Part1 AP Environmental Science Reviews 第一部分 AP环境科学知识复习

Chapter 1 Earth Systems and Resources 第一章 地球系统和资源

1 Earth Science Concepts地球科学的概念

1.1 Geologic Time Scale 地质时间表（表1—1—1）

衡量地球的年龄有两种时间表：一种是相对时间表，基于岩石层的形成和生命的进化；一种是辐射时间表，基于岩石层中化学元素的自然放射性。最大的时间单位是世纪（Eon，也叫“宙”）。世纪可以被分为很多个纪元(Era，也叫“代”)。纪元（Era）又可以分为周期（Period，也叫“纪”）、时期(Epoch，也叫“世”)、阶段(Stage，也叫“期”)，即：Eon→Eras→Periods→Epochs→Stages。

1.2 Earth Structure地球的结构（图1—1—1）

地球是由很多层所组成的，而大部分地理运动都发生在地球的表面。

●Earth core地核

At Earth's center is a dense core consisting mostly of iron, solid in the inner core and molten in the outer core.

●The mantle地幔

Surrounding the core is a thick layer of less dense, elastic rock called the mantle.

●The crust地壳

The thin, brittle, low-density layer of rock that covers Earth's surface. The crust can be subdivided into two main parts: basalt-rich oceanic crust and granite-rich continental crust.

●Asthenosphere软流圈

A portion of the upper mantle called the asthenosphere contains specially soft rock, melted in some areas.

●Lithosphere岩石圈

The harder rock above the asthenosphere is what we know as the lithosphere. The lithosphere includes both the uppermost mantle and the crust.

1.3 Plate Tectonics 板块运动（图1—1—2）

地球表面主要是由15大板块所构成的，包括：

Juan de Fuca Plate胡安·德富卡板块

Pacific Plate太平洋板块

North American Plate 北美洲板块

South American Plate 南美洲板块

Caribbean Plate 加勒比板块

Scotia Plate斯科舍板块

African Plate 非洲板块

Eurasian Plate欧亚大陆板块

Arabian Plate阿拉伯板块

Indian Plate 印度板块

Philippine Plate 菲律宾板块

Australian Plate 澳大利亚板块

Antarctic Plate 南极洲板块

Nazca Plate纳斯卡板块

Cocos Plate科科斯板块

板块运动可能会形成山脉，或是引起一些自然灾害，比如地震（earthquakes）、火山喷发(volcanic eruptions)、海啸(tsunamis)、山体滑坡(landslides)等；板块运动还有可能造成地质资源分布不均衡。AP Tips： 这里经常出选择题板块构造可分为三大类板块边界（plate boundaries），分别是：

●Divergent plate boundary离散板块边界

At divergent plate boundaries, tectonic plates push apart from one another as magma rises upward to the surface, creating new lithosphere as it cools.

For example: the Mid-Atlantic Ridge.

相邻的板块朝相反的方向移动，如下所示：

●Convergent plate boundary 聚合板块边界

Two plates converge or come together, can give rise to different outcomes—a subduction zone (俯冲带) or orogenic belt（造山带）. Volcanoes are often located on the upper continental plate.

For example: the Cascade Mountain Range. It extends north from California's Sierra Nevada Mountains and includes Mount Saint Helens.

相邻的板块朝相向的方向移动，如下所示：

●Transform fault转换断层

Where two plates meet, they may slip and grind alongside one another. The friction and the stress buildup from the sliding plates frequently cause earthquakes—a common feature along transform boundaries.

For example: the San Andreas Fault in California represents such a boundary and is the cause of frequent earthquakes in that area.

相邻的板块错开移动，如下所示：

1.4 Tilt of the Earth's Axis 地轴倾斜角（图1—1—3）

地球的轴向倾斜与黄道面（地球在太阳系中运行的轨道平面）的夹角称为地轴倾斜角（也就是黄赤交角）。地球目前已经轴向倾斜约23.5°。四季就是由于地轴倾斜所产生的。

Results in the Northern hemisphere being tilted toward the Sun during its summer months of June-September and the Southern hemisphere to be likewise in December-March. The seasons are a result of the tilt of the Earth's axis.

1.5 Uneven Heating of the Earth's Surface 受热不均的地球表面（图1—1—4）

由于地球是一个球体，因此太阳辐射不能均衡地到达地球表面。

Sunlight is much more concentrated at the equator where the radiation is more direct. The differences in heating from the equator to the poles help create our global wind patterns.

2 The Atmosphere大气

2.1 Components of the Atmosphere大气层的组成

大气层主要包含7种成分，分别是78%的氮气（nitrogen）、21%的氧气（oxygen）、0～4%的水蒸气（water vapor）、小于1%的二氧化碳（carbon dioxide）、远小于1%的甲烷（methane）、远小于1%的一氧化二氮（nitrous oxide）、远小于1%的臭氧（ozone）。

●Nitrogen氮气

氮气是生物体最基本的营养物质（fundamental nutrient）。

●Oxygen 氧气

氧气可以通过光合作用（photosynthesis）而产生，通过细胞呼吸作用(cellular respiration)被利用。

●Water vapor 水蒸气

水蒸气含量最多的地方聚集在赤道周围、海洋上空和热带地区。

●Carbon dioxide 二氧化碳

由于化石燃料的燃烧（burning of fossil fuels）和森林的砍伐(deforestation)，二氧化碳在大气层中的含量逐年增加。

●Methane 甲烷

甲烷在大气层中的含量也显著增加，主要是由于化石燃料的燃烧（burning of fossil fuels）、矿物开采（coal mining）、垃圾填埋（landfills）、洪水（flooding）等原因，这样会引起温室效应的加剧。

●Nitrous oxide 一氧化二氮

一氧化二氮也会引起温室效应的加剧，它正以3%的速度逐年增加。

●Ozone 臭氧

臭氧层可以吸收紫外线（UV radiation），但是臭氧空洞(ozone hole)现象近年来越来越严重。

2.2 The Structure of the Atmosphere大气层的结构（图1—1—5）

2.2.1 Troposphere 对流层

对流层位于地球表面上空0～11km。在对流层内，温度随着海拔的上升而下降。天气变化就发生在对流层。

The bottommost layer provides us the air we need to live. The movement of air within the troposphere is largely responsible for the planet's weather. 75% of atmosphere's mass is in the troposphere.

2.2.2 Stratosphere 平流层

平流层位于海平面上空11～50 km。臭氧层位于平流层中。由于臭氧层可以吸收热量，在平流层内温度随海拔上升而上升。

Similar in composition to the troposphere, the stratosphere is 1,000 times drier and less dense. It contains ozone (17～30km above sea level). Ozone and oxygen absorb and scatter the sun's UV radiation.

2.2.3 Mesosphere 中间层

在平流层上面是中间层，位于海平面上空50～80 km。温度随海拔升高而降低，是最冷的一层。

Air pressure is extremely low here, meteors burn up in this layer.

2.2.4 Thermosphere 热层

热层位于大气层中最顶层，海拔80～500 km。由于γ射线、x射线和紫外线的存在，热层内的温度随海拔的升高而升高。

Molecules are converted into ions which results in the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere. The aurora borealis most often occurs from September to October and from March to April.

2.3 Weather and Climate 天气和气候

2.3.1 气候和天气的区别

气候是指某一个地区长期平均的天气状况；而天气是指某一地区在某一瞬间或某一短时间内大气状态和大气现象的综合。

The climate of an ecosystem is that area's general pattern of atmospheric or weather conditions over long periods of time. In contrast, weather is the local area's short-term temperature, precipitation, humidity and other physical conditions of the troposphere measured over hours or days.

2.3.2 Properties of Air, Water, and Land 空气、水和陆地

Solar energy creates continuous evaporation from ocean water, especially at the equator, thereby transferring heat from the oceans to the atmosphere. This creates cyclical convection cells that circulate air, heat, and moisture across the surface of the earth.

Examples:

●El Niño Southern Oscillation (ENSO) 厄尔尼诺现象

赤道太平洋冷水域中海温周期性异常升高，这些异常热量进入大气后影响全球气候。季风洋流由美洲走向亚洲，使太平洋海温升高，从而带来热带降雨。2～7年后该模式被打乱，使风向逆转，热流转向美洲，带走热带降雨。

Every few years in the Pacific Ocean, there is a disruption of the ocean-atmosphere system. Rather than pushing warmer water away from the coast of South America, trade winds weaken or reverse direction, pushing warmer water toward the coast of South America, which suppresses the thermocline. The result is a decrease in upwelling that causes a reduction in primary productivity by the phytoplankton and therefore a dramatic decline in many fish populations. The changing wind patterns also shift precipitation, causing flooding in some areas, such as Peru, and bringing drought to other areas, such as Brazil and parts of Indonesia.

常见问题：

引起厄尔尼诺现象的原因：

a．信风减弱，暖流往东移。Trade winds weaken and warm water moves eastward.

b．由于上涌，美洲沿岸的海水上层营养丰富。Upper ocean layer keeps nutrient-rich water from upwelling along coast of the Americas.

c．海洋里的热量释放到大气中，从而改变急流的路线。Ocean heat is released into atmosphere and alters path of jet stream.

在正常情况下，南太平洋的季风洋流是从美洲走向亚洲，使太平洋表面的水保持温暖，给印度尼西亚周围带来热带降雨（见图1—1—6）。

受到厄尔尼诺现象的影响后，正常洋流和季风走向每2～7年被打乱一次，使风向和洋流发生逆转，太平洋表层的热流就转而走向美洲，带走了亚洲的热带降雨（见图1—1—7）。

●La Niña 拉尼娜（又称反厄尔尼诺）

拉尼娜是与厄尔尼诺相反的现象，即赤道太平洋冷水域中海面温度异常降低。拉尼娜也会让全球的气候异常，使得美国西岸天气异常干燥，而日本、朝鲜等国家异常寒冷。拉尼娜的成因是信风将热海水吹向太平洋西部，使得太平洋西部海水温度升高，气压下降。

Typically follows an El Niño, cools coastal surface water and restores upwelling events. La Niña, in general, has the opposite effects on the ocean-atmosphere system than El Niño. However,it can mean more Atlantic coast hurricanes as well as colder winters in the northeastern United States but warmer, drier winters in the southeastern United States.

●Rain shadow effect 雨影效应（图1—1—8）

雨影效应指较高的山脉阻隔了季风，使迎风坡面降水增多，背风坡面降水减少。

As prevailing winds pick up moisture from the ocean and move across land, the moving air mass is forced upward over mountains. As this air mass rises it will cool and release much of its moisture as rain and snow on the windward side of the mountain. On the leeward side the descending air is therefore drier. As this air descends, it warms and picks up moisture from the landscape below, thereby leading to arid and semi-arid conditions on this side of the mountain.

●The greenhouse effect 温室效应

温室效应指大气中的温室气体（包括水蒸气、甲烷、二氧化碳等）通过对长波辐射的吸收而阻止地表热能耗散，从而导致地表温度增高的现象。

The earth's climate has greatly fluctuated over the last 5 billion years from ice age events to long periods of warming. However, our climate has been relatively stable over the last 2,000 years. According to the EPA, our current global average temperature is approximately 15°C, but without an atmosphere the average temperature would be only -18°C. The difference between the natural atmospheric temperature and temperature we actually experience is accounted for by the warming properties of the earth's atmosphere known as the greenhouse effect.

Primarily only four naturally produced gases—water vapor, methane, carbon dioxide, and nitrous oxide—help influence the earth's average temperature by significantly contributing to the greenhouse effect. These gases allow incoming, shorter-wavelength UV radiation through the atmosphere but trap outgoing longer-wavelength infrared radiation being emitted from the earth's surface. They emit even longer infrared radiation back into the troposphere thereby warming the lower atmosphere. Without these greenhouse gases our planet would be too cold for most living organisms to survive.

●Coriolis effect科里奥利效应

科里奥利效应指的是地球沿着其倾斜的主轴自西向东旋转而产生偏向力，使得在北半球所有水平移动的物体包括气团等向右偏斜，而南半球的所有移动物体向左偏斜的现象。该效应对大气的影响有：

气旋（cyclone）：由于地球自转而产生，以低气压为中心的周围大气在压力差的驱动下向低气压中心定向移动。这种移动受到科里奥利效应的影响，形成旋转气流。在北半球，旋转气流将沿逆时针方向移动，在南半球，旋转气流将沿顺时针方向移动。

The Coriolis effect causes air to move in a curved path, which is caused by the Earth spinning on its axis. As air moves from the equator to pole, air will travel east faster than the land beneath it causing the air to follow a curved path. Thus, the Coriolis effect causes wind flowing from high pressure area to low pressure area. In the Northern Hemisphere, the Coriolis effect cause things to curve to the right. In the Southern Hemisphere, the Coriolis effect causes things to curve to the left.

信风（trade winds）：在北半球，信风来自于东北方向，因此称为东北信风。在南半球，信风来自于东南方向，因此称为东南信风。

In the Northern Hemisphere, trade winds come from the NE, so they are called Northeast trade winds. In the Southern Hemisphere, trade winds come from the SE, so they are called Southeast trade winds. Trade winds are named for their ability to quickly propel trading ships across the ocean. The trade winds that blow between about 30 degrees latitude and the equator are steady and strong, and travel at a speed of about 11 to 13 mph.

西风和西风带都是由于科里奥利效应所产生的。

Another types of moving air mass is called a westerly, which travels south and west in the Northern Hemisphere and north and west in the Southern Hemisphere near the equator (between 30 degrees to 60 degrees). The movement of air that accounts for the westerlies, called the Ferrel cell, is the reverse of Hadley cell. Westerlies are another result of the Coriolis effect. Polar easterlies are formed by similar forces; in polar easterlies, winds between latitudes 60 degrees and the North Pole blow from the north and east, and winds between 60 degrees and south pole blow from the south and east（见图1—1—9）.

3 Global Water Resources and Its Use 全球水资源及其利用

3.1 Fresh Water 淡水

3.1.1 Groundwater 地下水

Groundwater is the water that fills underground porous spaces. Aquifers are deep underground layers of porous rock material, gravel, sand, silt, or clay where groundwater flows. Aquifers that receive insufficient recharge are non-renewable, and the term water mining refers to withdrawals from these aquifers since eventually the water will be depleted.

How to protect groundwater resources（如何保护地下水）：

a. subsidize water conservation strategies

b. implement water conservation practices in residential homes

c. increase the price of water to discourage waste

d. reduce the number of water-intensive crops being grown, especially in arid and semi-arid regions

3.1.2 Surface Water地表水

Surface water includes rivers, lakes, wetlands, estuaries, and the ocean. A watershed is the land surrounding these bodies of water that contribute to surface runoff into them.

●Hydroelectric power station水力发电站

水力发电站的原理：In many areas, fast-flowing rivers are dammed to create freshwater reservoirs and in many cases to provide hydroelectric power. Once a river is dammed the terrestrial area behind the dam will flood, creating a reservoir that stores the surface water runoff that would have once flowed directly into the river.

建造水力发电站有利也有弊（见表1—1—2）。

Examples of major dams:

Three Gorges Dam 三峡大坝

长江三峡水利枢纽工程，简称三峡工程，是世界上规模最大的水电站，也是中国长江中上游段最大的水利枢纽工程，是南水北调的一部分。该工程自筹建起就引发社会各界关于环境、移居等的争论。

The Three Gorges Dam is the world's largest hydroelectric dam. This hydroelectric dam is capable of producing the same energy output as 22 coal-burning power plants, yet does not produce the carbon dioxide emissions that coal does. However, some scientists say this saving in carbon dioxide emissions will be offset by methane gases being released from the decomposition of vegetation in the large reservoir.

Dams in the Colorado River Basin科罗拉多河流域的大坝

The Colorado River, flowing from Colorado to the Gulf of California, generates its water flow from annual snowmelt in the Rocky Mountains. Two major dams along the Colorado River are the Hoover Dam, which creates the Lake Mead reservoir, and the Glen Canyon Dam, which creates the Lake Powell reservoir.

●Water transfer projects 调水工程

很多国家开创调水工程，将水从资源丰富地区运送到资源不足的地区。以下是几个著名的调水工程：

Aral Sea Water Transfer Project

California Water Transfer Project

China's Water Transfer Project

3.1.3 水资源的利用（图1—1—10）

Less than 1% of the global water supply is readily available as freshwater. Globally, the main uses of groundwater and surface water are for irrigation (70%), industrial processes (20%), and the rest for human consumption.

发展中国家缺乏干净的饮水资源。

People in developing nations lack access to clean drinking water: Over 1.6 million people die each year from preventable diseases contracted from contaminated drinking water.

3.1.4 Water Conservation 水资源的保护

●Proper irrigation could reduce water loss合理灌溉可以减少水资源的浪费

Irrigation methods that reduce water loss include drip irrigation; center pivot; irrigate crops with treated urban wastewater; irrigate at night to reduce water lost to evaporation; don't grow water-thirsty crops in arid and semi-arid regions; increase government subsidies for efficient irrigation practices; use soil moisture monitors to irrigate only when needed; increase use of polyculture or organic farming practices instead of monoculture; use rainwater harvesting for smaller agricultural fields (in developing countries).

●Improving industrial and residential water conservation 改善工业和生活用水的保护

The largest use of domestic water comes from flushing toilets. According to the United Nations studies, the largest source of water loss in both industrial and residential practices is leaks in pipes, valves, and water mains.

措施：Fix leaks in pipes and water mains; also, increase prices for water; require the use of water meters; recycle water used in industrial processes; use low-flow showerheads and low-volume toilets; use grey water systems (collect water from showers, bathtubs, dishwashers, and clothes washers and then reuse this water on lawns, to wash cars, or to flush toilets).

●Increasing fresh water supplies 增加淡水供给

许多国家都在寻求增加淡水资源的方式和方法。脱盐作用是将海水和湖水里的盐分减少的一个过程，是一个相当有效的提供淡水资源的方法。反渗透和蒸馏是脱盐作用的两种方式。

Desalination（脱盐作用）is a process that removes dissolved salts from ocean water or from brackish seas and lakes. This can provide valuable freshwater in areas facing water shortages. Two methods of desalination are:

a. reverse osmosis（反渗透作用）: use external pressure to push saline water through membranes that separate the solutes from the solvent.

b. distillation（蒸馏作用）: heating saltwater until evaporation begins. This steam is collected and condenses as freshwater as the salts have been left behind in solid form.

4 Soil and Soil Dynamics 土壤和土壤动力学

4.1 Soil Composition 土壤组成

Due to differences in geography, parent material, climate, age, and the presence of soil organisms, soil can take thousands of years to form. The particle size of the broken-down parent material influences the texture and porosity of the soil. Particle sizes arranged in order from large to small are sand, silt, and clay.

4.2 Soil Horizons 土壤层次（图1—1—11）

土壤通常按纵向分为很多层，分别为O、A、B和C层。O层是最表层，含有很多有机物质；A层含有很多矿物质，最利于植物根部水分和矿物质的吸收；B层含有较低浓度的矿物质和有机物；C层是最底层。

Soil is usually formed into horizontal layers called soil horizons. For most soil, nearly all of the living organisms are found close to the surface.

Example of soil horizon:

●O horizon

Surface layer, composed of partially decomposed organic material and/or leaf litter.

●A horizon

Topsoil, which is composed of mineral-containing weathered parent material and organic matter (humus). Plants spread most of their roots to absorb water and minerals in the A horizon.

●B horizon

Subsoil, which contains a lower concentration of organic material than the first two layers and a higher concentration of mineral particles.

●C horizon

Composed of weathered parent material sitting on top of bedrock.

Soil texture土壤粗密度

根据沙子、泥沙、黏土在土壤中的百分比，可以利用土壤三角形（soil triangle）（见图1—1—12）来判断该土壤的粗密度（soil texture）。方法如下：

a. Clay side first. Extend a line horizontally from the percent clay (the line should be parallel to the side labelled “percent sand”).

b. Silt side second. Extend a line diagonally downward from the percent silt (the line should be parallel with side labelled “percent clay”).

c. Sand side last. Extend a line diagonally upward and to the left from the percent sand (this line should be parallel with side labelled “percent silt”).

For example: if a soil is 30% clay, 30% silt, and 40% sand, the texture is clay loam.

4.3 Soil Erosion 土壤侵蚀

After plowing or harvesting, soil that is exposed to the elements is susceptible to being blown away by winds or washed away by water. Although soil is a renewable resource, the rate of formation of new soil is slow and most soil is currently being used unsustainably.

4.4 Soil Conservation 土壤保护

免耕农业、梯田、等高耕种、防风林等都是防止土壤侵蚀的有效措施（见表1—1—3）。