第七章 微生物生态VIP专享VIP免费

Chapter6MicrobialecologyandresourcesEcology生态学Resources资源Twoterms:1.Microbialecology:Isnowusedinageneralwaytodescribethepresenceanddistributionofmicrobes.Itisthestudyofthebehaviorandactivitiesofmicrobesintheirnaturalenvironments.2.Environmentalmicrobiology:Incomparison,relatesprimarilytoall-overmicrobialprocessesthatoccurinasoil,waterorfood,asexamples.itisnotconcernedwiththeparticularmicroenvironmentwherethemicrobesactuallyarefunctioning,butwiththebroader-scaleeffectsofmicrobialpresenceandactivities.6.1Microbesinnatureecosystem6.1.1MicrobesandmicroenvironmentInamicrobialecosystem,individualcellsgrowtoformpopulations.Metabolicallyrelatedpopulationsconstitutegroupingscalledguilds.Setsofguildsconductingcomplementaryphysiologicalprocessesinteracttoformmicrobialcommunities.Microbialcommunitiestheninteractswithcommunitiesofmicrobestodefinetheentireecosystem.6.1.2DistributionofmicrobesThedistributionofmicrobesinnatureecosystemdependsontheresources(nutrients)availableandonthegrowthconditions.Temperature,PH,wateravailability,light,oxygenofahabitatdefinethenicheforeachparticularmicrobes.1.Insoil(1)organismsinsoilsoilisthehabitat(环境)foravarietyoforganisms,includingbacteria,actinomycetes,fungi,protozoa,insects,nematodes（线虫）,wormsandmanyotheranimals.Virusesalsoarepresentinsoils.Thiscomplexbiologicalcommunitycontributestotheformation（形成）,maintenance（维持）,andinsomesituations,thedegradation（降解）anddisappearance（消失）ofsoils.(2)Soilsasanenvironmentformicrobes:Amajorcharacteristicofsoilstheyaretypicallynotwatersaturated（饱和）,makingitpossibleforoxygentopenetrateintothepassagesandporessoilsalsocancontainisolatedregionswhicharewatersaturated,andtheseisolatedregionsbecome“mini”aquatic（水生的）environments.Themicroenvironmentbacteriatendtobepresentasisolatedmicrocolonies（微菌落）onsurfacesandinpores,whicharecoveredbythinwaterfilms.Filamentous（丝状的）fungiareabletogrowonandbetweentheseaggregated（聚集的）particles,orprotozoamoveinwaterfilmsandgrazeonbacteria,especiallywhentheyarenotprotectedinsoilpores.proportionofdifferentsoilmicrobesinsoilAerobicbacteria70%Actinomycetes13%Fungi3%Otherorganisms0.02%Anaerobicbacteria14%Microbialnumberandbiomassincultivatedfieldsoil:microbesNumbers/gBiomass(g/m3)bacteria108160actinomycetes107160molds106200yeasts105algae10432protozoa103382.InwaterAmajorfactorinaquaticenvironmentsisthemovementofmaterials,whethertheybegaseous,solid,orinthedissolvedphase.Themicrobesareabletorespondrapidlytoselecttheirmostsuitableenvironment.(1)Differenttypesofwater①FreshwaterTypesofmicrobialcommunitiesaccordingtothecontentsoforganicsubstancesDistributionofmicrobesinfreshwaterNutrientenrichmentStimulatesthegrowthofplants,algae,andbacteria.Cyanobacteriaandalgaecancontributetomassiveblooms(水华)instronglynutrientenrichmentlakes.②marineenvironmentMicrobesinoceanAlgae(藻类),Bacillus(芽孢杆菌属),Pseudomonas(假单胞菌属),Vibrio(弧菌属)andsoon.DistributionofmicrobesinoceanEuphoticzone（透光区）Aphoticzone（无光区）Bathypelagezone（深海区）;Hadalzone（超深渊海区）光照区耐压范围中度嗜压范围极端嗜压范围NorthpoleandsouthpolePolaromonas(极地单胞菌属)，Marinobacter(海杆菌属)，Psychroflexus(嗜冷弯曲菌属)，Iceobacter(冰杆菌属)，Polibacter(极杆菌属)，Psychromonasantarcticus(南极嗜冷单胞菌属)Redtide(2)Nutrientcyclesinaquaticenviron...