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1、Chapter6MicrobialecologyandresourcesEcology生态学Resources资源Twoterms:1.Microbialecology:Isnowusedinageneralwaytodescribethepresenceanddistributionofmicrobes.Itisthestudyofthebehaviorandactivitiesofmicrobesintheirnaturalenvironments.2.Environmentalmicrobiology:Incomparison,relates
2、primarilytoall-overmicrobialprocessesthatoccurinasoil,waterorfood,asexamples.itisnotconcernedwiththeparticularmicroenvironmentwherethemicrobesactuallyarefunctioning,butwiththebroader-scaleeffectsofmicrobialpresenceandactivities.6.1Microbesinnatureecosystem6.1.1Microbesandmicro
3、environmentInamicrobialecosystem,individualcellsgrowtoformpopulations.Metabolicallyrelatedpopulationsconstitutegroupingscalledguilds.Setsofguildsconductingcomplementaryphysiologicalprocessesinteracttoformmicrobialcommunities.Microbialcommunitiestheninteractswithcommunitiesofmi
4、crobestodefinetheentireecosystem.6.1.2DistributionofmicrobesThedistributionofmicrobesinnatureecosystemdependsontheresources(nutrients)availableandonthegrowthconditions.Temperature,PH,wateravailability,light,oxygenofahabitatdefinethenicheforeachparticularmicrobes.1.Insoilorgani
5、smsinsoilsoilisthehabitat(环境)foravarietyoforganisms,includingbacteria,actinomycetes,fungi,protozoa,insects,nematodes(线虫),wormsandmanyotheranimals.Virusesalsoarepresentinsoils.Thiscomplexbiologicalcommunitycontributestotheformation(形成),maintenance(维持),andinsomesituations,thedeg
6、radation(降解)anddisappearance(消失)ofsoils.(2)Soilsasanenvironmentformicrobes:Amajorcharacteristicofsoilstheyaretypicallynotwatersaturated(饱和),makingitpossibleforoxygentopenetrateintothepassagesandporessoilsalsocancontainisolatedregionswhicharewatersaturated,andtheseisolatedregio
7、nsbecome“mini”aquatic(水生的)environments.Themicroenvironmentbacteriatendtobepresentasisolatedmicrocolonies(微菌落)onsurfacesandinpores,whicharecoveredbythinwaterfilms.Filamentous(丝状的)fungiareabletogrowonandbetweentheseaggregated(聚集的)particles,orprotozoamoveinwaterfilmsandgrazeonbac
8、teria,especiallywhentheyarenotprotectedinsoilpores.proportion