Lecture 5Continuing Fossil Fuels & Renewable ResourcesMay 4,.docx
- 1. Lecture 5 Continuing Fossil Fuels & Renewable Resources May 4, 2016 Oil Like coal, most of the oil on Earth was formed millions of years ago Certain warm shallow seas, such as the Gulf of Mexico and Tethys Sea were so ideal for life that organic material was formed faster than it could decompose Large masses of organic material became buried at the sea bottom, were heated and pressurized, forming oil. The present day distribution of oil lines up with these ancient shallow seas Majority of oil reserves are in Middle Eastern countries In elemental composition, oil is similar to coal Mostly carbon, but also hydrogen, nitrogen, oxygen and sulfur As a liquid, oil can be distilled (separated) into other fuels such as gasoline, kerosene, and diesel fuel Oil Extraction As a liquid, oil can be pumped directly out of the ground. This eliminates the need for mining.
- 2. A long drill is used to bore deep into the Earth to reach the deposit. The hole is lined with a steel pipe and cement. The top is outfitted with a collection of pipes and valves The ease of transporting oil has enabled drilling at very remote locations At its peak, Alaska accounted for about 25% of the U.S. oil production It is transported to the southern ports of the state through the Alaska Oil Pipeline. As a liquid, oil can also escape more easily, forming an oil spill Oil spills are devastating to marine life Penetrates through the fur and feathers of animals, reducing their ability to fly, float, and insulate themselves Benthic organisms, living at the bottom of the sea, can be suffocated Entire populations of krill and plankton can be wiped out Oil Reserves Of the fossil fuels, oil has been the most quickly depleted Peak oil is defined as the point at which all known oil reserves have been tapped and production will begin declining in the following years. The U.S. reached its peak production in the 1970s The estimated date of worldwide peak oil is unknown
- 3. OPEC Organization of Petroleum Exporting Countries (OPEC) is comprised of 13 countries. Members: Algeria, Angola, Ecuador, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, United Arab Emirates, and Venezuela. In 2010, OPEC holds about 77% of the entire world’s crude oil reserves. The U.S. has only about 2% of the world’s proven oil reserves. China has 1.1% and India has 0.4%. Japan as none It will be necessary to find alternatives to or other sources of crude oil to sustain the today’s usage. Natural Gas Natural gas is actually a mixtures of gases 50-90% methane Smaller amounts of propane and butane As a gas, it is the most difficult fossil fuel to transport A supply of natural gas exists above most oil wells, however, if no pipelines are nearby, it will often simply be burned off. Natural gas has a relatively small amount of pollution produced by burning it (Only two waste products-CO2 & Water vapor) Natural Gas Extraction Hydraulic Fracturing or Fracking-a controversial technique used to extract natural gas from rock formations (such as shale) that are not very permeable. Fracturing has become an increasingly popular tool for extracting natural gas, especially with the discovery of the methane-rich Marcellus Shale
- 4. First, a mixture of water and other chemicals is pumped into a narrow hole drilled into the rock formation. The pressure created from this fluid causes the rock formation to crack. Sand is injected afterwards to fill the cracks, because it is more permeable and allows the methane to seep out. There are two big issues that make hydraulic fracturing controversial Millions of gallons of water are needed to “frack” the well The water that returns back to the surface called, flow-back water, is contaminated with minerals, fracturing fluid chemicals and natural gas itself. The disposal of flow-back water has been a major source of contamination Due to an exemption given to gas drillers in a 2006 law, they do not have to disclose the full list of chemicals injected into a well. These chemicals include carcinogens and endocrine disruptors Water collected from a well in rural Bradford County, Pennsylvania. Energy Consumption Fossil fuels currently provide about 85% of all commercial
- 5. energy in the world. Other renewable sources (wind, solar, hydroelectric) make up 7% of commercial power Nuclear power makes up 8% of commercial power The richest 20 countries consume nearly 80% of natural gas, 65% of oil, and 50% of coal production annually On average, each person in the U.S. & Canada uses more than 300 GJ of energy annually In the poorest countries of the world, each person generally consumes less than one GJ annually. Energy & Renewable Resources “The use of solar energy has not been opened up because the oil industry does not own the sun.” Ralph Nadar Chapter 13 Net Energy only energy that counts The usable amount of high-quality energy available from a given quantity of an energy resource is its net energy yield: the total amount of useful energy available from an energy resource minus the energy (or cost) needed to make it available to consumers. We can express net energy as the ratio of energy produced to the energy used to produce it. As the ratio increases, the net energy also rises. When the ratio is less than 1, there is a net energy loss. Net energy ratios for various energy systems over their
- 6. estimated lifetimes differ widely (see graphs) Nonrenewable Energy As we have learned, nonrenewable energy (including fossil fuels and nuclear power) make up the majority of the U.S. energy portfolio. In the long-term, there are two major issues with this reliance: Dwindling supplies Environmental pollution Nonrenewable-are finite and will eventually be used up (most of our sources of coal, oil & natural gas have already been tapped) As supplies of these resources tighten, they will become more expensive to extract and the price will increase. Pollution The extraction, transport and burning of fossil fuels is also a highly polluting process. CO2 emissions vary with different energy resources Types of Energy Fossil fuels have a lot of modern applications, that we use in our everyday lives and the strategies for replacing them is going to vary for each. Electricity (hydroelectricity, wind energy, geothermal, and solar
- 7. energy) Fuel for Transportation (oil, gasoline, petroleum) Heat (biomass, solar heating, and geothermal heating) Nuclear Energy Electricity Electricity works by passing electrons from a power source through a series of wires, called a circuit. Within the circuit there are devices that use the energy released by the electrons to do work (as light, heat, etc.) Electric power is measured in watts, the rate at which electrons moving through a circuit are doing work Standard incandescent light bulb consumes 60 W of power A medium-sized car will consume about 100,000 W Renewable Electricity The greatest renewable source of electricity production currently in use is hydroelectricity Hydropower Hydroelectric power plants use running water to spin a turbine and generate electricity Hydroelectricity is very economical, with costs per kwh similar to coal Wind Energy Wind energy is similar to hydroelectricity, except that moving air provides the force to spin the generator. Wind turbines are able to orient themselves to face the
- 8. oncoming wind As the air passes through, the blades rotate These are attached to a shaft, which connects to the turbine. A single wind turbine can generate 1-7 megawatts of energy per year, not enough for a large population. Wind farms are large numbers of wind turbines clustered together The Gansu Wind Farm in China produces 6 billion kilowatt- hours of electricity per year. Wind power is comparable in cost to coal Possible negative impacts of wind turbines include: Disruption of bird and bat migration pathways, Noise and Disruption of scenery Geothermal Energy Geothermal power, like nuclear and coal, works by boiling water to steam. Naturally-occurring heat from the Earth is used in place of fuel. At a geothermal plant, two wells are drilled. One injects cold water towards the underground heat. The second directs steam to the turbine
- 9. Solar Energy An enormous amount of energy (over 1,000 watts per square meter) hits the Earth every day. This energy is very diffuse, spread out across the entire surface area of the planet. Two separate technologies have been developed to convert solar energy into electricity. Parabolic solar collection involves using curved reflective surfaces that collect light and focus it onto a concentrated point. The heat is absorbed and used to boil water into steam, which spins a turbine. Photovoltaic cells capture solar energy and convert it directly to electrical current. Solar electricity tends to be 1.5-2 times the cost of electricity from coal or other renewable sources. Not available on overcast days or at night. Geography Electricity generation by solar, wind, hydrokinetic, or geothermal plants is restricted by the natural geography of the United States. The Great Plains have the highest average wind speeds and the greatest potential for wind power. Areas with significant elevation differences and river courses
- 10. are ideal for hydroelectricity generation. The western states are the most favorable for geothermal energy production. The deserts of the southwest are ideal for solar electricity generation. Heat Besides electricity, significant amounts of fossil fuels are burned for heat, especially natural gas. LEED (Leadership in Energy and Environmental Design, awards certificates to buildings that are designed to reduce heat loss and waste, through proper insulation. Biomass Traditionally, humans have relied on burning biomass, such as wood, charcoal, and dung as a source of heat. These fuels will replenish, but produce similar levels of pollution to fossil fuels. Excess demand can also lead to deforestation. Solar Heating Energy from the sun can also be gathered to use as a source of
- 11. heat. Passive solar heat structures have no moving parts, but use south-facing windows to gather and absorb as much solar heat as possible. Active solar heat structures pump water or another liquid through a collector. Can be used for household radiant heating, or as a source of hot water for showers and cooking. Geothermal Heating Using heat stored in the soil, underground rocks and fluids in the earth’s mantle. A geothermal heat pump system can heat and cool a house by exploiting the temperature differences between the surface and underground Transportation The third major energy needed is fuel for transportation. Most of the cars, planes, and ships of the world run on petroleum products – gasoline, diesel, etc. Alternative Fuels Vehicles can be run on other fuels besides petroleum-based ones. Biofuels, like ethanol, are generated from using bacteria or yeast to ferment plant matter. Currently, the biggest source of this plant matter is corn which can influence food prices.
- 12. Hydrogen fuel cells use a chemical reaction between hydrogen and oxygen gas to generate an electric current. H2 + O2 → H2O Refueling is difficult, as pure hydrogen is a gas and difficult to store and transport safely. No waste products are produced, except for water vapor. Cars could be indirectly run on renewable energy if they had powerful enough batteries to store a charge needed to run the car for long periods of time. Lead-acid batteries, currently in use, are too large and do not hold enough energy. Nickel-Metal Hydride batteries, used in early generation hybrid cars, have a higher storage capacity, but will quickly lose a stored charge when not in use. Lithium-ion batteries are the smallest and have the best storage capacity, but are also expensive to produce. The Tesla Model S runs on lithium-ion batteries, with a range of 265 miles. Nuclear Energy “Nuclear power is a hell of a way to boil water.” Albert Einstein Nuclear power plant is a highly complex and costly system designed to perform a relatively simple task: to boil water to produce steam that spins a turbine and generates electricity. A controlled nuclear fission reaction (splitting of nucleus) is used to provide the heat. Control rods are moved in and out of the reactor core to
- 13. regulate the amount of power produced. Mining for and processing and enriching of the uranium to make fuel. Uranium-235 has an extremely large nucleus that can be split when it is hit with a high-speed neutron. This is the splitting of the nucleus into two smaller fragments. 44 A coolant, usually water, circulates through the reactor’s core to remove heat, which keeps fuel rods and other materials from melting and releasing massive amounts of radioactivity into the environment. One big advantage to nuclear power is that, under normal conditions, it does not release any air pollution, only steam. Energy Conversion Efficiencies In addition to finding alternative, renewable energy sources, it is also important to reduce energy consumption. Energy Efficiency is a measure of the percentage of energy consumed that actually performs the desired work. Incandescent light bulbs: 5-10% efficient Compact fluorescent: 20-33% efficient LED: 40-60% efficient Commercial Energy wasted 84% 46
- 14. Reducing energy waste is the most efficient way to provide more energy, reduce pollution and environmental degradation and slow climate change. A nuclear power plant, wastes about 65% of the energy in its nuclear fuel A coal-fired plant, wastes about 66% of its energy How commercial energy flows through the U.S. economy Promoting Renewable Energy Distributional surcharges are small charges levied on all utility customers to help finance research and development of renewable energy. A renewable portfolio is a state mandated minimum percentage of energy that utilities must get from renewable sources. Green pricing is the practice of some electricity suppliers offering plans (at a premium) that only use renewable sources for electricity. California has enacted a 33% renewable portfolio standard set for 2020. Promoting Renewable Energy The energy star program is a federal initiative to promote and provide incentives for purchasing more efficient devices and appliances. Energy conservation tends to be highly tied to consumer prices. In response to 1970’s oil prices, average U.S. automobile gas-
- 15. mileage increased from 13 mpg in 1975 to 28.8 mpg in 1988. Falling fuel prices in the 1980s-early 2000s discouraged further improvements in fuel economy. The recent popularity of smaller cars, hybrid cars, and electric cars has improved average MPG again. Politics and Economics play a big role Governments can use three strategies to help stimulate or reduce the short-term and long-term use of a particular energy resource. Keep the prices of selected energy resources artificially low to encourage their use Keep the prices of the others artificially high to discourage their use Emphasize consumer education and information Next week’s assignments Journal # 2-Due 05/11/16 Lecture Worksheets #5 & #6 Due by end of class Reading Assignments: Readings: Chap. 11 (pgs. 254-271); Chap. 15 (pgs. 376-388); Chap. 16 (pgs. (412-427) Journal # 2 Congratulations!! YOU are now the leader of the entire world. List the four most important features of your energy policy and
- 16. explain why each of them is important and how they relate to each other. (Use your lecture notes, textbook and personal thoughts to answer) Unit 2-Lecture 4 Agriculture, Aquaculture & Non-renewable Resources April 27, 2016 Agriculture • About 10,000 years ago, humans began to shift from hunting for and gathering their food to growing it and raising animals for food and labor. • Today, three systems supply most of our food. • Croplands produce mostly grains. • Rangelands, pastures, and feedlots produce meat. • Fisheries and aquaculture provide us with seafood. • About 66% of the world’s people survive primarily on plant crops. • Only a few species of mammals and fish provide most of the world’s meat and seafood. Food Production has increased dramatically • Since 1960, there has been an increase in global food
- 17. production from all three of the major food production systems because of technological advances. • Tractors, farm machinery and high-tech fishing equipment. • Irrigation. • Inorganic chemical fertilizers, pesticides, high-yield grain varieties, and industrialized production of livestock and fish. Staple Crops • 2/3 of human food consumption is comprised of just three staple crops-Wheat, Corn and Rice. Rank Commodity Production (metric tons) 1 Sugar Cane 1.8 Billion 2 Maize 88.5 Million 3 Rice 722 Million 4 Wheat 701 Million 5 Milk (cow) 614 Million
- 18. 6 Potatoes 373 Million 7 Sugar Beet 273 Million Most of the major world food staples are plants. • Why? In an ecological pyramid, only about 10% of the energy in one trophic level will be incorporated into the next. • Consuming plants directly is more efficient than raising animals • 7-12 pounds of grain is required to produce a single pound of beef Simplified rock cycle • The rock cycle is the interaction of physical and or chemical processes that change rock from one form to another • It takes millions of years for this cycle to happen
- 19. Three Major Types of Rocks • A mineral -an element or inorganic compound that occurs naturally in the earth’s crust as a solid with a regular internal crystalline structure. • Rock is a solid combination of one or more minerals found in the earth's crust. • Some rocks, such as limestone and quartzite contain only one mineral while most consist of two or more minerals • Three broad classes: • Sedimentary rock (limestone, sandstone) • Igneous rock (granite) • Metamorphic rock (slate, marble) Soil -Soil is a mixture of minerals and partially decomposed organic matter -Soil begins as rock, but is gradually broken down through erosion. • Mechanical erosion: physically breaking down of rock by wind and water
- 20. • Chemical Erosion: changes in the molecular structures • Forest soil has an O horizon, which is mostly non-decomposed plant litter. • Grasslands have a much deeper A horizon, which contains a lot of organic matter mixed with some minerals (also called topsoil). • Both grasslands and forests have a layer of clay, mostly made of minerals with little organic matter, B horizon. • The last layer in both ecosystems is parent material or C horizon, which is the bedrock from which the soil was formed. Topsoil erosion is a serious problem in parts of the world • Soil erosion is the movement of soil components, especially surface litter and topsoil from one place to another by the actions of wind and water. • Erosion of topsoil has two major harmful effects. • Loss of soil fertility through depletion of plant nutrients in topsoil. • Water pollution in nearby surface waters, where eroded
- 21. topsoil ends up as sediment. This can kill fish and shellfish and clog irrigation ditches, boat channels, reservoirs, and lakes. Erosion from Water • Mechanical erosion from rainfall takes four forms ranked by severity: • Splash erosion: tiny crater caused by the impact of a single drop of water • Sheet erosion: transportation of loose soil particles along a flow of runoff water • Rill erosion: occurs when the flowing water merges into small channels. • Gully erosion: the most severe-caused by rapidly flowing water creating deep channels in the ground. Wind Erosion • In arid regions, wind is the major cause of erosion • One of the worst storms of the Dust Bowl dumped 12 million pounds of eroded topsoil on Chicago.
- 22. Topsoil erosion: world-wide Soil Conservation • Soil conservation involves using a variety of ways to reduce soil erosion and restore soil fertility, mostly by keeping the soil covered with vegetation. • Contour plowing: reduces water erosion by planting crops along the slope of the land rather than straight up and down. • Terracing: converts steeply sloped land into a series of flattened terraces • The stair-like terracing slows the downward runoff of water, reducing erosion • Windbreaks: Farmers can establish windbreaks, or shelterbelts, of trees
- 23. around crop fields to reduce wind erosion. Alley Cropping -involves one or more crops planted together in strips or alleys between trees and shrubs, which provide shade. Strip cropping involves planting alternating strips of a row crop and another crop that completely covers the soil, called a cover crop. • The cover crops trap any soil that erodes from the row crops Agricultural Water Usage • Irrigation, the application of water to soil, accounts for largest single share of global water use • Irrigation systems are compared with efficiency, a percentage of the amount of water withdrawn that actually makes it to the roots of target plants. • Most irrigation systems are inefficient, with only about 40% of the applied water actually reaching the crops.
- 24. Furrow or Gravity Flow Irrigation: works by delivering large amounts of water through small, parallel channels that run through the field. -Water usually comes from an aqueduct system or nearby river. (40-60% efficient) If surge valves are used-80% Drip Irrigation: uses porous tubes above or below ground that gradually deliver water to the roots of individual plants. -Above or below ground pipes or tubes deliver water to individual plant roots. 90-95% efficient Center-pivot irrigation: involves a piece of equipment that rotates around a single point, creating a circle shaped irrigation field. -Water usually pumped from underground and sprayed from mobile
- 25. boom with sprinklers. 80% efficient -95% with LEPA system Fertilizer • Lack of three nutrients can slow plant growth: • Nitrogen, Phosphorous and Potassium • These nutrients are depleted during each growing season and must be replenished • Inorganic Fertilizer: synthetically made from mined minerals • Use has grown nine-fold worldwide since the 50s Organic fertilizer: derived from plant and animal matter • Animal manure-is the dung and urine of livestock • Compost is organic matter that has been decomposed by bacteria, fungi, and other microorganisms
- 26. Animal Agriculture Domestication • As with plants, each of the animals we now raise as a source of food once lived in the wild. • Generations of breeding and artificial selection, has resulted in domesticated animals growing larger and producing more food, but are now dependent on us to survive. • Also similar to plants, animals are grown in more crowded conditions to maximize production for each farm • These operations are called Concentrated Animal Feeding Operations (CAFO) Meat production has grown steadily • ~Half the world’s meat comes from livestock grazing on grass in unfenced rangelands and enclosed pastures. • The other half is produced through an industrialized system in which animals are raised mostly in densely packed feedlots and CAFOs, where
- 27. they are fed grain, fish meal, or fish oil, and typically doctored with growth hormones and antibiotics. • Feedlots and CAFOs and the animal wastes and runoff associated with them, create serious environmental impacts on the air and water. Types of Cattle Beef Cattle • Open pasture or rangeland • Cattle is moved to feedlots to be “finished.” • The process of finishing involves minimizing the movement of the cattle and providing them a much more energy intensive diet Dairy Cattle • Cows are raised indoors • Dairy cows are bred every 12-14 months in order to collect their milk. • ~80% of milk is produced in factory farms • They are grouped and herded into milking stations twice a day • Large producers are able to schedule their cows so there are constantly milking one part of the herd
- 28. Chickens • The domestic chicken are omnivorous, feeding on insects, fruit and seeds • Two Main Types of Domesticated chickens • Laying hens: have been bred for high levels of egg production (~250/yr) • Broiler hens: have been bred to grow large and quickly Chickens Laying hens • Over 90% are raised in rows and columns of small identical battery cages • Female chicks are placed in cages and spend their entire lives there • Each hen gets a space of ~a sheet of paper • Light levels are near constant at least 17 hours/day
- 29. Broiler hens • Have much larger thighs and breasts than other breeds of chicks • Reach full slaughter weight in 2 months • Raised in pens instead of cages to prevent bruising of the meat Pigs • Adult males live alone, while females and offspring travel in large groups • Boars are omnivores, feeding on mostly plant matter but also insects, worms, eggs and even small mammals • Typically raised indoors in temperature- controlled batch pens • Tails are often cut off at birth to prevent biting Health Issues • Intensive factory farming of animals has created a lot of secondary health effects in both animals and humans • Antibiotics are administered to all animals in large operation to reduce the amount of
- 30. illness and maximize their growth rate • ~70-80% of the antibiotics manufactured in the US are used on animals • Food recalls: E.coli and Salmonella are common in large animal operations due to the amount of manure and overall health of the animal • Manure is collected and stored and can runoff into nearby water sources Alternative animal agriculture • Cage-free: animals are not kept in battery cages. Confined pens may still be used • Certified Humane: animals “must be able to perform natural behaviors such as nesting.” • Free range: animals receive a certain minimum amount of outdoor access • Organic: animals were raised with organic feed and not given antibiotics Fisheries & Aquaculture • One of the earliest forms of large-scale fishing is pole
- 31. fishing, where a line is attached to a baited hook, which can catch and pull in the fish. • Of all the fishing methods, pole fishing has the lowest rate of bycatch; species of fish that are unwanted and accidentally caught. Pole Fishing Pole fishing in the Maldives. Photo by Greenpeace. • As the world population grew, so did the demand for seafood. • 15% of the world uses seafood as a primary source of protein. • Other methods began to take the place of pole fishing to meet the demand. • Longline fishing is a commercial fishing technique where baited hooks are attached to a
- 32. single, long fishing line that trails behind a ship. Long Line Fishing • Compared to pole fishing, longline fishing has a much higher rate of bycatch. • Sea birds are highly vulnerable during setting of the line. • Sea turtles, sharks, and other fish are also accidentally caught. • Fishing practices began to be exploited fully starting with the arrival of the Fairtry. • First ship to be fully-equipped with a trawler, processing plant, and storage freezers. • The fastest and most efficient way to catch fish is by trawling, where a large net is dragged behind a ship. • If the net actually drags along the bottom, it is called bottom trawling. Trawling
- 33. • Trawling has the highest rates of bycatch, since any species big enough to be caught in the net will be trapped. • Bottom-trawling has the added side effect of damaging any habitat at the bottom of the sea floor, such as coral reefs. • The large commercial trawlers were incredibly successful in Newfoundland, harvesting over 800,000 tons of cod in 1968. • In following years, harvests began to decrease. • Canada evicted the fishing fleets of other countries from its waters, but harvests continued to decline. • In 1988, fisheries managers called for a 50% reduction in allowable catch. Officials only reduced it by 10%. • The majority of the world’s fisheries are at their maximum sustainable yield.
- 34. • This is the maximum that can be harvested without diminishing the population for future years. • Overexploited fisheries are being harvested at unsustainable levels. • Over time, these can become depleted fisheries with stocks so low that fishing cannot be supported. • The Marine-Trophic Index is a measurement of the average trophic level of the total catch from a fishery. • With the loss of the cod, fishermen began pursuing herring, capelin, crabs, and other lower trophic-level organisms. • Up to the 1960s, the only regulations on fishing were territorial waters; exclusive fishing zones that reached 12 miles off each coastline. Fishing Regulations • The advent of long-range industrial fishing vessels, like the Fairtry, led to the creation of
- 35. exclusive economic zones, which extended 200 miles from each nation’s coastline. • Each nation has exclusive rights over all marine resources discovered within these zones. • Many countries now establish restrictions on the amount of fish that can be harvested within their waters. • In the United States, annual catch limits have been established and enforced by the National Oceanic and Atmospheric Administration (NOAA) since 2012. • These catch limits are lower than the maximum sustainable yield, meaning the stocks are able to recover each year. • Fully-protected marine reserves, where no living organisms can be legally harvested, have also been established to protect areas especially high in biodiversity. • As the limits of wild seafood harvesting have become increasingly clear, industries are
- 36. now beginning use aquaculture; the process of farming aquatic organisms. Aquaculture • The farming of saltwater organisms is called mariculture. • Most mariculture operations work by taking eggs or immature fish and raising them in long, rectangular nets called fish pens. • Feed and other supplements are added to the top of the pen. • Wastes drop out the bottom of the pen to the sea floor. • These operations are vulnerable to many of the same issues as large animal farms, including antibiotic overuse and manure. • Fish farming can be combined with hydroponics to create aquaponics. • Waste water from fish farming is circulated through plants, which absorb the waste as nutrients and clean the water.
- 37. • Any fish labeled as farmed was raised in a mariculture or aquaponics facility. • Wild caught fish is just that – it was caught from a body of water. Consumer Labels • MSC Certification is a label attached to any seafood that follows sustainable fishing practices, as established the Marine Stewardship Council. Geology Geologic Earth • Three Major Zones: • The core: innermost zone- extremely hot, with a solid inner part surrounded by liquid core of molten material • The mantle: surrounds the core and is thick solid rock, but under its rigid outermost layer is a zone of hot, partly melted rock that flows
- 38. • The Crust: the outermost and thinnest zone of the earth. • Continental crust-underlies the continents • Oceanic crust-underlies the ocean basins and 71% of the earth’s crust Plate Tectonics • From the deepest ocean trench to the tallest mountain, plate tectonics explains the features and movement of Earth's surface in the present and the past. • Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. The plates act like a hard and rigid shell compared to Earth’s mantle. This strong outer layer is called the lithosphere. • Continents have split apart and joined as the plates shifted. How It Works • The driving force behind plate tectonics is convection in the mantle. Hot material near the Earth's core rises, and colder mantle rock sinks. • The convection drive plates tectonics through a combination
- 39. of pushing and spreading apart at mid-ocean ridges and pulling and sinking downward at subduction zones. • There are 3 types of plate boundaries. • Subduction Zones/Convergent Margins-two tectonic plates meet and one slides beneath the other back into the mantle, the layer underneath the crust. The cold, sinking plate pulls the crust behind it downward. • Divergent Margins-two plates are spreading apart, at seafloor- spreading ridges or continental rift zones • Transform Margins-slip-sliding plates that grind past each other with a mostly horizontal motion. Transform Divergent Subduction Plate Tectonics Plate Margins and Ring of Fire
- 40. Formation and Breakup of Pangea The Carboniferous Period • During the Carboniferous period, (350-300 million years ago), much of the Earth was ideal for plant growth • The overall climate was warm and the glaciers retreated • Much of the land mass was near the equator • The dominant plants during this time were fern-like trees • The trees evolved a new carbon-based chemical compound called lignin-formed the basis of their bark. • No bacteria, fungus, or insect had yet evolved the ability to decompose lignin. • The forest, with few limiting factors, grew massive and numerous • The surplus of photosynthesis drove oxygen levels up, reaching concentrations of 35% in the atmosphere
- 41. • A short, intense ice age eventually led to the demise of the these forests. • Nearly 50 million years of accumulated plant matter (lignin) became buried under swamps. • As the plant material was exposed to greater amounts of pressure and heat , it became coal. • Today, the countries with the greatest coal deposits line up with the locations of largest carboniferous swamps-North America, Northern Europe, and Asia. Nonrenewable Mineral Resources • A mineral resource is a concentration of naturally occurring material from the earth’s crust that can be extracted and processed into useful products and raw materials at an affordable cost • Minerals are classified as nonrenewable resources • An ore is rock that contains a large enough concentration of a particular mineral-often metal-to make it profitable for mining and processing.
- 42. Applications of Coal • Coal was first widely used in China • Europeans were astonished at its ability to produce heat • The demand for coal increased tremendously during the industrial revolution of the late 19th century as the steam engine was developed. • Today, it is almost exclusively used for electricity generation • Today, the largest coal-fired power plant in the world is the Taichung Power Plant, located in Taiwan. • The plant uses a total of nearly 15 million tons of coal per year • One open hopper train car holds 100-125 tons of coal • A coal train will have 100-125 cars • Taichung uses over 1,100 train loads of coal per year, just over 3 per day.
- 43. Coal Extraction • Shallow deposits of coal can be removed by surface mining • This process requires the removal of all vegetation and topsoil before the deposit can be accessed • Open-pit mining is where large holes are dug into the earth and the minerals removed • Strip mining-actually carves away horizontal beds of coal deposit close to the surface • Mountaintop removal- method that uses machines and explosives to expose seams of coal underneath entire mountain tops • Subsurface-underground mining, removes coal through deep tunnels and shafts
- 44. • Most of the removal is done by machine and conveyor belt • The mining machines generate high amounts of explosive dust • Coal dust can build up in the lungs over long periods of time, causing Black lung disease Coal-Generated Electricity • Once the coal is extracted, its potential energy is converted to electricity in a power plant. • The coal is pulverized into a powder, then blown into the boiler • The heat from the boiler converts water into steam • Pressure from the steam causes a giant set of turbine blades to spin • The shaft of the turbine is connected to a generator, where magnets spin within wire coils to generate electricity Coal • Coal is ~90% carbon, 4% hydrogen, 3% oxygen and 1% sulfur • This is similar to the chemical composition of
- 45. plants • When coal is burned for fuel, it combines with oxygen in the air to form several air pollutants: • Carbon Dioxide • Sulfur Dioxide • Nitrogen Oxides • Soot (fine black particulates) • Burning coal also produces a great deal of leftover ash • The ash contains toxins and heavy metals including arsenic, cadmium, chromium, lead, mercury and radioactive radium • The ash is usually mixed with water, to minimize dust, then pumped into a temporary storage pond • Eventually, 70-80% of this ash is disposed of in landfills. The rest is used in concrete, asphalt, and other applications Oil • Like coal, most of the oil on Earth was formed millions
- 46. of years ago • Certain warm shallow seas, such as the Gulf of Mexico and Tethys Sea were so ideal for life that organic material was formed faster than it could decompose • Large masses of organic material became buried at the sea bottom, were heated and pressurized, forming oil. • The present day distribution of oil lines up with these ancient shallow seas • Majority of oil reserves are in Middle Eastern countries • In elemental composition, oil is similar to coal • Mostly carbon, but also hydrogen, nitrogen, oxygen and sulfur • As a liquid, oil can be distilled (separated) into other fuels such as gasoline, kerosene, and diesel fuel Oil Extraction • As a liquid, oil can be pumped directly out of the ground. This eliminates the need for mining. • A long drill is used to bore deep into the Earth
- 47. to reach the deposit. • The hole is lined with a steel pipe and cement. • The top is outfitted with a collection of pipes and valves • The ease of transporting oil has enabled drilling at very remote locations • At its peak, Alaska accounted for about 25% of the U.S. oil production • It is transported to the southern ports of the state through the Alaska Oil Pipeline. • As a liquid, oil can also escape more easily, forming an oil spill • Oil spills are devastating to marine life • Penetrates through the fur and feathers of animals, reducing their ability to fly, float, and insulate themselves • Benthic organisms, living at the bottom of the sea, can be suffocated • Entire populations of krill and plankton can be wiped out The End
- 48. Next Week’s Assignments Due: Lecture Worksheet #5 Readings: Chapter 6 (pgs. 95-101; 104-118) & Chapter 12 STUDY FOR EXAM I