湖泊沉积物氮磷内源负荷模拟

SIMULATION OF INTERNAL LOADINGS OF NITROGEN AND PHOSPHORUS IN A LAKE

在对骆马湖沉积物及其间隙水物化性质、空间分布等分析基础上 ,在实验室控制的恒温静态条件下 ,模拟了软性富泥区柱状芯样在不同季节温度下的沉积物 水界面氮、磷交换过程。根据模拟不同温度下的柱状沉积物氮、磷释放速率及其代表时段下的物质释放量计算 ,以及应用孔隙水物质扩散模型进行的计算 ,全湖内源氮、磷负荷分别约为 ( 1 1 1 3.2± 71 .3)t/a和 ( 1 2 .5 0± 0 .95 )t/a,分别占骆马湖年氮、磷入湖量的 7.4%和 1 .2 %。沉积物中氮、磷含量差异大及铁含量较高可能是氮释放通量偏高和磷释放通量较小的主要因素。

On the basis of in situ investigation and analysis of the distribution of sludge and physio chemical characteristics of surficial sediment in Lake Luomahu during 1998, nutrient exchange patterns between sediment water interface were simulated with the soft sediment core samples at different temperatures (due to seasonal changes). The internal source was calculated by means of the release fluxes of nitrogen and phosphorus, together with the representative time section for each experimental temperature, and was compared with the result of concentration diffusion in interstitial water. The result indicates that the internal loadings of N and P in the whole lake are (1113.2±71.3) t /a and (12.50±0.95) t /a, respectively. Large differences between N and P contents and relatively high Fe contents in the soft sediment are the main factors that cause higher N release and lower P release.