东湖典型区域间隙水中营养盐的时空分布

以富营养化程度严重的浅水湖泊东湖为研究对象，通过持续采样调查，分析并比较了3个典型采样点柱状沉积物间隙水中营养盐的垂直分布和季节变化特征，结果表明东湖沉积物间隙水中营养盐浓度最高值一般出现在-5 cm以上，-5～-10 cm之间有一个快速降低的过程，-10～-26 cm之间趋于稳定，但也有小幅的波动；冬季间隙水中营养盐浓度明显低于其他季节，夏秋两季略高。分析认为沉积物间隙水中营养盐浓度受附近污染源直接影响较大，与上覆水水质有一定相关性，但不显著。间隙水中营养盐的季节变化主要因为冬季污染排放减少加速了间隙水中营养盐向上覆水的扩散、减少了水中营养盐在沉积物表层的沉积，以及温度降低导致微生物活动减少进而降低了有机物的矿化分解量。并且认为常规疏浚深度就可以有效移除东湖表层污染严重的沉积物

SPATIAL DISTRIBUTION AND SEASONAL VARIATION OF NUTRIENTS IN PORE WATER OF TYPICAL AREA OF EAST LAKE

The vertical distribution and seasonal variations of pore water nutrients of three typical columnar sampling sites were analyzed and compared by continual sampling and investigation in East Lake,a serious eutrophicated shallow lake in China.The results show that the highest value of pore water nutrient concentrations in East Lake sediment generally appearred in the above 5 cm,and a rapid decreasing process occurred between 5 cm to 10 cm,then it became stabilized with slight fluctuations between 10 cm to 26 cm.Nutrient concentrations in interstitial water in winter was significantly lower than other seasons,summer and fall was slightly high.It is suggested that the nutrient concentrations in sediment pore water was directly influenced by near by pollution sources,and related to that of overlying water,but not significantly.Low concentration of interstitial water nutrient pollution in the winter season,was mainly due to the decreasing of pollutant emissions which accelerated the upward diffusion of pore water nutrient to overlying water,reducing the deposition of nutrients on the surface of sediments,and the lower the temperature leading to reduced microbial activity and thus reduced the mineralization of organic matterand the amount of decomposition.Regular dredging depth can effectively remove the heavily polluted surface sediments of East Lake.