水域生态学ppt课件Ecosystem-(中文版).ppt

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1、Ch.4 生态系统Ecosystem,Basic Concepts of EcosystemMatter Cycle in EcosystemEnergy Flow in EcosystemDevelopment,Evolution,and Equilibrium of Ecosystem,1.生态系统的基本概念,1.1 生态系统定义Tansley(1935)called the integration of organisms and the physical world they share the ecosystem.群落与其非生物环境组成的统一体，即为生态系统Community plu

2、s physical environment is ecosystem.一定空间中共同生活的所有生物（即生物群落）与其环境之间由于不断地进行物质循环和能量流动过程而形成的统一整体，即为,Francis C.Evans(1956)summarized the essential points of this concept in brief assay:In its fundamental aspects,an ecosystem involves the circulation,transformation,and accumulation of energy and matter throu

3、gh the medium of living things and their activities.Photosynthesis,decomposition,herbivory,predation,parasitism,and other symbiotic activities are among the principal biological processes responsible for the transport and storage of materials and energy,and the interactions of the organisms engaged

4、in these activities provide the pathways of distribution.The food chain is an example of such a pathway.The ecologist,then,is primarily concerned with the quantities of matter and energy that pass through a given ecosystem and with the rates at which they do so.,群落和生态系统研究的区别,Community perspectives a

5、re grounded in evolutionary biology and focus on the dynamics of organism distribution and abundanceEcosystem perspectives are grounded in thermodynamics and focus on the dynamics of energy and materials through and around organisms,1.2 生态系统结构和功能,通过生态系统进行的物质循环cycling of matter和相关的能流flux of energy 为表

6、现其结构和功能特征提供了基础生态系统本身由三部分组成:自养生物(autotrophs),固定太阳能的生产者;异养生物(heterotrophs),利用生产者固定的能量和营养物，又将营养物还到系统的消费者和分解者;死亡的有机物质和无机物质，作为短期营养库，维持系统内营养物循环.生态系统功能的最基本过程是光合作用和分解作用.,1.3 生态系统的类型,按环境性质：水域生态系统(Aquatic Ecosystem)海洋生态系统(Marine Ecosystem):海岸带、浅海带（大陆架、上涌带、珊瑚礁）、远洋带淡水生态系统(Freshwater Ecosystem)：流水、静水陆地生态系统(Terre

7、strial Ecosystem)荒漠(desert)冻（苔）原(tundra)草原(grassland)森林(forest)湿地生态系统(Wetland Ecosystem),生态系统的类型,按人类影响程度自然生态系统：森林、草原、水域、沙漠、极地半自然生态系统（驯化生态系统）：农田、人工林、人工草地、牧场、鱼塘、养殖人工生态系统：城镇、工矿、宇宙飞船、实验,淡水生态系统分类,淡水生态系统,流水生态系统（河流）,急流水生态系统,缓流水生态系统,静水生态系统（河流）,水底区,水层区,沿岸带（划归湿地生态系统）,亚沿岸带,深底带,湖心带,深底带,水库生态系统,流水区,过渡区,静水区,1.4 水体

8、生态系统的特点,水体生态系统中，其环境由水的物理化学特性所决定:相对稳定的温度(for high heat capacity of water),相对较低的光照强度(decline with depth),相对丰富的可溶性无机和有机物质(for water as a good solvent)相对较低的溶氧和较高的水密度,etc.,水体生态系统的特点,在陆地生态系统中，细菌和真菌在分解作用中起主要作用；在水域生态系统中，细菌和真菌更多作为转换者，而浮游植物和浮游动物在营养物循环中起主要作用。,水体生态系统的特点,在水域生态系统中，特别是以浮游植物生产为主时，死亡细胞并不积累，容易自我分解(au

9、tolysis)，光合作用产量很高；此外，浮游植物生物量周转率(turn-over)高.The P:B ratios(production/biomass)average 0.042 for forests0.29 for other terrestrial systems17.0 for aquatic community.,水体生态系统的特点,在某些水域中，小的水生消费者周转率高，生物量金字塔pyramid of biomass可能是倒的inverted.,2.生态系统物质循环,2.1 有机物生产 光合自养生物(Photoautotroph):利用太阳能作为能源合成有机化合物的生物绿色植物

10、green plants、藻类algae和蓝细菌cyanobacteria,用H2O作为电子供体，是好氧生物；光合细菌(PSB,purple and green bacteria),有不同于绿色植物的吸收光的色素，利用含H2S的有机化合物作为电子供体，是厌氧生物.,化能自养生物(Chemoautotroph):氧化无机化合物（经常是硫化氢）来获得合成有机化合物所需能量的生物。它们大多是专一性的细菌，全部利用CO2 作为碳源，但能量来自于无机物质的需氧氧化。甲烷(e.g.Methanosomonas,Methylomonas)氨(硝化细菌,Nitrosomonas,Nitrococcus)氢(e

11、.g.Hydrogenomonas,Micrococcus),亚硝酸盐(硝化细菌,Nitrobacter,Nitrococcus)硫化氢、硫、亚硫酸盐(硫杆菌Thiobacillus)铁盐(铁杆菌Ferrobacillus,Gallionella).,2.2 有机物的分解,分解(Decomposition)是涉及渗出、破碎、分解代谢、合成代谢、固定和矿化等一系列连续的过程。分解牵涉到所有消费者，真正的分解者是细菌、真菌和多种多样的食碎屑者(detritivores)和食微生物者(microbivores).,分解涉及以下过程:死亡有机体可溶性化合物的渗出（leaching）破碎化（Fragme

12、ntation）细菌和真菌的分解（breakdown）动物消费细菌和真菌（Consumption）动物排泄有机和无机化合物（Excretion）胶状有机质凝集（Clustering）成较大的颗粒,分解相关的术语,渗出(Leaching):dissolving and removal of nutrients by water out of organic matter.破碎(Fragmentation):the reduction of leaves and other organic matter into smaller particles.It may be accomplished p

13、hysically by wind and trampling or chemically by digestion.分解代谢(catabolism)：Detritivores oxidize organic compounds,releasing energy,and degrade them into smaller and simpler products,processes collectively called,分解相关的术语,Fermentation(发酵):breakdown of carbohydrates and other organic matter under anae

14、robic conditions,converts sugars to organic acids and alcohols,inefficiently breaks down organic matter,lower the pH of substrate,and favors fungal activity.Mineralization(矿化):conversion of materials from organic to inorganic form.It results in the gradual disintegration of dead organic matter into

15、nutrients available to primary producers and microbes.,Bioremediation(生物修复):Using the trophic diversity of bacteria to solve environmental problems.EM(effective microbes)PSB(光合细菌)Bacilus(芽孢杆菌),etc.,2.3 营养物循环Cycling of Nutrients,生物圈物质循环涉及生物、地质和化学三个部分，所以叫生物地（球）化（学）循环.生物地化循环(biogeochemical cycles)可分为三大

16、类型：水循环、气体型(gaseous)循环和沉积型(sedimentary)循环.碳循环涉及生态系统中能量传递氮循环由微生物作用过程所驱动磷循环是典型的沉积型人类活动对氧、碳、氮、硫和磷循环的影响，导致巨大的生态干扰（温室效应等）,根据在Hubbard Brook研究得出的流域生态系统营养动态模型。该模型描述了一个有相对明确的边界的生态系统的输入和输出，这样的生态系统通过跨边界的流通与别的生态系统联系起来,CO2循环,Nitrogen cycle,Nitrogen cycle,Nitrogen fluxes in Sycamore Creek,Arizona.,磷循环PIP=颗粒无机磷;POP

17、=颗粒有机磷;DOP=溶解有机磷;DIP=溶解无机磷.,The Phosphorus Cycle,营养物再生nutrient regeneration途径，清楚的主要有以下5条：通过微生物分解和碎屑复合体通过动物排泄（excretion）通过微生物共生体（symbionts）植物之间直接再循环通过包括太阳能直接作用在内的物理方法通过使用燃料能量如工业固氮.在水域环境，特别是在死亡个体不大的情况下，25-75%的营养物可以在微生物作用之前，通过自溶(autolysis)释放出来,3.生态系统内能量流动Energy Flow in Ecosystem,生态系统内能量传递和转化规律服从热力学的两个定

18、律热力学第一定律(The first law of thermodynamics)“在自然界发生的所有现象中，能量既不能消失也不能凭空产生，它只能以严格的当量比例由一种形式转变为另一种形式”（Energy cannot be created from nothing and existing energy cannot be destroyed）。故又称为能量守恒定律.,热力学第二定律(The second law of thermodynamics)：在封闭系统中，一切过程都伴随着能量的改变，在能量的转递和转化过程中，除了一部分可以继续转递和做功的能量（自由能）外，总有一部分能量不能继续转递

19、和做功，而以热的形式消散，这部分能量使系统的熵和无序性增加。,A law of nature stating that the spontaneous direction of energy flow is from forms organized to less organized forms.The total amount of energy in the universe is spontaneously flowing from forms of higher to lower quality;with each conversion,some energy becomes rand

20、omly dispersed in a form(heat,most often)not as readily available to do work.,光能由自养生物固定，是初级生产(primary production)，由异养生物摄取并贮存，称次级生产(secondary production).能量通过生态系统内复杂的食物网被利用直至最后因分解作用而散失。能量传递主要途径是腐屑食物链和牧食食物链能量传递效率在自养生物和变温和恒温异养生物之间变动很大。,3.1 初级生产 Primary Production,基本概念初级生产量(Primary production)：植物光合作用吸收的

21、能量Energy assimilated by plants.初级生产力(Primary productivity)：光合作用储存能量的速率 The rate at which energy is stored by photosynthetic activity.总初级生产量Gross primary production(GPP)植物生产的干物质总量 the total amount of dry matter made by a plant;total photosynthesis.净初级生产量Net primary productivity(NPP)植物生产除去呼吸消耗后所得干物质总量

22、The overall gain of dry weight by the plant,after respiration has occurred.NPP=GPP-R.,现存量(Standing crop):某一时间单位面积(或体积）内的生物量。Amount of biomass per unit area at a given time.生物的现存量大小与其生产力关系不大。The size of their standing crop has little relationship to their productivity生物量(Biomass):活生物的重量，通常以单位面积内干重表示。

23、Weight of living material,usually expressed by dry weight per unit area.P/B系数（周转率）(P/B ratio,turnover rate)一个物种（一种物质）替换的速率。The rate of replacement of a species(or a substance)when losses to a system are replaced.,测定初级生产量的常用方法Common methods used to measure primary production,收割法(Harvesting)：Samples o

24、f plant tissue are obtained,dried,and weighted.Dry weight of plant biomass is used as measure of production.陆地植物和大型水生植物,测定初级生产量的常用方法Common methods used to measure primary production,CO2测定法(CO2 flux)：CO2 uptake of plant or plant part is measured in closed container.Terrestrial and aquatic 氧气测定法(O2 fl

25、ux)：多用于水域生态系统中，即黑白瓶法(light and dark bottle method)Production of O2 by plants or algae is measured in a closed container.,测定初级生产量的常用方法Common methods used to measure primary production,放射性碳示踪法(Radiocarbon tracer method)：Measurement of 14C-CO2 uptake.A quantity of radioactive carbon as a carbonate is a

26、dded and measured after 24 hr in closed container,then the amount of CO2 fixed is calculated.特别适用于生产力低的湖泊和海洋中,测定初级生产量的常用方法Common methods used to measure primary production,叶绿素含量测定法(Chlorophyll concentration)Chlorophyll is extracted and its concentration measured.Concentration is compared with the ra

27、te of assimilation of carbon per gram of chlorophyll for the particular plant or algae under study.通常用于水域生态系统中,初级生产力在下列有利条件组合下取得最大:充足的光照 intense sunlight温暖的气候warm temperatures充沛的雨水abundant rainfall丰富的营养ample nutrients水体（特别是远洋）初级生产一般受营养可得性制约。通常，淡水中磷是限制因子，而海洋中氮是限制因子。有意或无意地增加营养会刺激有害的生物生产（inadvertent ad

28、dition of nutrients may stimulate unwanted production：algae bloom&red tide),Production in Wetland and Aquatic Systems,Wetlands are often highly productive:swamps and marshes are especially productive because of their position at the interface of terrestrial and aquatic systemsProduction in aquatic s

29、ystems is highly variable:open oceans are unproductive(nutrient-limited)upwelling areas and continental shelf are more productiveestuaries,reefs,and coastal algal beds may be highly productive,Net Primary Productivity and Plant Biomass of World Ecosystems,3.2 食物链和生态效率,食物链（Food chain）：从植物开始，以肉食者终止，由生

30、产者和各级消费者组成的能量和营养传递序列（Movement of energy and nutrients from one feeding group of organisms to another in a series that begins with plants and ends with carnivores）Chinese proverbs“The large fish eat the small fish;the small fish eat the water insects;the water eat plants and mud”.(Eltons“food chain”)

31、,食物链,牧食食物链(grazing food chain)：以获的绿色植物为基础，从食草动物开始的食物链在深水水体生态系统和高收获率的生态系统中，牧食食物链占优势.腐（碎）屑食物链(detrital food chain)：以死的动植物残体为基础，从真菌、细菌和某些食有机碎屑或动植物残体动物开始的食物链。在多数陆地和潜水生态系统中，初级生产者现存量高而相对收获率低，则腐屑食物链占优势,Food Chainsin Different Ecosystems,Food web in neritic province.Phytoplankton are consumed by zooplankton

32、,which in turn are consumed by many animals,including jellyfish,ctenophores,herring,and baleen whales.,营养级(Trophic level)：一个营养级是指处于食物链某一环节上的所有生物。all organisms that are the same number of transfer steps away from the energy input into the system.,食物链（营养级）有限的假说,能流假说Energy flow hypothesis:能量约束限制了营养级的数量

33、.动态稳定假说(Dynamic stability hypothesis)：解释食物链较短的原因，是基于较长的食物链不稳定的事实，在较低的营养级上的波动会在较高营养级上放大，顶级捕食者会因此而灭绝。该假说认为：食物网较为复杂营养级相对较多，生物多样性较大，不如相对营养级较少的容易从干扰中恢复，因此也就不象食物网较为简单的来得稳定；该假说预言在不可预知的环境中，食物链较短。,物质循环和能量流动,图示能量流动()和营养物循环(-)之间的关系,E.P.Odum的生态系统流通示意图,显示能量的单向流动和物质的再循环。总初级生产量是系统吸收的总能量，系统的输入和输出包括那些迁入和迁出的生物或被风或水带入

34、或带出的残骸,(a)Energy flow in one trophic level.(b)A link between two trophic levels in a food web.Some of the energy that enters the trophic level represented by the large box on the left is lost or used for respiration and thus is not available to the next trophic level,which is represented by the smal

35、ler box on the right.The size of each box represents the total biomass in that trophic level.These diagrams could depict the interactions of individual organisms as well as those of trophic levels,in which case each individual would be depicted as a separate box,(b),E.P.Odum的生态能量流动“通用”模型,食物链某一环内能量分配

36、。能量被摄取、消化和用作生长和繁殖，能量通过排泄、分泌和最终死亡而失去,湖泊生态系统营养物循环和能量流动模型。气象、地质和生物作用输入从流域进入静水系统。营养物和能量通过一些途径运行，部分营养物和能量积聚在底层沉积物中。,流水水体能量流动途径,河流生态系统能量流动.Note the great dependency on materials from terrestrial sources and inflow from upstream,and the role of coarse particulate organic matter(CPOM),fine particulate organ

37、ic matter(FPOM),and dissolved organic matter(DOM).Primary production contributes little to energy flow.Energy values in kcal/m2/yr are based on Bear Brook,Hubbard Forest,New Hampshire.,能量利用生态效率,生态效率(Ecological efficiency)，也称传递效率(transfer efficiency)，是指能量从一个营养级传递到后一营养级的百分比.林德曼营养效率定律(Lindemans law of

38、trophic efficiency)：能量从一个营养级向下一个营养级传递的效率约为10，故也称十分之一定律。5%20%,Definition of several energetic efficiencies,能量有关术语,摄取量(intake)：植物吸收的能量或动物摄取的食物能量排遗量(egestion)：动物所排遗或吐掉的不能消化的能量（粪能）同化量(assimilation)：动物消化吸收的能量摄取量排遗量同化量同化量呼吸量(respiration)排泄量(excretion)生产量(production)生态效率利用效率总生产效率,Lindeman对明尼苏达州一个小湖泊的研究表明，利

39、用效率exploitation efficiencies低得令人惊讶：植食性herbivores:20%肉食性carnivores:33%,Some General Rules同化效率随营养级而提高；Assimilation efficiency increases at higher trophic levels.净和总生产效率随营养级而下降；Net and gross production efficiencies decrease at higher trophic levels.营养级间生态效率平均大约10；Ecological efficiency averages about 10

40、%.大约只有1%的植物净生产量能传递到第三营养级作为生产量:能量金字塔很快变窄；the pyramid of energy narrows quickly.要提高人类食物供应量意味着要吃食物链低端产品。To increase human food supplies means eating lower on food chain!,Question for thought,Why are herbivorous and detritivorous fishes more often utilized for food in Asia than in North America?,恒温动物和变温

41、动物的同化效率和生产效率(based on data from Andrzejewska&Gyllenberg 1980),A:assimilation(同化量);P:production(生产量);C:consumption(食物消费量)A/C(Assimilation efficiency,同化效率);P/C(gross production efficiency,生产效率);P/A(net production efficiency,净生产效率),生态锥体(Ecological pyramid)：能量金字塔Pyramid of energy：能量通过营养级传递逐级减少，如把通过各营养级的

42、能流量作图，就成为一个金字塔形，称为能量金字塔。永远是正的。以生物量和个体数目表示即为生物量和数量金字塔Pyramid of biomass(number)。它们可能有倒置的Chinese proverbs“Large fowl cannot eat small grain”and“One hill cannot shelter two tigers”imply the concept of pyramid of number.,Pyramid of Biomass,Bioconcentration(生物浓缩)：a process that results in an organism hav

43、ing a higher concentration of a substance than is in its surrounding environmental media,such as stream water.Bioaccumulation(enrichment,富集作用)：a general term for the accumulation of substances,such as pesticides(DDT),methylmercury(甲基汞),or other organic chemicals in an organism or part of an organism

44、Bioconcentration differs from bioaccumulation because it refers only to the uptake of substances into the organism from water alone.Bioaccumlation is the more general term because it includes all means of uptake into the organism.,Biological magnification(amplification,enlargement,生物放大)The ever-incr

45、easing concentration of a chemical compound(non-degradable or slowly degradable substance)in the tissues of an organism as it is passed up the food chain.,Effects of biological amplification.Even though the initial pollution of DDT to this aquatic system was at apparently harmless levels,fish would

46、die and birds would die from DDT poisoning.The highest trophic levels accumulate the most DDT in concentrations that can be fatal or inhibit reproduction,4.生态系统发育、进化和平衡Development,Evolution,and Equilibrium of Ecosystem,4.1 生态系统发育 生态系统发育，更多称之为生态演替ecological succession涉及到物种结构和群落作用随时间的变化.Autogenic Prim

47、ary&Secondary succession.,Trends to be expected during the course of autogenic succession(Odum E.P.1983,“Basic Ecology”)Energetics 1.Biomass(B)and organic increase 2.Gross production(P)increase in primary;little change in secondary 3.Net production decrease 4.Respiration(R)increase 5.P/R ratio moves

48、 toward unity(balance)6.B/P ratio increases(conversely,P/B decrease)Nutrient cycling,7.Element cycles increasingly closed 8.Turnover time and storage of essential elements increase 9.Cycling ratio increase 10.Nutrient retention and conservation increase Species and community structure 11.Species com

49、position change(relay floristics and faunistics)12.Diversity-richness component increase 13.Diversity-evenness component increase 14.r-Strategists largely replaced by K-strategists 15.Life cycles increase in length and complexity,16.Size of organism and/or propagule(seed,offspring,and so on)increase

50、s 17.Mutualistic symbiosis increase*Stability 18.Resistance increase*19.Resilience decrease*Overall strategy 20.Increase efficiency of energy and nutrient utilization*Trend based on theoretical considerations,yet to be validated in the field.,生物圈的长期进化是由外源(allogenic)力，如地质和气候变化以及来自于生态系统生物活动的内源(autogen