Chap.11 the flux of energy and matter through ecosystems

Chap.11 the flux of energy and matter through ecosystems

鄭先祐 (Ayo)國立臺南大學 環境與生態學院生物科技學系 生態學 (2008)

Essentials of Ecology 3rd. Ed.

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The flux of energy and matterThe flux of energy and matter

• 11.1 introduction

• 11.2 primary productivity

• 11.3 the fate of primary productivity

• 11.4 the process of decomposition

• 11.5 the flux of matter through ecosystems

• 11.6 global biogeochemical cycles

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11.1 introduction11.1 introduction

• Standing crop ( 現存量 )

• Biomass ( 生物質量 )

• Primary productivity ( 基礎 ( 初級 ) 生產力 )

• Gross primary productivity( 粗基礎生產力 )

• Net primary productivity( 淨基礎生產力 )

• Secondary productivity( 二級生產力 )

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Historical landmarksHistorical landmarks

• A classic paper by Lindeman (1942) laid the foundations of a science of ecological energetics ( 生態能量學 ).

• He attempted to quantify the concept of food chains and food webs by considering the efficiency of transfer between trophic level- from incident radiation received by a community through its capture by green plants in photosynthesis to its subsequent use by bacteria, fungi and animals.

• Lindeman’s paper was a major catalyst that stimulated the International Biological Programme (IBP).

• The subject of the IBP was ‘the biological basis of productivity and human welfare’.

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• Recently, deforestation, the burning of fossil fuels and other human influences are causing dramatic changes to global climate and atmospheric composition, and can be expected in turn to influence patterns of productivity and the composition of vegetation on a global scale.

• The International Geosphere -Bioshpere Programme (IGBP), established in the early 1990s, was to predict the effects of changes in climate and atmospheric composition on agriculture and food production.

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The Food and Agriculture Organization (FAO) of the UN

The Food and Agriculture Organization (FAO) of the UN

1. A likely decline in precipitation in some food-insecure areas such as southern Africa and the northern region of Latin America.

2. Changes in seasonal distribution of rainfall, with less falling in the main crop-growing season

3. Higher night-time temperatures, which may adversely affect grain production

4. Disruption of food supply through more frequent and severe extreme weather events.

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11.2 primary productivity11.2 primary productivity

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• Fig. 11.1 Photosynthetic efficiency for three sets of terrestrial communities in the US. Desert ecosystems receive the greatest levels of radiation, but are much less efficient than forests in converting it to biomass.

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• Fig. 11.2 (a) above-ground net primary productivity (NPP) of grass in savanna regions of the world in relation to annual rainfall.

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• Fig. 11.2 (b) total NPP in relation to both annual precipitation and temperature on the Tibetan Plateau for ecosystems including forests, woodlands, shrublands, grasslands and desert.

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• Fig. 11.3 seasonal development of maximum daily gross primary productivity (GPP) for confer forests in temperate locations. Daily GPP is expressed as the percentage of the maximum achieved in each forest during the 365 days of the year.

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• Fig. 11.3 seasonal development of maximum daily gross primary productivity (GPP) for confer forests in boreal locations. Daily GPP is expressed as the percentage of the maximum achieved in each forest during the 365 days of the year.

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• Fig. 11.4 (a) the relationship between gross primary productivity (GPP) of phytoplankton and phosphorus concentration in some Canadian lakes.

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• Fig. 11.4 (b) a location associated with ocean upwelling• (c) a location where nutrient concentrations are much

lower.

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11.3 the fate of primary productivity11.3 the fate of primary productivity

• Fig. 11.5 the relationship between primary and secondary productivity for (a) zooplankton in lakes (b) bacteria in fresh and sea water.

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• Fig. 11.5 the relationship between primary and secondary productivity for (c) caterpillars in relation to a histogram of annual rainfall on the Galapos island of Daphne Major.

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Energy transfer efficienciesEnergy transfer efficiencies

• Consumption efficiency (CE)– The CE of herbivores are approximately 5% in

forests, 25% in grasslands and 50% in phytoplankton-dominated communities.

– Vertebrate carnivores may consume 50-100% of production from vertebrate prey but perhaps only 5% from invertebrate prey, while invertebrate predators consume perhaps 25% of available invertebrate prey production.

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• Assimilation efficiency (AE)– Bacteria and fungi digest dead organic matter

externally and typically absorb almost all the product (AEs of 100%)

– AEs are typically low for herbivores, detritivores, and microbivores (20-50%) and high for carnivores (around 80%).

– Seeds and fruits may be assimilated with efficiencies as high as 60-70%, and leaves with about 50%, while the AE for wood may be as low as 15%.

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• Production efficiency (PE)– PE varies according to the taxonomic class of

the organisms concerned.– Invertebrates in general have high efficiencies

(30%-40%).amongst the vertebrates, ectotherms have intermediate values for PE (around 10%), whilst endotherms, convert only 1-2% of assimilated energy into production.

– Microorganisms tend to have very high PEs.

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• Overall trophic transfer efficiency– = CE x AE x PE– It was generally assumed that trophic transfer

efficiencies were around 10%; indeed some ecologists referred to a 10% law.

– Transfer efficiencies varied between about 2% and 24%-- although the mean was 10.13%.

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• Fig. 11.6 the pattern of energy flow through a trophic compartment .

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• Fig. 11.7 General patterns of energy flow for (a) forest (b) grassland

• Relative sizes of boxes and arrows are proportional to the relative magnitude of compartments and flows.

• DOM, dead organic matter; LSC, live consumer system; NPP, net primary production.

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• Fig. 11.7 General patterns of energy flow• Relative sizes of boxes and arrows are proportional to

the relative magnitude of compartments and flows.• DOM, dead organic matter; LSC, live consumer

system; NPP, net primary production.

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• Fig. 11.8 Box plots for a range of ecosystem types showing: (a) percentage of net primary production (NPP) consumed by herbivores and (b) percentage of NPP entering the dead organic matter (DOM) compartment.

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11.4 the process of decomposition11.4 the process of decomposition

• Immobilization is what occurs when an inorganic nutrient element is incorporated into organic form, primarily during the growth of green plants; for example, when CO2 becomes incorporated into a plant’s carbohydrates.

• Decomposition involves the release of energy and the mineralization of chemical nutrients– the conversion of elements from organic back to an inorganic form.– Bacteria and fungi are early colonists of newly dead

material.

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• Fig. 11.9 size classification by body width of organisms in terrestrial decomposer food webs.

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11.5 the flux of matter through ecosystems

11.5 the flux of matter through ecosystems

• Energy flow

• Matter cycles– Biogeochemical cycles

• Nutrient budgets– Nutrient inputs– Nutrient outputs

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• Fig. 11.12 components of the nutrient budgets of a terrestrial and an aquatic system.

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• Fig. 11.13 annual carbon budget for a ponderosa pine forest in Oregon, USA, where the trees are up to 250 years old. The numbers above ground represent the amount of carbon contained in tree foliage, in the remainder of forest biomass, in understory plants and in dead wood on the forest floor.

• gC/m2

• gC/m2/yr

30Fig. 11.14 pathways of carbon atoms in the ocean.

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11.6 Global biogeochemical cycles11.6 Global biogeochemical cycles

• 11.6.1 the hydrological cycle

• 11.6.2 the phosphorus cycle

• 11.6.3 the nitrogen cycle

• 11.6.4 the sulfur cycle

• 11.6.5 the carbon cycle

• 11.6.6 human impacts on biogeochemical cycles

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• Fig. 11.15 the hydrological cycle, showing volume of water in the reservoirs of oceans, ice, rivers and lakes, ground water and atmosphere and on the move as precipitation, runoff, evaporation and vapor transport (106km3/yr)

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Fig. 28.10 Our total water supply. Most freshwater is

frozen in glaciers and ice caps. A minuscule amount(0.003% of the to total) exists as vapor

in the atmosphere.

Fig. 28.10 Our total water supply. Most freshwater is

frozen in glaciers and ice caps. A minuscule amount(0.003% of the to total) exists as vapor

in the atmosphere.

Water and the coming crisis

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11.3 水的循環是生態体系元素循環的範例。11.3 水的循環是生態体系元素循環的範例。

雨量

地下水

雨量 蒸發

大氣

單位： km3 ； 轉換的單位： km3 / 年

佔 97%量

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全球水量的分佈全球水量的分佈

• 全球水量估計有 1,400,000,000 km3 ，• 海洋有 1,350,000,000 km3 ( 佔 97%) 。• 冰層有 27,500,000 km3

• 地下水有 8,200,000 km3

• 河流水有 40,000 km3

• 陸域雨量有 111,000 km3

• 海洋雨量有 385,000 km3

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• Fig. 11.16 the major global pathways of nutrients

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Fig. 11-12 全球氮循環。單位： 1012 g

人為產生

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陸域

Fig. 11-15 The global phosphorus cycle. 貯存庫的單位： 1012g P 循環的單位： 1012g P/ 年

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Fig. 11-18 全球硫循環。單位： 1012g

人為的

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Fig. 11-7 全球碳循環。 單位： 1015g ；轉換單位；每年 1015g

粗基礎生產量呼吸量

分解量

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全球碳循環的平衡

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