胶州湾及其邻近海域的浮游植物－种类组成与数量变化

研究胶州湾浮游植物的物种组成与时空分布的特点，对于了解该湾生态系统的现状与历史变化趋势以及生态系统对自然条件变化和人类干扰的响应具有重要意义。 本文根据2004年每月一次采集的浮游植物样品，分析了胶州湾浮游植物的物种组成和优势种的时空分布情况。调查发现浮游植物共142种，分属于6门53属，其中硅藻门40属113种，占总物种数的79.6%；甲藻门10属24种，占总物种数的16.9%；其它为金藻门1属2种，裸藻1属1种，绿藻1属2种。浮游植物丰度周年波动范围为11.12－14602.39×104cells/m3，全年平均为1857.55×104cells/m3。全年丰度最高的藻为环纹劳德藻(Lauderia annulata)，出现在2月份，而全年的丰度最高值也出现在2月份。在胶州湾中，硅藻所占比例最大，平均为97.44%，最高为99.95%，最低为82.55%。浮游植物的丰度的周年变化：有两个高峰，分别出现在2月份和10月份，是典型的温带海域双高峰的分布形式。 胶州湾浮游植物的优势种分析，采用Kikvidze等（2002）提出的确定优势种数量的计算方法，再依据各物种的优势度排序最终确定优势种。其中在多样性最低的6月和10月，优势种数目均为1种，分别为丹麦细柱藻（Leptocylindrus danicus）和中肋骨条藻（Skeletonema costatum）。而在多样性指数较低的1月、2月，优势种数目分别为2和3；而在物种多样性比较高的5月、7月、11月，由于分布相对比较分散，所以优势种数量较多。这说明这个方法可以较好地完成对胶州湾浮游植物群落分析时确定优势种的目标。优势种出现频率较多的种类为中肋骨条藻（1、3、4、5、8、10、11、12月）、洛氏角毛藻(Chaetoceros lorenzianus)（7、8、9、11、12月）、尖刺拟菱形藻(Pseudonitzschia pungens)（2、3、5、7月）、加拉星杆藻(Asteronella kariana)（1、2、3、5月）、密联角毛藻(Chaetoceros densus)（5、11、12月）、扭鞘藻(Streptothece thamesis)（7、8、9月）、夜光藻(Noctiluca scintillancs)（4、5、7月）、奇异菱形藻(Nitzschia paradoxa)（5、11、12月）,对这些种的时空分布进行了分析。 对2004年胶州湾的浮游植物数据进行分层聚类分析后，发现可以将胶州湾划分为三个海区：湾南与湾外海区、湾中西部海区、湾东海区。

The interplay of circulation, tidal mixing, nutrient inputs, sediment and temperature produces spatial and temporal heterogeneous conditions for phytoplankton growth. Phytoplankton plays a vital role in the bay ecosystem. Jiaozhou Bay was a typical area affected by natural variation and human activities. The phytoplankton composition and spatio-temporal distribution is critical parameter to understand the status of the bay system, to evaluate the affection of human activities. This work can also serve as background information to other bay ecosystems. The study is based on the samples of phytoplankton taken from the Jiaozhou Bay monthly in 2004. Species composition and spatio-temporal distribution of dominant species were investigated. One hundred and forty two species were identified. The total abundance of phytoplankton varied from 11.12 to 14602.39×104cells/m3，and the annual average abundance was 1857.55×104cells/m3. The highest abundance of phytoplankton was investigated in February. The algae which had the year’s highest abundance was Lauderia annulata and its highest abundance appeared in February too. In Jiaozhou Bay，phytoplankton was dominated by the diatom with the average relative abundance of 97.44%, varied from 82.55% to 99.95%. There were two peaks in the variance of the phytoplankton abundance around the year, which were in February and October respectively. These results agreed with the typical temperate sea’s two climaxes of the phytoplankton variation. The number of the dominant species were determined by the measurement proposed by Kikvidze etc. (2002), and then to verify the species’ order according to the dominance index. For the lowest biodiversity, there was only one dominant species in both June and October, which was Leptocylindrus danicus and Skeletonema costatum respectively. While in May, July and November, the months with high biodiversity, there were much more dominant species for the evenness of the distribution. It shows that this method is suitable to determine the number of dominant species in Jiaozhou Bay. The dominant species appeared frequently were: Skeletonema costatum（1、3、4、5、8、10、11、12）、Chaetoceros lorenzianus（7、8、9、11、12）、Pseudonitzschia pungens（2、3、5、7）、Asteronella kariana（1、2、3、5）、Chaetoceros densus（5、11、12）、Streptothece thamesis（7、8、9）、Noctiluca scintillancs（4、5、7）、Nitzschia paradoxa（5、11、12）. The Jiaozhou Bay ecosystem can be divided into three parts according to the results of the cluster analysis: the southern estuary mouth and outer area, the bay’s middle and east area and the nearshore of the bay’s east zone.