Module 3 Lesson 1: People and the Forest REVIEWER-312 PDF

Module 3 Lesson 1: People and the Forest  Monoculture- Ecological simplification in which only one type of plant is cultivated over a large area. FORESTS and their ROLES...

Module 3 Lesson 1: People and the Forest  Monoculture- Ecological simplification in which only one type of plant is cultivated over a large area. FORESTS and their ROLES  Disadvantage of monocultures: at increased risk of damage from insect  Provide many goods and services to pests and disease-causing support human society microorganisms.  occupy less than one-third of Earth’s  Sustainable forestry- the use and total land area. management of forest ecosystems in  Timber harvested from forests is used an environmentally balanced and for fuel construction materials, and enduring way paper products.  Wildlife Corridor- A protected zone  supply nuts, mushrooms, fruits, and that connects isolated unlogged or medicines. undeveloped areas.  provide employment for millions of  Harvesting Trees people worldwide and offer recreation  about 3.5 million m3 (120 million ft3) and spiritual sustenance in an of wood are harvested annually increasingly crowded world. (forfuelwood, timber, and other products) ROLE OF FORESTS IN THE HYDROLOGIC  5 countries with the greatest tree CYCLE harvests: United States, Canada, Russia, Brazil, and China  regulating global biogeochemical  About 50% of harvested wood is cycles like those for carbon and burned directly as fuelwood or used to nitrogen make charcoal.  Photosynthesis by trees removes large quantities of heat-trapping carbon Harvesting trees dioxide from the atmosphere and fixes  Selective Cutting it into carbon compounds, while  mature trees are cut individually releasing oxygen back into the or in small clusters while the atmosphere. rest of the forest remains intact,  act as carbon “sinks,” which may help allows the forest to regenerate mitigate climate warming, naturally.  produce oxygen for cellular respiration  The older, mature trees are of organisms selectively harvested from time  Tree roots hold vast tracts of soil in to time, and the forest place, reducing erosion and mudslides regenerates itself naturally.  protect watersheds; moderation of  Shelterwood Cutting water flow provides a more regulated  The removal of all mature trees flow of water downstream in an area over an extended  Forest soils remove impurities from period. In the first year of water, improving its quality. harvest, undesirable tree  provide a variety of essential habitats species and dead or diseased for many organisms trees are removed. Forest Management  As younger trees mature, they produce seedlings, which can  Management for timber production continue to grow as the now- disrupts a forest’s natural condition mature trees are harvested. and alters its species composition and other characteristics.   Seed Tree Cutting Boreal Forests and Deforestation  almost all trees are harvested  Extensive deforestation in boreal from an area forests due to logging began in the late  a scattering of desirable trees is 1980s. left behind to provide seeds for  Boreal forests occur in Alaska, the regeneration of the forest. Canada, Scandinavia, and northern  Clear-Cutting Russia and are dominated by  A logging practice in which all coniferous evergreen trees such as the trees in a stand of forest are spruce, fir, cedar, and hemlock. cut, leaving just the stumps.  the world’s largest, covering about Deforestation 11% of Earth’s land.  primary source of the world’s industrial  The temporary or permanent wood and wood fiber. clearance of large expanses of forest for agriculture or other uses. 2 types of tropical forests  Causes of the decades-long trend of  Tropical Rain Forests deforestation includes:  prevail in warm areas that receive  fires caused by drought and land clearing practices 200 cm (79 in) or more of precipitation annually.  expansion of agriculture  are found in Central and South  construction of roads  tree harvests America, Africa, and Southeast Asia, but almost half of them are in  insects just three countries: Brazil,  disease Democratic Republic of the Congo,  mining. and Indonesia  Most of the world’s deforestation is  Tropical Dry Forests currently taking place in Africa and  occur in other tropical areas where South America annual precipitation is less but is Results of Deforestation still enough to support trees.  India, Kenya, Zimbabwe, Egypt,  decreased soil fertility and Brazil  Uncontrolled soil erosion  Increased sedimentation of waterways Why are tropical rain forests caused by soil erosion harms disappearing? downstream fisheries.  Population growth  formation of deserts  Deforestation  Disruption of Regulation of water flow  Agricultural expansion → alternating periods of flood and  economic, social, and government drought factors  extinction of many species  3 agents: subsistence agriculture,  habitat modification and destruction commercial logging, and cattle  regional and global climate changes ranching  increase in global temperature by  For fuelwood releasing carbon originally stored in  Wood as heating and cooking fuel the trees into the atmosphere as  wood cut for fuel is converted to carbon dioxide charcoal, which is then used to power steel, brick, and cement factories. Lesson 2 People and waters The Importance of Water  Aquifers  underground reservoirs in which  All life forms, from unicellular bacteria groundwater is stored to multicellular plants and animals, contain water. Properties of Water  Humans are composed of  Consisting of two atoms of approximately 60 percent water by hydrogen and one atom of oxygen. body weight.  polar  Drinking water  high melting/ freezing point (0°C,  agriculture, manufacturing, mining, 32°F) energy production, and waste  High boiling point (100°C, 212°F) disposal.  most water exists in the liquid form  97%-saltwater organisms need.  Fresh water is distributed unevenly  high heat capacity  A solvent  In nature, water is never completely The Hydrologic Cycle and Our Supply of pure because it contains dissolved Fresh Water gases from the atmosphere and  Hydrologic Cycle dissolved mineral salts from the land  water continuously circulates Water Pollution through the environment, from the ocean to the atmosphere to the  A physical or chemical change in water land and back to the ocean that adversely affects the health of  provides a continual renewal of the humans and other organisms. supply of fresh water on land  Liquid and Solid Precipitation  Continuously falls from atmosphere to the land and ocean.  Evaporation  Continuously moves water vapor from the land and ocean into the atmosphere.  Surface Water  Precipitation that remains on the surface of the land and does not seep down through the soil.  Runoff  The movement of fresh water from precipitation and snowmelt to rivers, lakes, wetlands, and the ocean.  Drainage Basin, or Watershed  the area of land drained by a single river or stream  Groundwater  The supply of fresh water under Earth’s surface that is stored in underground aquifers. Eutrophication: An Enrichment Problem  The most common pollutants, such as pesticides, fertilizers,  Oligotrophic and organic compounds, seep  Lakes, estuaries, and slow- into groundwater from municipal flowing streams that have sanitary landfills, underground minimal levels of nutrients; storage tanks, backyards, golf Supports small populations courses, and intensively of aquatic organisms cultivated agricultural lands  Eutrophication  enrichment of a lake, an The Global Ocean estuary, or a slow-flowing  ocean is a vast wilderness stream  It teems with life—from warmblooded  by inorganic plant and algal nutrients mammals such as whales to such as phosphorus; softbodied invertebrates such as  Eutrophic jellyfish.  an enriched body of water→  It is essential to the hydrologic cycle increased photosynthetic that provides water productivity; presence of vast  It affects cycles of matter on land, numbers of algae and influences our climate and weather, cyanobacteria and provides foods that enable millions  Artificial Eutrophication of people to survive.  Overnourishment of an aquatic ecosystem by nutrients such as Patterns of Circulation in the Ocean nitrates and phosphates due to human activities such as  Gyres agriculture and discharge from  Large, circular ocean current sewage treatment plants. systems that often encompass an entire ocean basin. 2 Sources of Water Pollution  Coriolis effect 1. Point source pollution  influences the paths of surface,  is discharged into the or shallow, ocean currents just environment through pipes, as it does the winds sewers, or ditches from specific  Earth’s rotation from west to east sites such as factories or causes surface ocean currents to sewage treatment plants; swerve to the right in the Northern relatively easy to control Hemisphere legislatively, but accidents still  In the Southern Hemisphere, ocean occur. currents swerve to the left, thereby 2. nonpoint source pollution moving in a circular, counterclockwise  Pollution that enter bodies of pattern water over large areas rather Vertical Mixing of Ocean Water than being concentrated at a single point of entry.  Variations in the density (mass per unit volume) of seawater affect deep-ocean Polluted Runoff- Pollutants that enter bodies currents. of water over large areas rather than at a  Cold, salty water is denser than single point cause nonpoint source pollution. warmer, less salty water. Groundwater Pollution  Colder, salty ocean water sinks and flows under warmer, less salty water,  drinking water from generating currents far below the groundwater, is also withdrawn surface. for irrigation and industry.   Ocean Conveyor Belt  Atlantic hurricanes are stronger and  moves cold, salty deep-sea more numerous than usual during a La water from higher to lower Niña event latitudes, where it warms up.  affects regional and possibly global climate Lesson 3: People and Climate  shifts from one equilibrium state to another. El Niño–Southern Oscillation Atmosphere and Climate Earth’s atmosphere  El Niño–Southern Oscillation (ENSO)  is a thin layer of mixed gases that  A periodic, large-scale warming of extends upward approximately 500 surface waters of the tropical km. eastern Pacific Ocean that  It contains the air we breathe and temporarily alters both ocean and protects us from the heat blast atmospheric circulation patterns. radiated from the sun.  Every 3 to 7 years, the trade winds 4 distinct zones of the atmosphere weaken, and the warm mass of water expands eastward to South America, 1. Troposphere – is in the lowest region increasing surface temperatures in the closest to the Earth’s surface where usually cooler east Pacific most of the weather occurs. Weather  During an ENSO event, however, the includes temperature, atmospheric colder, nutrient-rich deep water is pressure, precipitation, cloudiness, about 150 m (490 ft) below the humidity, and wind. Climate is the surface, and the warmer surface typical weather patterns that occur in a temperatures and weak trade winds place over a period of years. The  pre1997–1998 ENSO- the strongest uppermost layer of the troposphere is on record, caused more than 20,000 called tropopause. deaths and $33 billion in property 2. Stratosphere - approximately 18 km damage worldwide above tropopause which has almost  TAO/ TRITON array- instruments no water vapor and nearly 1,000 times collect oceanic and weather data more ozone (O3). Near the earth’s during normal conditions and El Niño surface ozone is a pollutant, but in the events vent upwelling stratosphere it absorbs certain wavelengths of sun’s radiation, La Niña protecting life on the earth’s surface.  in Spanish, “the girl child” The uppermost layer of stratosphere is  occurs when the surface water called stratopause. temperature in the eastern Pacific 3. Mesosphere (middle layer) – the Ocean becomes unusually cool and coldest layer of the atmosphere which westbound trade winds become reaches approximately 80km above unusually strong. the earth’s surface. Meteors usually  often occurs after an El Niño event and burn up in this region. is considered part of the natural 4. Thermosphere (heated layer) – a oscillation of ocean temperature. region where aurora borealis (northern  typically causes wetter-than-usual lights) and aurora australis (southern winters in the Pacific Northwest, lights) occur. warmer weather in the Southeast, and drought conditions in the Southwest. Earth absorbs heat radiation from the sun Mitigation of Global Climate Change: unequally across the globe. Near the  Developing alternatives to fossil fuels equator receives more incoming solar radiation (insolation) than at high  Reducing energy use latitudes. This energy absorption warms the  Energy-pricing Strategies atmosphere slightly. About half of insolation  Planting and maintaining forests reaches the earth’s surface. Some of this  Innovating technology for carbon energy is reflected by bright surfaces, such management as snow, ice, and sand. The rest is absorbed  Increasing efficiency of coalfired power by the earth’s surface and by water. Surfaces plants that reflect energy have a high albedo  Increasing fuel economy of motor (reflectivity). vehicles  Redesigning cities to reduce reliance on single occupant vehicles Causes of Global Climate Change  Insulating buildings to reduce the need for heating in the winter and cooling in 1. Human Activities the summer.  Greenhouse effect is the natural warming of the Earth’s surface that Adaptation to Global Climate Change results from trapping the sun’s heat  People living in coastal areas could be in the earth’s atmosphere. These moved inland, away from the dangers gases in the atmosphere that keep of storm surges. the sun’s heat from escaping are called greenhouse gasses.  Construction of massive sea walls to 2. Volcanic eruption protect coastal land.  During volcanic eruption, huge  Countries with temperate climates are amount of natural aerosols like evaluating semitropical crops to carbon dioxide, sulfur dioxides, salt determine the best substitutes for crystals, volcanic ashes or dust, traditional crops as the climate warms. and even microorganisms like  Large lumber companies are bacteria and viruses are released developing heat- and drought-resistant to the atmosphere. strains of trees that will be harvested 3. Orbital Changes when global climate change may be  the earth’s movement around the well advanced. sun can also cause climate change as proposed by the Milankovitch theory though its impact is considered as insignificant in our present climate patterns. Effects of Climate Change  Global temperature rise  Warming ocean  Shrinking ice sheets  Glacial retreat  Decreased snow cover  Rise of sea level  Declining Arctic Sea ice  Extreme Events  Ocean Acidification Lesson 4 Energy is mixed with limestone to neutralize acidic compounds produced during Energy Consumption combustion.  Human society depends on energy.  In the United States several large  World energy consumption has power plants are testing fluidizedbed increased every year since 1982, combustion, and a few small plants are with most of the increase occurring already using this technology. in developing countries.  The Clean Air Act Amendments of 1990 provide incentives for utility Coal companies to convert to clean coal  the most abundant fossil fuel in the technologies. world Oil and Natural Gas  found primarily in the Northern Hemisphere  Petroleum, or crude oil, is a liquid  The largest coal deposits are in the composed of hundreds of hydrocarbon United States, Russia, China, compounds. Australia, India, Germany, and  Oil is also used to produce South Africa petrochemicals, compounds used to make products such as fertilizers, Coal Mining plastics, paints, pesticides, medicines,  2 basic types of coal mines: surface and synthetic fibers. and subsurface (underground) mines.  During petroleum refining, the  Surface Mining - extraction of mineral compounds are separated into and energy resources near Earth’s different products—such as gases, jet surface by first removing the soil, fuel, heating oil, diesel, and asphalt— subsoil, and overlying rock strata. based on their different boiling points  Subsurface Mining - extraction of  natural gas contains only a few mineral and energy resources from hydrocarbons: methane and smaller deep underground deposits. amounts of ethane, propane, and butane. Environmental Impacts of Coal  Propane and butane are separated  Acid Mine Drainage - Pollution from the natural gas, stored in caused when sulphuric acid and pressurized tanks as a liquid called dangerous dissolved materials, such liquefied petroleum gas, and used as lead, arsenic, and cadmium, wash primarily in rural areas as fuel for from coal and metal mines into nearby heating and cooking. lakes and streams.  Methane is used to heat residential  One of the most land - destructive and commercial buildings, to generate types of surface mining is electricity in power plants, and for a mountaintop removal. variety of purposes in the organic  Acid Deposition - coal contains sulfur chemistry industry. and nitrogen that, when burned, are  Natural gas use is increasing in three released into the atmosphere as sulfur main areas: electricity generation, oxides (SO2 and SO3) and nitrogen transportation, and commercial oxides (NO, NO2, and N2O), many of cooling. which form acids when they react with  Natural gas is often used in water. cogeneration, a clean and efficient process in which natural gas is used to Making Coal Cleaner produce both electricity and steam; the  Fluidized-Bed Combustion - A clean- heat of the exhaust gases provides coal technology in which crushed coal  energy to make steam for water and  Fusion - two small atoms are space heating combined, forming one larger atom of  Natural gas efficiently fuels residential a different element and commercial air-cooling systems Conventional Nuclear Fission Environmental Impacts of Oil and Natural Uranium ore Gas  mineral fuel used in conventional  Extracting, transporting, and burning nuclear power plants oil and natural gas create a variety of  nonrenewable resource present in environmental problems. limited amounts in sedimentary rock in  burning oil and natural gas produces Earth’s crust. CO2 that contributes to global climate change. Enrichment  Burning oil also leads to acid deposition and the formation of  The process by which uranium ore is photochemical smog. refined after mining to increase the  Natural gas, on the other hand, is a concentration of fissionable U-235. relatively clean, efficient source of Nuclear Reactor energy that contains almost no sulphur and releases far less CO2, fewer  A device that initiates and maintains a hydrocarbons, and almost no controlled nuclear fission chain particulate matter compared to oil and reaction to produce energy for coal. electricity. A typical nuclear reactor  One risk of oil and natural gas contains 150 to 250 fuel assemblies. production relates to their transport,  A typical nuclear power plant has four often over long distances by pipelines main parts: the reactor core, the steam or ocean tankers. generator, the turbine, and the  Natural gas leaks, while rare, can lead condenser to massive explosions.  Nuclear fission occurs in the reactor  Oil spills create environmental core, and the heat produced by fission damage, particularly in aquatic is used to produce steam from liquid ecosystems, where an oil slick can water in the steam generator. travel great distances.  The turbine uses the steam to generate electricity, and the condenser Nuclear Energy cools the steam, converting it back to a  The energy released by nuclear fission liquid. or fusion. Nuclear Energy and Fossil Fuels  Involves changes in the nuclei of atoms; small amounts of matter from  Worldwide, nuclear power production the nucleus are converted into large is steadily increasing. amounts of energy.  In part, this is due to concerns about  Nuclear reactions produce 100,000 climate change, but it is primarily times more energy per atom than is driven by an increasing demand for available from a chemical bond energy. between two atoms.  nuclear energy emits few pollutants  Fission - The splitting of an atomic into the atmosphere. nucleus into two smaller fragments,  Nuclear energy can also provide accompanied by the release of a large power without producing climate amount of energy. altering CO2.  spent fuel- Used fuel elements that were irradiated in a nuclear reactor   Nuclear power Plants produce does not require mechanical devices radioactive coolant fluids and gases in to distribute the collected heat. the reactor Which are extremely Photovoltaic Solar Cells dangerous, and the hazards of their health and environmental impacts  A wafer or thin film of solid-state require that special measures be taken materials, such as silicon or gallium to ensure their safe storage and arsenide, that is treated with certain disposal. metals in such a way that the film  At high temperatures, the metal generates electricity when solar encasing uranium fuel can melt, energy is absorbed. releasing radiation; this is called a  Photovoltaics generate energy that meltdown can pump water, refrigerate  water used in a nuclear reactor to vaccines, grind grain, charge transfer heat can boil away during an batteries, and supply rural homes accident, contaminating the with lighting. atmosphere with radioactivity.  PVs creates no air or water  Nuclear power risks are involuntary pollution but the manufacturing and potentially catastrophic process requires industrial chemicals, many of which are toxic Radioactive Wastes  A means of producing electricity in  classified as either “low level” or “high which the sun’s energy is level.” concentrated using mirrors or  low-level radioactive wastes - Solids, lenses onto a fluid-filled pipe; the liquids, or gases that give off small heated fluid is used to generate amounts of ionizing radiation. electricity.  high-level radioactive wastes -  are inherently more efficient than Radioactive solids, liquids, or gases other solar technologies because that initially give off large amounts of they concentrate the sun’s energy. ionizing radiation.  Hydrogen is a clean fuel; it produces water and heat as it Direct Solar Energy burns, but it produces no sulfur  sun produces a tremendous amount of oxides, carbon monoxide, energy, most of which dissipates into hydrocarbon particulates, or CO2 space. emissions.  Only a small portion is radiated to  It does produce some nitrogen Earth. oxides, though in amounts fairly  Solar energy differs from fossil and easy to control nuclear fuels in that it is always  Hydrogen has the potential to available; provide energy for transportation  Solar energy will deplete only when (in the form of hydrogenpowered the sun’s nuclear fire burns out. automobiles) as well as for heating buildings and producing electricity. Heating Buildings and Water  fuel cell - A device that directly  Active Solar Heating - A system of converts chemical energy into putting the sun’s energy to use in electricity. A fuel cell requires which collectors absorb solar energy hydrogen and oxygen from the air. and pumps or fans distribute the collected heat.  Passive Solar Heating - A system of putting the sun’s energy to use that Indirect Solar Energy Wind Energy  Some renewable energy sources  wind energy- Electric energy obtained indirectly use the sun’s energy. from surface air currents caused by  Combustion of biomass (organic the solar warming of air matter) is an example of indirect solar  Wind produces no waste and is a energy because plants use solar clean source of energy. energy for photosynthesis and store  It produces no emissions of sulfur the energy in biomass. dioxide, carbon dioxide, or nitrogen  Windmills, or wind turbines, use wind oxides. Every kilowatt-hour of energy to generate electricity. electricity generated by wind power  The damming of rivers and streams to rather than fossil fuels prevents as generate electricity is a type of much as 1 kg (2.2 lb) of the hydropower—the energy of flowing greenhouse gas CO2 from entering water. the atmosphere.  one concern is the deaths of birds and Biomass Energy bats.  Biomass - Plant and animal material Hydropower used as fuel.  Biomass fuel, which may be a solid,  A form of renewable energy that relies liquid, or gas, is burned to release its on flowing or falling water to generate energy. electricity  Solid biomass fuels such as wood,  more efficient than any other energy charcoal (wood turned into coal by source for producing electricity; about partial burning), animal dung, and peat 90 % of available hydropower energy (partly decayed plant matter found in is converted into consumable bogs and swamps) supply a electricity. substantial portion of the world’s  form of solar energy in greatest use energy.  10 countries with the greatest  Biogas- usually composed of a mixture hydroelectric production are: of gases (mostly methane), is like (decreasing order) Canada, the United natural gas. It is a clean fuel—its States, Brazil, China, Russia, Norway, combustion produces fewer pollutants Japan, India, Sweden, and France than either coal or biomass biogas Disadvantages: digesters use microbial decomposition of household and agricultural wastes  Building a dam changes the natural to produce biogas for cooking and flow of a river: Water backs up, lighting flooding large areas of land and  When biogas conversion is complete, forming a reservoir, which destroys the solid remains are removed from plant and animal habitats. the digester and used as fertilizer.  Native fishes are particularly being  Biomass can also be converted into harmed by dams because the original liquid fuels, especially methanol river ecosystem is so altered. (methyl alcohol) and ethanol (ethyl  The migration of spawning fish is also alcohol), which can replace gasoline in altered internal combustion engines.  Below the dam, the once-powerful  Bio diesel- made from plant or animal river is reduced to a relative trickle. oils  The natural beauty of the countryside is affected, and certain forms of wilderness recreation are made impossible or less enjoyable, although  the dams permit water sports in the reservoir Geothermal energy  Energy from Earth’s interior, used for space heating or generation of electricity.  typically associated with volcanism  considered environmentally benign because it emits only a fraction of the air pollutants released by conventional fossil fuel–based energy technologies. The most common environmental hazard is the emission of hydrogen sulfide (H2S) gas, which comes from the very low levels of dissolved minerals and salts found in the steam or hot water. Tidal Energy  A dam built across a bay can harness the energy of large tides to generate electricity. As the tide falls, water flowing back to the ocean over the dam’s spillway turns a turbine and generates electricity through tidal energy.  Cannot become a significant resource worldwide because few areas experience large enough differences in water level between high and low tides to make power generation feasible  Disadvantages: high cost of building a tidal power station and potential environmental problems associated with tidal energy in estuaries.