【作者】 陈光荣；

【导师】 刘正文；

【作者基本信息】 暨南大学 ， 水生生物学， 2007， 博士

【摘要】 浮游动物在淡水生态系统中起着重要的作用，它的分布主要受到食物、捕食、水温、水生植物等的影响。目前，对广东省城市湖泊的浮游动物没有一个系统全面的了解，也少有在其功能方面作出探讨。本研究采用野外普查、重点调查、设立生态恢复示范区相结合的手段，研究了广东主要城市湖泊浮游动物的种类组成、丰度、优势种种群变化等群落特征，分析了影响浮游动物群落分布的相关因子；研究了典型湖泊—惠州西湖浮游动物群落对富营养化的响应，探索了生态恢复中浮游动物、鱼类、水生植物的相互作用关系，应用稳定性同位素技术研究了示范区的食物网结构。广东主要城市湖泊浮游动物采样普查中共检到轮虫94种，以臂尾轮属（17种）、异尾轮属（14种）和腔轮属（15种）出现种类最多，共占检到轮虫种类的49％，枝角类7科14属20种、桡足类4科12属15种，三大桡足类均有检出。浮游动物丰度处于51.20到1450.00 ind·L^-1间，平均丰度为（427.29±38.36）ind·L^-1，其中，轮虫平均丰度为（345.95±32.33）ind·L^-1；枝角类平均丰度为（5.89±0.97）ind·L^-1；桡足类平均丰度为（23.66±4.83）ind·L^-1；无节幼体（含无节幼体、桡足幼体）平均丰度为（58.40±8.50）ind·L^-1。轮虫丰度占据浮游动物丰度的优势，为（79.63±2.48）％，枝角类、桡足类相对丰度则较低，分别为（1.37±0.21）％、（5.58±1.07）％，浮游动物优势种有广生多肢轮虫、裂足臂尾轮虫、剪形臂尾轮虫、萼花臂尾轮虫、角突臂尾轮虫、裂痕龟纹轮虫、刺盖异尾轮虫、长三肢轮虫、卜氏晶囊轮虫等。广东城市湖泊检到的轮虫中占据种类组成和丰度优势的为集中分布于热带和亚热带地区的种类；浮游动物丰度与叶绿素含量呈显著正相关（r=0.426，p＜0.01），其中轮虫丰度与叶绿素含量呈显著正相关（r=0=534，p＜0.01），枝角类丰度和叶绿素含量相关性不明显；广东省城市湖泊中大多数均有鱼类，在人工专门放养鱼类的湖泊，枝角类、桡足类的丰度和相对丰度普遍更低，以小型的浮游动物轮虫占据绝对优势。在有水生植物的湖泊，枝角类、桡足类的相对丰度较高；浮游动物丰度与富营养评分结果呈显著正相关（r=0.374，p＜0.01），其中轮虫丰度与富营养评分结果呈显著正相关（r=0.479，p＜0.01），浮游动物丰度与总氮（r=0.286，p＜0.05）、高锰酸盐指数（r=0.289，p＜0.05）、悬浮物含量（r=0.404，p＜0.01）呈正相关，与透明度（r=-0.242）、pH（r=-0.237）呈负相关。根据各湖浮游动物组成进行聚类分析表明广东城市湖泊各分类浮游动物优势种均为富营养化指示种，与水质指标评价结果一致。惠州西湖五个子湖2005年三次调查共检出浮游动物55种，其中轮虫38种，枝角类10种，桡足类7种，各子湖浮游动物检出丰度处于147.3到726.1 ind·L^-1之间，轮虫丰度占据优势，1月份浮游动物丰度较低，5月和9月浮游动物丰度较高，以9月枝角类、桡足类丰度较高。优势种多为富营养化指示种，浮游动物的分布情况与水体水质特征关系密切：2005年1至10月对西湖示范区中浮游动物的初步研究表明：与未修复的平湖相比，浮游动物种类增加，枝角类和桡足类丰度增加，而轮虫丰度显著降低，多样性指数随之增加，优势种趋向清水型种类。水生植被在为浮游动物提供庇护的同时，也为杂食性鱼类繁育提供了场所；2006年的研究表明：水生植被的生物量3月份时为1.249 kg·m^-2，逐步增加到9月份为9.167 kg·m^-2，渔获量从3月份的17.50 kg到9月份时降低至7.61 kg，示范区浮游动物丰度低于平湖，其中大型浮游动物丰度高于平湖，轮虫丰度则呈较少，示范区和未进行修复的平湖浮游动物体长均主要分布于0.2mm内，体长大于0.6mm的分布比例示范区的是未修复平湖的两倍，浮游动物的生物量二者差别不大，表明水生植被恢复结合鱼类调控是富营养化治理的有效措施。惠州西湖示范区的水生高等植物的δ¹³C平均为（-20.1±0.3）‰，δ¹⁵N平均值为（5.9±0.3）‰，和水生高等植物相比，附生藻类和浮游颗粒有机物的δ（13）C相对较小，分别为-23.0‰和-28.0‰，δ¹⁵N相差不大，分别为5.7‰和5.5‰。三者δ¹³C的高低依次为沉水植物＞附生藻类＞浮游颗粒有机物。示范区主要优势种鱼类罗非鱼的δ¹³C平均为（-23.8±0.6）‰，δ¹⁵N平均为（11.0±0.1）‰，由δ¹³C及应用质量平衡模型得出罗非鱼的附生（底栖）生物食性比例超过80％，表明示范区的沉水植物带不仅提供了庇护所，也间接增加了鱼类的食物来源。更多还原

【Abstract】 Zooplankton is an important component of aquatic ecosystem. The distribution of zooplankton mostly influenced by food, predation, water temperature and macrophytes etc. Now knowledge on community characterstics and function of zooplankton in urban lakes of Guangdong Province remains scarce. In this thesis, Based on the field investigation and setting up demonstration project of restoration, species composition, abundance, and dominant species variation of zooplankton in urban lakes of Guangdong Province were studied and analyzed in relation to the environmental factors. The response of zooplankton community to eutrophication and ecological restoration in Huizhou West Lake were studied and the relationship between macrophyte, zooplankton and fish were discussed, and the food web structures and trophic relationships in demonstration area were studied using stable carbon and nitrogen isotopes.Zooplankton in 14 urban lakes of Guangdong Province were investigated in the year 2005.94 species of rotifers were identified, the largest fraction belonged to the following families: Brachiomidae（17）＞Lecanidae（15）＞Trichcercidae（14）, 20 species of cladocerans and 15 species of copepods were observed. The abundance of zooplankton was 51.20-1450.00 ind·L^-1, and the average abundance was （427.29±38.36） ind·L^-1. The average abundance ofrotifers, cladoeerans, copepods and nauplius were（345.95±32.33）ind·L^-1, （5.89±0.97） ind·L^-1, （23.66±4.83） ind·L^-1 and （58.40±8.50） ind·L^-1. The relative abundance of rotifers, cladocerans and copepods were （79.63±2.48）%, （1.37±0.21）% and （5.58±1.07）%, the zooplankton population was primarily dominated by rotifers. The dominant species included Polyarthra trigla, Schizocerca diversicornis, Brachionus forficula, B. calyciflorus, B. angularis, Anuraeopsis fissa, Trichocerca capucina, Filinia longiseta, and Asplanchna brightwelli etc.The dominant species of rotifers in 14 urban lakes of Guangdong Province are tropical and subtropical species. The abundance of zooplankton was significantly positively correlated with chlorophyⅡa concentration （r=0.426, p＜0.01）, among it the rotifer abundance was significantly correlated with chlorophyⅡαconcentration （r=0.534, p＜0.01） but the cladoceran abundance had no positive correlation with chlorophyⅡα. Fishes were found in every urban lake, the abundance of cladoceran and copepods were lower and the rotifer abundance was on the absolute predominance in those urban lakes that feed fish specially. But the relative abundance of cladoceran and copepods were more higher when there had macrophyte in lake. The zooplankton abundance had a significant positive correlation with concentrations of TN （r=0.286, p＜0.05）, COD_Mn（r=0.289, p＜0.05）, SS（r=0.404, p＜0.01） but had negative correlation with transparence and pH. Zooplankton distribution appears to broadly related to lake trophic.Investigation on the zooplankton of Huizhou West Lake which composed of five small connected lakelets were carried out for three times from January to September 2005. 55 species of zooplankton including 38 species of Rotifers, 10 species of Cladocerans and 7 species of Copepods were found. The abundance of zooplankton were between 147.3 and 726.2 ind·L^-1 and the abundance of Rotifer were on predominance. The dominant species mostly were the indicators of eutrophication and the distribution of zooplankton were related closely to the water quality combined with correlative analyse of abundance of zooplankton and chemical and physical index of water. In order to control the eutrophication and restore the water quality, an ecological restoration project was carried out including planktivorons and benthivorous fish removal and macrophyte restoration in December, 2004. We investigated the zooplankton of demonstration area and un-restored Pinghu from January to December, 2005. The results showed that, in demonstration area, the water quality was improved greatly, the number of zooplankton species increased and the abundance of large-sized species included cladocerans and copepods increased. But the abundance of rotifers decreased significantly. Accordingly the index of diversity enhanced, at the same time the preponderant species in demonstration area tended to change to clear water species. In the period of March to September, 2006, we investigated macrophyte, zooplankton and fish in demonstration lake area. The biomass of macrophyte increased gradually from 1.249 kg.m-2 in March to 9.167 kg·m^-2 in September and the catch offish per month dropped from 17.5 kg in March to 7.61 kg in September. The abundance of zooplankton in demonstration area was lower than Pinghu （un-restored lake）, however large-sized zooplankton was more abundant in restored area. The body size of zooplankton mostly was between 0 mm and 0.2 mm both demonstration area and Pinghu and the percentage of body size larger than 0.6 mm in demonstration area was two time higher than that in Pinghu. The biomass of zooplankton had no significant difference.The average values ofδ¹³C andδ¹⁵N of submersed macrophytes respectively were （-20.1±0.3）%o and （5.9±0.3）%0 in demonstration area of Huizhou West Lake, Compared to macrophytes theδ¹³C values of periphyton and seston were lower and the values were -23.0‰and -28.0‰, respectively, and theδ¹⁵N values of periphyton and seston were 5.7‰and 5.5‰. Theδ^<sup>13C values had an order: macrophytes＞periphyton＞seston and theδ¹⁵N values were similar. The average values ofδ¹³C andδ¹⁵N oftilapia in demonstration area were （-23.8±0.6）%0 and （11.0±0.1）%0. By using aδ¹³C mass balance model, it is estimated that the contributions of periphyton to the diet oftilapia were 80%.更多还原