Chap. 3 Energy in Ecological Systems (II) 鄭先祐 (Ayo) 國立台南大學 環境與生態學院 2008 年 2 月至 6 月

3. energy in ecological systems (part II)2 Energy in Ecological systems 1.The Laws of Thermodynamics ( 熱力學定律 ) 2.Solar radiation and the energy environment 3.Concept of productivity 4.Energy partitioning in food chains and food webs 5.Energy quality: eMergy 6.Metabolism and size of individuals: the ¾ power principle

3. energy in ecological systems (part II)3 Energy in Ecological systems 7.Complexity theory, energetics of scale, and the law of diminishing returns 8.Concepts of carrying capacity and sustainability 9.Net energy concept 10.An energy-based classification of ecosystems 11.Energy future 12.Energy and money

3. energy in ecological systems (part II)4 5 Energy Quality: eMergy  Energy quality, 能量不能僅有量的大小，亦有品質的好壞。同 量但不同形式的能量，其作功的能力大不相同， 也就是品質各不相同。並不是所有每 1 卡能量 都具有同樣的品質。  eMergy (embodied energy), as the sum of the available energy already used directly or indirectly to create a service or product.

3. energy in ecological systems (part II)5 Fig Diagram showing how increasing energy concentration (quality) accompanies decreasing energy quality.

3. energy in ecological systems (part II)6 Fig Diagram showing how increasing energy concentration (quality) accompanies decreasing energy quality.

3. energy in ecological systems (part II)7 Table 3-10

3. energy in ecological systems (part II)8 6 Metabolism and Size of Individuals: The ¾ Power Principle  The ¾ Power Principle the rate of metabolism in individual animals tends to increase as the ¾ power of their body weight. Fig Relationships between (A) respiration and body weight and (B) respiration per unit weight and total body mass.

3. energy in ecological systems (part II)9 7 Complexity Theory, Energetics of Scale, and the Law of Diminishing Returns  Law of diminishing returns when maintenance energy costs balance the available energy, the theoretical maximum size or carrying capacity has been reached, beyond which decreasing returns of scale set in  C = N(N-1)/2

3. energy in ecological systems (part II)10 8 Concepts of Carrying Capacity and Sustainability  Carrying capacity ( 承載量 ) Maximum carrying capacity Optimum carrying capacity Economic carrying capacity (economic welfare threshold)  Maximum sustained yield (optimum density)

3. energy in ecological systems (part II)11 Fig Carrying capacity in relation to sigmoid population growth. (A) Growth curve

3. energy in ecological systems (part II)12 Fig Carrying capacity in relation to sigmoid population growth. (B) change in growth curve depending on population size.

3. energy in ecological systems (part II)13 Concept of sustainability  Sustain = to keep in existence + to support + to maintain + to supply  Sustainability = maintaining natural capital and resources

3. energy in ecological systems (part II)14 Fig Trends in the gross national product (GNP) index and the index of sustainable economic welfare (ISEW) in the US.

3. energy in ecological systems (part II)15 Fig Energy-generating windmills in eastern Germany.

3. energy in ecological systems (part II)16 9 Net Energy Concept Fig Concept of net energy.

3. energy in ecological systems (part II)17 10 An Energy-Based Classification of Ecosystems  Four classes of ecosystems 1.Natural, unsubsidized solar-powered ecosystems 2.Natural, solar-powered ecosystems subsidized by other natural energies. 3.Human-subsidized solar-powered ecosystems 4.Fuel-powered, urban-industrial techno- ecosystems

3. energy in ecological systems (part II)18 Table 3-11

3. energy in ecological systems (part II)19 11 Energy Futures  Energy 1.Age of muscle power 2.Age of fossil fuels 3.Age of atomic energy  Future: solar energy and fuel-cell (hydrogen) Ocean thermal energy conversion (OTEC)

3. energy in ecological systems (part II)20 Peaceful uses of atomic energy  At the first international conference (Geneva in 1955), the chair of the conference, Homi J. Bhabha of India, described three ages of humanikind.  Bhabha believed the coming of the atomic age would close the gap between rich and poor nations.

3. energy in ecological systems (part II)21

3. energy in ecological systems (part II)22

12 Energy and Money

3. energy in ecological systems (part II)24 Fig Energy flow model of an estuarine ecosystem harvested for seafood.

3. energy in ecological systems (part II)25 圖 8 傳統的經濟活動。海灣區對人類的實際價值至少是 此區生產的魚獲量價值的十倍。紅色線表示能量的循流； 淡藍色線表示貨幣之流通。

3. energy in ecological systems (part II)26

3. energy in ecological systems (part II)27 圖 9 人類的能源支持體系。由人工和農業生態系來的 能量，貨幣流通大致配合能量的循流；但是從自然態系 而來的能量，並無貨幣配合。紅色線表示能量的循流； 淡藍色線表示貨幣之流通。 科技 系統 農林漁牧 生態系 自然生態系 世界 經濟 化石 燃料 太陽 能 能源 能量轉換 能量享用

3. energy in ecological systems (part II)28 圖 3. 經濟的狹窄觀點和寬廣觀點。傳統經濟學理是立基 於狹窄觀點，新寬廣觀點認識到自然生態環境對經濟活 動所提供的價值。基本內容摘譯自： Young(1992) ， p.10 ， Figure 1.4 。

3. energy in ecological systems (part II)29 問題與討論 Ayo 台南站：