长江口北支水域浮游动物的研究

依据2003年7月（丰水期）和 2004年1月（枯水期）对长江口北支水域环境调查资料，研究了长江口北支水域浮游动物分布变化成因.结果表明,丰水期浮游动物生物量较高，平均为234.38 mg·m^-3,涨、落潮时分别为141.35和327.40 mg·m^-3;枯水期为188.81 mg·m^-3,涨、落潮时变化不大，分别为184.69和192.93 mg·m^-3；涨潮时长江口北支西侧水域生物量高于东侧,落潮时则相反；潮汐对种类数的影响不明显;多样性指数(H')值涨潮大于落潮.丰水期涨潮时北岸生物量高于南岸，落潮时相反，而枯水期两岸差别不如丰水期明显.长江口北支浮游动物分布的变化与长江口门外浮游动物数量季节变动和潮流携带有关，与长江径流关系不明显.柯氏力通过潮夕作用，是长江口北支南北两岸生物量差异形成的重要原因.

Zooplankton in north branch waters of Changjiang Estuary

Based on the investigation data during the high-water (July, 2003) and low-water (January, 2004) periods, a causal analysis was made on the variation of zooplankton distribution in the north branch waters of the Changjiang Estuary. The results showed that in high-water period, the average of zooplankton biomass was 234.38 mg x m(-3), being 141.35 mg x m(-3) in flood tide and 327.40 mg x m(-3) in ebb tide, while in low-water period, it was 188.81 mg x m(-3), being 184.69 mg x m(-3) in flood tide and 192.93 mg x m(-3) in ebb tide. The biomass increased from the east to the west in flood tide, but a contrary trend was observed in ebb tide. The species number did not change obviously both in flood tide and in ebb tide. The value of diversity index (H') was higher in flood tide than in ebb tide. In high-water period, the biomass near the north shore was higher than that near the south shore, but it was contrary in the ebb tide. The difference between the waters of two shores was not obvious in low-water period as in high-water period, though the trend of biomass variation was similar. The variation of zooplankton distribution in the north branch waters of the Changjiang Estuary had a close relation with the seasonal changes of zooplankton biomass outside the Changjiang Estuary and the tide, but not significantly related with the Changjiang runoff water. Coriolis force accounted for the difference of zooplankton biomass in the waters of two shores via tide movement.