全球生態學 (Global Ecology)

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1 全球生態學 (Global Ecology)
Chap.23 + 補充教材 鄭先祐 (Ayo) 國立臺南大學 環境生態研究所 教授 環境與生態學院 院長

2 Global Ecology and Human Ecology
目錄 Global Ecology 大氣層 (Atmospheric Envelope) Concepts El Nino and La Ninas (氣候變遷) 氮肥的增加 對生物多樣性的衝擊 溫室效應 臭氧層破洞 Global Ecology and Human Ecology

3 圖1. 從月球看地球。地球是一個多水的行星。(Apollo 12 於月球拍攝的照片)。(Fig. 23.1)
Global Ecology and Human Ecology

4 Global Ecology and Human Ecology
人在樹林中，只能看到樹木，沒有看到森林的全貌。 於 年間，太空人將從太空拍攝地球的照片傳回地球，人類首次得以走到畫框外面而看到整個地球。 結果，1970年人們發起地球日(Earth day)。許多環保法令陸續頒布，關心全球環境的輿論興起，以及提出環境影響評估的要求。 Global Ecology and Human Ecology

5 Global Ecology and Human Ecology
21st century Peter Vitousek (1994) This is the first generation(第一個世代) in history with the tools to examine how humanity has changed the Earth. This may be the last generation (最後一個世代) that has a chance to affect the course of those changes significantly. Global Ecology and Human Ecology

6 大氣層 (Atmospheric Envelope)
Exosphere (散逸層) Thermosphere (熱成層) Mesosphere (中間層) Stratosphere (平流層) Troposphere (對流層) Global Ecology and Human Ecology

7 Global Ecology and Human Ecology
Green-house effect 倘若沒有陽光照射地球，地表的平均溫度約是 -18oC。 目前平均是15oC。 提高約33oC的溫度。 Global Ecology and Human Ecology

8 Greenhouse Effect (溫室效應)
Heat is trapped near the earth’s surface by greenhouse gases: (Water Vapor, Carbon Dioxide, Methane, Ozone, Nitrous Oxide, and CFC’s) Absorb infrared and reemit most back to earth. 30 % Solar energy reflected back by clouds, particulate matter, etc. 70 % Absorbed by atmosphere/surface. Global Ecology and Human Ecology

9 Essay 28.5 The greenhouse effect
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10 Essay 28.5 The greenhouse effect
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11 Global Ecology and Human Ecology
Greenhouse Effect Fig. 23.2 Global Ecology and Human Ecology

12 Global Ecology and Human Ecology
Concepts El Nino and La Ninas (氣候變遷) Human activity has greatly increased the quantity of fixed nitrogen cycling(氮循環的量) through the biosphere. Rapid changes in global patterns of land use threaten biological diversity. (威脅生物多樣性) Human activity is increasing the atmospheric concentration of CO2, which may be increasing global temperatures. (溫室效應) Global Ecology and Human Ecology

13 El Nino Southern Oscillation 聖嬰-南方震盪
The name El Nino (聖嬰) originated when this climatic seemed limited to the west coast of South America. (南美洲的西部沿岸) During an El Nino, a warm current appears off the west coast of Peru (祕魯的西部沿岸), generally during the Christmas season(聖誕節) . The term Southern Oscillation refers to an oscillation in atmospheric pressure (氣壓) that extends across the Pacific Ocean(太平洋區). Global Ecology and Human Ecology

14 Global Ecology and Human Ecology
歷史軌跡 Gilbert Walker(英國數學家)，印度天文觀測站主任(1904)。 印度於 發生乾旱而糧食欠收。 Walker 研析如何預測季節雨量。 Walker (1924) 發現太平洋的大氣壓與季節雨量的關係。 東太平洋的氣壓下降，西太平洋的氣壓會上升。反之，西太平洋的氣壓下降，會造成東太平洋的氣壓上升。(southern oscillation) Global Ecology and Human Ecology

15 Southern oscillation index
Is determined by the difference in barometric pressure between Tahiti (大溪地) and Darwin, Australia (澳洲的達爾文港) (Fig. 23.4). Walker noticed that low values of the index were associated with drought(乾旱) in Australia(澳洲), Indonesia(印尼), India(印度), and parts of Africa(部分非洲). Also suggested that winter temperatures in Canada (加拿大的冬天溫度) were somehow connected to the Southern Oscillation. Global Ecology and Human Ecology

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Jacob Bjerknes (1966,1969) A professor at the UCLA. El Nino – Southern Oscillation (相關聯) Walker circulation (Fig. 23.5) Global Ecology and Human Ecology

17 Global Ecology and Human Ecology
於聖嬰時期，暴風會向東移動。 於反聖嬰時期，太平洋的暴風會向西移動。 Fig Walker circulation, El Nino, and La Nina. Global Ecology and Human Ecology

18 Global Ecology and Human Ecology
El Nino and La Ninas During El Nino, 太平洋東邊的熱帶海面溫度會比平常高，氣壓則會比較低。 如此會增加太平洋東部的暴風(Promotes the formation of storms) 因此，增加東太平洋的雨量，減少西太平洋地區的雨量。 La Ninas, 相反的情況。 Global Ecology and Human Ecology

19 El Nino and Marine Populations
平常，南美洲西海岸海面的水溫都比較低 低的海面水溫，是來自海面下的湧升流。 當聖嬰時期，海面的水溫上升。 海面下的湧生流停止，減少營養的供應(湧升流帶來的)，因此減少浮游植物的產量。 Global Ecology and Human Ecology

20 El Nino and Marine Populations
於聖嬰時期，海面的水溫明顯的上升 於非聖嬰時期，海面的水溫比較冷。 Global Ecology and Human Ecology

21 El Nino and Great Salt Lake
Strong El-Nino of was source of many storms deep into interior of N. America. Increased precipitation with Great Salt Lake basin. lake rose 3.7 m. Wurtsbaugh and Smith Berry found lake salinity dropped by 50 g/l and the lake was invaded by predaceous insect Trichocorixa verticalis. Global Ecology and Human Ecology

22 El Nino and Great Salt Lake
Predator reduced population of brine shrimp from 12,000 to 74 per m3. Phytoplankton biomass increased significantly. By 1990, lake level fell 2.8 m, and salinity returned to 100 g/l. All ecosystem changes were reversed. Global Ecology and Human Ecology

23 El Nino and Kangaroo Populations
Red Kangaroo (Macropus rufus) occupies most of Australia’s semiarid interior. During wet period with plenty of food, females will simultaneously have a baby following, a younger offspring in the pouch, and an embryo waiting to enter the pouch. Under marginal conditions, most young die soon after leaving the pouch. If food becomes scarce, females stop lactating and young die in embryo stage. Global Ecology and Human Ecology

24 El Nino and Kangaroo Populations
Kangaroos breed quickly and young enter the pouch within 60 days of onset of significant rainfall. By reproducing large numbers of offspring under favorable conditions, kangaroos increase the number of adults that will face El Nino induced droughts. Cairns and Grigg found a tight coupling of M. rufus populations to El Nino. Global Ecology and Human Ecology

25 Human Activity and Global Nitrogen Cycle
As human civilization developed intensive agriculture and industrial processes, we began to manipulate nitrogen cycle on massive scale. Vitousek N - fixing bacteria/plants 100 Tg/yr Marine environments Tg/yr Lightning Tg/yr Human sources Tg/yr Global Ecology and Human Ecology

26 Tropical Deforestation
Support at least half of earth’s species. Skole and Tucker reported tropical forests occur in 73 countries and once covered 11,610,360 km2. Brazil contains 1/3 of total. Highest deforestation rate. Estimated by 1978, 78,000 km2 deforested. Annual rate of deforestation was 15,000 km2. Global Ecology and Human Ecology

27 Tropical Deforestation
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28 Edge Effects and Tropical Deforestation
When a forest fragment is isolated due to cutting, its edge is exposed to greater amounts of solar radiation and wind. Physical environment along forest edges is hotter and drier and solar intensity is higher. Fragmentation decreases diversity of many animal groups. Global Ecology and Human Ecology

29 Edge Effects and Tropical Deforestation
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30 Human Influence on Atmospheric Composition
Record of atmospheric composition during last 160,000 years was extracted from ice cores in Greenland and Iceland. Samples of atmosphere trapped in ice. Core indicated two very large fluctuations in atmospheric CO2 concentrations. 140,000 years ago. 13,000 years ago. Global Ecology and Human Ecology

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Fig Global Ecology and Human Ecology

32 Human Influence on Atmospheric Composition
Periods of low CO2 correspond to low temperatures experienced during ice ages, while high levels correspond to interglacial periods. During 19th and 20th centuries, concentration of atmospheric CO2 increased dramatically. Global Ecology and Human Ecology

33 Global Ecology and Human Ecology
If greenhouse gases continue to rise at the current rate, between 2030 and 2050, the average temperature on Earth will rise by about 1.5oC to 10oC. If the temperature should rise 4oC, these scientists forecast massive changes in weather and ocean currents. Global Ecology and Human Ecology

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Fig Global Ecology and Human Ecology

35 Human Influence on Atmospheric Composition
Fossil fuel burning alone produces more than enough CO2 (5,600 Tg/yr) to account for recent atmospheric concentrations (3,500 Tg/yr). Three major periods of interruptions: World War I Great Depression World War II Global Ecology and Human Ecology

36 Depletion and Recovery of the Ozone Layer
In 1985, British Antarctic Survey discovered major reduction in atmospheric ozone. Attention focused on stopping chlorofluorocarbons (CFCs). 1987 Montreal Protocol Largest hole to date in 2000. 2003 saw first reported evidence the ozone layer is recovering. Global Ecology and Human Ecology

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38 Global Ecology and Human Ecology
問題與討論 Global Ecology and Human Ecology