Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
The Biosphere Chapter 48 Impacts, Issues Surfers, Seals, and the Sea Giant waves and starving sea lions were two results of the 1997-1998 El Niño event that affected climates around the world The Biosphere The biosphere includes all places where we find life on Earth • Hydrosphere (ocean, ice caps, and all other bodies of water) • Lithosphere (Rocks, soils, and sediments) • Lower portions of the atmosphere 48.1 Global Air Circulation Patterns Climate • Average weather conditions – such as cloud cover, temperature, and humidity – over time Regional climates differ because of variations in factors that influence winds and ocean currents • Intensity of sunlight • Distribution of land masses and seas • Elevation Seasonal Changes Seasonal changes arise because the Earth is tilted on its axis about 23 degrees relative to the plane of its orbit around the sun The hemisphere tilted toward the sun is in summer – with longer days and more intense sunlight – while the other hemisphere is in winter Earth’s Tilt and Seasons A Summer solstice (June). Northern hemisphere is most tilted toward sun; has its longest day. D Spring equinox (March) Sun’s direct rays fall on equator; length of day equals that of night. 23° Sun B Autumn equinox (September) Sun’s direct rays fall on equator; length of day equals that of night. C Winter solstice (December) Northern hemisphere is most tilted away from sun; has its shortest day. Fig. 48-2, p. 862 A Summer solstice (June). Northern hemisphere is most tilted toward sun; has its longest day. D Spring equinox (March) Sun’s direct rays fall on equator; length of day equals that of night. 23° Sun B Autumn equinox (September) Sun’s direct rays fall on equator; length of day equals that of night. C Winter solstice (December) Northern hemisphere is most tilted away from sun; has its shortest day. Stepped Art Fig. 48-2, p. 862 Animation: Air circulation and climate I Animation: Air circulation and climate II Sunlight and Air Circulation The equator receives more sunlight energy than the poles Regional differences in surface warming is the start of global air circulation patterns • Warm air rises and holds more moisture (areas of high rainfall) • Cool air sinks and is drier (areas where deserts form, 30°latitude north and south) Variation in Solar Intensity With Latitude Factors Affecting Air Circulation Patterns Earth’s rotation and curvature cause air masses that move north or south to be deflected to the east or west Heating and cooling of land masses causes differences in air pressure and regional winds Climate and Global Air Circulation Patterns Initial Pattern of Air Circulation Prevailing Wind Patterns D At the poles, cold air sinks and moves toward lower latitudes. E Major winds near Earth’s surface do not blow directly north and south because of Earth’s rotation. Winds deflect to the right of their original direction in the Northern Hemisphere and to the left in the Southern Hemisphere. C Air rises again at 60° north and south, where air flowing poleward meets air coming from the poles. B As the air flows toward higher latitudes, it cools and loses moisture as rain. At around 30° north and south latitude, the air sinks and flows north and south along Earth’s surface. A Warmed by energy from the sun, air at the equator picks up moisture and rises. It reaches a high altitude, and spreads north and south. Cooled, dry air descends easterlies (winds from the east) westerlies (winds from the west) northeast tradewinds (doldrums) southeast F For example, air tradewinds moving from 30° south toward the equator is deflected to the left (west), as westerlies the southeast trade winds. The winds are easterlies named by the direction from which they blow. Fig. 48-4, p. 863 Harnessing Sun and Wind Unlike fossil fuels, sun energy and wind energy are renewable resources Solar energy can be used directly as a heating source, or indirectly through photovoltaic cells to charge batteries or produce hydrogen fuels Wind turbines need lots of wind, but can produce electricity day or night 48.2 Something in the Air Pollutants • Natural or synthetic substances released into air, water or soil in greater than natural amounts, that disrupt normal processes Polar Winds and Ozone Thinning Ozone molecules (O3) high in Earth’s atmosphere (ozone layer) protect life from harmful UV radiation Manmade chlorofluorocarbons (CFCs) release chloride radicals that continue to degrade ozone Polar winds concentrate CFCs over the Antarctic, resulting in an “ozone hole” The Damaged Ozone Layer Fig. 48-5a, p. 864 Altitude (kilometers above sea level) 80 70 mesosphere 60 50 40 stratosphere 30 20 10 0 ozone layer troposphere Fig. 48-5a, p. 864 Fig. 48-5b, p. 864 South America Antarctica Fig. 48-5b, p. 864 Animation: How CFCs destroy ozone No Wind, Pollution and Smog Smog • An atmospheric condition in which air pollutants accumulate to high concentration in cool, still air because winds can’t disperse them from under a layer of warm air (thermal inversion layer) • Photochemical smog forms when exhaust fumes combine with oxygen to form nitrogen dioxide and other photochemical oxidants Thermal Inversion and Smog cooler air cool air warm air Fig. 48-6, p. 864 cool air warm inversion layer cool air Fig. 48-6, p. 864 Wind and Acid Rain Acid rain • A wet acid deposition containing nitric acid, sulfuric acid, and sulfate and nitrate salts • Formed by interaction of pollutants (sulfur dioxides, nitrogen oxides) with moisture in the air • Corrodes metals, stone and other materials • Kills trees, fish and other organisms • Winds disperse these pollutants far from their sources Precipitation and pH Windborne Particles and Health Wind carries airborne allergens and pollutant particles that can irritate respiratory systems and trigger asthma attacks on a global scale Vehicle exhaust is a major source of dangerous particulate pollution Global Distribution of Radioactive Fallout from Chernobyl 48.1-48.2 Key Concepts Air Circulation Patterns Air circulation patterns start with regional differences in energy inputs from the sun, Earth’s rotation and orbit, and the distribution of land and seas These factors give rise to the great weather systems and regional climates 48.3 The Ocean, Landforms, and Climate Air masses, oceans, and landforms affect regional temperature and moisture levels The ocean, a continuous body of water, covers more than 71 percent of Earth’s surface Driven by solar heat and wind friction, the ocean’s upper 10 percent moves in currents that distribute nutrients through marine ecosystems Surface Currents and Climate Surface currents flow clockwise in the northern hemisphere and counterclockwise in the southern hemisphere On east coasts of continents, currents carry heat energy from the equator toward the poles; on west coasts, cold water flows toward the equator Major Climate Zones and Surface Currents Animation: Major climate zones and ocean currents Rain Shadows and Monsoons Rain shadow • When warm, moist air is blocked by a mountain range, more rain falls on the windward side and less rain falls on the leeward side Monsoon • Differential heating of water and land causes winds that change seasonally, resulting in heavy rains in summer, drought in winter Rain Shadow Effect Prevailing winds move moisture inland from the Pacific Ocean. Rain shadow on side facing away from the prevailing winds makes arid conditions. Clouds pile up and rain forms on side of mountain range facing prevailing winds. 4,000/ 75 moist habitats 3,000/ 85 1,800/ 125 1,000/ 25 15/ 25 2,000/ 25 1,000/ 85 Fig. 48-10, p. 867 Fig. 48-10, p. 867 Fig. 48-10, p. 867 Coastal Breezes and Land Breezes A Afternoon; land is warmer than sea; breeze blows onto the shore cool air warm air B Evening; sea is warmer than land; the breeze blows out to sea Fig. 48-11, p. 867 Animation: Rainshadow effect 48.3 Key Concepts Ocean Circulation Patterns Interactions among ocean currents, air circulation patterns, and landforms produce regional climates, which affect where different organisms can live 48.4 Biogeographic Realms and Biomes Biogeographic realms • Early naturalists divided Earth’s land masses into six realms with characteristic plants and animals Biomes • Finer divisions of land realms where different physical conditions with distinct kinds of plants support characteristic communities Biomes Global distribution of biomes is a result of topography, climate, and evolutionary history • Most biomes occur on more than one continent Global Distribution of Biomes Animation: Major biomes 48.5 Soils of Major Biomes Plants obtain water and nutrients from soil • Properties of soil impact primary production Each biome has a characteristic soil profile, with different amounts of inorganic and organic components (humus) • Topsoil (A horizon) is most important for plants Soil Profiles for Some Major Biomes 48.6 Deserts Deserts Deserts are regions that receive an average of less than 10 cm (4 in) of rain per year Most deserts are located around 30° north and south latitudes, where dry air sinks Deserts tend to be hot by day and cold by night, with nutrient-poor soils Desert Communities Many plants and animals in deserts have adaptations that minimize their need for water • Plants: Spines or hairs retain humidity; CAM plants open stomata only at night; shrubs have efficient, extensive root systems • Animals: Physiological adaptations (kangaroo rat); burrowing (tortoise); nocturnal activity (bats) The Sonoran Desert, Arizona 48.7 Grasslands, Shrublands, and Woodlands Animation: Acid deposition Grasslands Grasslands form in the interior of continents between deserts and temperate forests • Strong winds, infrequent rain, periods of drought • Perennial grasses fix carbon by C4 pathway Shortgrass and tallgrass prairies once dominated the North American plains • Farming destroyed extensive grass roots that held topsoil, causing the Dust Bowl Savannas Savannas are broad belts of grasslands with a few shrubs and trees • Warm, with rainy and dry seasons • Fires maintain grasslands Found between tropical forests and hot deserts in Africa, India and Australia • African savannas support abundant wildlife Three Examples of Grasslands Fig. 48-16, p. 872 Dry Shrublands and Woodlands Dry shrublands • Low rainfall, frequent fires; short, woody shrubs • South Africa, Mediterranean regions, and California (chaparral) Dry woodlands • Low rainfall; drought-tolerant trees • Eucalyptus forests of Australia, oak forests of California and Oregon California Chaparral 48.8 More Rain, Broadleaf Forests Semi-Evergreen Forests Broadleaf (angiosperm) trees dominate moist forests in both temperate and equatorial regions Semi-evergreen forests • A mix of broadleaf trees that retain leaves year round and deciduous broadleaf trees • Tropics of Southeast Asia and India Broadleaf Forests Tropical deciduous forests • Less than 2.5 cm (1 in) of rain in dry season • Most trees shed leaves at start of dry season Temperate deciduous forests • Moderate rains throughout the year • In fall, trees become dormant, leaves turn brilliant colors and drop North American Temperate Deciduous Forest Tropical Rain Forests Evergreen broadleaf forests • Form between 10°north and south • Warm temperatures and high rainfall, 130-200 cm (50-80 in) per year • Most complex biome in structure and diversity • Shady canopy, rapid decomposition and mineral cycling Animation: Chernobyl fallout Animation: Global air circulation patterns Animation: Soil profiles Animation: Terrestrial biomes Animation: Thermal inversion and smog