长江口最大浑浊带浮游植物的生态研究

THE ECOLOGICAL STUDY ON PHYTOPLANKTON IN MAXIMUN TURBID ZONE OF CHANGJIANG ESTUARY

研究海区浮游植物数量的时空变化具有相当明显的潮汐节律特征。具体表现为：１．洪、枯水期均为大潮的数量高于小潮的数量，洪季前者为后者的６．８倍；枯季前者为后者的６．１倍。２．洪、枯期的大小潮期，基本上都以涨憩的数量高于落憩的数量。３．洪、枯季均为大潮期的数量空间分布不均，疏密分布（斑块）现象明显。此外，１９８８年枯季的大小潮期的数量均要比洪季的数量为高。此一现象与调查区外侧的浮游植物的空间分布状况密切相关。种类组成较为单纯，在数量上以骨条藻和圆筛藻等低盐沿岸性种占绝对优势。粗根管藻和距端根管藻等高盐外海暖流性种在洪季所占比例也相当大，是一种较为特殊的现象。

In this surveying area,the time and spatial quantitative variation of phyto-plankton bear an obvious characteristics of tide.It shows as follows: 1.The amount of phytoplankton biomass in spring tide was larger than that in neap tide inboth flood and dry seasons.In flood season,the amount in spring tide was 6.8 times ashigh as that in neap tide;in dry season, the amount in spring tide was 6.1 times as highas that in neap tide.2.The amount of phytoplankton biomass in tidal flood was more larg-er than that intidal ebb both in spring and neap tides and in flood and dry seasons.3.Thequantitative spatial distribution was not even in spring tide offlood and dry seasons.Thespot or the variation of density distribution was obvious. Besides,the amount of phyto-plankton biomass in both spring and neap tides of dryseason in 1988 was much larger thanthat in flood season.This had a close relation with spatial distribution of phytoplanktonoutside this surveying water.The species composition was not complicated and low salini-ty and coastal species are absolutely dominant such as Skeletonema and Coscidiscus.Butsome high salinity,off-sea tropical species such as Rhizosolenia robusta Rhcalcas-avis-constituted a higher percentage inflood season.It is a special phenomenon.