Horizontal distribution characteristics of crustacean planktons and its relationship with environmental factors in Lake Xuanwu, Nanjing City

Abstract

于2010年7月对玄武湖三个区域(荷花区、湖岸区、敞水区)的浮游甲壳动物水平分布进行了分析,并探讨了浮游甲壳动物种类、丰度分布与环境因子的关系.结果显示:荷花区、湖岸区、敞水区的氮磷营养盐浓度无显著差异,三个区域pH逐渐变高.相比其他区域,荷花区叶绿素a浓度最高而总悬浮质浓度最低.荷花区浮游甲壳动物丰度显著高于敞水区和湖岸区.全湖枝角类优势种为模糊秀体溞、微型裸腹溞、尖额溞以及壳纹船卵溞.桡足类的优势种为北碚中剑水蚤和台湾温剑水蚤.与其他湖区相比,荷花区浮游甲壳动物种类最多,且检出缺刺新秀体溞等稀有枝角类.冗余分析(RDA)表明与玄武湖浮游甲壳动物优势种分布相关的重要环境因子为总悬浮质、叶绿素a和总溶解磷浓度.结合浮游甲壳动物种类、丰度分布及环境因子分析得出,模糊秀体溞更倾向于分布在敞水区,而荷花区为其余大部分浮游甲壳动物种类提供了合适的生存条件.;A comparative study on the horizontal distribution of crustacean planktons was carried out in three different areas(water lily vegetation area, littoral zone and pelagic zone) in Lake Xuanwu on July 31, 2010. The relationship between distributions of crustacean planktons and environmental factors was analyzed. The results showed that the abundance of crustacean planktons was significantly higher in the water lily vegetation area than in the littoral and pelagic zone. The dominant species of cladocera during the survey were Diaphanosoma dubium, Moina micrura, Alona sp. and Scapholeberis kingi. Mesocyclops pehpeiensis and Thermocyclops taihokuensis dominated the copepod community. Comparing to other areas, most species of crustacean planktons were occurred in the water lily vegetation area, such as a rare cladocera Neodiaphanosoma volzi. Redundancy analysis showed that the most important factors impacting on the horizontal distribution of crustacean planktons were concentrations of total suspended solids, chlorophyll-a and total dissolved phosphorus. Thus, aquatic macrophytes such as water lily vegetation might provide adequate refuge to crustacean planktons with poor swimming ability, and might be one important factor to determine the horizontal distribution of crustacean planktons in Lake Xuanwu.