【作者】 蔡桢；

【导师】 薛俊增；

【作者基本信息】 上海海洋大学 ， 水生生物学， 2011， 硕士

【摘要】 为了阐明浮游甲壳动物对水温垂直分布演变的生态响应机制,本研究选取两处大型深水水库(新安江水库、三峡水库)水域生态系统为对象,研究了不同类型水库中浮游甲壳动物垂直分布演变模式的特点及其与水温垂直分布季节性差异的关系。具体结果如下:(1)、对新安江水库四季昼夜垂直水温数据的测定显示,新安江水库是典型的分层型水库,春季垂直断面即有分层现象,变温层分布在5-25m,水温最大变化梯度为0.70℃/m;夏季是温跃层最显著的季节,深度为10-25m,水温最大变化梯度为1.19℃/m;秋季和冬季坝前段水体水温呈混合型分布。(2)、对新安江水库浮游甲壳动物四季昼夜垂直样品的分析共鉴定枝角类5科8种,蚤状溞（Daphnia pulex)和透明溞（D. hyalina)为四季优势种,短尾秀体溞(Diaphanosoma brachyurum)和简弧象鼻溞（Bosmina coregoni)为夏季优势种。桡足类共鉴定3目5科12属19种,一种小剑水蚤(Microcyctops sp.)、粗壮温剑水蚤(Thermocyclops dybowskii)、广布中剑水蚤(Mesocyclops leuckarti)、绿色近剑水蚤(Tropocyclops prasinus prasinus)为四季优势种,透明温剑水蚤(T. hyalinus)为春、夏两季优势种,腹突荡镖水蚤(Neutrodiaptomus genogtbbosus)、台湾温剑水蚤( T. taihokuensis )为春季优势种,右突新镖水蚤( Neodiaptomus yangtsekiangensis)为夏季优势种。新安江水库浮游甲壳动物的主要优势种类在水柱的各个水层均有分布,垂直分布为聚集分布的格局,但程度不高;种群平均滞留水深各季节及各时间段变化较大,春、夏季节整体分布在变温层(10-25m)内,秋、冬季则涉及整个垂直水柱;昼夜迁移现象明显,迁移尺度依次为冬季>秋季>春、夏季,迁移模式类群间各不相同,枝角类在春、夏、冬季都为正常迁移,秋季为反向迁移,桡足类则四季均为正常迁移。总体而言,温跃层的出现对大多数浮游甲壳动物影响不大,表现仅为降低了他们昼夜垂直移动的幅度,而蚤状溞则是被温跃层阻挡其垂直迁移的种类。(3)、对三峡水库主要支流库湾(大宁河库湾、香溪河库湾)垂直水温数据的监测表明,三峡水库大宁河库湾四季水温垂直分布与水深呈线性相关,垂直水柱温度的差异按季节温度的升高而升高。三峡水库香溪河库湾,夏季0-5m温度下降相对较快,但不形成温跃层,春、秋、冬三季垂直水温呈混合型分布。(4)、对三峡水库大宁河库湾周年垂直水层样品分析共鉴定枝角类5科5属8种,简弧象鼻溞和透明溞是四季优势种，短尾秀体溞是夏秋两季优势种.共鉴定（木+尧）足类3目6科12种,汤匙华哲水蚤(Sinocalanus dorrii)为四季优势种,球状许水蚤(Schmackeria forbesi)和虫宿温剑水蚤(T. vermifer)为夏、秋两季的优势种。三峡水库香溪河库湾四季昼夜垂直样品分析共鉴定枝角类5科6属12种,冬季未鉴定到枝角类,简弧象鼻溞为三季的优势种，短尾秀体溞、长肢秀体溞（D. leuchtenbergianum)、多刺秀体溞（D. sarsu)和脆弱象鼻溞（B. fatalis)是夏季的优势种。桡足类则鉴定到3目3科7属8种,在垂直分布上并不形成季节性的优势种。三峡水库大宁河库湾浮游甲壳动物垂直分布的连续性在月份间不同,枝角类优势种类在春、夏两季垂直水层分布较为连续,桡足类种类多在春、夏、秋三季垂直水层分布较为连续,种类间差异较大。垂直分布格局整体呈现聚集分布,大部分种类聚集程度随水温下降而升高。香溪河库湾浮游甲壳动物的垂直分布格局同样体现着随水温升高而降低的趋势,一昼夜中以正午前的聚集程度最高。三峡水库大宁河库湾浮游甲壳动物平均滞留水深种间差异较大,春夏两季整体多分布在10-25m的水体中层,秋、冬季没有明显滞留水层;其中,短尾秀体溞会随水温的增加而下移。香溪河库湾枝角类垂直分布水层涉及整个水柱,昼夜迁移行为明显,均为正常迁移模式,迁移幅度各种类间差异极大,秀体溞和脆弱象鼻溞在温度较高时迁移尺度较大,简弧象鼻溞则随季节无明显变化。总体而言,三峡水库浮游甲壳动物垂直分布的变化受水温垂向分布差异性的影响较小,种群垂直分布仅是与温度的关系仅为季节性演替的所造成的个体滞育或食物水平变化的响应。三峡水库季节性调水加速水体的混合,有利于支流库湾浮游甲壳动物的垂直分布及昼夜迁移。(5)、不同类型水体水温垂直分布的演变对浮游甲壳动物垂直分布及昼夜迁移的影响不同,这与水文动力学因素有关。桡足类的垂直分布对于这种变化的响应机制为向上层食物密集处聚集,枝角类则进入温跃层;昼夜迁移的响应则均为提早向上迁移的时间(以延长上迁时间)。更多还原

【Abstract】 In this study, two subtropical, lager, deepwater?reservoirs (Xin’anjiang Rerservior, Three Gorges Reservoir) were selectesd, investigated the relationship between the seasonal changes of vertical distribution and diel migration of pelagic crustacean in the water column and the seasonal vertical heterogeneity of water temperature in these two reserviors, to clarify the ecological responses of pelagic crustaceans to the vertical distribution of water temperature in large deepwater reservoirs. The main result are as follows:(1) In the investigation period, Xin’anjiang Reservior was represent to be a typical stratified reservior. In spring there is a week epilimnion between 5-25m, the temperature descend? gradient was 0.70℃/m. In summer there will be a strong themocline in the depth range from 10 to 25 m, the max temperature descend?gradient was 1.19℃/m. Then in autumn and winter, the water colum was represent to be homogeneous.(2) In the investigation we indentified 5 families 8 species of cladocera, in which the Daphnia pulex and D. hyalina was dominated species all year around, and Diaphanosoma brachyurum and? Bosmina coregoni was the dominated species mainly in summer. Besides, we indentified 3 orders 5 families 12 genera 8 species of copepod, in which Microcyctops sp., Thermocyclops dybowskii, Mesocyclops leuckarti, Tropocyclops prasinus prasinus was dominated species all year around, and T. hyalinus was the dominated specie mainly in spring and summer, Neutrodiaptomus genogtbbosus, T. taihokuensis was dominated mainly in spring, Neodiaptomus yangtsekiangensis was the dominated specie only in summer. The mainly dominated species was present in each layers, and be agminated, but not prominent. The main resident depth was varied in different season and time. In spring and summer the pelagic crustacean group was mainly stay at the depth of epilimnion (10-25m), while in autumn and winter rhe main resident depth was extend to the whole water column, and was totally accompanying with the phenomenon of diel vertical migration (DVM), which the amplitude was winter > autumn > spring and summer. Also, there were differences in the pattern among groups, such as cladoceras were normal migration in spring, summer and winter, while reverse migration in autumn, copepods were normal migration in 4 seasons. Overall, the thermocline has little influence to most pelagic crustacean species, only had reduced the amplitude of DVM, but for D. pulex, particularly, maybe was astricted under the thermocline.(3) The data of the vertical water temperature in the mainly tributary of Three Gorges Reservior (Daning Bay, Xiangxi Bay) show that, there was a linear correlation between the depth and water temperature in Daning Bay, the water column temperature difference was intensified with the rise of water temperature. Otherwise, in summer, water column temperature was descent fast from 0 to 5 m, but the therocline wasn’t shaped in Xiangxi Bay. Further more, in spring, autumn and winter the water column was homogeneous in temperature.(4) In the investigate period of Daning Bay, we indentified 5 families 5 gemus 6 species of cladocera, in which B. coregoni and D. hyalina was dominated in 4 seasons, and D. brachyurum was the dominated specie in summer and autumn. we also indentified 3 orders 6 families 12 species in copepod, in which, Sinocalanus dorrii was dominated all year around, Schmackeria forbesi and T. vermifer was the dominated species mainly in summer and autumn. In the investigate period of Xiangxi Bay, we indentified 5 families 5 genus 12 species in cladocera, except winter. B. coregoni was the dominated specie in the three seasons, D. brachyurum, D. leuchtenbergianum, D. sarsu, B. fatalis was the dominated species only in summer. And there was 3 order 3 families 7 genus 8 species in copepod, but didn’t have dominated species.The patterns in vertical distribution of pelagic crustacean in Daning Bay was varied each month, and the cladocera group represent to be successive in water column in spring and summer, while the copepod group was in spring, summer and autumn, varying in species. The pattern of vertical distribution was aggregated, more with the descend of water temperature. Spectacularly, the same as in Xiangxi Bay, indeed, the degree of agregatiton was highist in 10:00. The main resident depth in water column was varied in species, but mainly stay in the depth of 10-25m in spring and summer. In autumn and winter there was no clear MRD in water column, and the D. brachyurum was in deeper layer when the tenperature wans high. The nomal migration of cladocera was obviously and almost migration to all layers, different in species. The amplitude of DVM by Diaphanosoma and?B. fatalis was more in high temperature, B. coregoni was show no significant changes in any season.Totally speaking, the vertical distribution of pelagic crustacean in Three Gorges Rerservior changed little by the influence of water column temperature difference, and the vertical distribution of the group correlated with the temperature just to be seasonal changes in individual diapause or food level. What’s more, the seasonal dispatching of the Three Gorges Reservior was make for the vertical migration of pelagic crustacean.(5) The spatially structured of water temperature in different reserviors result in the different vertical migration of pelagic crustacean, it can be due to the hydrological dynamics facters. In this habitat, for copepod groups, they will gather into the surface layer where has plenty of food, and for cladocera, they will gather into the thermocline. The reserponse of pelagic crustacean in DVM are all reprensent to be earlier the migration time to the surface layer (to lengthen the migration time).更多还原