Biogeochemical Cycle: SulfurBy Jeff Roberge

IntroductionBiogeochemical Cycle- the cycle of matter through the Earth since:Earth is a closed systemAll matter is conservedAll matter cycles (since none is destroyed)Cycle consists mostly of macronutrientsC, H2O, O, N, P, S, K, Na, Fe, MgBut also of Micronutrients (B, Cu, Mo)(Introduction)

IntroductionFlow of a chemical through certain subdivisionsAtmosphereLithosphereHydrosphereBiosphereUsually of Elements

(Institute)

IntroductionSulfur- S, it is an elementNaturally found in earthAt room temp., it is a solidPresent in proteins, amino acids, vitamins, and enzymes, necessary for plants and animalsOften reacts with hydrogen creating hydrogen sulfideCan dissolve in waterWith metals in water, forms metal sulfides;sulfates in air(Sulfur)

Sulfur Cycle(Part IV)

Sulfur CycleIn ground: most found in rocks, or salt in earth, or as sediment at bottom of oceanFound as S, H2S, SO4-2, (NH4)2SO4Enter ground: Plants absorb, or left by acid deposition (fog or precipitation)As SO4-2, (NH4)2SO4, and then turn H2S by bacteria, decay, and plant useStored: Ground, rock, ocean, somewhat in air(Oxygen)

Sulfur CycleSulfur is transferred into biosphere then back into ground, or from ground to atmosphereMicroorganisms turn it into H2S (gas) Oxidized in atmosphere to SO2, and then to H2SO4 (an acid) with water contactMined ores released to atmosphere in factories as H2S and SO2Volcanoes and hot springs

Sulfur CycleDeposited next in waterThrough precipitation, dry deposition, leachingRainfall= deposited 73E12 grams sulfur in 1960SO4-2 leaches from soil into ocean as sedimentH2SO4 falls into oceanDimethyl Sulfide, carbonyl sulfide (biogenic gases), released by plankton returns back into atmosphere (turns into SO2)Either re-evaporated, left as sediment for long time, or deposited on land 20E12 grams of sulfur a year deposited on land by seaWhen back on land, cycle repeats

Driving ForceDriven by: constant addition of sulfur to environment by earths interior (geosphere)Human disturbance, addition of sulfur to atmosphere, (also dug up from environment)Natural processes (incl. Biological, hydrological, due to suns energy)Plant uptake, microbes (Desulfovibrio sp. or Desulfotomaculum sp.)(A Black Smoker)

Percentages of SulfurCommon in ground as FeS2Reservoirs (in 10E18 grams of sulfur):Oceanic Rocks= 2375 (accurate to 820)Sediment= 7800 (accurate to 1700)Freshwater= .003 (accurate to .002)Ice= .006 (accurate to .002)Atmosphere= 3.6Sea= 1280 (accurate to 55)Organic= .00562http://www.soils.wisc.edu/soils/courses/451/20b.%20Global%20S%20cycle.ppt (Sulfur Cycle)

Percentages of SulfurMost sulfur in particulate formTherefore it is a sedimentary cycleVery short residence time in atmosphere (1-2 days)Even in atmosphere, found as aerosols (

Human EffectWhen mine ores, sulfur/sulfides released into soilCombustion of fossil fuelsRelease of SO2, causes acid rain, increases amount already present28% of sulfur in rivers from pollution, mining, erosion, etc.Help move cycle but also upset balance- too much S means acid rainHydrodesulphurization (refine hydrocarbons)- surplus of S in Alberta Canada(Arial)(Sulfur Mining)

ConclusionSulfur Cycle is important to biological and natural processes although humans role impacts nature in a negative wayDriving force for life, supported first life

Works CitedA Black Smoker Venting. NOAA. 17 Nov. 2008 .Arial Photograph of Eggborough Power Station. June 2005. 17 Nov. 2008 .Institute for Computational Earth System Science. 1 March 2005. University of California. 17 Nov. 2008 .Introduction to Biogeochemical Cycles Chapter 4. 26 Jan. 1998. University of Colorado at Boulder. 17 Nov. 2008 .Oxygen Family. 2008. Advameg Inc. 17 Nov. 2008 .Part IV of "Matter cycles": The sulfur cycle. 2006. Lenntech Water Treatment and Air Purification. 17 Nov. 2008 .Sulfur. AK Collectibles. 17 Nov. 2008 .Sulfur Cycle. University of Wisconsin: Department of Soil Science. 17 Nov. 2008 .Sulfur Mining. 2008. Microsoft. 17 Nov. 2008 .