太湖不同湖区夏季蓝藻生长的营养盐限制研究

中国环境科学2012,32(12)：2230~2236ChinaEnvironmentalScience太湖不同湖区夏季蓝藻生长的营养盐限制研究许海,秦伯强,朱广伟*(中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,江苏南京210008)摘要：采集太湖6个湖区水样,利用营养盐添加,现场培养实验研究了水华蓝藻在不同湖区水体中生长的氮、磷限制情况和蓝藻的生长潜力.结果表明,梅梁湾水体只有氮、磷同时添加才对蓝藻生物量具有显著的促进作用,表明该湖区水华蓝藻的生长不仅存在磷限制,而且存在明显的氮限制.在太湖西部河口区、竺山湾和贡湖湾,蓝藻对单独的氮添加没有反应,而单独磷添加和氮磷同时添加对蓝藻生长具有同样的促进作用,表明磷是这些区域藻类生长的主要限制因子.东太湖水体不论氮磷单独还是同时添加对蓝藻生长均没有促进作用,表明存在氮磷以外的限制因子.氮磷供应充足的情况下,梅梁湾和西部河口区水体培养的蓝藻生长速率最高,表明这两个水域蓝藻的生长潜力最大,氮磷输入极易刺激蓝藻大量增殖,这在一定程度上解释了为什么蓝藻水华在这两个区域更为严重.蓝藻在贡湖湾和胥口湾水体中生长速率较低,在东太湖水体中的生长速率最低,因此这些水域的蓝藻增殖潜力较低.关键词：太湖；浮游植物；营养盐限制；生长潜力；生物实验中图分类号：X524文献标识码：A文章编号：1000-6923(2012)12-2230-07NutrientlimitationofcyanobacterialgrowthindifferentregionsofLakeTaihuinsummer.XUHai,QINBo-qiang,ZHUGuang-wei*(StateKeyLaboratoryofLakeScienceandEnvironment,NanjingInstituteofGeographyandLimnology,ChineseAcademyofSciences,Nanjing210008,China).ChinaEnvironmentalScience,2012,32(12)：2230~2236Abstract：AninsitunutrientenrichmentbioassaywasconductedusingsurfacelakewatercollectedfromsixstationsofLakeTaihu.Theobjectiveofthestudywastoinvestigatenutrientlimitationofgrowthofphytoplankton,muchofwhichwasdominatedbycyanobacteria,indifferentareasofthelake.TheresultsshowedthatinMeiliangBay(station3),phytoplanktonbiomass(Chla)increasedsignificantlywithcombinedadditionofnitrogen(N)andphosphorus(P),withnosignificanteffectfromindividualadditionsofNorPseparately,suggestingthatnutrientlimitationofthesetwonutrientsmaybetightlycoupled.Intherivertransitionzoneinthewesternareaofthelake(station10),andinZhushanBay(station16)andGonghuBay(station13#),chlaintheNaloneadditiontreatmentsdidnotincreasesignificantlycomparedtotheinitialchla,butPadditiontreatments(both+Pand+NP)ledtosignificantlyhigherchlaconcentrationsthanthecontrol,reflectingN-repleteandP-deficientbiomassinthesethreeareas.Intheeasternpartofthelake(station24),additionsofNandPindividuallyandtogetherdidnotstimulategrowthcomparedwiththecontrol,suggestingfactorsotherthanNandPmaylimitphytoplanktongrowth.UnderconditionswhereNandPproducedcellsthatwererepleteint