福建山美水库表层沉积物不同形态硅分布特征及其环境意义

采用Tessier连续提取法研究了亚热带典型山区深水水库-福建泉州山美水库沉积物中不同形态硅(可交换离子态硅IEF-Si]、碳酸盐结合态硅CF-Si]、铁锰氧化物结合态硅IMOF-Si]和有机硫化态硅OSF-Si])的时空分布特征及其环境意义.结果表明,山美水库平水期、丰水期、枯水期表层沉积物中不同形态硅总含量分别为3043.50~4414.24,2711.17~3676.89,3198.44~4444.28mg/kg,平水期>枯水期>丰水期;其空间分布特征为:库尾区>水库中部区>近坝区>入库区.该水库中IEF-Si和CF-Si相对含量少,活性大.虽然可交换态硅的含量较少,其释放潜能有可能对水生生态系统营养状况及初级生产产生影响;CF-Si对环境因子尤其是pH值特别敏感;IMOF-Si和 OSF-Si相对含量高,IMOF-Si可能是山美水库硅补充的最主要途径;而OSF-Si是比较稳定形态的硅,其分布规律与受不同时期沉积下来的沉积物类型和环境影响有关.平水期、丰水期CF-Si与IMOF-Si呈显著正相关关系(P<0.05,r=0.728;P<0.05,r=0.672),丰水期、枯水期IMOF-Si与OSF-Si均呈显著正相关关系(P =0.05,r=0.757; P <0.01,r=0.832).

Distribution characteristics and environmental significance of different silicon forms in surface sediments of Shanmei Reservoir

Tessie's sequential extraction method was used to analyze different forms of silicon (IEF-Si, CF-Si, IMOF-Si and OSF-Si) in surface sediments from a subtropical mountain deepwater reservoir-Shame Reservoir in Quanzhou City, and their temporal and spatial distribution were investigated. Total concentrations of silicon in surface sediments ranged in 3043.50~4414.24, 2711.17~3676.89, 3198.44~4444.28mg/kg in normal water period, dry season and wet season, respectively. Total concentrations of silicon in surface sediments of this reservoir from high to low was as follows: tail zone of reservoir, central zone of reservoir, near-dam zone, storage zone. IEF-Si and CF-Si accounted for a small proportion of total silicon, but they were active species. Although IEF-Si content was low, its potential release was likely to impact the trophic state of aquatic ecosystem and the primary production. CF-Si was sensitive to environmental factors, especially pH. The percentages of IMOF-Si and OSF-Si were much larger than those of other two forms. Mobility of IMOF-Si was probably the main way to supply Si in the Shanmei Reservoir. OSF-Si was relatively stable and its distribution was linked with the sediment type and environmental. The concentrations of CF-Si and IMOF-Si were positively correlated during normal water period (P<0.05,r=0.728) and wet season (P<0.05,r=0.672). The concentrations of IMOF-Si and OSF-Si also had significantly positive correlation in wet season (P<0.05,r=0.757) and dry season (P<0.01,r=0.832), respectively.