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河口SiO2-3-Si浓度的变化直接影响到水体的营养盐结构和生态系统.根据2010年8月、11月和2011年5月的现场调查资料,对长江口区域一个水文年(跨三峡水库三期蓄水)硅酸盐的分布特征和变化趋势进行了分析.结果表明,长江口及其邻近海域硅酸盐分布与盐度分布极其相似,整体呈现近岸高、外海低的特点;截取一断面分析发现存在上升流,硅酸盐等值线有抬升趋势.3个季节硅酸盐平面分布各有其季节性特点,但总体浓度夏季高于秋季,秋季高于翌年春季;在整个调查区域SiO2-3-Si/DIN值是10月>8月>5月,而SiO2-3-Si/PO3-4-P值是5月>8月>10月;3个季节SiO2-3-Si浓度与盐度都呈显著负相关关系.与历史资料比较得出,2010—2011年长江口海域营养盐比值小于2004年,也小于1985—1986年,可见三峡工程蓄水对长江口SiO2-3-Si/DIN、SiO2-3-Si/PO3-4-P降低的影响.
The change of SiO2-3-Si concentration in the estuary directly affects the nutrient structure and ecosystem of the water body.According to the field survey data in August, November and May, 2010, The results show that the silicate distribution and salinity distribution are very similar in the Changjiang Estuary and its adjacent waters, showing the characteristics of high nearshore and low outer sea; A cross-sectional analysis shows that there is an upwelling flow and the Silicate contours have a tendency of uplifting. The three seasonal silicate distributions have their own seasonal characteristics, but the overall concentrations are higher in summer than in autumn and fall in the following spring. Throughout the survey The SiO2-3-Si / DIN value of the area is from October> August> May, while that of SiO2-3-Si / PO3-4-P is from May to August> October. There was a significant negative correlation between the concentration and salinity.Compared with the historical data, the nutrient ratio in the Changjiang Estuary in 2010-2011 was less than that in 2004 and less than that in 1985-1986. -Si / DIN, SiO2-3-Si / PO3-4-P.