【作者】 徐达；

【导师】 唐学玺；

【作者基本信息】 中国海洋大学 ， 生态学， 2008， 博士

【摘要】 赤潮是全球性的海洋生态灾害，近年来，我国近岸海域赤潮发生的频率、波及范围和危害程度呈上升趋势。赤潮对海洋生态环境、渔业资源和海水养殖业直接或间接造成了不可估量的负面影响，成为当前污染生态学研究的热点之一。海洋浮游动物的选择性摄食作用和微藻间的竞争作用很大程度上影响着浮游植物种群的变化，控制着海洋初级生产力的节律、规模和归宿。因此，赤潮微藻的种间竞争作用和浮游动物摄食作用在赤潮生消过程中起着相当重要的作用。其次，因臭氧衰减而导致的UV-B（280nm-320nm）辐射增强是目前颇受关注的全球性的重大环境问题之一。UV-B辐射增强不仅能够对海洋生物构成伤害，影响着海洋生物的种群动态，而且还会对整个海洋生态系统产生明显的影响。本文以我国沿海常见的赤潮微藻-中肋骨条藻（Skeletonema cotatum）为实验对象，采用实验生态学的方法探讨了微藻间竞争作用，浮游动物摄食作用和UV-B辐射增强作用对其种群消长动态的影响。以期阐明UV-B辐射增强、赤微藻的种间竞争作用和浮游动物摄食活动对赤潮微藻种群动力学的影响，为揭示赤潮发生的机制和赤潮的治理提供科学依据，研究结果如下：1．不同起始接种密度对中肋骨条藻实验种群动态的影响采用单养的方式研究了不同起始接种密度对中肋骨条藻种群动态的影响。结果表明：单养条件下，起始接种密度对中肋骨条藻的种群动态变化有明显的影响，随着起始接种密度的增加，种群增长进入指数生长期和静止期的时间以及达到最大种群密度的时间缩短，所达到的种群最大密度降低。2．与3种海洋微藻共培养条件下中肋骨条藻实验种群动态的变化与青岛大扁藻、新月菱形藻和金藻8701共培养的结果表明，3种海洋微藻对中肋骨条藻种群的增长都表现出抑制作用，但抑制作用的强弱在三者间存在着一定的差异。3种共培养海洋微藻对中肋骨条藻种群增长的抑制作用由大到小的顺序为：青岛大扁藻＞新月菱形藻＞金藻8701，青岛大扁藻的抑制作用最明显，小新月菱形藻次之，金藻8701最不明显；共培养海洋微藻的起始接种密度同样影响中肋骨条藻种群动态的变化，随3种微藻接种密度的增加，对中肋骨条藻种群增长的抑制作用逐渐加强，表现在进入对数生长期的时间提前，使其对数期和静止期缩短，种群所能达到的密度峰值降低。3．单养条件下浮游动物摄食对中肋骨条藻实验种群动态的影响利用饵料浓差法和实验生态学方法研究了浮游动物对单养条件下中肋骨条藻种群动态的影响。结果显示：3种浮游动物对中肋骨条藻摄食率的顺序由大到小为：褶皱臂尾轮虫＞指状许水蚤＞猛水蚤；摄食率最大值分别为：403 cellsind^-1 h^-1，157cells ind^-1h^-1，15cells ind^-1 h^-1；滤水率则呈现不同的规律，由大到小依次为：指状许水蚤＞褶皱臂尾轮虫＞猛水蚤；最大值分别为：0．0057ml ind^-1 h^-1，0．0031 ml ind^-1 h^-1，0．0023 ml ind^-1 h^-1。中肋骨条藻起始接种密度不同，褶皱臂尾轮虫的摄食对其种群动态的影响也不同。随起始密度的增加，种群增长受褶皱臂尾轮虫的抑制作用逐渐增强。4．共培养条件下浮游动物摄食对中肋骨条藻实验种群动态的影响利用饵料浓差法和实验生态学方法研究了浮游动物对共培养条件下中肋骨条藻种群动态的影响。结果表明，褶皱臂尾轮虫的摄食作用改变了共培养体系中中肋骨条藻的种群动态规律，与青岛大扁藻共培养体系中的中肋骨条藻种群数量显著下降；而与小新月菱形藻和金藻8701共培养体系中，中肋骨条藻的种群数量呈增加趋势；随共培养体系中3种海洋微藻初始接种密度的增加，褶皱臂尾轮虫对中肋骨条藻种群增长的抑制作用逐渐减小。5．单养条件下UV-B辐射增强对中肋骨条藻实验种群动态的影响运用生态毒理学的方法研究了UV-B辐射增强对中肋骨条藻实验种群动态的影响。低于1．2J／m²的UV-B辐射处理对中肋骨条藻的种群增长有刺激作用，大于1．8J／m²时，随UV-B辐射剂量的增加，中肋骨条藻的种群增长的抑制作用逐渐增强；UV-B辐射增强对不同起始接种密度的中肋骨条藻种群增长的影响表现出一定的差异性，随中肋骨条藻起始密度的增加，UV-B辐射对中肋骨条藻的抑制作用呈现先减后增的规律。6．共培养条件下UV-B辐射增强对中肋骨条藻实验种群动态的影响运用生态毒理学的方法研究了共培养条件下UV-B辐射增强对中肋骨条藻实验种群动态的影响。研究结果显示，UV-B辐射胁处理改变了共培养体系中肋骨条藻的种群增长规律。与青岛大扁藻共培养体系中，UV-B辐射处理抑制了中肋骨条藻的种群增长，而在与小新月菱形藻和金藻8701的共培养体系中，UV-B辐射处理对中肋骨条藻的这种群增长有促进作用。7．浮游动物摄食、UV-B辐射增强与微藻间竞争作用对中肋骨条藻实验种群动态的联合影响运用生态毒理学和统计学的方法研究了浮游动物捕食、UV-B辐射增强与微藻间竞争作用对中肋骨条藻实验种群动态的复合影响。结果显示：低剂量（0．6 J／m²，1．2 J／m²）的UV-B辐射和褶皱臂尾轮虫捕食联合作用，对中肋骨条藻种群增长有明显的促进作用；高剂量（＞1．8 J/m²）的UV-B辐射和褶皱臂尾轮虫捕食联合作用对中肋骨条藻种群增长有显著的抑制效应；随中肋骨条藻初始接种密度的增加，低剂量（0．6 J／m²，1．2 J／m²）的UV-B辐射和褶皱臂尾轮虫捕食联合作用对中肋骨条藻的种群增长的促进作用明显加强，而高剂量（大于1．8J／m²）的UV-B辐射和褶皱臂尾轮虫捕食联合作用对中肋骨条藻的种群增长的抑制作用明显减弱；共培养微藻种类影响UV-B辐射与褶皱臂尾轮虫联合作用对中肋骨条藻种群增长抑制效应。抑制作用由大到小的顺序为：青岛大扁藻＞金藻8701＞小新月菱形藻；UV-B辐射与褶皱臂尾轮虫联合作用下，中肋骨条藻种群动态与3种共培养微藻的起始接种密度密切相关。随3种微藻起始接种密度的增加，中肋骨条藻种群数量逐渐下降。进一步证明微藻间的竞争作用以及由起始接种密度增加引起的竞争能力的增强都直接影响着中肋骨条藻的种群动态。更多还原

【Abstract】 Red tide was a global marine ecological calamity too.In recent years,there hasbeen an increase in frequency,affected area and extent of injury of red tide outbreaksin coastal waters of our country.Due to the worsened cultural environment andincreased nutrient enrichment,red tides occurred more frequency and greatharm,nutrient enrichment and harmful red tides in coastal waters had become one ofthe most important fields among worldwide-concerned,newly-emerging significantmarine environmental problems,which were associated with global changes and inbad need of being studied and solved.Zooplankton grazing played an important rolein the development of red tides,marine zooplankton selective grazing cansignificantly affect the phytoplankton community dynamics and control the rhythm,scale and fate of marine primary productivity.Enhanced UV-B （280nm-320nm）radiation resulting from ozone depletion is one of global environmental problems.Notonly marine organisms but also marine ecosystem can be affected by enhanced UV-Bradiation.UV-B radiation can significantly damage marine microalgae.The maintargets are protein,DNA and photosynthetic pigments,and so on.A common red tide-Skeletonema costatum was selected to serve as experimental materials,and its growthwere estimated under controlled laboratory conditions when stressed by othermicroalgae,zooplankton grazing and enhanced UV-B radiation.The results couldsupply experimental base to answer the effect of enhanced UV-B radiation,zooplankton grazing and interspecies on red tides,hence enhance our ability tounderstand and mitigate red t ides.Results showed:1 Effects of different initial cell densities of S.costatum on population growth ofS.costatumThe solitary culture and co-culture methods were used to examine the effects of initial cell densities of S.costatum and different species of microalgae on populationgrowth of S.costatum.The results showed that:The different initial cell densities ofS.costatum have the apparent effects on its population growth.With promotion of theinitial cell density,the time of entering exponential phase and stationary phase couldbe shortened,and the maximum population density could be decreased under solitarycultivated conditions.2.The change of population growth of S.costatum co-culture with three differentkinds of marine microalgaeThe different effects were presented on population growth of S.costatum whenstressed by different microalgae.The inhibitation effect of three species of co-culturedmicroalgae on S.costatum was P.helgolandicavar＞Ⅰ.galbana 8701＞N.closterium;The different initial cell densities of three species of co-cultured microalgae alsoaffected population growth of S.costatum,the inhibitation effect on S.costatum wasincreased gradually with increasing of initial cell densities of three species ofco-cultured microalgae;the inhibitation effects were showed with curtateexponential phase and stationary phase,and decreased the maximum populationdensity of S.costatum.3 Effect of zooplankton grazing on population growth of S.costatum undersolitary cultivatedThe diet-concentration differentia calculational method and experimentalecological method were selected to study the effect of zooplankton grazing onpopulation growth of S.costatum under solitary cultivated with other three speciesmicroalgae.The grazing rate of three species zooplankton from high to low was:B.plicatilis＞S.inopinus＞Harpacticus.The max grazing rate values of B.plicatilis,S.inopinus,Harpacticus were 403 cells ind^-1 h^-1,157cells ind^-1 h^-1,15cells ind^-1 h^-1respectively;Filtering rate were presented in another order,the order of filtering ratefrom high to low was S.inopinus＞B.plicatilis＞Harpacticus,The max filtering ratevalues of S.inopinus,B.plicatilis,Harpacticus were:0.0057 ml ind^-1 h^-1,0.0031 mlind^-1 h^-1,0.0023 ml ind^-1 h^-1;The effect of B.plicatilis grazing on S.costatum wasvaried under different initial cell density of S.costatum under solitary cultivated conditions,the inhibitation effect of B.plicatilis on S.costatum was increasedgradually with increasing of initial cell densities of S.costatum.,4 Effect of zooplankton grazing on population growth of S.costatum underco-cultivated conditionThe diet-concentration differentia calculational method and experimentalecological method were selected to study the effect of zooplankton grazing onpopulation growth of S.costatum under co-cultivated conditions with other threespecies microalgae.Population growth of S.costatum was altered by ingestion ofB.plicatilis under co-cultivated condition with other three species microalgaerespectively,the population cell density of S.costatum was decreased significantly incultured system of P.helgolandicavar,and there were enhanced growth effect ofS.costatum in cultured system of I.galbana 8701 and N.closterium;the inhibitationeffect of B.plicatilis on S.costatum was decreased gradually with increasing of initialcell densities of three species of co-cultured microalgae.5 Effect of enhanced UV-B radiation on population growth of S.costatum undersolitary cultivatedThe ecotoxicological method was used to determine the effect of enhanced UV-Bradiation on population growth of S.costatum under solitary cultivated with otherthree species microalgae.The results were showed as follows:UV-B radiation couldstimulate the growth of S.costatum when the dose was lower than 1.2J/m² while UV-Bradiation also exhibited inhibitation effect to the growth of S.costatum when the dosewas higher than 1.8J/m²,and inhibitation effect was enhanced with the increasing ofUV-B radiation dose;The effect of enhanced UV-B radiation on S.costatum waschanged under different initial cell density of S.costatum under solitary cultivatedconditions,the inhibitation effect of enhanced UV-B radiation on S.costatum waspresented an increasing first and then decreasing gradually with increasing of initialcell densities of S.costatum;6.Effect of enhanced UV-B radiation on population growth of S.costatum underco-cultivated conditionsThe ecotoxicological method was used to determine the effect of enhanced UV-B radiation on population growth of S.costatum under co-cultivated conditions withother three species microalgae.The results were showed as follows:Populationgrowth of S.costatum was changed by enhanced UV-B radiation under co-cultivatedcondition with other three species microalgae respectively,the population cell densityof S.costatum was decreased significantly in cultured system of P.helgolandicavar,and there were enhanced growth effect of S.costatum in culturedsystem of L galbana 8701 and N.closterium;the inhibitation effect of enhanced UV-Bradiation on S.costatum was increased gradually with increasing of initial celldensities of three species of co-cultured microalgae.7 Combined effect of enhanced UV-B radiation and ingestion of B.plicatilis onpopulation growth of S.costatum under solitary cultivated and co-cultivatedconditionsThe experimental ecological method and statistics method were selected todetermine the combined effect of enhanced UV-B radiation and ingestion ofB.plicatilis on population growth of S.costatum under solitary cultivated andco-cultivated conditions with other three species microalgae.The results were showedas follows:Combined effects of lower dose （0.6 J/m²,1.2 J/m²） UV-B radiation andB.plicatilis grazing had decreased inhibitations effect on population growth ofS.costatum,while an enhanced inhibitations effect was presented when joint stressedby higher dose （＞1.8 J/m²） UV-B radiation and B.plicatilis grazing;the inhibitationeffect stressed by Combined effects of UV-B radiation and B.plicatilis grazing onS.costatum was decreased gradually with increasing of initial cell densities ofS.costatum under solitary cultivated conditions;The inhibitation effect stressed bycombined effects of UV-B radiation and B.plicatilis grazing on population growth ofS.costatum can be changed under the co-cultured system of three species microalgae.The inhibitation effect of three species of co-cultured microalgae on populationgrowth of S.costatum was P.helgolandicavar＞L galbana 8701＞N.closterium;Thedifferent initial cell densities of three species of co-cultured microalgae also affectedpopulation growth of S.costatum under combined effects of UV-B radiation andB.plicatilis grazing,the population density of S.costatum was decreased gradually with increasing of initial cell densities of three species of co-cultured microalgae.更多还原