闽江下游及河口海域水体中悬浮物的分布特征

DISTRIBUTION PATTERN OF SUSPENDED PARTICULATE MATTERS IN THE LOWER REACH AND ESTUARY OF THE MINJIANG RIVER

采用重量法与浊度法对闽江下游及河口海域中的悬浮物进行了研究。通过对悬浮物的调查得出:平水期水体中悬浮物含量为5.67～493.8mg/L,平均为114.2mg/L,几乎所有的测站底层悬浮物含量高于表层。从上游向海方向,悬浮物呈增加趋势,高值区出现在琯头到英屿河段的底层,丰水期悬浮物含量为6.9～138.7mg/L,平均为29.7mg/L,呈中层>底层>表层的分布;同时,悬浮物浓度呈渐增之势,没出现悬浮物明显的富集。平水期温度、盐度、浊度断面资料显示,平水期上下层混合较为均匀,没有出现水体分层现象,在河口区有盐楔存在,最大浑浊带出现位置与盐度2～5.5的区域相对应。根据悬浮物的物质来源、水动力环境的分布特征,在调查时段内可将闽江口最大浑浊带划归为"海源——潮致型"。

The distribution pattern of suspended particulate matters （SPM） in the lower reach and estuary of the Minjiang River is studied in this paper. The results suggest that SPM content in the nor- mal period of water charge ranges from 5.67 to 493.8 mg/L,with an average of 114.2 mg/L,and the content of SPM is higher at the bottom at almost all the stations. From northwest to southeast, SPM keeps an increasing trend towards the sea. A peak value appears at the bottom layer of the Guantou to Yingyu section. SPM content during the period of high-water charge is around 6, 9-138.7 mg/L, with an average of 29.7mg/L. The SPM content displays a noticeable distribution pattern of middle layer bottom surface. From the upper reach to the sea, the concentration of suspended matters smoothly increases ,without significant enrichment. Based on the data of temperature,salinity and turbidity, it is inferred that the upper and lower layer are more or less uniformly mixed during normal-water period, and there is no stratification of water. A salt wedge regime is developed in the estuary,and the turbidity maximum zone occurs in the region where salinity is around 2-5.5. According to the source and dis- tribution of SPM,combined with its hydrodynamic environment,it is concluded that the Minjiang River Estuary turbidity maximum zone in the period of investigation belongs to the category of ＂marine source and tide drive＂.