香溪河沉积物中碳·氮元素分布特征

目的]研究靠近三峡大坝的第一大支流香溪河沉积物中碳氮元素分布特征。方法]以三峡水库典型支流香溪河入河口河段为对象,于2015年春季开展了柱状沉积物采样调查,初步研究了该区域碳、氮等生源要素的分布特征。结果]调查河段沉积物总碳含量为1.74%~3.52%,总氮含量为0.10%~0.30%。总碳含量的沿程变化表现为靠近河口的沉积物中总碳平均含量低于上游,深度变化是靠近河口采样点的表层沉积物中总碳含量显著高于底层。而总氮含量的沿程变化和深度变化没有总碳变化明显。δ13C值随深度的增加而增加,靠近河口的沉积物中δ13C值小于上游采样点。结论]该研究为认识香溪河沉积物中生源要素的分布特征及水生生态系统的演变过程提供了科学依据。

Distribution Characteristics of Carbon and Nitrogen Elements in the Sediments of Xiangxi River

Objective] To research the distribution characteristics of carbon and nitrogen elements in the sediments of Xiangxi River, which was the biggest tributary near the Three Gorges Dam.Method] With estuary stream segment of Xiangxi River as the research object, sam-pling survey of core sediments was carried out in the spring of 2015.Distribution characteristics of biogenic elements of carbon and nitrogen were preliminarily researched in this region.Result] Total carbon content (TC) in sediments varied between 1.74% and 3.52%, and the total nitrogen content (TN) varied between 0.1% and 0.3%.The mean concentration of TC near the estuary was lower than the upstream sediments.The concentrations of TC in the sediments close to the estuary gradually decreased from the surface to the bottom .The variation of TN along the river from the estuary to the upstream WAS not significant compared with the total carbon .The isotopic analysis showed the δ13 C value increased with the enhancement of the depth.The overallδ13 C in the sample sites near the estuary was lower than the sampling point in upstream. Conclusion] This research provides scientific references for the distribution characteristics of biogenic elements in sediments of Xiangxi River and the evolution process of aquatic ecosystem.