SULFUR CYCLE Group 5 Rey D. Abelita William Arcilla Jesher Arsenio Emma Fernandez Issa Maslog
AN INTRODUCTION – WHAT SULFUR IS• Sulfur (Sulphur in UK) is a member of Group VIA-> same as oxygen. Its name was derived from soufre, an Old French word which means “to burn”.• Antoine Lavoisier-> Helped convinced the Scientific Comm. That Sulfur = an element not a compound.• Oxygen unlike Sulfur, is in the second period, hence, no d orbitals.• The d orbitals allows additional electrons to be accommodated = six bonds instead of Oxygen’s two bonds.
AN INTRODUCTION – SULFUR AND ITS IMPORTANCE • In humanity, it is produced most specially in industries where it is used as solvent, catalyst and reactant to produce different organic compounds. (H2SO4) • In ecosystems as a whole, no matter what form (SO 2, H2SO4, H2S), Sulfur in its soluble form ===>plants ==>series of metabolic processes. ( starts photosynthesis) ---> Sulfur-bearing amino acids. • Sulfur -> Helps retain cellular structure; provides chemical links that creates collagen and keratin; Activator of minerals and vit.; • Sulfur (in protein assembly and structure) bonds-> known as disulfide bonds- > plays an important role. • Sulfur is also an important component of diff. enzymes such as coenzyme A, and of standard amino acids such as Cysteine. • Producers -------> Consumers [Sulfur in Amino Acids]
THE SULFUR CYCLE• The sulfur cycle gaseous and sedimentary phases.• As an introductory note -> The long term sedimentary phase, Sulfur is tied up in organic and inorganic deposits, released by weathering and decomposition.• The gaseous phase permits the circulation on a global scale. [to be expound later]• Their main difference is in their exchange sites/ sites of occurrence. Sedimentary phase is mainly on the Earth’s surface (i.e rocks, sediments, etc.) while the gaseous form is on the atmosphere.• Reservoir: Oceans (aerosol/SO 4) ===> (CH3)2S, Atmosphere (Sulfur Dioxide, Hydrogen Sulfide and Sulfates) , Organic and Inorganic Deposits (Sedimentary Rocks, Igneous Rocks such as pyrite or FeS 2.)• Exchange Pools: Hot Springs, Geysers, Surfaces of the Ocean,, Fossil Fuel Combustion, Volcanoes, Decomposing Matter
• Sedimentary cycle • Weathering of rock and leaching of its minerals, transport, deposition and burial.• Gaseous Cycle • A biogeochemical cycle with the main reservoir or pool of nutrients in the atmosphere and ocean
SULFUR ENTERS THE BIOSPHERE THROUGH • Natural Activity Carried through Weathering of rocks terrestrial environments and decomposition in salt solution. Consumers Plants
SULFUR ENTERS THE ATMOSPHERE THROUGH• Natural Activity • Human Activity Volcanic eruptions, Burning of fossil gases released by fuels, acidic drainage decomposition from mines Enters atmosphere as H2S and reacts with oxygen to form SO2
SO2 is soluble in Acid rain (H2SO4) H2Oconsumers plants
Death of Sulfur to the consumers atmosphere Ponds, lakes,seas and oceans soil
Different kinds of bacteria process this sulfur Non-photosynthetic photosyntheticColorless sulfur Purple bacteria bacteria Green bacteria
Sulfate particles become part of dry deposition. (DRYFALL) Gaseous forms combines with moisture and are transported in precipitation.(WETFALL)
Oceans Large sources of aerosols that contain sulfate(SO4) Most are redeposited in oceans as precipitation and dryfall. Dimethylsulfide((CH3)2S) major gas emitted from oceans Estimated 16 x1012 grams S/year is emitted
Freshwater wetlands and anoxic soils Hydrogen sulfide (H2S) Forest fires 3 x 1012 grams/year Marine Plants 130 x 1012 grams/year Volcanic activity 10 x 1012 grams S/year
Eruption of Mt. Pinatubo (1991)release on theorder of 5 to 10 x 1012 grams Sulfur
Adding all anaerobic oxidation of organic matter 200 x 1012 grams/year
Since the Industrial Revolution, humanactivities have contributed to the amount ofsulfur that enters the atmosphere, primarily through the burning of fossil fuels and the processing of metals.
What exactly are we doing? Burn sulfur-containing coal and oil to produce electric power. Refine sulfur-containing petroleum to make gasoline, heating oil, and other useful products. Convert sulfur-containing metallic mineral ores into free metals such as copper, lead, and zinc. Mining erosion (exposure of mineral sulfides)
Emissions from these, along with nitrogen emissions, react with chemicals in the atmosphere SULFATE SALTS ACID RAIN Damage the natural environment(affects both plants and animals) as well as man-made environmentsweathering/corrosion of buildings
Dry Deposition Gaseous sulfur dioxide component of the sulfur cycle and the nitrogen oxides of the nitrogen cycle mix in the atmosphere. Some of this mixture returns to the Earth as particulate matter and airborne gases, known as dry deposition
Effects For humans, it irritates the respiratory tract, from the nose then moves into the lungs and attacks sensitive tissues. High concentrations have caused a number of air-pollution disasters characterized by higher than expected death rates and increased incidences of bronchial asthma.
Wet deposition Major portion of D.D. is transported away from the source in a direction influenced by the atmospheric circulation. During their transport, sulfur dioxide and nitrogen dioxide and their oxidative products participate in complex reactions involving hydrogen chloride and other compounds, oxygen and water vapor. These reactions dilute solutions of strong acids (nitric and sulfuric acids). Eventually they come to earth in acidic rain, snow and fog. Sulfur dioxide combines with atmospheric moisture to form sulfuric acid which falls on land and water and forms significant part of acid rain
Effects Causes major damage to vegetation in areas surrounding the source of emission Injures or kills exposed plants Acidic aerosols present during periods of fog, light rain and high relative humidity together with moderate temperatures do the injury. External surfaces of the leaves absorb the aerosols. When dry, leaves and needles take up sulfur dioxide through the stomata. In the leaf, the sulfur dioxide rapidly reacts with moisture forming sulfuric acid.
Symptoms to sulfur damage are a bleached look to deciduousleaves and red-brown needs onconifers, partial defoliation and reduced growth.
Nutrient deficient soils Acid rain low pH level of soil nutrient leaching reduce solubility and availability (macronutrients) and high availability of micronutrients (Al, Fe, Manganese toxicity) inhibits fungal and bacterial activity reduce humus production, mineralization and fixation of nutrients
Low pH level Nutrient Acid Rain of soil leaching Affects activity of Low: Macro High toxicitymicroorganis High: Micro msReduced humus Nutrient production,mineralization and nutrient fixation deficient soils
In water… Sulfate and nitrogen ions replace bicarbonate ions, pH declines, and the concentration of metallic ions, especially aluminum, increases. Although adult fish and some aquatic organisms can tolerate high acidity, a combination of high acidity and high level of aluminum can kill them.
Eggs and larvae of frogs and salamanders are sensitive to acidic water. Cause decline in amphibians/increased rate of mortality. Acidic waters – toxic to invertebrates either killing them directly or interfering with calcium metabolism (causing crustaceans to lose the ability to recalcify their shells after molting)