lecture(Human_Impact_Environment)

lecture(Human_Impact_Environment) - Human Impact on the...

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Unformatted text preview: Human Impact on the Biosphere Biosphere Human Impacts Human Humans Humans are using energy and altering the environment at astonishing rates the We We are altering natural processes before we even understand them before Developing vs. Developed Developing In developing countries, per capita resource use is high but growing, as is population size In developed countries, population growth has slowed but per capita resource use is already high Pollutants Pollutants Substances Substances with which an ecosystem has had no prior evolutionary experience experience No No adaptive mechanisms are in place to deal with them deal Air Pollutants Air Carbon oxides Sulfur oxides Nitrogen oxides Volatile organic compounds Photochemical oxidants Suspended particles Chemistry 101 Chemistry Acid anhydrides: oxides of nonmetals CO 2 , NO2 and SO3 These react with water to form oxyacids. CO H2O ­­­> H2CO3 (carbonic acid) HNO and H SO are also formed in 3 2 4 the atmosphere 2 + Acid Rain and Architecture Acid On campus we have some architectural damage attributable to acid rain. The limestone lentils and pillars on the older building are dissolving away! CO2(g) H2SO4(aq) + CaCO3(s) H2O(l) + +CaSO4(aq) Industrial Smog Industrial Gray­air smog Forms over cities that burn large amounts of coal and heavy fuel oils; mainly in developing countries Main components are sulfur oxides and suspended particles Photochemical smog Photochemical Brown­air smog Forms when sunlight interacts with components from automobile exhaust Nitrogen oxides are the main culprits Hot days contribute to formation Thermal Inversion Thermal Weather pattern in which a layer of cool, dense air is trapped beneath a layer of warm air cool air warm inversion air cool air Cities Are Often Plagued with Thermal Inversions Thermal Caused by the Acid Deposition Acid release of sulfur and nitrogen oxides Coal­burning power plants and motor vehicles are major sources Effect of Ozone Thinning Effect Increased amount of UV radiation reaches Earth’s surface affects human health primary productivity UV damages DNA and negatively UV also affects plants, lowers Ozone Thinning Ozone In early spring and In summer ozone layer over Antarctica thins over South America Seasonal loss of Seasonal ozone is at highest level ever recorded level Antarctica Ozone in Earth’s Atmoshere Ozone Ozone Concentration Ozone from 1962 to 1996 http://www.igf.edu.pl/igf/atmosphere.htm Recipe for Ozone Loss Recipe “The polar winter leads to the formation of the polar vortex which isolates the air within it. Cold temperatures form inside the vortex; cold enough for the formation of Polar Stratospheric Clouds (PSCs). As the vortex air is isolated, the cold temperatures and the PSCs persist. Once the PSCs form, heterogeneous reactions take place and convert the inactive chlorine and bromine reservoirs to more active forms of chlorine and bromine. No ozone loss occurs until sunlight returns to the air inside the polar vortex and allows the production of active chlorine and initiates the catalytic ozone destruction cycles. Ozone loss is rapid. The ozone hole currently covers a geographic region a little bigger than Antarctica and extends nearly 10km in altitude in the lower stratosphere” http://www.atm.ch.cam.ac.uk/tour/part3.html Protecting the Ozone Layer Protecting CFC production has been halted in developed countries, will be phased out in developing countries Methyl bromide will be phased out Even with bans it will take more than 50 years for ozone levels to recover Generating Garbage Generating Developed Developed countries generate huge amounts of waste amounts Paper Paper products account for half the total can reduce pollutants, save volume volume Recycling Recycling energy, ease pressure on landfills energy, Garbage Barge Solution Garbage Landfills Landfills Land Use Land Almost 21 percent of Earth’s land is used for agriculture or grazing unsuitable for such uses high ecological cost About half the Earth’s land is Remainder could be used, but at a Green Revolutions Green Improvements in crop production Introduction of mechanized agriculture and practices requires inputs of pesticides, fertilizer, fossil fuel Improving genetic character of crop plants can also improve yields Data From the UN Data INDIA REACHING 1 BILLION ON AUGUST 15: NO CELEBRATION PLANNED PLANNED Lester R. Brown and Brian Halweil Falling water tables are now also threatening India's food production. The International Water Management Institute (IWMI) estimates that withdrawals of underground water are double the rate of aquifer recharge. As a result, water tables are falling almost everywhere. http://www.worldwatch.org/node/1656 Aquifer Depletion Aquifer Deforestation Deforestation Removal Removal of all trees from large tracts of land land 38 million acres logged each year is used for fuel, lumber Wood Land is cleared for grazing or crops Clear Cutting of Forests Clear Increased leaching and soil erosion Increased flooding and Effects of Deforestation Effects sedimentation of downstream rivers Regional precipitation declines Possible amplification of the greenhouse effect Regions of Deforestation Regions Rates of forest loss are greatest in Brazil, Indonesia, Mexico, and Columbia Highly mechanized logging is proceeding in temperate forests of the United States and Canada Rainforests Rainforests Forests Burning Forests Reversing Deforestation Reversing Coalition of groups dedicated to saving Brazil’s remaining forests Smokeless wood stoves have saved firewood in India Kenyan women have planted millions of trees NAIROBI (AFP) Feb 23, 2005 NAIROBI NAIROBI (AFP) Feb 23, 2005 “Kenyan Nobel peace laureate Wangari Maathai on Wednesday urged developing nations to help fight global warming and support the Kyoto Protocol on climate change by joining her tree­planting campaign.” Destroying Biodiversity Destroying Tropical Tropical rainforests have the greatest variety of insects, most bird species variety Some Some tropical forest species may prove valuable to humans valuable Our Our primate ancestors evolved in forests like the ones we are destroying Primates Primates Many primate species are threaten or endangered. Desertification Desert Conversion Conversion of large tracts of grassland to desertlike conditions Conversions Conversions of cropland that result in more than 10 percent decline in productivity productivity Global Desertification Vulnerability Global The Dust Bowl The Occurred in the 1930s in the Great Plains Overgrazing and prolonged drought left the ground bare 1934 winds produced dust storms that stripped about 9 million acres of topsoil Caption: "Dust Over Texas." Huge boiling masses of dust that blocked out the sun were common sights in Texas during the Dust Bowl years. In: "To Hold This Soil", Russell Lord, 1938. Miscellaneous Publication No. 321, U.S. Department of Agriculture. Ongoing Desertification Ongoing Sahel region of Africa is undergoing rapid desertification Causes are overgrazing, overfarming, and prolonged drought One solution may be to substitute native herbivores for imported cattle Linear dunes of the Sahara Desert encroach on Nouakchott, the capital of Mauritania. The dunes border a mosque at left (photograph by Georg Gerster). Gerster). Water Use and Scarcity Water Most Most of Earth’s water is too salty for is expensive and human consumption human Desalinization Desalinization requires large energy inputs requires Irrigation of crops is the main use of freshwater Mean Annual Precipitation Mean Water Distribution Water Negative Effects of Irrigation Negative Salinization, mineral buildup in soil Elevation of the water table and waterlogging Depletion of aquifers Salinization, mineral buildup in soil Salinization, http://waterquality.montana.edu/docs/methane/irrigation_suitability.shtml Groundwater Groundwater Aquifers ­ Porous layers of sand, gravel, or rock lying below the water table. Recharge Zone ­ Area where water – Artesian ­ Pressurized aquifer intersects the surface. (Water flows without pumping) infiltrates into an aquifer. – Recharge rate is often very slow. Presently, groundwater is being removed faster than it can be replenished in many areas. Depleting Groundwater Depleting Groundwater is the source of nearly 40% of fresh water in the US. – On a local level, withdrawing water faster than it can be replenished leads to a cone of depression in the water table, On a broader scale, heavy pumping can deplete an aquifer. – Ogallala Aquifer Mining non­renewable resource. Depleting Groundwater Depleting Ogallala Aquifer Ogallala Extends from southern South Dakota to central Texas Major source of water for drinking and irrigation Overdrafts have depleted half the water from this nonrenewable source Ogallala Aquifer Ogallala “The Ogallala Aquifer within the boundaries of the North Plains Groundwater Conservation District is declining at an average of 1.74 feet per year (1,082,631 acre ft).” The aquifer is cut off from natural recharge sources. http://www.npwd.org/Ogallala.htm Aquifer Problems Aquifer Sink Holes and Karst Topography Sink CaCO3 + H2SO4 CaSO4 + H2O +CO2 http://www.soils.umn.edu/academics/classes/soil2125/doc/1-snkle.htm Water Pollutants Water Sewage Animal wastes Fertilizers Pesticides Industrial chemicals Radioactive material Excess heat (thermal pollution) Groundwater Pollution Groundwater Wastewater Treatment Wastewater Primary treatment – Use of screens and settling tanks – Addition of chlorine to kill pathogens Secondary treatment – Microbes break down organic matter Tertiary treatment removes additional toxic substances; rarely used Sewage Treatment Sewage More than 500 pathogenic bacteria, viruses, and parasites can travel from human or animal excrement through water. Natural Processes – In many areas, outdoor urination and defecation is the norm. processes can quickly eliminate waste. When population densities are low, natural Municipal Sewage Treatment Municipal Primary Treatment ­ Physical separation of large solids from the waste stream. Secondary Treatment ­ Biological degradation of dissolved organic compounds. – Effluent from primary treatment transferred into trickling bed, or aeration tank (chlorinated) before release into nearby waterway. Effluent from secondary treatment is usually disinfected Municipal Sewage Treatment Municipal Tertiary Treatment ­ Removal of plant nutrients (nitrates and phosphates) from secondary effluent. – Chemicals, or natural wetlands. In many US cities, sanitary sewers are connected to storm sewers. – Heavy storms can overload the system, causing by­pass dumping of raw sewage and toxic runoff directly into watercourses. Municipal Sewage Treatment Municipal CSO Tunnels and Treatment Facilities (Atlanta, GA 2005) Facilities “The tunnel is part of a storage and treatment system that involves capturing and storing combined sewer overflows. The overflows are stored in a large underground tunnel in bedrock similar to the rock that comprises Stone Mountain. When a storm is over, the captured CSO volume is conveyed to a separate treatment system for removal of pollutants and reduction of harmful bacteria with sodium hypochlorite disinfection followed by dechlorination with sodium bisulfite before discharge to receiving waters. The City is building two facilities, the West Area CSO storage tunnel and the East Area CSO underground linear storage facility to handle the overflows.” Milestone Completion Date for West Tunnel October 2007 West These will collect storm water for treatment. http://www.cleanwateratlanta.org/CSOTunnels/ Oxygen-Demanding Wastes Oxygen-Demanding Water with an oxygen content > 6 ppm will support desirable aquatic life. – Water with < 2 ppm oxygen will support mainly detritivores and decomposers. Oxygen is added to water by diffusion from wind and waves, and by photosynthesis from green plants, algae, and cyanobacteria. – Oxygen is removed from water by respiration and oxygen­consuming processes. Oxygen-Demanding Wastes Oxygen-Demanding Biochemical Oxygen Demand ­ Amount of dissolved oxygen consumed by aquatic microorganisms. – Dissolved Oxygen Content ­ Measure of dissolved oxygen in the water. Effects of oxygen­demanding wastes on rivers depend on volume, flow, and temperature of river water. – Oxygen Sag ­ Oxygen levels decline downstream from a pollution source as decomposers metabolize waste materials. Oxygen Sag Oxygen Water Wars? Water Per capita amount of freshwater available is decreasing International conflicts over water use and quality have already occurred Building dams or dumping pollutants effect countries downstream Weiss Lake Organization Declares War! War! “Weiss Lake Improvement Association is the environmental and ecological watchdog for Weiss Lake and against ‘Metro Atlanta’ from taking our WATER.” (Coosa River Drainage) Energy Use Energy Only Only 10 percent of energy used in energy developed countries is from renewable sources renewable Less Less developed countries rely more heavily on renewable sources (primary biomass) (primary Fossil Fuels Fossil Coal, oil, natural gas Main energy source of developed countries Burning of fossil fuels contributes to global warming Oil Oil Reserves are declining Many reserves are in ecologically fragile wilderness areas Environmental costs of extracting and transporting reserves from such areas are high Total Energy Consumption Total Domestic Product Domestic Oil and Gas Injection Wells Typically, when oil and gas are extracted, large amounts of salt water (brine) are also brought to the surface. This salt water can be very damaging if it is discharged into surface water. Coal Coal Extensive reserves exist Mining is very destructive Burning coal releases sulfur dioxides that cause acid deposition Coal Strip Mining Coal EPA targets utilities’ mercury pollution “Coal­burning power plants in the United Updated: 3:03 p.m. ET March 15, 2005 (AP) States now emit an estimated 48 tons a year of mercury, and the EPA rule aims to reduce that to 31.3 tons in 2010, 27.9 tons in 2015, and 24.3 tons in 2020.” http://www.msnbc.msn.com/id/6448213/did/7185001 How Mercury Gets into the Food Chain Chain http://www.msnbc.msn.com/id/6448213/did/7185001 EPA’s Cap and Trade Policy Cap EPA sets yearly limits on mercury emissions Industry is assigned a quantity of tradable mercury emissions certificates These are bought and sold by power companies (bid/ask system). Some companies “over pollute” and some “under pollute” Each year the EPA reduces allowable emission quantities leading to an economic solution to pollution Nuclear Energy Nuclear Used extensively in some energy­poor developed countries Little support in the United States Emits fewer air pollutants than burning coal, but creates radioactive wastes Potential for meltdown Chernobyl Accident - 1986 Chernobyl Core meltdown at a nuclear power plant in the Ukraine 31 immediate deaths, radiation sickness and death for others Europe Cloud of radiation spread by winds across Long­term health impacts downwind Map of Chernobyl Region Map “When the Civaux nuclear power plant comes on line sometime in the next 12 months, France will have 56 working nuclear plants, generating 76% of her electricity.” (Frontline) Nuclear Power in France Nuclear Some Alternatives…… Solar-Hydrogen Energy Solar-Hydrogen Photovoltaic Photovoltaic cells use sunlight energy to split water Hydrogen Hydrogen gas produced in this way can be used as fuel or to generate electricity electricity Clean, renewable technology Fuel Cells Fuel Farmed Hydrogen Farmed Photobiological Hydrogen Production Aquatic algae bio­engineered to produce hydrogen gas rather than sugars via photosynthesis Place algae in a clear tube, reduce sulfur, place in sunlight, and collect the hydrogen! Hydrogen from Algae Hydrogen Chlamydomonas reinhardtii Shec – labs System Shec Mirror array focuses sunlight on a hydrogen generator (850 C) Waste gases (methane, CO2, etc) are heated and converted to hydrogen gas. Hydrogen gas (plus O2) is used to power fuel cells. www.shec­labs.com/press/images.php Wind Energy Wind An indirect use of solar energy Wind farms are arrays of turbines Can supplement needs of some regions but is not dependable enough on it own Giant wind turbines at Aapua, Sweden http://www.xahlee.org/Whirlwheel_dir/windturbine.html San Gorgonio Field Near Palm Springs, CA Springs, Overview of Wind Energy in California “the year 2004, wind energy in California produced 4,258 million kilowatt­hours of electricity, about 1.5 percent of the state's total electricity. According to the Electric Power Research Institute, the cost of producing wind energy has decreased nearly four fold since 1980. The levelized cost of energy from wind turbines in 1993 was about 7.5 cents per kilowatt/hour. With current wind research and development efforts, the Energy Commission estimates that newer technologies can reduce the cost of wind energy to 3.5 cents per kilowatt­hour.” http://www.energy.ca.gov/wind/overview.html Electricity Costs (2003) Electricity Fusion Energy is released when atomic nuclei fuse This process produces solar energy Attempts to mimic this process on Earth require use of lasers, magnetic fields source Not yet a commercially viable energy Changes in the World of Life Adaptations of species have changed the environment Photosynthetic organisms that arose during the Proterozoic altered the atmosphere by adding oxygen Change is natural Humans and Change Humans Unlike previous species, human have the capacity to observe and make decisions about the changes they bring about. A couple of examples of using misplaced resources…. Gas for the Greenhouse Gas "By transporting CO2 by pipeline from the Shell refineries in Pernis to the cultivators in the Westland, the emission of greenhouse gas can be greatly reduced. At the same time, the farmers can save a lot of money; there is no more need for them to produce their CO2 themselves". http://www.radionetherlands.nl/features/science/051107rf OCAP Waste CO2 Used in OCAP Greenhouses Greenhouses 6 CO2 + 6 H2O + sunlight C6H12O6 + 6O2 “Anything Into Oil” Changing World Technologies, Inc. “…Carthage, Missouri, turkey plant accumulates 1.3 million gallons a day of turkey grease, guts, fat, and feathers that is stored in lagoons and sent to waste treatment facilities” Estimated production of fuel oil, 500 barrels a day. http://www.perc.org/perc.php?id=290 “Twenty tons of slaughterhouse turkey parts, freshly dumped by a truck, await processing into oil, gas, and minerals at the thermal conversion process plant in Carthage, Missouri. When the plant reaches full capacity in the fall, it will process 10 dump trucks of leftovers, one tanker truck of blood, and one tanker truck of discarded restaurant grease every 24 hours.” ...
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This note was uploaded on 02/04/2011 for the course BIOL 4486 taught by Professor Staff during the Fall '08 term at Kennesaw.

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