地学前缘 ›› 2011, Vol. 18 ›› Issue (6): 161-168.

• 论文 • 上一篇    下一篇

长江干流颗粒有机碳及其同位素组成的季节性输送特征

茅昌平, 季峻峰, 罗郧, 袁旭音, 杨忠芳, 宋垠先, 陈骏   

  1. 1. 南京大学 地球科学与工程学院， 南京大学 表生地球化学研究所， 江苏 南京 210093
    2. 污染控制与资源化国家重点实验室， 南京大学 环境学院， 江苏 南京 210093
    3. 中国地质环境监测院， 北京100081
    4. 河海大学 环境科学与工程学院， 江苏 南京210098
    5. 中国地质大学(北京) 地球科学与资源学院， 北京100083
  • 收稿日期:2011-10-07 修回日期:2011-10-20 出版日期:2011-11-25 发布日期:2011-12-05
  • 作者简介:茅昌平（1981—），男，博士后，地球化学专业。E-mail: maochangp@gmail.com
  • 基金资助:

    国家自然科学基金项目（41021002，41103051）；中国地质调查局项目“中国矿物碳汇潜力研究”（水［2011］011518）

Seasonal variation in the flux and isotopic composition of particulate
 organic carbon along the mainstream of the Changjiang River.

  1. 1. Institute of Surficial Geochemistry, Department of Earth Sciences, Nanjing University, Nanjing 210093, China
    2. State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210093， China
    3. China Institute for GeoEnvironmental Monitoring, Beijing 100081, China
    4. College of Environmental Science and Engineering, Hohai University, Nanjing 210098, China
    5. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
  • Received:2011-10-07 Revised:2011-10-20 Online:2011-11-25 Published:2011-12-05

PDF (PC)

2304

摘要：

2007年夏季和冬季对长江干流悬浮物进行了季节性采样，系统分析了悬浮物颗粒有机碳含量及稳定碳同位素的组成，研究了其空间分布以及季节变化特征。结果显示，长江干流夏季颗粒有机碳含量在0.4%~1.3%，冬季含量在0.7%~2.2%。冬季和夏季颗粒有机碳平均δ13C值分别为-24.74‰和-24.83‰，季节性差异不大，在空间分布上，冬季上游值要高于中、下游，而夏季不明显。长江干流悬浮物C/N比值的季节性变化不大，在空间上C/N比值有从上游向下游略微降低的趋势。长江上游悬浮物总体上具有较中下游略高的δ13C值，在夏季主汛期，中下游悬浮物δ13C值保留了较多的上游特征。而在冬季枯水期，中下游悬浮物δ13C值明显低于上游值，使入海悬浮物的δ13C值相对减小，这可能是由于在枯水期中下游物质贡献量相对增加和中下游水生植物的相对增多造成的。最后，计算了2007年5月到2008年4月长江一年的颗粒有机碳通量为1.46 Mt/a，相比长江三峡蓄水前有机碳的通量有较大减少。

关键词: 长江, 有机碳同位素, 季节变化, 三峡工程

Abstract:

Suspended particulate matter (SPM) samples were collected along the Changjiang mainstream in summer and winter 2007 to investigate the distribution of organic particulate organic carbon (POC) concentrations and the stable isotopic composition of POC (δ13C) within the river system. The results indicate that the POC% has a range from 0.4% to 1.3% in summer and 0.7% to 2.2% in winter. The mean δ13C values of the POC in winter and summer are -24.74‰，-24.83‰, respectively. The C/N ratio has no significant seasonal variability. The δ13C values of upper reaches are higher than the values of the middle and lower reaches in winter (low flow season). The relative decrease in δ13C values during the low flow season from the upper to lower reaches could be interpreted as the result of an increase in the soil erosion rate and channel erosion in the middle and lower reaches after dam construction, except for flood events during which rivers are also strongly influenced by relative more contribution of phytoplankton from the middle and lower reaches. We got a total organic carbon flux of 1.46 Mt/a after impoundment of the Three Gorges Dam which could have caused a sharp reduction in sediment load of the Changjiang River.

Key words: Changjiang River, organic carbon isotope, seasonal variations, Three Gorges Dam

中图分类号: