东太湖沉积物中氮的积累与水生植物沉积

 为揭示浅水湖泊沉积物中氮的积累及其与水生植物间的关系，1993年11月在东太湖42个样点上采集了沉积物柱状样品并进行了分析。东太湖硬度小于5kgf/cm²的松软淤积层平均厚度0.96m，全湖淤积量149×106t。粉沙质淤积物中总氮（TN）含量0.009％～0.801％，总有机碳（TOC）含量0.01％～17.36％，变幅极为悬殊。总氮含量与总有机碳含量间呈密切的线性正相关TN（％）＝0.0251TOC（％）＋0.0063，表层沉积物中总氮和总有机碳含量都与水生植物的现存量有较为显著的正相关。这说明，氮和有机碳主要经过水生植物的生物沉积途径进入沉积物，水生植物有将湖水中的氮传输到底泥中，使其进入地球化学循环的功能，这对于降低湖水中的氮含量、防止富营养化有积极的意义

Nitrogen accumulation in the sediment of East Taihu Lake and biological sedimentation of aquatic plants

For the purpose to reveal the effects of macrophyte on nitrogen accumulation in the sediment of shallow lakes, column sediment samples were taken and analyzed at 42 points in Lake East Taihu in November,1993. The mean depth of the soft sediment was 0.96 m, the hardness was less than 5 kgf/cm2, and the total amount of the soft sediment was about 149 million ton(in dry weight).In the silty sediment, the content of total nitrogen(TN) varied from 0.009% to 0.801%, and the content of total organic carbon(TOC) varied from 0.01% to 17.36% in different samples.Very close linear relation existed between TN and TOC,with TN(%)=0.0251 TOC(%) 0.0063;and linear relations were also found between exist biomass of aquatic plants and TN or TOC content of the surface-layer sediment. It reveals that both TN and TOC get into the sediment through biological sedimentation of aquatic plants in the lake;the aquatic plants transports nitrogen from the lake water to the sediment where the nitrogen joins geochemical cycle;and thus surely contributes to reduction of nitrogen level of the lake water and prevention of the lake from eutrophication.