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1、1,淡水生态学Freshwater ecology,源自暨南大学水生所,2,淡水生态学Freshwater ecology is the study of the structure, function, and change of organisms in fresh waters as affected by their dynamic physical, chemical, and biotic environments. .,3,湖泊分区 (Lake zones),沿岸带,敞水带,真光层 透光层,沉水植物,浮叶植物,挺水植物,底栖带,湖沼带,4,湖泊类型与起源,5,（一）构造湖Tect
2、onic lakes,basins formed by movements of the earths crust,（二）火山口湖Volcanic lakes,（三）河成湖Fluvial Lakes,6,（四）牛轭湖,7,（五）堰塞湖Landslide lakes,lakes formed by rock slides, mudslides damming streams in valleys,8,（六）冰川湖Glacial lakes,是由冰川挖蚀成的洼坑和水渍物堵塞冰川槽谷积水而成的一类湖泊,9,（七）岩溶湖Solution lakes,典型的岩溶湖是由碳酸盐类地层经流水的长期溶蚀所产生的
3、岩溶洼地、岩溶漏斗或落水洞等被堵，经汇水而形成的一类湖泊。,formed by the slow dissolving of soluble rock by water. Most formed in areas with limestone bedrock.,10,(八)海成湖Shoreline lakes,created at irregularities or indentations along the coastline of large lakes. Usually result of long shore currents depositing material as a spi
4、t or bar at the mouth of the indentation,11,（九）风成湖Aeolian lakes,formed by wind activity in arid regions which may erode broken rock or redistribute sand forming dune由风吹起的沙丘lakes. Generally temporary. 。,12,（十）人工湖Anthropogenic lakes,dams and excavations by humans,13,Animal activity,Beaver Dam,14,(十一)陨
5、石湖Meteorite lakes,crater from meteorite impacts, e.g., large one in northern Quebec,15,Limnological mean depth=V/Ao Maximum depth (zmax),16,Relative depth (zr),expresses the zmax as a percentage of the mean diameter平均直径 of the lake.,17,岸发展系数Shoreline development (DL),岸发展系数（岸线长与相同面积圆形湖泊岸线长之比）Shorelin
6、e development is calculated as DL = L/(2* sqrt( *Ao),18,河道及流域的主要特征 河流长度 L（km）： 自河源沿河道至河口的长度称为河流长度，或称河长。落差：河段两端的河底高程差。,19,河网密度: 单位面积内的河流总长度称为河网密度。它表示一个地区河网的疏密度。,20,河流连续体理论RCC River continuum concept 由源头集水区的第一级河流起，河水向下流经各级河流流域，形成一个连续的、流动的、独特而完整的系统，称为河流连续体。,21,Comparison of Aquatic Systems,22,Photosynt
7、hetically active radiation (PAR), i.e., radiant energy between 400 700 nm wavelengths. Always 4649 of all energy.,23,光在水中的传播 Light penetration ,penitrein in water,The percentage of the surface light absorbed or scattered in a 1m long vertical column of water, is called the vertical extinction coeffi
8、cient. This parameter is symbolized by k.,24,透明度Transparency,Transparency :Depth to which visible light penetrates,25,Photic or Euphotic Zone - extends from surface to depth where light is 1% of incident light at surface. Region of net O2 production during the day due to photosynthesis (P/S) O2 decl
9、ines during night - respiration (decomposition processes).Aphotic Zone - extends from bottom of photic zone to bottom of lake. Light levels too low for photosynthesis so respiration processes dominate over production processes and aphotic zone uses O2.,26,Compensation Depth：depth at which incident l
10、ight is reduced to about 1% so P/S = respiration.,27,Epilimnion湖上层 湖面温水层 warm upper layer;Metalimnion- layer斜温层 水体变温层of rapid change in temperature (e.g., thermocline) ;Hypolimnion: 均温层、深水层cold bottom layer, about 4;,28,Lake stratification and seasonal turnover 生态学意义,29,This pattern (spring turnover
11、 summer stratification fall turnover winter stratification) is typical for temperate 温带的深水湖泊deep lakes.,30,LAKE DEPTH MATTERS,Deep LakesStratify分层Shallow LakesContinuous Nutrient Recycling,31,水的特性 Characteristics of water 热容量很大,热容量Specific heatThe amount of heat required to raise temperature of a un
12、it mass of a substance 1.,32,密度Density,Nonlinear 非线性relation of density to temperature is unique to water. Maximum density of pure water is 1.000 g/cm3 at 3.94 . Density of pure water at 0 is 0.99987 g/cm3. As temperature increases beyond 4 density decreases at an increasing rate.,33,Shift from lami
13、nar层流 to turbulent紊流 flow in a fluid in a smooth tube is related to the viscosity粘度 and density of the fluid, its velocity, and the size of the channel or tube through which the fluid流体 flows. Reynolds Number 雷诺系数, Re, is used to determine if flow is laminar or turbulent in a tube.Re = (pDv)/p is de
14、nsity, D is the diameter of the channel or tube, v is velocity, and is viscosity. Re 1,000 flow is turbulent.,34,surface seiches .,35,河水流 River Currents,. Inflow movements related to temperature, dissolved substances, and suspended particles.,36,3 types of inflow movement: Overflow - river water is
15、less dense than lake water and so stays at the surface, Underflow - river water density is greater than lake water and so flows along the bottom, e.g., spring melt runoff. Interflow - river water density is greater than epilimnion but less than meta- or hypolimnion.,37,The watershed, also called the
16、 drainage basin, is all of the land and water areas that drain toward a particular river or lake. Thus, a watershed is defined in terms of the selected lake (or river). There can be subwatersheds within watersheds. For example, a tributary 支流to a lake has its own watershed, which is part of the larg
17、er total drainage area to the lake(or river).,38,天然水体的pH值在6-8 之间，是一个很好的缓冲体系，碳酸化合物是水体缓冲作用的重要因素。,缓冲能力,39,溶解氧（DO）Dissolved Oxygen 溶解于水中的分子态氧 mg/L化学需氧量（COD） Chemical Oxygen Demand 氧化水中有机物(或其它还原性物质)所需化学氧化剂的量，以mgO2/L计,重要指标,40,好气条件下水中有机物被微生物所氧化，在一定期间内所消耗的溶解氧的量，单位 mg/L， BOD5称五日生化耗氧量。,生化需氧量(BOD) Biochemical
18、oxygen demand,41,水中有机物完全氧化所需氧的量（燃烧法），单位是mg/L。,总需氧量（TOD）Total Oxygen Demand,42,水体中氧气大主要来源与消耗？,43,Redfield 比,A. C. Redfield (1958) 通过研究海洋浮游植物发现的。,磷往往是淡水生态系统的限制因子,44,Fe-P相互作用 Fe-P interactions,Under oxygenated conditions (e.g., in the epilimnion or at overturn) ferrous (Fe2+) is oxidized to ferric (Fe3
19、+). Fe3+forms Fe(OH)3 or FePO4 if phosphate is present.,45,PO43-,PO43-,Fe+,Fe(OH)3,PO43-,Dissolved iron (Fe3+) in the water and sediments can bind to P and create an insoluble precipitate,Called the “iron trap”, and happens only when the hypolimnion contains oxygen,46,As the hypolimnion becomes anox
20、ic, Fe+ gains an electron and is reduced to Fe+,Fe+,Fe+,Fe(OH)3,Fe+ forms soluble salts with PO4,Fe+,Fe(OH)2,Under anoxic conditions get net flux of P out of the sediments,PO43-,PO43-,This is called internal loading内源污染 and increases P concentrations in the water column at turnover,47,Ammonification
21、:蛋白质通过水解降解为氨基酸,然后氨基酸中的碳(不是氮)被氧化而释放出氨(NH3)的过程。,2、氨化作用,蛋白质,NH3,氨化作用,48,3、硝化作用,是氨的氧化过程。第一步：硝化菌把氨（或铵）转化成NO2-第二步：硝化菌把NO2- 氧化成NO3-,NO2-,NH3,NH4+,NO3-,亚硝化细菌,硝化细菌,49,Some nitrogen is lost to the air by denitrification. Here, bacteria convert nitrate or nitrite to gaseous nitrogen and a bit of nitrous oxide.
22、,4、反硝化作用,NO2-,NO3-,NO ,N2O ,NO2-,N2 ,第一步：反硝化菌把硝酸盐还原为亚硝酸盐，释放出NO；第二步：反硝化菌把亚硝酸盐进一步还原成N2O和N2；N2O（笑气）与2个全球变化过程相关：在同温层与氧反应，破坏臭氧，增加大气中的紫外辐射；在对流层作为温室气体，促进气候变暖。,50,浮游植物 phytoplankton,是一个生态学概念，是指在水中营浮游生活的微小植物，通常就是指浮游藻类。,51,有些种类在小水体和浅水水体中常大量繁殖，使水体呈现色彩，这一现象称为“水华”(water bloom)。有些藻类在海水中大量繁殖，形成“赤潮”（red tide）。,52,蓝
23、藻生态分布特征,蓝藻类分布很广，淡水、内陆盐水、湿地都有分布。蓝藻一般喜高温好强光，喜高pH和静水，喜低氮高磷。水平分布上下风位多于上风位，静水易孳生。,53,Attached algae periphyton cont.附着藻类,Ecological differences from phytoplanktonFixed depth re light, wave action and temperature zonesCloser to sediment nutrient sourcesExposed to higher levels of nutrients from watershed
24、May act as biofilter生物过滤器 on the sediments in unproductive lakesInteractions with macrophytes,54,55,二、大型水生植物的生态作用,PLANT,1.初级生产者：物质循环、能量流动、信息传递,56,2、原材料,57,3、。,58,4.丰富饵料资源,59,5.提供栖息地,60,6.防风固堤防侵蚀,防侵蚀,61,7、水文功能,Hydrological Process of Ecosystem,Rainfall,Canopy interception,Throughfall,stemflow,Underst
25、ory,interception,Litter interception,Soil storage,Evapor transpiration,Evaporation,Runoff,Transpiration,62,8、Light extinction,63,9,64,10,65,11、Sedimentation and resuspension,66,12、Purification ,pjurifikein 净化 提纯,67,13,68,14、化感作用,化感作用：植物和微生物通过释放化学物质促进或抑制其他个体或自体的现象；,69,15景观美学教育,70,16、小气候调节功能,71,17、生物多
26、样性和生态系统稳定性,生态系统的稳定性,72,湖泊生态系统的主要消费者之一，个体小，数量多，代谢活动强烈，能以浮游植物、细菌、碎屑等为食，控制着藻类和细菌的种群数量和群落结构；,蚤状水蚤,Zooplankton主要生态功能,73,浮游植物通过浮游动物被转化成次级生产,74,食物网中更高营养级的鱼类和其它水生动物的饵料，在生态系统的物质循环中起到承上启下的作用,75,通过排泄和分泌作用，参与物质循环排放的无机磷和无机氮能供给初级生产和细菌繁殖所需，强烈影响着湖泊生态系统食物网中营养级动态。总之，种群动态变化和生产力的高低:湖泊生态系统结构,功能生态过程维持生态系统的平衡,76,77,底栖动物（z
27、oobenthos或benthic animal）是指生活史的全部或大部分时间生活于水体底部的水生动物群，一般包括水生环节动物、水生软体动物、甲壳动物和水生昆虫。,78,3按照成体大小:不能通过500m孔径筛网的动物称为大型底栖动物（marofauna）。能通过500m孔径筛网但不能通过42m孔径筛网的动物为小型底栖动物（meiofauna）。能通过42m孔径筛网的动物为微型底栖动物（nanofauna）。,79,底栖效应,1.通过对营养物质的吸收、转化、降解、排泄等过程参与生态系统的物质循环;,80,2. 影响着水体对污染物的容纳量和自净能力;,81,3.限制着浮游植物的生长; 4.通过摄食
28、细菌和真菌而调整水体中有机物的分解。5.生物扰动者,进行有机物、颗粒物和微生物的混合并重新分配到水体或底泥深处,82,6.有可能通过食物链向上传递，产生生物放大效应。7. 调整着溶解氧的含量,83,8.次级生产者,进行生物物质的第二次生产，是食物链的重要成员、能量流动的主要渠道，几乎所有的底栖动物都是次级生产者。,84,9.粉碎者,能破碎有机物质，增大其表面积，为下一步的腐烂、分解做好准备;,85,10.自然界的滤水器，尤其是双壳类和螺类能通过滤食和分泌物絮凝作用控制和沉降浮游植物和悬浮物，增加水体透明度，降低营养盐含量等；,86,11水生态系统能量流动的中间环节；12.水生态环境质量优劣的重
29、要表征；,87,淡水生态系统中的鱼类Fish in freshwater ecosystem,88,终生生活在水里、用鳃呼吸、用鳍游泳的脊椎动物。,89,Of the migratory species （回游种类）there are two general types of migration:,Anadromous （溯河）- fish feed and grow in the oceans and migrate into freshwater to spawn, 如中华鲟. Catadromous （降河）- fish feed and grow in freshwater and m
30、igrate into the ocean to spawn, 如鳗鱼.,90,Fish feeding guilds,Most fish are somewhat opportunistic in their feeding habits but in general, the majority of the food they eat enables fishery biologists to place them into feeding guilds.Planktivores consume planktonBenthivores consume benthosPiscivores c
31、onsume fishDetritivores consume organisms that live on detritus or mud (biofilm)Omnivores consume a variety of foods opportunistically,91,富营养化的概念： 富营养化（Eutrophication）是由于植物营养盐，特别是氮、磷等，的大量输入，导致水体（包括湖泊、河流、水库、海洋等）生产力上升的一种现象（过程）。,1、水体富营养化概念,92,水体富营养化的控制因子,水温光照营养盐（浓度、N/P比等）伪空胞和垂直迁移水动力条件对捕食压力的适应化感作用厌氧/黑暗环
32、境的适应湖泊形态,93,Noxious algae (scums, blue-greens, taste and odor, visual) Excessive macrophyte growth (loss of open water) Loss of clarity (secchi depth goes down) Possible loss of macrophytes Low dissolved oxygenBlue-green algae inedible by some zooplankton (reduced food chain efficiency) Toxic gases
33、(ammonia, H2S) in bottom water Possible toxins from some species of blue-green algae Drinking water degradation Carcinogens（致癌物质）Loss balance of ecosystem,EUTROPHICATION,94,总之，水华发生时，散发腥臭味，夜间大量消耗水中溶解氧，死亡后产生羟氨或硫化氢，对水生动物有毒，破坏生态平衡，危害渔业，也使水的其他利用价值降低。,95,水生态系统常用修复措施,96,人为修复外源污染控制底泥疏浚底泥覆盖水动力调控机械除藻和化学除藻 暴气降低水位及干化提高透明度营养盐钝化 水生植物修复鱼类修复浮游动物修复底栖动物的修复生物浮床自然修复,
