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2008年度浮游动物监测报告(摘要)
作者:    点击次数:9961    发布时间:2009-10-19      【字体:
 

 

 

摘要:

2008年,我们对崇明东滩保护区潮间带潮沟中的浮游动物进行了空间分布和时间动态调查。

在空间分布上,于20084月和7月在南、北、东部共6条潮间带潮沟开展了2次调查。调查发现南部潮沟盐度最低,为0.2-0.6 ppt,属于淡水潮沟;7月,北部和东部潮沟的盐度变化范围在12.2-14.8 ppt之间,比较接近;4月,北潮沟盐度最高,为20.2-20.6 ppt,显著高于东部潮沟(3.9 - 4.0 ppt)。总体上说,崇明东滩潮间带潮沟水体盐度的南北梯度十分明显。空间分布调查中共发现浮游动物29/分类单元,4月和7月平均密度分别为53638132916 ind/m3。其中桡足类是优势类群,占浮游动物总密度的84 %。优势桡足类物种(> 桡足类总密度的20%)有3个,分别是华哲水蚤,火腿许水蚤和三角大吉猛水蚤。与长江口潮下带邻近海域的浮游动物报道比较,潮间带潮沟浮游动物群落的一个特点是具有很大数量的底栖桡足类类群(猛水蚤)。在空间分布上,浮游动物密度与盐度有一定关系,南部淡水潮沟中浮游动物数量总是最小;4月北潮沟盐度最高,浮游动物数量也相应最高;7月东部潮沟盐度与北潮沟相当,其浮游动物数量也相应上升。CCA分析结果表明,盐度和浊度是影响浮游动物空间分布的主要环境因子。

在时间分布上,我们选择东滩东部的一条潮沟,于200711月-200810月开展了12次月调查,共记录浮游动物34/分类群,年平均密度为45255 ind./m3,其中桡足类是优势类群,有27种。华哲水蚤、火腿许水蚤和四刺窄腹剑水蚤是常年均出现的优势种类,年平均密度分别为598448013511 ind./m3。浮游动物总密度、Shannon-Wiener多样性指数、浮游类群、底栖类群和优势桡足类密度的月变化均极显著,一般在58月数量最大,但底栖桡足类数量在2月份达到最高。浮游动物群落结构在枯水期(11-4月)与丰水期(5-10月)间差异明显。

 

 

Abstract

In 2008, the spatial and temporal distributions of zooplanktons in intertidal creeks in Chongming Dongtan Nature Reserve were investigated.

Spatially, two surveys were carried out in April and July in six creeks located in the southern, northern and eastern parts of Dongtan marshes, respectively. The salinity of southern creeks was the lowest among investigated creeks, ranging from 0.2 to 0.6 ppt during the surveys. In July, the difference in salinity between northern and eastern creeks was relatively small, ranging from 12.2 to 14.8 ppt. In April, the salinity in the northern creeks (20.2-20.6 ppt) was the highest among six creeks and was significantly higher than that in the eastern creeks (3.9 - 4.0 ppt). Generally, the salinity gradient of creeks was evident from north to south of Dongtan. The spatial investigation yielded 29 zooplankton taxa with the mean density of 53638 and 132916 ind/m3 in April and July, respectively. Copepod was the dominant group, accounting for 84 % of the total zooplankton density. Dominant copepod species (> 20 % of total copepod density) were Sinocalanus sinensis, Schmackeria poplesia and Tachidius triangularis. Compared to those results from zooplanktonic studies of the subtidal and vicinity coast areas of the Yangtze River estuary, there were a great amount of benthic copepods in the intertidal areas. Spatially, the density of zooplankton appeared to closely relating with water salinity. The zooplankton density in the freshwater southern creeks was always the lowest among surveyed creeks. In April, the northern creeks had highest salinity and also most abundant zooplankton. In July, the eastern and northern creeks had relatively similar salinity and also relatively similar amount of zooplankton individuals. CCA analyses revealed that the salinity and turbidity were two main environmental factors influencing the spatial pattern of zooplankton community.

Temporally, a total of 12 monthly surveys were conducted from November 2007 to October 2008 in a selected creek in the eastern part of the Dongtan marshes. A total of 34 zooplankton taxa were recorded with the mean density of 45255 ind/m3. Copepod was the dominant group. Sinocalanus sinensis, Schmackeria poplesia and Limnoithona tetraspina were dominant species occurred in each month with their mean density attaining 59844801 and 3511 ind/m3. The variation of the total density of zooplankton, Shannon-Wiener diversity index, densities of planktonic copepods, benthic copepods and dominant copepod species were all significant, attaining the highest from May to August generally, only the density of benthic copepods was the highest in February. The differences in zooplankton community structure were evident between the dry seasons and the flood seasons.