环境学院研究生专业英语

研究生专业英语选编：汤兵广东工业大学环境科学与工程学院2005年1月目录CHAPTER ONE ENVIRONMENTAL INTERRELATIONSHIPS (1)1THE FIELD OF ENVIRONMENTAL OF SCIENCE (1)2THE INTERRELATED NATURE OF ENVIRONMENTAL PROBLEMS (1)3AN ECOSYSTEM APPROACH (3)4REGIONAL ENVIRONMENTAL CONCERNS (3)4.1The Wideness North (3)4.2The Agricultural Middle (4)4.3The Dry West (5)4.4The Forested West (6)5 SUMMARY (6)CHAPTER TWO Interactions: Environment and Organisms (8)1ECOLOGICAL CONCEPTS (8)1.1Environment (8)1.2Limiting Factors (9)1.3Habitat and Niche (10)2THE ROLE OF NATURAL SELECTION AND EVOLUTION (11)2.1Species Definition (11)2.2The Mechanism of Natural Selection (11)3KINDS OF ORGANISM INTERACTIONS (13)3.1Predation (14)3.2Competition (14)3.3Symbiotic Relationships (15)3.4Commensalism (15)3.5Mutualism (16)4COMMUNITY AND ECOSYSTEM INTERACTIONS (16)4.1Major Roles of Organisms (17)4.2Energy Flow Through Ecosystems (17)4.3Food Chains and Food Webs (18)5NUTRIENT CYCLES IN ECOSYSTEMS (19)5.1Carbon Cycle (19)5.2Nitrogen Cycle (20)5.3Phosphorus Cycle (21)6SUMMARY (21)CHAPTER THREE Water as a Source of International Conflict (23)1THE ROOTS OF CONFLICT (23)2EFFICIENCY VS. EQUITY (23)3ULTIMATE MARKET EFFICIENCY (24)4REGIONS OF POTENTIAL CONFLICTS (24)4.1The Middle East (24)4.2The Indian subcontinent. (25)5POTENTIAL BENEFITS OF INTEGRATED MANAGEMENT (26)6CONCLUSION (27)CHAPTER FOUR HOW EXCESSIVE WATER USE AFFECTS WATER QUALITY (28)1DEVELOPING NEW WATER-SUPPLY RESERVOIRS (28)2OVERIRRIGATING AGRICULTURAL LANDS (29)3OVERUSING WATER TO MAINTAIN URBAN LANDSCAPES (30)4FAILED OR FAILING ONSITE DISPOSAL SYSTEMS (30)5SALINITY INTRUSION IN COASTAL AQUIFERS (30)6LOSS/REDUCTION OF WETLANDS AND RIPARIAN HABITATS (30)7REDUCTION OF INSTREAM FLOWS (31)CHAPTER FIVE AUTOMOBILES AND OZONE (32)1WHAT IS OZONE? (32)2WHY IS OZONE A PUBLIC HEALTH PROBLEM? (32)3HOW IS OZONE FORMED? (32)4WHAT'S BEEN DONE TO CONTROL OZONE LEVELS? (32)5WHY AREN'T OZONE LEVELS DROPPING? (33)6PROMISING SOLUTIONS (33)7POSSIBLE CLEAN FUELS (33)CHAPTER SIX ELECTROCHEMICAL GENERATION OF HYDROGEN PEROXIDE FROM DISSOLVED OXYGEN IN ACIDIC SOLUTIONS (35)1ABSTRACT (35)2INTRODUCTION (35)3EXPERIMENTAL (37)4RESULTS AND DISCUSSION (39)4.1Stability of hydrogen peroxide (39)4.2Optimal cathodic potential (40)4.3Effect of oxygen purity and mass flow rate (42)4.4Effect of cathode surface area (42)4.5Effect of pH (43)4.6Effects of temperature and supporting electrolyte (44)4.7Potential profile and energy consumption (45)5CONCLUSIONS (45)6ACKNOWLEDGEMENTS (46)7REFERENCES (46)CHAPTER ONE ENVIRONMENTALINTERRELATIONSHIPS1THE FIELD OF ENVIRONMENTAL OF SCIENCEEnvironmental science is an interdisciplinary area of study that includes both applied and theoretical aspects of human impact on the world. Since humans are generally organized into groups, environmental science must deal with politics, social organization, economics, ethics, and philosophy. Thus, environmental science is a mixture of traditional science, societal values, and political awareness.Environmental science as a field of study is evolving, but it is rooted in the early history of civilization. Many ancient cultures expressed a reverence for the plants, animals, and geographic features that provided them with food, water, and transportation. These features are still appreciated by modem people. The following quote from Henry David Thoreau(1817-1862) is over a century old but is consistent with current environmental philosophy:I wish to speak a word for Nature, for absolute freedom and wildness, as contrasted with a freedom and culture merely civil. to regard man as an inhabitant, or a part and parcel of Nature, rather than a member of society.The current interest in the state of the environment began with philosophers like Thoreau and received an additional push by the organization of the first Earth Day on April 22. 1970. Subsequent Earth Days reaffirmed this commitment, as have similar Earth Days since then. As a result of this continuing interest in the state of the world and how people affect it, environmental science is now a standard course on many college campuses and is also a pan of most high school course offerings. Most of the concepts covered by environmental science courses had previously been taught in ecology, conservation, or geography courses. Environmental science incorporates the scientific aspects of these courses with input from the social sciences, such as economics, sociology and political science, creating a new interdisciplinary field.2THE INTERRELATED NATURE OF ENVIRONMENTAL PROBLEMS Environmental science is by nature an interdisciplinary field. The world environmental is usually understood to mean the surrounding conditions that affect people and other organisms. In a broader definition, environment is everything that affects an organism during its lifetime. From a human perspective, environmental issues involve concerns about science, nature, health, employment, profits, politics, ethics, and economics.Most social and political decisions are made with respect to political jurisdictions, but environmental problems do not necessarily coincide with these artificial, political boundaries. For example, air pollution may involve several local units of government, several states or provinces, and even different nations. The forest fires that raged in Mexico in 1998 had a severe impact on air quality in Texas. On a more local level, the air pollution problems in Juarez, Mexico, are also problems in El Paso, Texas. But the issue is more than air quality and human health. Lower wage rates and less strict environmental laws haveinfluenced some industries to move to Mexico for economic reasons. Mexico and many other developing nations are struggling to improve their environmental image and need the money generated by foreign investment to improve the conditions and the environment in which their people live.Air pollutants produced in the major industrial regions of the United States drift across the border into Canada, where acid rain damages lakes and forests. A long-standing dispute exists between the United States and Canada over this issue. Canada claims that the United States should be doing more to reduce emissions that cause acid rain, and the United States claims it is doing as much as it can. In another example, farmers who use water from the Colorado River for irrigation reduce the quality and quantity of water entering Mexico. This causes political friction between Mexico and the United States.The issue of declining salmon stocks in the Pacific Northwest of the United States and British Columbia, Canada is another example of political friction over a shared natural resource. It has been calculated that on the U.S. side of the salmon issue alone there are five federal Cabinet level departments, two federal agencies, five federal laws in question as well as numerous Tribal treaties, commissions and court decisions. All of this is in addition to many state level departments, commissions, and rulings. If all of this was not sufficient you still have the international bodies such as the United Nations and the international treaties that impact the fate of the salmon. Considering all this attention, maybe it is not that surprising that the plight of the salmon is in such a dangerous state.Because of all these political, economic, ethical, and scientific links, solving environmental problems is complex. The problems seldom have simple solutions. However, international organizations such as the International Joint Commission have had major bearing on the quality of the environment over broad regions of the world.The International Joint Commission was established in 1909 when the Boundary Waters Treaty was signed between the United States and Canada. The treaty was established in part to provide that the "boundary waters and waters flowing across the boundary shall not be polluted on either side to the injury of health or property of the other." The Commission has been instrumental in identifying areas of concern and encouraging the cleanup of polluted sites that affect the quality of the Great Lakes and other boundary waters. In general, the two governments have listened to the Commission's advice and have responded by initiating cleanup activities.The first worldwide meeting of heads of state directed to concern for the environment took place at the Earth Summit, formally known as the United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro in 1992. Most countries have also signed agreements on sustainable development and biodiversity. In 1997, representatives from 125 nations met in Kyoto, Japan for the Third Conference of the United Nations Frame work Convention on Climate Change. This conference, commonly referred to as the Kyoto Conference on Climate Change, resulted in commitments from the participating nations to reduce their overall emissions of six greenhouse gases (linked to global warming) by at least 5 percent below 1990 levels between 2008 and 2012. The Kyoto Protocol, as the agreement was called, was viewed by many as one of the most important steps to date in environmental protection and international diplomacy. It may be yearsbefore we will know if all countries that signed these agreements will meet their commitments to environmental improvement, but they have at least stated their intention to do so.The United Nations, through the United Nations Educational, Scientific, and Cultural Organization (UNESCO) and the United Nations Environment Programme (UNEP), has supported many environmental programs. A recent undertaking is the International Environmental Education Programme (IEEP). This program recognizes the need for both formal environmental education in schools and the informal education that occurs through the media and groups of interested citizens. Conferences on environmental education were first held during the 1970s and continue to the present.3AN ECOSYSTEM APPROACHThe natural world is organized into interrelated units called ecosystems. An ecosystem is a region in which the organisms and the physical environment form interacting unit. Weather affects plants, plants use minerals in the soil, and affect animals, animals spread plant seeds, plants secure the soil, and plants evaporate water, which affects weather.Ecosystems sometimes have fairly discrete boundaries, as is the case with a lake or island. Sometimes the boundaries are indistinct, as in the transition from grassland to desert. Grassland gradually becomes desert depending on the historical pattern of rainfall in an area.An ecosystem approach requires a look at the way the natural world is organized. Where do the rivers flow? What are the prevailing wind patterns? What are the typical plants and animals in the area? How does human activity affect nature? The task of an environmental scientist is to recognize and understand the natural interactions that take place and to integrate these with the uses humans must make of the natural world. To illustrate the interrelated nature of environmental issues, we will look at several regions of North America and highlight some of the key features and issues of each.4REGIONAL ENVIRONMENTAL CONCERNSNo region is free of environmental concerns. Most regions tend to focus on specific, local environmental issues that apply directly to them. For example, protecting endangered species is a concern in many parts of the world. It has become a matter of particular concern in the Pacific North-west where an endangered species known as the northern spotted owl appears to required undisturbed, mature forests for its survival. In most metropolitan areas the: problem of endangered species is purely intellectual, since the construction of cities has essentially destroyed the previously existing ecosystem. Here we present a number of regional vignettes to illustrate the complexity and interrelatedness of environmental issues.4.1The Wideness NorthMuch of Alaska and Northern Canada can be characterized as wilderness--areas with minimal human influence. Much of this land is owned by governments, not by individuals, so government policies have a large effect on what happens in these regions. These areas have important economic values in their trees, animals, scenery, and other natural resources. Exploitation of the region's natural resources involves significant trade-offs. Usually, a portion of the natural world is altered permanently, but the area altered is so small that manypeople consider it insignificant. Because of the severe climate, northern wilderness areas tend to be very sensitive to insults and take a long time to repair damage done by unwise exploitation. Mining, oil exploration, development of hydroelectric projects, and harvesting of timber all require roads and other human artifacts, involve the insertion of new technologies into native culture, and generate economic benefits.In the past, many short-term political and economic decisions failed to look at long-term environmental implications. Today, however, people are concerned about these remaining wilderness areas. Politicians are more willing to look at the scientific and recreational values of wilderness as well as the economic value of exploitation.Native people, who consider much of this region to be their land, have become increasingly sophisticated in negotiating with state, provincial, and federal governments to protect rights they feel they were granted in treaties. They are sensitive to changes in land use or government policy that would force changes in their traditional way of life.Native people, other concerned citizens, business interests, and environmental activists have become increasingly sophisticated in influencing decisions made by government. The process of compromise is often difficult and does not always assure wise decisions, but most governments now realize they must listen to the concerns of their citizens and balance economic benefits with social and cultural benefits.4.2The Agricultural MiddleThe middle of the North American continent is dominated by intensive agriculture. This means that the original, natural ecosystems have been replaced by managed, agricultural enterprise. It is important to understand that this area was at one time wilderness. Today, you would need to search very hard to find regions of true wilderness in Iowa, Missouri, or southern Manitoba. Some special areas have been set aside to preserve fragments of the original natural plant and animal associations, but most of the land has been converted to agriculture wherever practical.The economic value generated by this use of a rich soil resource is tremendous, and consequently most of the land is privately owned. Governments cannot easily control what happens on these privately held lands. But governments indirectly encourage certain activities through departments of agriculture that encourage agricultural research, grant special subsidies to farmers in the form of guaranteed prices for their products and other special payments, and develop markets for products. Yet because the economic risks involved in farming are great, the number of farmers constantly declines. There are a number of reasons for farm failures, including drought, disease, and lack of markets.One of the major, nonpoint pollution sources (pollution that does not have an easily identified point of origin) is agriculture. Air pollution in the form of dust is an inevitable result of tilling the land. Soil erosion occurs when soil is exposed to wind and moving water and leads to siltation of rivers, impoundments, and lakes. Fertilizers and other agricultural chemicals blow or are washed from the areas where they are applied. Nutrients washed from the land enter rivers and lakes where they encourage the growth of algae, lowering water quality. The use of pesticides causes concern about human exposure, effects on wild animals that are accidentally exposed, and residues in farm products.Since many communities in this region rely on groundwater for drinking water, the useof fertilizers and pesticides, and their potential for entering the groundwater as a result of unwise or irresponsible use, is a concern. In addition, many farmers use groundwater for irrigation, which lowers the water table and leaves less groundwater for other purposes.In an effort to stay in business and preserve their way of life, farmers must use modem technology. Careful use of these tools can reduce their impact; irresponsible use causes increased erosion, water pollution, and risk to humans.4.3The Dry WestWhere rainfall is inadequate to support agriculture, ranching and raising livestock are possible. This is true in much of the drier portions of western North America. Because much of the land is of low economic value, most is still the property of government, which encourages its use by providing water for livestock and irrigation at minimal cost, offering low rates for grazing rights, and encouraging mining and other development.Many people believe that government agencies have seriously mismanaged these lands. They assert that the agencies are controlled by special interest groups and powerful politicians sensitive to the needs of ranchers, that they subsidize ranchers by charging too little for grazing rights, and that they allow destructive overgrazing because of the economic needs of ranchers. Ranchers argue that they need access to government-owned land, cannot afford significantly increased grazing fees, and that changing government policies would destroy a way of life that is important to the regional economy.Water is an extremely valuable resource in this region. It is needed for municipal use and for agriculture. Many areas, particularly the river valleys, have fertile soils that can be used for intensive agriculture. Cash crops such as cotton, fruits, and vegetables can be grown if water is available for irrigation. Because water tends to evaporate from the soil rapidly, long-term use of irrigated lands often results in the buildup of salts in the soil, thus reducing fertility. Irrigation water flowing from fields is polluted by agricultural chemicals that make it unsuitable for other uses such as drinking. As cities in the region grow, an increasing conflict arises between urban dwellers who need water for drinking and other purposes, and ranchers and farmers who need the water for livestock and agriculture. Increased demand for water will result in shortages, and decisions will have to be made about who will ultimately get the water. If the urban areas get the water they want, some farmers and ranchers will go out of business. If the agricultural interests get the water, urban growth and development will have to be limited and expensive changes will have to be made to conserve domestic water use.Because population density is low in most of this region, much of the land has a wilderness character. Increasingly, a conflict has developed between the economic management of the land for livestock production and the desire on the part of many to preserve the "wilderness." Designating an area as wilderness means that certain uses are no longer permitted. This offend s individuals and groups who have traditionally used the area for grazing, hunting, and other pursuits. A long history of use and abuse of this land by overgrazing, modification to encourage plants valuable for livestock, and the introduction of grasses for livestock has significantly altered the region so that it cannot truly be called wilderness. The low population density does, however, provide a remoteness and wild character that many seek to preserve.4.4The Forested WestThe coastal areas and mountain ranges of the western United States and Canada receive sufficient rainfall that coniferous forests are the dominant vegetation. Since most of these areas are not suitable for farmland, they have been maintained as forests with some grazing activity in the more open forests. Governments and large, commercial timber companies own large sections of these lands. Government forest managers (U.S. Forest Service, Bureau of Land Management, Environment Canada, and various state and provincial departments) historically have sold timber cutting rights at a loss and are thought by many to be too interested in the production of forest products at the expense of other, less tangible values. In 1993, the U.S. Forest Service was directed to stop below-cost timber sales.This policy change has become a major issue in the old-growth forests of the Pacific Northwest where timber interests maintain that they must have access to government-owned forests in order to remain in business. Many of these areas have significant wilderness, scenic, and recreational value. Environmental interests point out that it makes no sense to complain about the destruction of tropical rainforests in South America while North America makes plans to cut large areas of previously uncut, temperate rainforest. Are the intangible values of preserving an ancient forest ecosystem as important as the economic values provided by timber and jobs?Environmental interests are concerned about the consequences logging would have on organisms that require mature, old-growth forests for their survival. Grizzly bear habitat in Alaska and British Columbia could be altered significantly by logging; the northern spotted owl has become a symbol of the conflict between logging and preservation in Oregon and Washington; and preservation of coastal redwood forests has become an issue in northern California.5SUMMARYArtificial political boundaries create difficulties in managing environmental problems because most environmental units, ecosystems, do not coincide with political boundaries. Therefore, a regional approach to solving environmental problems, one that incorporates natural geographic units, is ideal. Each region of the world has certain environmental issues that are of primary concern because of the mix of population, resource use patterns, and culture.Environmental problems become issues when someone finds a situation offensive. This inevitably leads to a confrontation between groups that have different views on what constitutes an environmental problem. Many social, economic, ethical, and scientific inputs shape a person's opinions. The process of environmental decision making must take all of these inputs into account and arrive at an acceptable compromise.Environmental problems are people problems. They occur because the uses of natural resources, which some people feel are justified, result in a diminished environment for others in the region. Environmental problems are defined by the person who perceives the problem. When perceptions differ, conflict occurs. Environmental decisions inevitably involve economic considerations because someone is receiving value from the resources being used or someone perceives an economic loss because a use has been withdrawn.Some argue that economic considerations should not be important when making environmental decisions; others argue that economic considerations can resolve all environmental issues.Some argue that regulation is necessary to protect resources; others argue that regulation hinders valuable use of resources.Some consider nonhuman organisms as important as humans; others feel that humans have a special place in nature.Some are against change; others recognize that change must occur.With all these differing opinions, compromise is the only way to resolve the conflicts. The social institution of government must play a role. Economic evaluation is important. Recognition of the validity of opposing points of view is essential. The field of environmental science seeks to find that middle ground.CHAPTER TWO INTERACTIONS: ENVIRONMENT ANDORGANISMS1ECOLOGICAL CONCEPTSThe science of ecology is the study of the way organisms interact with each other and with their nonliving surroundings. It deals with the ways in which organisms are molded by their surroundings, how they make use of these surroundings, and how an area is altered by the presence and activities of organisms. These interactions involve energy and matter. Living things require a constant flow of energy and matter to assure their survival. If the flow of energy and matter ceases, the organisms die.All organisms are dependent on other organisms in some way. One organism may eat another and use it for energy and raw materials. One organism may temporarily use another without harming it. One organism may provide a service for another, such as when animals distribute plant seeds or bacteria break down dead organic matter for reuse. The study of ecology can be divided into many specialties and be looked at from several levels of organization. Before we can explore the field of ecology in greater depth, we must become familiar with some of the standard vocabulary used.1.1EnvironmentEverything that affects an organism during its lifetime is collectively known as its environment. Environment is a very broad concept. For example, during its lifetime an animal such as a raccoon is likely to interact with millions of other organisms (bacteria, food organisms, parasites, mates, predators), drink copious amounts of water, breathe huge quantities of air, and respond to daily changes in temperature and humidity. This list only begins to describe the various components that make up the raccoon's environment. Because of this complexity, it is useful to subdivide the concept of environment into abiotic (nonliving) and biotic (living) factors.Abiotic factors include the flow of energy necessary to maintain any organism, the physical factors that affect it, and the supply of molecules required for its life functions. The ultimate source of energy for almost all organisms is the sun; in the case of plants, the sun directly supplies the energy necessary for them to maintain themselves. Animals obtain their energy by eating plants or other animals that eat plants. Ultimately, the amount of living material that can exist in an area is determined by the amount of energy plants, algae, and bacterial can trap.Other physical factors include such things as climate (average weather pat- terns over a number of years); temperature (average annual temperature as well as daily variations); precipitation, including its type (rain, snow, hail), amount, and seasonal distribution; type of soil present (sandy or clay, dry or wet, fertile or infertile); and even the three-dimensional shape of the space the organism inhabits.All forms of life require atoms such as carbon, nitrogen, and phosphorus, and molecules such as water, to construct and maintain themselves. Organisms constantly obtainthese materials from their environment by eating food or taking them up through the process of photosynthesis. The atoms are used for a period of time as part of the organism's body structure, and eventually are returned to the environment through respiration, excretion, or death and decay.The structure and location of the space organisms inhabit is also an important abiotic aspect of their environment. Some are at sea level; others are at high elevations. Some spaces are homogeneous and flat; others are jumble of rocks of different sizes. Some are close to equator; others are near the poles.The biotic factors influencing an organism include all forms of life with which it interacts. Plants that carry on photosynthesis; animals that eat other organisms; bacteria and fungi that cause decay; and bacteria, viruses, and other parasitic organisms that cause disease are all part of an organism's biotic environment.1.2Limiting FactorsAlthough organisms interact with their surroundings in many ways, certain factors may be recognized as key to a particular species success. A shortage or absence of a key factor restricts the success of the species; thus the factor is known as a limiting factor. Limiting factors may be either abiotic or biotic and can be quite different from one species to another. Many plants are limited by scarcity of water or specific soil nutrients. Animals may be limited by climate or the availability of a specific food. For example, many snakes and lizards are limited to the warmer parts of the world, and Monarch butterflies require milkweed plants as food for their developing caterpillars.The limiting factor for many species of fish is the amount of dissolved oxygen in the water. In a swiftly flowing, tree-lined mountain stream, the level of dissolved oxygen is high and so provides a favorable environment for trout. As the stream continues down the mountain, the steepness of the slope decreases, which results in fewer rapids where the water tumbles over rocks and becomes oxygenated. In addition, the canopy of trees over the stream usually is thinner, allowing more sunlight to reach the stream and warm. the water. Warm water cannot hold as much dissolved oxygen as cool water. Therefore, slower-flowing, warm-water streams contain less oxygen than rapidly moving, cool streams. Fish such as black bass and walleye are adapted to such areas, since they are able to tolerate lower oxygen concentrations and higher water temperatures. Trout are not able to survive under such conditions and are not found in warm, less well-oxygenated water. Each of these species has a specific range of tolerance to oxygen concentration and water temperature. Thus, low levels of oxygen and high water temperatures are limiting factors for the distribution of trout.Other factors such as the abundance of silt may influence the ability of water to support certain species of fish. Silt reduces visibility, making it difficult for fish to find food, and covers gravel beds needed for spawning. Under these conditions, the bass and walleye may be replaced by such species as carp and catfish, which have an even greater ability to withstand high temperatures and low oxygen concentrations and are better able to survive in water with a high amount of silt.The amount of grass available for food is a limiting factor for grazing animals; the saltiness (salinity) of water is limiting for many kinds of ocean animals and prevents their。