【作者】 蒲新明；

【导师】 吴玉霖；

【作者基本信息】 中国科学院海洋研究所 ， 环境海洋学， 2000， 硕士

【摘要】 本文通过现场调查、现场实验、室内实验等方法对长江口外海区浮游植物生长的限制情况进行了研究。根据课题的出海安排，重点对春季（1999年5月份）和秋季（1998年11月份）的营养限制的分布区域和强度的变化进行详细的研究，并通过与历史资料的比较对本海区的营养限制情况进行了季节变化和空间变化的描述。1.详细地探讨了浮游植物与营养盐的相互作用的关系，分析了营养盐对浮游植 物的生理生化、种群增长、生产力、群落组成的各种影响；对关于二者关系 的各种研究方法进行了概括和比较，并对人为影响浮游植物群落结构的前景 进行了展望。2.1998年11月在长江口及周围海域进行了一个航次的环境调查，并在室内以 中肋骨条藻为实验藻种，应用营养加富生物测定法对本海域浮游植物的营养 需求状况进行了研究。该海域叶绿素a、初级生产力和浮游植物数量的高值 区都在离口门一个经度左右的海区，中肋骨条藻是最重要的优势种。根据调 查和实验结果将该海域划分为三个部分：近河口光限制区、过渡带光和磷酸 盐限制区、远河口氮盐限制区。Fe不是本海区的限制因子。P与N分别为潜 在营养限制因子的界线大致沿盐度为31‰的等盐线。并指出，以溶解无机氮 磷比为判断标准有可能高估了磷的限制作用。3.1999年5月在长江口及周围海域进行了环境调查，通过对该海域的浮游植 物、叶绿素、营养盐、温度、盐度等进行分析，并结合现场实验和室内模拟 实验，对本海域浮游植物的营养限制状况进行了研究。调查期间受冲淡水流 量、流向和水体垂直分层的影响，冲淡水影响的范围和磷限制的范围相对于 1998年11月都有所扩展。现场对26号站的加富实验直接证实了磷的限制作 用；和室内对26、41号站位的营养加富实验也都证实了磷限制的结论。根 据营养盐的来源和限制情况，将该海区划分为：光限制区、P限制区、台湾 暖流影响区和黄海沿岸流影响区。本次调查处在春季水华的结束阶段，因而 浮游植物的数量和种类数都很低。 蒲新明 长江口区浮游植物营养网制因子的研究 硕士学位论文 4．对浮游植物在各季节的数量和组成情况进行了比较，探讨了浮游植物在各季 节中优势种的变化及主要影响因素的特点。在调查海域，春秋两季中肋骨条／＄是最主要的优势种；夏季在近河口区中肋骨条藻数量在浮游植物中占绝大 ’多数，而在上升流影响的海域，洛氏角刺藻的数量最高；冬季圆筛藻数量相 对较高。浮游植物量季节变化上以秋季最高，春夏次之，冬季最低。 5．对长江及其河口区N、P的行为进行了分析，指出：造成高N低P现象的原 因不一定是由于流域内N和P输入的失衡，在长江及其河口区特殊的理化环 境中N和P不同的生物地球化学循环特征是造成这种现象的主要原因。P的 主要存在形式是在悬浮物中并容易沉积，是导致在污染加剧情况下PO／I保 持稳定并河口外的海区中P相对于N不足的主要原因。更多还原

【Abstract】 In this paper, nutrient status of phytoplankton was studied in the Changjiang Estuary in each of the four seasons, especially in spring and autumn. Field investigation and lab experiment answered the following questions: Which nutrient limit the growth of phytoplankton, when and where does limitation happen? 1. The relationships between phytoplankton and nutrients were completely reviewed. The influences of nutrients on the physiology and biochemistry of phytoplankton cells, population growth, phytoplankton production, community structure was listed. And four methods dealing with the relationships were compared. 2. During November 16-23, 1998, community structure of phytoplankton, Chl-a, primary production and the physical and chemical environmental factors were investigated in the Changjiang Estuary. The nutrients limiting algal growth II ~fliI,l potential (AGP) were estimated by dissolved inorganic N:P ratios as well as by nutrient enrichment bioassays using Skeletonema costatum as the test algae. P was severely limiting at both stations by the method of N:P ratios, but by bioassays P was the most important nutrient regulate phytoplankton growth at station 26(1230 E, 310 N) and N at station 6(122 40?E, 310 40?N). The Changjiang Estuary may be divided into three parts: light-limited area, light- and phosphorus-limited area and nitrogen-limited area. 3.During May 11 to May 15, 1999, we took on a cruise in the Changjiang estuary and adjacent areas to determine which nutrient is the limiting factor of the growth of phytoplankton. From the analyses on the density of phytoplankton, chlorophyll a, nutrients, temperature and salinity, as well as the result of field and lab experiments, we know that P is the limiting factor in the diluted areas and is more limiting than Nov. 1998. This is due to the volume and direction of the diluted water and the vertical steady state of water. This area is divided into four parts according to the nutrient status of phytoplankton. 4. Phytoplankton density and dominant species in each season was compared. Skeletonema cosfatum is the dominant species in spring and autumn, and in the inner part of the estuary in summer, Chaetoceros lorenzianus is the dominant species in outer part of the estuary in summer; Coscinodiscus spp. dominants phytoplankton in winter. 5. The biogeochemical character of the main nutrients N and P in the Changjiang River and its estuary was analyzed. P tends to exit in the suspended matter and easy to deposit in the sediments. This is the main reason why P does not rise as pollution increases.更多还原