长江口北港和北支浮游动物群落生态学比较研究

IOCAS-IR > 海洋环流与波动重点实验室

	长江口北港和北支浮游动物群落生态学比较研究
其他题名	The comparison of the zooplanktonic communities in the North Channel and North Branch of the Changjiang Estuary
	高倩
学位类型	博士
	2008-06-06
学位授予单位	中国科学院海洋研究所
学位授予地点	海洋研究所
关键词	盐度温度长江口浮游动物群落优势种
摘要	浮游动物是河口生态系统的重要组成部分，在食物网中，浮游动物是浮游植物捕食者，对浮游植物有摄食压力，所以控制浮游植物数量的增长。同时，浮游动物还是鱼类的饵料，从而影响渔业资源的数量。长江口是各种经济鱼、虾和蟹的重要产卵场、索饵场和洄游场。长江口各个分汊的分流量的差异较大，导致不同分汊的水文环境明显不同，其中最为明显就是北港和北支水域。然而以往对浮游动物的研究仅限于某一水域，没有对整体水域进行研究，本文选择最具代表性的北港和北支水域，对两水域浮游动物的群落生态特征进行比较研究。本论文的数据来源于2004年5、8、11月和2005年2月在长江口北港和北支水域4个航次的海洋综合调查资料。通过采用优势度和优势种贡献率等生态学指标，同时结合逐步回归分析，讨论了温、盐与浮游动物总丰度变化的关系。结果表明，就四季而言，浮游动物总丰度和盐度呈显著正相关，和温度负相关。而就单个季节而言，除了5月和2月落潮，总丰度和盐度均呈显著正相关，与温度相关关系不显著。调查水域优势种主要为河口半咸水种或近海种。北港的盐度约为0-5, 表现为长江淡水特征；北支的盐度约为12-28，表现为长江径流和外海水团混合水团的特征。上述优势种的盐度适应和水团分布特征决定了长江口浮游动物分布的时空变化，即盐度较高的水域往往有较高的丰度，北支的总丰度和生物量均大于北港。此外，在长江口口内水域，水温较低的枯水期，浮游动物丰度高于水温较高的丰水期，温度的季节波动，以及主要优势种中华华哲水蚤（Sinocalanus sinensis）对低温环境的适应，是调查水域浮游动物总丰度季节变化的重要因素。另一方面，本论文通过物种多样性、累积优势度曲线等群落水平的指标和相似性检验分析（ANOSIM），对长江口北港和北支浮游动物群落及其主要优势种的差异，以及主要生态因子对浮游动物群落的影响进行了分析。结果表明，北港主要由潮汐影响的淡水和低盐水组成，北支由中、高盐水组成。春季，北港浮游动物丰度和多样性均低于北支，主要优势种为中华华哲水蚤；北支优势种种数较多，主要是真刺唇角水蚤（Labidocera euchaeta）。夏季，北港和北支的多样性较接近，但是种类组成差别较大，北港以中华华哲水蚤和太平洋纺锤水蚤（Acartia pacifica）为主构成河口半咸水群落，北支以由火腿许水蚤（Schmackeria poplesia）、虫肢歪水蚤（Tortanus vermiculus）和太平洋纺锤水蚤等构成河口低盐群落。秋季，北港的丰度和多样性均低于北支，两个水域的群落差异明显，北港主要由中华华哲水蚤构成，北支由小拟哲水蚤（Paracalanus parvus）、针刺拟哲水蚤（Paracalanus aculeatus）、真刺唇角水蚤和中华哲水蚤（Calanus sinicus）等近岸和外海种组成。冬季，两个水域种数和多样性均较低，群落差别达四季最小，中华华哲水蚤占绝对优势。温度和盐度及其相互作用是决定长江口浮游动物群落特征的最主要因素。其中温度是造成研究水域浮游动物群落季节变化的主要因素，而由径流和外海水之间的消长引起的盐度变化是造成北港和北支浮游动物群落区域变化的决定因素。
其他摘要	Zooplankton plays an important role in aquatic food webs, both as a resource for consumers on higher trophic levels and as a conduit for packaging the organic material in the biological pump. Changjiang (Yangtze River) Estuary is an important fishery spawning, nursery, and migration ground. The Changjiang Estuary is characterized by multi-order bifurcations, and the salinity is different between branches or channels, especially between the North Channel (NC) and North Branch (NB). Most of the previous studies on zooplankton have only included one branches of water; therefore, these studies would not represent the whole Changjiang Estuary. To further the study of zooplankton in the Changjiang Estuary, the zooplanktonic communities between the NC and NB is compared. Seasonal zooplankton samples from stations in the Changjiang Estuary were collected from May, 2004 to February, 2005. The dominant species are determined by the dominance and then the contribution of each dominant species to total abundance of zooplankton is determined  (standard regress index). Moreover, the relationship between the salinity and abundance was studied by stepwise linear regression. During the whole year, the salinity was positively correlated with abundance, while the temperature, negatively. Linear regression analysis also showed a high positive correlation with salinity for total abundance in August and November, while in February and May, no obvious relations. The most abundant communities were composed of neritic and brackish-water species. The NC (salinity <5), was greatly diluted by freshwater while the NB was brackish water with salinity range from 12-28. Consequently, a decline in abundance of zooplankton was evident along the estuarine haloclines from the maximum in area of high salinity to minimum in the limnetic zone. Total zooplankton abundance and biomass were lower in NC than the NB in all seasons. In short, the salinity influences the abundance of each species of zooplankton, finally determines the total abundance of the zooplankton. Further more, a winter peak in the abundance existed, which might be caused by the flourishing of Sinocalanus sinensis, a widely distributed species in the Changjiang Estuary. Then, the feature of zooplanktonic communities and the difference of dominant species of the NC and NB were analyzed. Species diversity indices, K-dominance curves, or other community level indices and analysis of similarities (ANOSIM) were applied to discriminate the communities. Moreover, the effect of ecological factors, especially salinity and temperature on the dominant species and communities in these waters is discussed. The results indicate that, the NC is composed of tidal water and oligohaline water; while the water of NB is featured by mesohaline or polyhaline. Hence, the zooplanktonic communities in these two waters are significantly different. In spring, the abundance and diversity of community in NB were larger than those in NC, the dominant species in NC was only Sinocalanus sinicus, while in NB there were several dominate species, among which Labidocera euchaeta was most important of all. In summer, the diversity indices were peak, the species richness and total abundance of zooplankton in NC is less than those in NB. The NC was made up of oliohaline communities, and NB was composed of brackish species, e.g. Schmackeria poplesia, Tortanus vermiculus, and etc. Thus, the communities in these two waters were significantly different. In autumn, similar to spring, the abundance and diversity of community in NB were larger than that in NC. As usual, in NC S. sinicus was the most importance species, while in NB, zooplankton was composed of neritic community which consists of Paracalanus parvus, P. aculeatus, L. euchaeta, Calanus sinicus, and etc. As a result, there were evident and significant differences between the zooplanktonic communities in NC and NB. In winter, due to low temperature, salinity might be not the limit factor for S. sinicus. This was supported by the fact that the burgeoning of S. sinicus, which is widely distributed, but its occupation of the more saline waters depends upon a seasonal reduction of temperature. In short, salinity and its combined effect with temperature are key factors, which determine the characters of the zooplanktonic communities. Temperature mainly influences the seasonal alteration of the dominant species, thus the communities, while the salinity, influenced by the interaction between runoff and ocean mass, determines the local zooplankton communities in the NC and NB.
页数	72
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/543
专题	海洋环流与波动重点实验室
推荐引用方式 GB/T 7714	高倩. 长江口北港和北支浮游动物群落生态学比较研究[D]. 海洋研究所. 中国科学院海洋研究所,2008.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
10001_20052800681212（2886KB）			限制开放	--	浏览