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1、J.LakeSci.(湖泊科学),2008,20(2):228-234http://www.jlakes.org.E-mail:jlakes@niglas.ac.cn©2008byJournalofLakeSciences∗背角无齿蚌滤食对营养盐和浮游藻类结构影响的模拟1,2111∗∗杨东妹,陈宇炜,刘正文,吴庆龙(1:中国科学院南京地理与湖泊研究所,南京210008)(2:中国科学院研究生院,北京100049)摘要:利用微型生态系统研究背角无齿蚌(Anodontawoodiana)高密度养殖情况下对微
2、型生态系统水柱中不同形态氮磷浓度和浮游藻类群落结构的影响,结果显示蚌的高强度滤食:(1)减少微型生态系统中悬浮态氮的含量,明显增加了水柱中的溶解性氮、磷含量,但是对总氮、总磷和正磷酸盐含量没有显著影响;(2)显著减少所有浮游藻类的数量和生物量,提高水体透明度,同时迅速改变微型生态系统中浮游藻类的群落结构,降低了微囊藻等蓝藻的数量及其所占的相对百分比,而绿藻所占的比例迅速上升;(3)导致微型生态系统的生态结构发生了显著变化,上行效应(Bottom-upeffects)在浮游藻类与营养盐的关系方面发生了变化
3、,实验组水柱中氮、磷含量与浮游藻类的相关关系显著降低;(4)并不能有效降低微型生态系统的富营养水平.关键词:微型生态系统;背角无齿蚌;氮;磷;浮游藻类;生物调控Top-downeffectsofAnodontawoodianaonnutrientconcentration＆phytoplanktoncommunitycompositioninamicrocosmecosystem1,2111YANGDongmei,CHENYuwei,LIUZhengwen&WUQinglong(1:NanjingIns
4、tituteofGeographyandLimnology,ChineseAcademyofSciences,Nanjing210008,P.R.China)(2:GraduateSchoolofChineseAcademyofSciences,Beijing100049,P.R.China)Abstract:MicrocosmexperimentswereconductedtostudytheimpactsofintensivecultivationofAnodontawoodianaonnutrie
5、ntconcentration(differentformsofphosphorusandnitrogen)andphytoplanktoncommunitystructure.Theresultsshowedthatthebivalveincreasedtheconcentrationoftotalsolublephosphorus,totalsolublenitrogen,andwatertransparency,buthaddecreasedtheconcentrationofparticleni
6、trogen.Therewere,however,nosignificantinfluencesonthetotalphosphorus,totalnitrogen,andortho-phosphorus.TheintensefilterfeedingofAnodontawoodianastronglyrestrainedthegrowthofphytoplankton.Apparentchangesofphytoplanktoncommunitystructurewereobserved.Theper
7、centageofCyanobacteriasp.decreasedgreatly,whilethepercentageofChlorophytesp.increasedduringthefirst30days’experiment.TherewasaslightincreaseofBacillariophytesp.percentage,butnochangeofCryptophytesp.Thebottom-upeffectofnutrient(i.e.phosphorus,nitrogen)onp
8、hytoplankton,whichwassignificantinthecontrol(nofeeding),hadbeenshiftedtothestrongtop-downeffectsbasedontheSpearmancorrelationanalysisbetweennutrientconcentrationandbiomassofphytoplankton.Withthedecreasingofphytoplanktonabu
