or α-metallic phosphorus).
  120. 120. BLACK PHOSPHORUS   Black phosphorus is the least reactive allotrope and the thermodynamically stable form below 550 °C. It is also known as β-metallic phosphorus and has a structure somewhat resembling that of graphite. High pressures are usually required to produce black phosphorus, but it can also be produced at ambient conditions using metal salts as catalysts.
  121. 121. HISTORY   Phosphorus was the 13th element to be discovered. For this reason, and also due to its use in explosives, poisons and nerve agents, it is sometimes referred to as "the Devil's element". It was the first element to be discovered that was not known since ancient times.
  122. 122. HISTORY  The discovery of phosphorus is credited to the German alchemist Hennig Brand in 1669, although other chemists might have discovered phosphorus around the same time. Brand experimented with urine, which contains considerable quantities of dissolved phosphates from normal metabolism. Working in Hamburg, Brand attempted to create the fabled philosopher's stone through the distillation of some salts by evaporating urine, and in the process produced a white material that glowed in the dark and burned brilliantly. It was named phosphorus mirabilis ("miraculous bearer of light"). His process originally involved letting urine stand for days until it gave off a terrible smell. Then he boiled it down to a paste, heated this paste to a high temperature, and led the vapours through water, where he hoped they would condense to gold. Instead, he obtained a white, waxy substance that glowed in the dark. Brand had discovered phosphorus.
  123. 123. BIOLOGICAL ROLE   DNA and RNA where it forms part of the structural framework of these molecules. Living cells also use phosphate to transport cellular energy in the form of adenosine triphosphate (ATP). Nearly every cellular process that uses energy obtains it in the form of ATP. ATP is also important for phosphorylation, a key regulatory event in cells. Phospholipids are the main structural components of all cellular membranes. Calcium phosphate salts assist in stiffening bones.
  124. 124. BIOLOGICAL ROLE   An average adult human contains about 0.7 kg of phosphorus, about 85–90% of which is present in bones and teeth in the form of apatite, and the remainder in soft tissues and extracellular fluids (~1%). The phosphorus content increases from about 0.5 weight% in infancy to 0.65–1.1 weight% in adults. Average phosphorus concentration in the blood is about 0.4 g/L, about 70% of that is organic and 30% inorganic phosphates.
  125. 125. PHOSPHORUS CYCLE   The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth. The production of phosphine gas occurs only in specialized, local conditions.
  126. 126. PHOSPHORUS CYCLE 
  127. 127. EXPLANATION OF THE PHOSPHORUS CYCLE  Like water, carbon, oxygen, and nitrogen, phosphorus must be cycled in order for an ecosystem to support life. The phosphorus cycle is the movement of phosphorus indifferent chemical forms from the surroundings to organisms and then back to the surroundings. Phosphorus is often found in soil and rock as calcium phosphate which dissolves in water to form phosphate. The roots of plants absorb phosphate. Humans and animals that eat the plants reuse the organic phosphate. When the humans and animals die, phosphorus is returned to the soil.
  128. 128. SEDIMENTARY CYCLES  • Phosphorus • Sulfur
  129. 129. SULFUR   Sulfur or sulphur (British English) is a chemical element with symbol S and atomic number 16. It is an abundant, multivalent nonmetal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow crystalline solid when at room temperature. Chemically, sulfur can react as either an oxidant or reducing agent. It oxidizes most metals and several nonmetals, including carbon, which leads to its negative charge in most organosulfur compounds, but it reduces several strong oxidants, such as oxygen and fluorine.
  130. 130. PHYSICAL PROPERTIES   Sulfur forms polyatomic molecules with different chemical formulas, with the best-known allotrope being octasulfur, cyclo-S8. Octasulfur is a soft, brightyellow solid with only a faint odor, similar to that of matches. It melts at 115.21 °C, boils at 444.6 °C and sublimes easily.
  131. 131. CHEMICAL PROPERTIES   Sulfur burns with a blue flame concomitant with formation of sulfur dioxide, notable for its peculiar suffocating odor. Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene.
  132. 132. ALLOTROPES  The structure of the cyclooctasulfur molecule, S8.
  133. 133. ALLOTROPES   Amorphous or "plastic" sulfur is produced by rapid cooling of molten sulfur—for example, by pouring it into cold water. X- ray crystallography studies show that the amorphous form may have a helical structure with eight atoms per turn. The long coiled polymeric molecules make the brownish substance elastic, and in bulk this form has the feel of crude rubber. This form is metastable at room temperature and gradually reverts to crystalline molecular allotrope, which is no longer elastic. This process happens within a matter of hours to days, but can be rapidly catalyzed.
  134. 134. X-RAY CRYSTALLOGRAPHY  X-ray crystallography is a method used for determining the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of X-rays to diffract into many specific directions.
  135. 135. ISOTOPES   Sulfur has 25 known isotopes, four of which are stable: 32S (95.02%), (0.02%). Other than 33S (0.75%), 35S, 34S (4.21%), and 36S with a half-life of 87 days and formed in cosmic ray spallation of 40Ar, the radioactive isotopes of sulfur have half-lives less than 170 minutes.
  136. 136. NATURAL OCCURRENCE  Most of the yellow and orange hues of Io are due to elemental sulfur and sulfur compounds, produced by active volcanoes. Native sulfur crystals
  137. 137. NATURAL OCCURRENCE   Sulfur, usually as sulfide, is present in many types of meteorites. Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. It is normally present as troilite (FeS), but there are exceptions, with carbonaceous chondrites containing free sulfur, sulfates and other sulfur compounds. The distinctive colors of Jupiter's volcanic moon Io are attributed to various forms of molten, solid and gaseous sulfur.
  138. 138. NATURAL OCCURRENC E   On Earth, elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire; such volcanic deposits are currently mined in Indonesia, Chile, and Japan. Such deposits are polycrystalline, with the largest documented single crystal measuring 22×16×11 cm. Historically, Sicily was a large source of sulfur in the Industrial Revolution.
  139. 139. HISTORY   Being abundantly available in native form, sulfur (Latin sulphur) was known in ancient times and is referred to in the Torah (Genesis). English translations of the Bible commonly referred to burning sulfur as "brimstone", giving rise to the name of 'fire-and-brimstone' sermons, in which listeners are reminded of the fate of eternal damnation that await the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur" (likely due to its association with volcanic activity).
  140. 140. HISTORY   In 1777, Antoine Lavoisier helped convince the scientific community that sulfur was an element, not a compound. With the sulfur from Sicily being principally controlled by the French market, a debate ensued about the amount of sulfur France and Britain got. This led to a bloodless confrontation between the two sides in 1840. In 1867, sulfur was discovered in underground deposits in Louisiana and Texas. The highly successful Frasch process was developed to extract this resource.
  141. 141. FRASCH PROCESS   The Frasch process is a method to extract sulfur from underground deposits. It is the only economic method of recovering sulfur from elemental deposits. Most of the world's sulfur was obtained this way until the late 20th century, when sulfur recovered from petroleum and gas sources (recovered sulfur) became more commonplace.
  142. 142. HISTORY   In the late 18th century, furniture makers used molten sulfur to produce decorative inlays in their craft. Because of the sulfur dioxide produced during the process of melting sulfur, the craft of sulfur inlays was soon abandoned. Molten sulfur is sometimes still used for setting steel bolts into drilled concrete holes where high shock resistance is desired for floor-mounted equipment attachment points. Pure powdered sulfur was used as a medicinal tonic and laxative. With the advent of the contact process, the majority of sulfur today is used to make sulfuric acid for a wide range of uses, particularly fertilizer.
  143. 143. BIOLOGICAL ROLE   Sulfur is an essential component of all living cells. It is the seventh or eighth most abundant element in the human body by weight, being about as common as potassium, and a little more common than sodium or chlorine. A 70 kg human body contains about 140 grams of sulfur.
  144. 144. MAIN EFFECTS ON CLIMATE   The main direct effect of sulfates on the climate involves the scattering of light, effectively increasing the Earth's albedo. The effect is strongly spatially non-uniform, being largest downstream of large industrial areas.
  145. 145. MAIN EFFECTS ON CLIMATE   The first indirect effect is also known as the Twomey effect. Sulfate aerosols can act as cloud condensation nuclei and this leads to greater numbers of smaller droplets of water. Lots of smaller droplets can diffuse light more efficiently than just a few larger droplets.
  146. 146. TWOMEY EFFECT   Twomey effect — describes how cloud condensation nuclei (CCN), possibly from anthropogenic pollution, may increase the amount of solar radiation reflected by clouds. This is an indirect effect.
  147. 147. MAIN EFFECTS ON CLIMATE   The second indirect effect is the further knock-on effects of having more cloud condensation nuclei. It is proposed that these include the suppression of drizzle, increased cloud height, to facilitate cloud formation at low humidities and longer cloud lifetime. Sulfate may also result in changes in the particle size distribution, which can affect the clouds radiative properties in ways that are not fully understood. Chemical effects such as the dissolution of soluble gases and slightly soluble substances, surface tension depression by organic substances and accommodation coefficient changes are also included in the second indirect effect.
  148. 148. SULFUR CYCLE   The sulfur cycle is the collection of processes by which sulfur moves to and from minerals (including the waterways) and living systems. Such biogeochemical cycles are important in geology because they affect many minerals. Biogeochemical cycles are also important for life because sulfur is an essential element, being a constituent of many proteins and cofactors.
  149. 149. SULFUR CYCLE 
  150. 150. SULFUR CYCLE 
  151. 151. STEPS OF SULFUR CYCLE   The cycle begins with the weathering of rocks, which releases stored sulfur.  Sulfur comes into contact with the air, converting it to sulfate (SO4).  Sulfate is taken up by plants and microorganisms and is changed to organic form.  Sulfur moves up the food chain.  When organisms die, some of the sulfur is released back to sulfate and enter microorganisms.
  152. 152. STEPS OF SULFUR CYCLE   Natural sources emit sulfur into the air.  Sulfur eventually settles back to the Earth or comes through rainfall, with some also going to the ocean.  Sulfur is also drained to rivers and lakes, eventually to the oceans.  Some of the sulfur from oceans go back to the atmosphere through the sea spray.  Remaining sulfur go to ocean floor and form ferrous sulfide, which is responsible for the black color of most marine sediments.
  153. 153. EFFECTS OF SULFUR CYCLE ON NATURE   Sulfur is one of the processes that allow natural weathering and other natural processes.  Sulfur Cycle does not allow acid rains because it regulates the amount of sulfur present in the atmosphere, hydrosphere, and lithosphere.  Sulfuric acid forms sulfuric acid smog when it mixes with water vapor.
  154. 154. EFFECTS OF HUMAN PROGRESS ON THE SULFUR CYCLE   Human activities since the start of the Industrial Revolution contributed to most of the sulfur that enters the atmosphere. One-third of all sulfur that reaches the atmosphere comes from human activities.  Emissions from human activities react to produce sulfate salts that create acid rain.  Sulfur dioxide aerosols absorb ultraviolet rays, which cools areas and offsets global warming caused by greenhouse effect.