西大海湖沉积物营养盐垂直分布特征变化分析

通过对西大海湖心柱状沉积岩芯有机质(OM)、总氮(TN)、总磷(TP)、磷形态和粒度指标的测试和分析,探讨其垂向分布特征及影响因素.结果表明,营养盐中OM、TN和TP的含量分别为0.633%~2.756%、0.150%~0.429%和648.00~1 480.67 mg·kg-1.Ca-P是TP的主要部分,占TP含量66.04%.1843~1970年间,Ca-P、IP、OM含量变化较小,Fe/Al-P、OP、TP、TN含量波动较大;1970~1996年间,Ca-P、IP、TP含量变化均呈减小趋势,Fe/Al-P、OP、OM含量不同程度上先减少后增加,TN波动较大;1996~2009年营养元素含量相对波动较大,Fe/Al-P、OP和OM的平均含量是3个阶段中最高的.西大海湖沉积岩芯营养元素污染来源以工业废水、生活污水和化肥农药的流失为主.沉积物中C/N比值显示有机质主要来源于水生生物.沉积物粒度组成以黏土和细粉砂为主.相关性研究表明,Ca-P、IP与TP均呈显著的正相关关系,表明Ca-P对IP、TP的增长贡献大.

Vertical Distribution Characteristics and Analysis in Sediments of Xidahai Lake

The organic matter (OM), total nitrogen (TN), total phosphorus (TP), the morphological changes of phosphorus and the particle size in columnar sediment core of Xidahai Lake were analyzed, to discuss the vertical distribution characteristics and influencing factors. The results showed that the contents of OM, TN and TP were 0.633%-2.756%, 0.150%-0.429% and 648.00-1480.67 mg ·kg^-1 respectively. The contents of Ca-P, IP and OM changed less, the contents of Fe/Al-P, OP, TP and TN fluctuated from 1843 to 1970; The contents of Ca-P, IP and TP tended to decrease, the contents of Fe/Al-P, OP and OM first decreased and then increased to different degree, TN fluctuated largely from 1970 to 1996; The nutrient elements contents showed relatively large fluctuation from 1996 to 2009, the average contents of Fe/Al-P, OP and OM were the highest in the three stages. The sediment core nutrients pollution sources were mainly from industrial wastewater, sewage and the loss of fertilizers of Xidahai Lake. The ratio of C/N in the sediments showed that organic matter was mainly from aquatic organisms. The sediment particle size composition was dominated by clay and fine silt. The correlation studies showed that Ca-P, IP and TP were significantly positively correlated, showing that the contribution of Ca-P to IP and TP growth was large.