Environmental Systems ENVS 2150
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Joey Harber MD
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This 38 page Class Notes was uploaded by Joey Harber MD on Wednesday September 30, 2015. The Class Notes belongs to ENVS 2150 at Western Michigan University taught by Johnson Haas in Fall. Since its upload, it has received 31 views. For similar materials see /class/216912/envs-2150-western-michigan-university in Environmental Studies at Western Michigan University.
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Date Created: 09/30/15
Like N S can form gaseous and dissolved aqueous chemical species 4 3029 3 elemental sulfur solid Pleduced by VOlcanoes 21 sulfide dissolve can bond with metals to form minerals ie FeS2 39 39 pyrite ZnS sphalerite PbS galena 59427 3 sulfate dissolved H28 by free radicals in the atmosphere OH 302 sulfur dioxide gas HZS hydrogen sul de gas Also produced by burning fossil fuels mainly COAL Down from 6 V IQQC Change mainly due to US amendments to the Clean Air oxidation w w Act in 1990 V Fall of USSR also reduced amount ofS output from industrial coal burning European Union EU has tightened limits on S emissions from coal burning TierI39mquot lot continue Fhiva s use cfcoafi s inclewng bu with no S Emlo loil control 8029 Microbial Sulfate Reduction Rapidly oxidizes in the atmosphere forming lIZSO4 Sulfuric acid Anaerobic bacteria can use sulfate in seawater as a source ij m add deg 07 add rain ngoxidizing energy to convert metabolize organic matterto 2 I rb lry If t r V t I a Ihese bacteria are common in organicrich mud in coastal A r 0 H V I rs U3 w Jen lnxtlon owu UIILcCIQIF CuchIJpP u du 1e It r Y H II t Forms pa aerosols Can scatter sunlight cooling the Earth s surface 804239 2 CHZO 2H gt H28g 2002g 2HZO energy Can contribute to cloud formation droplet nucleation Iquot 39 39 E Iquot Dimethyl Sulfide DMS Production quot Marine algae produce dimethyl sulfide DMS as a waste product CH380H3 Plankton probably produce DMS as a regulator of cellular osmotic balance Oxidized to SO2 in the atmosphere Formation of Pyrite FeSz quot Anaerobic sulfatereducing bacteria can also reduce Felll n In organicrich marine sediments the action of these bacteria can result in the formation of dissolved Fe and H28 or 8239 88042 2Fe203hematite 15 CHZO 16H gt 4FeS2pyrite 15002 23H2O Important on a global basis Estuarine and marine sediments Formation of mineral pyrite sequesters Fe and S in sediments w Net reaction consumes Pic matte am produces 602 quotth no net 02 consu notes higher 02 iei AND higher 002 levels Microbial Hydrogen Sulfide Oxidation v Aerobic bacteria that use volcanic or geothermal H28 and sunlight to fix carb on a Photosynthetic green and purple sulfur bacteria H2Sg 20029 2H2O light gt 30427 2 CH2O 2H a Chromatium Thiocapsa ThiospiriIum Ectothiorhodospira Or nonphotosynthetic sulfide oxidizing bacteria HZS9 2029 gt 804239 2H Weathering of Pyrite FeSZ v Aerobic bacteria can respire and fix carbon by oxidizing pyrite Thiobacilus Acidothiobacilus 4Fe82pyrite 15CO2 23HZO gt 88042 2Fe203hematite 15 CH2O 16H Occurs when pyriterich sediments are uplifted and weathered BUT weathering would normally occur much later than burial 10s to 100s of millions of years later so Can result in global drops in CO with no consequent OZ producquot n Promote owequot 02 levels AND lower 02 eye39s Biological Sulfur Transformations Prelndustrial 8 Cycle from Chameides and Perdue 1997 o Weathering of Pyrite FeSz Environmental Effects The net reaction 4FeSZpyrite 15002 23H2O gt 88042 2Fe203hematite 15 CHZO 16H Produces four moles of acid per mole of weathered pyrite In natural weathering lowpyrite rocks are slowly weathered and thus do not yield significant acidification of soils rivers But mining for highconcentration pyrite rocks produces large amounts of exposed pyrite in one place Pyrite weathering in air Wholesale acid production Acid Mine Drainage Prelndustrial 8 Cycle from Chameides and Perdue 1997 Prelndustrial 8 Cycle from Chameides and Perdue 1997 Welamp Dry 5 39 Welamp Dry v ulcanues 2 1 my Reduced Sediments Pyrite 4800000000 Tg PreIndustrial 8 Cycle from Chameides and Perdue 1997 PreIndustrial 8 Cycle from Chameides and Perdue 1997 Atmospheric t N 39 Atmospheric 32 T9 L 32 T9 H mm Oceanic Oceanic Sulfur Sulfur 1600000000 T9 7 1500000000 Tg Hwy Pints quot Mute Oxidized Sediments 2 mm Oxidized Sedimems at mm Gypsum quot 39 Gypsum quot 39 Reduced Reduced CaSO 2HZO Sedimems casoi ZHzo Sediments 6400 00000 Tg Pym mm minimquot 6400 00000 Tg Pym 4000000000 Tg WW 4000000000 Tg Major Geochemical Oceanic Structure Accumulations ofwater above oceanic crustal plates also along lowlying edges of continental plates Shallow ocean along passive continental margins where sediments can collect on continental edges I Tectonics governs cycling of rock solid earth materials Deepest regions ofthe ocean correspond with trenches at active subduction zones Atmosphere medium for gasphase transport 0 cean floor a vast plain essentially featureless geologically exceptions being midocean ri volcanic features intraplate volcanic activity hotspots Oceans predominant water reservoir on Earth medium for d Issolved chemical transport may also mediate continuation of tectonic system Driving Energy Sources Tectonics Earth s interior heat from radioactive decay OceansAtmosphere solar radiation Oceanic Structure mm Sunlgm zone Ocean depth Average depth 3700 meters Mariana Trench 11033 m In comparison Mt Everest is 8850 m above sea level Deepest point in Atlantic Ocean Puerto Rico trench 8648 m Indian Ocean Java trench 7125 m Ocean water temperature Lowest is about 2 C in polar waters Equatorial surface waters can reach about 30 C Salinity 35 per mil dissolved solids 35 salts by weight Mostly NaCI Na CI39 SO43 Ca3 Mgit K make up 99 of dissolved ocean salts Ocean Water Composition Sources of sea salts Chemical weathering of oceanic crust material basalt Minor contribution from continental crustal weathering most dissolved components from continental weathering are deposited on sea oor as sediments eventually subducted Hydrothermal activity at midocean rifts volcanic heating of water in ocean crust dissolves salts minerals released into oceans from hot springs at seafloor Ancient oceans geologic evidence suggests ocean water has been fair1y constant in composition through geologic time with only minor variations Mg Ca ratio has changed mainly due to increases and decreases in rate of midocean volcanism Ocean Circulation Surface currents winddriven prevailing regional winds drive movement of shallow ocean water Direct in uence if wind only down to 100200 in Driving force imparted to water can extend down to 1 km or more Upwelling currents a type of winddriven current that significantly influences ocean biological productiVIty Occur where prevailing winds drive surface ocean water away from the coast Deeper water rises to replace surface water Deep cold water is richer in phosphorus P a limiting nutrient Coastal upwelling areas account for most of the oceans biological productivity and most of commercial sh catches Results in changes to major sedimentary minerals formed by sea life Calcite versus aragonite both CaCOa Ocean upwelling current Continental Shelves Upwelling regions shown in circles Oceansiplay aigoverning role in global climate controlling the 39 39 0 39 Ugh several 39 39 Geologic timescales millions of years Oceanic deposition of limestone Cacog Subduction and volcanic rerelease of CO2 from limestone Burialexhumation of organic carbon on continental shelves Millennial timescales 100s 1000s of years Equilibration of CO2 between oceans and atmosphere Thermohaline oceanic circulation Thermohaline oceanic circulation A global system of surface and deep ocean currents a Driven not by39win d but by temperaturedensity changes in ocean water as it circulates As surface ocean water reaches the North Atlantic near Greenland it becomes colder and therefore denser 42 water sinks pulling a downward current to the ocean Deep cold dense ocean water circulat until it reaches the tropics runs up against the continental edge v 15 up and rises again The entire system forms a close 00 constantly circulating Delivers COZ to the deep ocean also moves heat from tropics to poles ie Gui Stream Current Depends on orientation of continents Likely has not been a permanent feature of global oceanic circulation Equilibration of 302 between oceans and atmosphere r 39CarD39On dioxide dissdlves into ocean water C029 1 39 002W The mOre CO2 in the atmosphere the more dissolves in the oceans If CO2 is suddenly added to the atmosphere eg vol s the oceans will take up some of the extra to re establish equilibrium Governed by a chemical reaction above that is determinate or predictable given the known volumes of the atmosphere and oceans and the total mass of CO2 available to both reservoirs Takes time ocean c ate slowly and about 5000 years are required to achieve complete equilibrium with the deep ocean 1 Map ofgglobal thermohaline circulation system Climate Control Geologic Timescales Burial Exhumation of organic carbon River deltas productive shallow inland seas collect dead organic matter in sedimen s Plankton rain down constantly onto sea oor Dead plant material delivered by rivers from inland Eventually can form into coal petroleum Carbon that is sequestered into sediments is removed from the global C cycle and thus from the atmosphere When organic carbon in sediments is exhumed by tectonic uplift of continental shelves it will weather return to the atmosphere as COZ Depends on location of deposition rate of regional tectonic uplift Climate Control Geologic Timescales Deposition of limestone requires Ca from mineral weathering on the continents delivered by rivers to the ocean COZ from the atmosphere drawn in as oceanic CO2 is used up by plankton growth The faster Ca is delivered to the oceans the faster limestone is deposited onto the ocean floor And the faster CO2 is drawn out of the atmosphere Mineral weathering on the continents controls the rate of limestone production in the oceans and therefore the rate of CO2 drawdown from the atmosphere Climate Control Geologic Timescales Oceanic deposition of limestone Marine plankton that are calcareous produce a shell ofCaCOa mineral calcite or aragonite mos cal areous plankton are 0 sin glecelled algae Dead plankton shells constantly rain down through the oceanic water column and collect onto sea oor Carbonate shoals example Bahamas Eventually calcite sands are buried compressed into limestone ClimateOcean Feed back Hot Climate high CO2 concentration in atmosphere Warmer atmosphere more evaporation from oceans more precipitation Wth more rainfall continental rocks are exposed to more intense weathering Chemical weathering reactions proceed faster at higher temperatures More Ca is delivered to oceans by river drainage from the continents More plankton growth thus more limestone production CO2 is bled from the atmosphere eventually cooling the planet Without subduction and volcanism COZWould undergo a oneway tn to the ocean oor 7quot COId Climate I0W1CO2 concentration in atmosphere No retum ofCOztothe atmosphere eventually E6 21 would freeze over a Colder atmosphere less evaporation from oceans less precipitation u And climate slows the rate of rock weathering n Arid climate means less river ow to the oceans n Less Ca is delivered to oceans by river drainage from the continents Less plankton growth less limestone is produced W39 1112 maman was CO2 is allowed to build up in the atmosphere eventually warming t the plane a Seafloor hotsprings along MORs Likelyto have occurred in the oceans but not in shallow water Complex vigorous chemica cycling 039 The chemical conditions favoring life were most favorable in the Chimneys rhade 0f F632 PyritehCaSOA deepvocea n at hiyr lroi ermal vents along MORs gyp 39m Alhundant based 73 Suffunusiirg fjacteria iuytjlcli i Carbon can exist in the gaseous state or as solid or dissolved chemical species Controlling processes Atmosphe r i p s 39 3029 carbon dioxide Photosynthesis CH4g methane 39 Respiration re Oceans Dissolved carbonate COST and bicarbonate HCOSV Fixed carbon occurs in different forms 39 organic carbon olcanic relea 39 Id dead organic matter 39 c 39ocarbons 7 108 years carbon drawdown from plant productivity turn of CO2 to atmosphere by breakdovim of organic matter Longert escaies 1009 of years 1000s of year3 Ocean circulation dissolution ofCO2 into ocean water uptake and release Geologic timescales millions of years se ofCOZ via subductionrelated processes Formation and burial of calcite in oceans limestone formation Weathering ofsilicate minerals on t Kerogen viscous black Cum found in shales solid carbonaceous rock Petrole m liquid carbonaceo es e continents u us r Na ural gas mostly methane some Burial oforganic carbon in sedimentary basins seas deltas idue xhumation and weathering of organic carbon uplift Omar hydrocarbon gases Pyrite formationweath ering Inorganic carbon Plane 39 escales biliions Carbonate rock limestn Forcing of Ccycle by variations in solar luminosity CaCOa calcite is most common Asdiscussedea rlier S cycle Formation of pyrite by bacterially promoted processes in Rockslncm tngly oldnr any uckslncreaslngly alder sedlmemaly basms lt lault Mldonzan rldge gt 83042 2Fe203hematite 15 CH2O 16H lgt tiFeS pyrite 15002 23H2O a Important on a global basis at reaction consumes organic matterana produces 302 with no net 62 consume quot K Fran r crO levels ANI 7it39 CO I is Submitting ocle i I 2 J I 2 at 39 39 y rapior bun of organic matter lack of oxygen In Lid fos cfu iJ reduc 27 This process probably contributed to high 02 levels high CO2 levels in Carboniferous period 360286 Ma Reverse pyrite weathering reverses the effect A major control on atmosphericCOZ over geologic timescales o Operates because of the confluence of several different processes Poorly understood until recently I First39proposed by Edelman 1845 but ignored until recently Wea ng popularized by Raymo and Ruddiman 1992 Maury F 1 1 7122 Silicate weathering erodes rock and produces a ux of dissolved Ca2 Weathering of silicate rocks on the continents 0 Plf iosvriih Converts dissolved calcium CO2 into solid calcite deposits CaCOa onto sea oor E leases dissolved Ca 10 rivers oceans Siimul39 phyto annion produciivily in oceans drawing down 202 to make I o s s wl are deposited on sea oo 002 is returned to the atmosphere eventually by subduction volcanism Tao t 39I s Recycles mineral carbonate into atmosphere via volcanism CaSio3 co2 gt caz 0203 cosz qgt CaC03s 53025 rocks air dlElvEd dlElvEd limeaune Emergent properties a 39 39 ting Acts as a ihcr cgulaiion svsiem in 39m i t maintain atmospheric As climate warms mineral weathering accelerates removing 002 from air temperature Within b undari55 59d9d for fey OVel39 billions 0f years As climate cools phytoplankton activity diminishes slowing CO2 drawdown 2 Basedion workiof Robert Berner Yale and colleagues I Based on C isotopic evidence limestone rock record tectonics Long to read is low rd doors a Stellar evolution drives the slow but steady expansion of the Sun Over GeologicPlanetary time Sun is brightening 20 Atmospheric CO2 BeI Temperatu Kahru ampEpsteiri lBEE l mperamre ac CO2 relative to modern 8 o m p o o Age Ma Age Ga Nut an Opeannded Sysmn mum mymmmmmmmzhgwmlmmhuumwnax anunh p mmemnhurhvmmnvmunWWW umw nburmmmmuuamawmnnhum JIMEHL ngw uy W 96000 Tgyr 43000 Tgyr 000 r 000 gyr production respiration ao39ooo Tglyr h 9 production respiration 30mm Tglyr ha 9 79300 TQM 40000 Tgyr 40000 Tgyr decay decay 40000 Tgyr 40000 Tgyr litterfall litterfall 33300 Tgyr 93quot 37000 Tgyr C Chameides and Perdue 1997 Chameides and Perdue 1997 3m Ian a 96000 Tgyr 43000 Tgyr 000 r 000 gyr production respiration ao39ooo Tglyr ha 9 79300 Tglyr production respiration 30300 ENquot ha 9 79300 T9YI39 3 000 T r 48000 Tgyr 48000 Tgyr respiration decay g i 1H decay 39 40000 Tglyr 40000 Tgyr 40000 Tgyr productlon litterfall litterfall 33300 Tgyr 95quot 37000 Tgyr 33300 Tgyr 95quot 37000 Tgyr C C 0 Tgyr 0 Tgyr 20 V 2 Hiram weathering weathering Jay W r 900 Tgyr respiration 3 Carbonate Sediments Carbonate Sediments 7oooooooooo T9 200 TQM 7oooooooooo T9 200 TQM sedimentation sedimentation Chameides and Perdue 1997 Chameides and Perdue 1997 Atmosphere 600000 Tg c as coz 96000 Tgyr 43000 Tgyr production respiration Living Terrestrial 43000 Tgyr 20 weathering Biosphere decay 330000 T m 43m TQM W E litterfall 33300 Tgyr k 0 Tgyr Carbonate Sediments 70000000000 T9 200 TQM sedimentation 100 Tgyr Chameides and Perdue 1997 weathering 30000 Tglyr aimceaquot 79900 Tgyr exchange 7 36000 Tglyr respiration 40000 Tglyr production 37000 Tgyr 3900 Tgyr respiration l sedimentation Atmosphere 600000 Tg c as coz 43000 Tgyr respiration 96000 Tgyr Elfocean production l 30000 T9 Yquot exchange 79900 Tgyr 36000 Tglyr 43000 TQM respiration vng 40000 Tgyr quot 7 m rf 39 e a 33300 Tgyr 069 C 0 Tgyr 20 weathering 40000 Tglyr production 37000 Tgyr 3900 Tgyr respir ion Carbonate Sediments 70000000000 T9 1 sedimentation 200 Tgyr sedimentation 100 Tgyr Chameides and Perdue 1997 weathering i gycllr x Complicated N can form compounds that are gaseous or volatile also can form watersoluble compounds N is needed by a life forms a Amino acid formation Protein synthesis a Nucleic acid formation 2 dinitrogen molecular nitrogen gas N M32 NZO nitrogen oxides gases ammonia gas can dissolve in waterto form NH ammonium Natural availability of fixed N is low in most ecosystems Fixed N acts as alin a 39 g gt Biological productivity would be higher in most cases if more oxrdaton r Ixed N were avallab e Not true in all biotic systems but this is the case in many NO N02 EZO 39Oxidationof NZ to form NO N02 N O Nitrogen fertilizer 83 Tgy Triple bond in N2 requires a great deal of energy to break Haber process Leg umes 4O Tgyi r Fixation requires heat or enzymatic catalysis Agricultural production a Heat Fossil Fuels 20 Tgyr Land use changes Biomass bumin 130 Tgyr Wetland draining 10 Tgyr Land clearing 20 Tg r uning Forest Fires High temperatures break N2 bonds and combine N with O r10 Teragrams ler 1 T5 I g Use nitrogenase enzyme to cleave N2 bond combine with H2 to form ammonia NH v V t30 Tgyr nonanthropogenicnonagricultural f Tmal Natural 140 Tgyr Cyanooactena symbiotic bacteria Rmzobium Frame a Industrial I39gyr nanu ct39 a act39icultual legume cultivation n55 burning 7 Human mdusmal development has more the k the amount am 3mm and mm of fixed N moving through the biosphere globally Biotic transformations NH3 assimilation Dissolved NH4t istaken up by bacteria plants converted to organic N amino acids Normally accomplished during photosynthesis in green plants a Ammonification Breakdown of dead organic matter releasing NHAt Accomplished by decomposing bacteria aerobically Nitrification Bacterial oxidation of NH4t to nitrate N03 done aerobically Nitrosomonas convert ammonium to nitrite NOZ39 Nitrobacter conver nitrite N0739 to nitrate I 0339 n Nitrate reduction Anaerobic bacteria reduce nitrate to NZ Some anaerobic bacteria can denitrify to 33920 Atmosphere max NO and N02 OH radicals in the troposphere NOX affects the OH concentration which can affect ox iz39cg lquot e atmosphere Photochemical smog NOX plus volatile hydrocarbons in sunlight can react to form low aStiiucle smog 7 Acid rain Oxidation of NOX produces i c acid vapor IINOS which falls out in rain Atmosphere nitrous oxide Global warming Nitrous oxide is a greenhouse gas 13 increase in atmosphere since preindustrial times Stratospheric ozone Oxidation of N20 in stratosphere can form NOX which can interfere with production destruction of ozone Atmosphere 3 ammonia Particulates A monia can react with or and sulfuric acid rapor UZ 04 to nucleatet rarticulates whic may offset greenhouse warming by preventing sunlight from reaching the earth s surface 5 Acid neutralization n cou ent aciri in atmospheric water droplets in clouds w Source of NOX x a ammonia by sun a can produce NOX which leads to ac rain and other eff s Pre Industrial N Cycle Pre Industrial N Cycle from Chameides and Perdue 1997 Pre Industrial N Cycle from Chameides and Perdue 1997 mini vile39nn 1 mm am is from Chameides and Perdue 1997 Pre Industrial N Cycle from Chameides and Perdue 1997 nSIWr 5311000 Ammml39 cz nu Assimizlinu 7nn mm in mi Ammml39 cz nu Assimizlinu 7nn mm iisn 1w Sedimentary Fossilized Organic N 2000000000 Tg from Chameides and Perdue 1997 Atmosphere Atmosphere I I I 7 5051 N29 Nag mmth a W 15800000000 Tg 15800000000 Tg Atmosphere N049 01 T9 lllriiczlinu errenrizlt Flinn 51w Hg s39nl39lzl39nn 5m 1w Ammml39 cz nu m my aim nln ll mnv gyr Residehce time average period thafa molecule of X spends in a given reservoir Calculated based on the size of the reservoir and the ux into or Atmosphere outof the reservoir Mommiczlnx39n on quot5 quot n EXAMPLE What isthe residence time ofN in the atmospheric N20g gt1 m reservoir 131m Tg Size of reservoir 1330 To Ocean Biosphere N Ammml39 cz nu Assimizlinu no my 55 1 Fluxes into reservoir 9 39I39gyr Terrestrial and ocean denitri cation and nitri cation processes co 39ch estria o osphere Precipitation Evaporation 063 x 102H 9 Lakes and Rivers 03 x 1in 9 River and Groundwater Discharge 036 x 102H 9 vegetative cover bedrock surface but 39Percent of Total Where Residence Time 972 Oceans 10003 of years avg yrs 215 Ice sheets 100005 of years 031 Groundwater 1005 quoto 1000 of years 0009 Lakes 105 of years 0001 Atmosphere 9 days 00001 Rivers weeks ts is practical for use by humans the Only C32 quot6 c all we39re on Eaiih is available on a practical basis for human activities Constant on millennial timescales Varies with climate Less would have been available during last Ice Age for example Wm WWWIHWI Atmosphere l Ema 013 x 100 g 1 mm Precipitation Evaporation g 3 inaduck c Mum mm m mum nasini Distribution of Precipitation Soil Moisture 2004 NCAA Surface Water WaterSheds G oundwater uifer structure Infiltration of precipitation into soil subsurface Vadose zone Region of the subsurface above the water table Not saturated with water pore spaces contain air Aquifers Porous geological formations in the subsurface Permeability dictates whether a rock formation can function as an aquifer Impermeable rocks like shale clay prevent infiltration of water act as poor aquifers aquitards Permeable rocks like sandstone fractured rocks limestone function as highcapacity aquifers Zone of Recharge Aquitard US Aquifer Map The 24 Most important aquifers in the US USGS data rmquot m Romans Anmie 5vmmAnaivmmmm 14 m uses Hude 24 with most mwanm eqmmana aumm svue x mus United Stats and one in m avibbzan Manda Ogallala Aquifer High Plains Aquifer Ogallala Aquifer Cambrian O dovician Aquifer System 0 Underlies parts ofIL WI IA MN MO MI 0 Most important aquifer in the upper Midwest Hma mum Renewable Energy Energy sources that effectively cannot be deQIeted through overuse However they can be used to a theoretical maximum capacity Renewable sources of energy are renewed constantly on a human timescale from much larger external sources of energy solar fusion gravity geologic radioactive decay etc Not Renewable Solar Fossil Fuels Nuclear Hydroelectric Geothermal some Biomass Wave Tida Geothermal some Renewables Use in the US 2003 data Quads 2003 j MSWLandfill Gas Biomass Biomass Biomass Other Geothermal j Hydroelectric of Electricity Demand Renewable Energy Use in the US 2000 Biomass energy Ham 1 Binmiss Ennrgy Rnsaurc Hierarchy ElmInes Energy 1 a 2mm nu Altuivml w mm 7 g V 7L J Asdoped Silicon crystal has a surplus of easilydislodged unpaired electrons It is an N h semi r Gadoped Silicon crystal has a surplus ofelectron holes in the lattice It is an P ypa 53micoi39iducicr The potential difference between the N and P surfaces acts like a battery The potential di erencc is pr directional Connect the two by a conducting material wire and the electrons can move back to Light disiodges he39eectr n5 om the Hype lattice the N side closing the circle and establishing an ei t vcai circuit lflinked the potciitia difference between the two crystals causes electrons to ow from the N side to the P side As long as light is supplied the potential is maintained and can be used to do work Buildup of positive charge at the P surface buildup ofnegative at the N surface l i A oped on rystal N type As oped S can crystal N type PV Technology Advantages Can construct PV cells using different compounds structures Can be deployed in a range of sizes shapes scalability No moving parts durable Slllcqn Cells No pollution noise etc Single crystal silicon expensive but high ef ciency Multicrystalline siiicon less expensive but lower ef ciency quot I ye 7 quot and rhean Polycrystalline thin lm plastic substrate r can be made into exible materials sheets Example materials CulnSg Cds CdTe Singlecrystalline thin film Employ GaAs gallium arsenide in very thin lms 39 mall amount on 39 PV Syste ms Figure 12 Connmm Solar Fowlr cap Ramm Pnhntlll 0 Potential Utility Very high at 10 lightconversion ef ciency about average for current tech a 100 square mile are of PV cells could supply entire US electricity demand Distributable power supply can be provided from rooftop units installations onto former brown elds does not need to be concentrated Into one large power plant site Low Extractive Impact toxic metals Ga As Cd In must by used but little in h V absolute quantity is needed per PV unit mining impact is moderatelow J Wk I 0 Current DisadvantagesLimitations Price currently price is not directly competi e with fossil fuels mostly t l r 39 nem t 2 Supply worldwide supply providers are small could not meet global demand at current production capacity Geography most ef cient in sunny areas or at least regions with little cloud cover mummy mumum Bnunn Huxh er39EzwwNdmldv V nd Power G wth in V nd Energy Using wind to turn a turbine generating electricity Efficient cheap 25000 No emissions power output is scaleable 20000 15000 Rest of World 10000 MW PV Installed Vl nd Power Wnd turbines Wind blows across blades turns a shaft connected to an electrical generator producing curren Can be manufactured at varying capacities 50 kW up to several MW Siting is important to access sustained winds Height is important must be above 30 m to minimize ground turbulence Advantages No emissions of any kind Cheap wind is competitive with fossil fuels now averaging 5 centskWh Scaleable can be sized from single turbines to hundreds ofturbines Disadvantages Newertechnology higher initial cost outlay than fossil plants of comparable ultimate power output Wind is intermittent although predictable averaged over a wide area Best sites are in more remote areas away from population centers mostly Noise aesthetics dangerto birds UNITED STATES ANNUAL AVERAGE WIND POWER mnwni n r class1 melnwesl m class Illehillwsl Ezrlr we at rm r en a Urn m 239 all class 3 or Healer aresuilahle in most len 2mm in marginal and Fe re D My rredcnrelgovl Vl nd Power Capacity 0 According to US DOE data Assuming moderate land use for wind and existing land use restrictions and assuming wind turbine siting within 10 miles of transmission lines Potential power output ofthe contig ous US using 50 m tall turbines of electricity annually sustainable perpetually into future 62 billion MWh total 2004 residential electricity demand in U 51 billion MWh total 2004 commercial electricity demand in US 94 billion MWh total 2004 industrial electricity demand in S v total US 2004 electricity demand Wind could supply ALL of residen al demand up to 30 of total t39 current demand But demand WII ncrease over I wm Power Cbssr nanon ream marm e mmr imaman ww m 7cm 0400 myquot mama m awrwn em 99an Imelda swam udlni mum sum gtwn mom m Wind Resources of Mi U DOE data oThis resource map shows w speed estimates at 50 meter utilityescale wind devel opme Maesarh Heel ran m wmn PM California 50 m Wind Resource Map Hydrogen Fuel Cells Generate electricity by reacting hydrogen and oxygen to produce an electric current Oxygen and hydrogen are not burned but are combined using a catalyst solid or liquid Catalysis of the reaction of H2 and O2 releases electrical energy produces H20 as a waste product Fuel cells operate using a variety of different designs some requiring high operating temperatures up to 10000 C for maximum efficiency Illinois 7 WWW Resource Map PEM FUEL CELL Electrical Current Excess 339 9 Water and Fuel Heal Oul e e Fuel ln Anode i Cathode Eleclmlyle Hydrogen Energy Storage Using H as an energy storage medium H is not naturallyoccurring in a free state H2 Must be obtained by splitting the water molecule by electrolsis Requires electricity to split water 2H20 2H2 02 1 Obtain electricity by for example solar wind hydro 2 Use electricity as dictated by demand 3 Extra electrical generation above demand is used to electrolze water making H2g and 02g 4 Hydrogen fuel is sold transported and used in fuel cells to deliver electricity on demand The Future Hydrogen Economy 0 Current Energy Economy Extractive 0 Fossil fuels are mined 0 Coal and natural gas are burned to produce heat to drive electric turbines generating electricity 0 Petroleum is refined to make liquid fuels for transportation 0 Hydrogen Economy Sustainable Electrical energy is generated directly using wind solar hydro Biomass can be used to meet temporary demand surges Excess generating capacity is used to produced hydrogen for fuel cell operation Instead of petrol fuels transportation technology is based on fuel cells or direct combustion of hydrogen Closed energy loop ultimately based on realtime solar input As surnpt39cns of Science 8 Events 39rbew patterns ur resuttnbm causes tnat can be derstu u 2 Mesa nature are tne same tnrbugnbuttne Unwerse and awe s have been V a smen ttn reasumng S mductwe tbegms wtn spasm t N 5 ya servatmns and Extends tn generahzat bns ew evmenee can mspruve tnebnes but absbtute pmuf tmbbsstbte e 9 W tne sun came up tumbnbw Are u sure Science v Pseudoscience Sctence 39dea swtth ngs tnat can be tested by b observe ton orWhtch can be dtsproved y evhjence Pseudosctence untesteb e or unrefutab e quotscienti c t ea onin39g is used everywhere Pohcework cnrmna nveshgahon Medtcine tan Engmeenng ctasstd Sctences enemtstry pnystcs btotogy geo ogy etc A snan 5 tonnat Way of descnbmg tne metnods of rattona tnougnt 1 Every measurement is an approximation but some are better than others The degree of error in a measurement is always more than zero but can be minimized estimated through replicate analyses use of standards etc Ex Age of rocks a Earth is 46 billion years old 2 01 billion years 2 error Measurements are always fuzzy but within limits Age of Earth is NOT a 46 billion years t 190 billion years Does theconclusion follow from the evidence Skeptical thinking is NOT stubborn refusal to accept anything or mistrust of everything It is rational thinking free of bias accepting the implications of hard evidence Extraordinary claims demand extraordinary evidence Don t be gullible 39quot 39 a testable or disprovable inference or assertion an idea that hasn t yet been tested 39 is a model based on verifiable hypotheses shown to be consistent with available data and observations and accepted as an explanation for some natural process Microbes not demons cause disease hings fall right Lookfor independent confirmation of observations a Can you doit again n Is your discovery reproducible or39repeatable w Is open39debate encouraged or is free exchange of information stifled v Privatelyfunded corporate research a Proprietaryinformation a National security secrets Is there an easier way of explaining the data a 5 arm don t make a complicated hypothesis when a simpler one will do a Face on Mars Orjust a funny rock formation Is there bias 5 Financial conflict of profit interest eg drug research a Religious conflict with established dogma Quantify v Measure measure measure It s easy to be fooled if you can t put a number on something u EX The Clean Air Act is bankrupting US businesses Really 1997 USEPA study costs of US CAA 523 billion benefits were from 6 to 50 trillion EX Acid rain is a hoax Rain is acidic anyway Really Natural rainfall has a pH of 56 from atmospheric COZ Polluted rainfall can drop to a pH of 2 battery acid Be in the uestiOn assuming the answer We can t end the death penalty because crime would grow out of control Really Can you prove that execution is a deterrent Switching to alternative energy would destroy the economy Is that so What about Europe or Japan a Nationalized health care is totally unworkable Then why does every other industrialized nation have it 1 Appeal to Ignorance Whatever has not been proved false must be true We don t know if Global Warming will happen so why try and curb our carbon emissions We don t have direct evidence of life on other planets so were alone in the Universe Every biochemical step in the formation of life on Earth isn t well understood right now so a god must have created life Inconsistency v Declining life expectancy in the former USSR was because of communism ls high infant mortality in the US because of capitalism Selective observation a My state has produced five presidents How many serial killers has it produced Statistics of small samples a They say one in five people is Chinese I know dozens of people and none are Chinese Left your hometown yet Weasel words c Laidoff fired enemy combatant disappeared police action war preowned used detainee prisoner Ad Hominem or Straw Man attacking the advocate or the advocate s group a Don39t trust anything he says He39s a liberal Confusing correlation with causation a Before women could vote there were no nuclear weapons False dichotomy exclusion of the middle a You39re either with us or you39re against us Argument from authority a Trust us we know what we39re doing You don39t need to know Argument from adverse consequences a Do what you39re told or terrorists will get you Mishandling of statistics n Our education system is failing Fully half of our students score below average I39ogl c I mescz aie Alwines a e based unme rock record at Events m earmjs pa st reeerded as features m racks e Devexeped stamng m we and bymmmg and ndustna gemugwstswhu needed m understand ruck siructures re anunsmps a mum avaaW mumquotmamwmnvmm we Vanna an v m W w New Eve muwemmw mm m a uhanmmeweve unknumn mm evens We mm M vecam m abmvw mm mmsmm may mummy w Dean dekvmmed new e unmade mm N am a be Geologic I Ime Eanh the Umvevse avevas y ed m cumpansun wnmhe hdman Meme Dw cuMu magme the scabs umme mvu ved an sqrnm jnaAge ofihe Earth e Radmmemc daung of mete n es moon rocks un emae M22uvsuna 27ml been mucessed mymdm anhe mm unhesmay Svs12m UPbdalmme ch o t em 57 a a mum veavs emund Hunks hav smcemeu mnumn n H mm 5 c m Wm m We 3 Age ofme un ased un nuc eav pWsms hm ml the Sun 5 huwmg n s Can ca cu ale mm mm We Sun has been here Age em 5 mummae m auveemem W m nae Geologic Timescale Units 0 Eons longest periods of time dividing Earth history measured in billions of years 0 Eras major time units dividing Eons measured in 100s of millions of years 0 Periods smaller units of time 10s of millions of years each denoting an interval of time between major distinguishing events like extinctions If geologic time were a calendar of one year January 139 Earth forms March 7 oldest surviving rocks on Earth s surface November 10 oldest shelled fossils November 22 rst fish November 28 rst land plants and animals December 11 Appalachian mountains begin to form December 13 dinosaurs appear December 14 rst mammals December 26 early morning Rocky mountains begin to form December 26 evening dinosaurs go extinct December 29 Himalayas begin to form December 31 evening Hominids appear December 31 115845 Latest ice age ends ice sheets retreat December 31 115945115950 Roman Empire December 31 115957 Columbus reaches the Americas December 31 115959 Industrial Revolution Formation of the Universe 0 137 billion years ago Big Bangquot Event Expansion of spacetime starting from a subatomic size Did not expand INTO space space ITSELF expanded Initial high energy state slowly cooled as space expanded Our universe is likely one aspect of an infinite progression of universes through time and hyperspace o Matter formed from energy only after enough time had elapsed History of the Universe Evidence Galaxies are rushing away from us in all directions Farther galaxies are moving faster 39 V Farther away longer ago v T 39 Ancientuniverse Starsformedbyc collar 5 of H clouds began l sinn expanded faStertha W Fu 39oh makes elomg 1 by combining their nuclei all the Cosmic microwave way upto rm back round I Ag of space is lled with When stars die sup 39 Violent energies In eprOSIon Jam dim microwave dla on 39 making heavier elements up to Usaiiium U Wavelength has azagggigzmthv39bn has plenty of heavy elements so 39 w now long V g 39 lb had 3 anti die befnse our ply rm could form A erglowquotofthe Big Bang Supernova remnant M1 39 NGC 1952 the Crab Nebula Exploded in 1054 AD v A HST NGC 604 in Galaxy M33 HST WFPC2 PHCQS27 ST Scl OFO August7199 Hui Vang UJL and NASA 5mm Mm ram Wm w t u 4Our solar system formed by collapse of a planetay nebula which started rotating Rotation and gravity brought most of the gas and dust toward the core of the cloud cThe core reaches a critical density and HA fusion starts igniting the Sun Smaller whorls and whirlpools of matter in the cloud condense to form other planets M16 Eagle Nebula Stellar Nursery starforming region Numerous protostars are visible inside the cloud which is several hundred lightyears across 39o Outer material in cloud is colder more ices gases Jupiter Pluto comets r lnner material is hotter boiling off ices and leaving rocky material Earth Venus Mars Our solar system began in one such nebula 46xbillion years ago Earth formed by accretion of material from the solar nebula dust Primordial earth began to separatev Chemically rock39s gas ices mostly be gravity impacts 39 Heavy elements iron nickel etc sank to the v Early earth Would have been molten with no appreciable higher denSlty atmosphere Lighter elements and gases COZ NZ ll2 H20 39 39 39 V boiled of39f forming an atmosphere some light gases were lost to space eg H2 Lighter rocks rich in Si rose to the surface forming an early 2 Period of Intense Bombardment 41 32 bill n years ago Mostlymolten s r w No oceans a 39 littent oceans After bombardment ends Most impacting material is used up has already hit something Sun Jupiter other planets Surface of Earth can start to cool solidify Cooling atmosphere allows water vapor to condense into rain which begins to accumulate on surface as early oceans Atmosphere is dominated by volcanic gases No free oxygen 0 in atmosphere yet
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