青藏高原典型湖泊湖岸带表层沉积物碳、氮、磷分析

Characteristics of organic carbon,nitrogen and phosphorus in surface sediments of typical littorals of three lake regions on Qinghai-Tibet Plateau

在青藏高原地区的尕海、纳木错和羊卓雍错3个湖区的典型湖泊湖岸带采集表层沉积物,测定总有机碳、总氮、总磷含量,分析营养元素间的原子比.结果显示:7处湖岸带表层沉积物有机碳含量介于1.19～46.84g/kg之间,其中尕海糊区的果茫滩最高;总氮含量介于0.26～10.84g/kg之间,尕海最高;总磷含量介于0.05～0.38g/kg之间,尕海最高;纳木错有机碳、总氮、总磷含量均为最低.湖岸带表层沉积物C/N的最大值和最小值均出现在尕海湖区,分别是尕海湖区果芒滩的19.04和尕海湖区尕海的2.85,其他两个湖区的值均在5～10之间;C/P均大于60;N/P值介于8.75～63.17之间;纳木错湖区的N/P和C/P均低于另外两个湖区.可以认为:磷是3个湖区潜在的营养限制因子;尕海存在外源氮输入;果芒滩沉积物有机质主要来源为陆生和水生维管束植物碎屑混合物,纳木错湖区和羊卓雍错湖区则为湖泊自生的水生生物碎屑混合物.

Surface sediments＇ samples of typical littorals of three lake regions,Gahai,Nam Co and Yamzho Yumco lake region,on Qinghai-Tibet Plateau were collected to measure total organic carbon,total nitrogen and total phosphorus content. The content of total organic carbon （TOC） varied from 1.19 to 46.84 g/kg,the content of total nitrogen （TN） varied from 0.26 to 10.84 g/kg,and the content of total phosphorus （TP） varied from 0.05 to 0.38 g/kg in different samples. Among them,total nitrogen and total phosphorus content in the surface sediment of Gahai Lake were the highest; organic carbon content in the surface sediment of Guomangtan Lake was the highest; and organic carbon,total nitrogen and total phosphorus content in Nam Co Lake were all the lowest. The highest and the lowest values of C/N both existed in surface sediments of Gahai Lake region,with 19.04 in Guomangtan Lake and 2.85 in Gahai Lake. Meanwhile,C/N in the other two lake regions were between 5 and 10. The values of C/P of surface sediments were higher than 60 in all regions,and the values of N/P were between 8.75 and 63.17. The results suggested that,phosphorus was the potential limiting nutrient element in these littorals of the three lake regions; there should existed extraneous nitrogen input in Gahai Lake; organic matters of surface sediments in the littorals of Nam Co and Yamzho Yumco Lake region mainly come from authigenic aquatic organisms,while organic matters in the littoral of Guomangtan Lake come both from aquatic and from terrestrial vascular plants.