摘要
通过对滇池流域宝象河水库沉积物TOC、TN、C/N、δ13C及粒度等指标的测定,分析了沉积物中有机碳的主要来源及其变化趋势。结果表明:水体中不同位置沉积物有机碳来源并不相同,距三岔河入库河口相对较近的沉积柱芯A中C/N比值介于2.93~11.73,δ13C值介于-23.66‰^-21.78‰,有机碳主要来源于水生生物,陆源输入贡献较小,有机碳含量受粒径大小影响显著;距三岔河入库河口相对较远的沉积柱芯B中,其TOC和TN含量较高,分别介于14.62~24.93 g?kg-1和2.11~3.3 g?kg-1,δ13C值变化范围为-28.36‰^-26.36‰,粒度以黏土和细粉砂为主,有机碳主要来源于水库周边陆源输入,受人类活动影响强烈。
Baoxiang river reservoir, a semi-natural water body, is characteristised by eutrophication, which is significantly harmful to regional human health and sustainable development. The sediments are sources and sinks of nutrients. In addition to providing important habitats for aquatic organisms, sediments play a significant role in determining the overall environmental quality of a watershed. Organic carbon in sediments plays an important role in release and transformation of aquatic pollutants, which is one of the main causes of eutrophication. In this study,profiles of TOC, C/N ratio, δ13C and grain sizes in the sediments of Baoxiang river reservoir, Dianchi watershed were used to demonstrate the sources and change of sedimentary organic matter and explore reservoir eutrophication sensitivity to human activities.Considering the characteristics of topography and human activities of the study area, with the help of GPS(Global Positioning System), two reservoir bottom sediments(A and B) profiles were collected during dry period. Our results showed that the sources of sedimentary organic matter were different in the different sampling locations. C/N ratios in the sediment A varied from 2.93 to 11.73, with bulk δ13C(‰) values ranging from-23.66‰ to-21.78‰. This indicated that organic matters mainly from aquatic organisms and terrestrial input contributed little to the sedimentary organic matters. The concentrations of organic matters were influenced significantly by the grain sizes. The concentrations of sedimentary organic matters and total nitrogen in the sediment B varied from 14.62 to 24.93 g ·kg-1, and 2.11 to 3.3 g·kg1, respectively,higher than that of the sediment A, and with bulk δ13C(‰) values of-28.36‰ to-26.36‰.The grain sizes were mainly composed of clay and silt. This demonstrated that organic matters in the sediment B came mainly from terrestrial input, which is an indication of the main effect of human activities, not the sediment grain size.Based on the volume percentage of sediment in
出处
《地理研究》
CSSCI
CSCD
北大核心
2015年第1期53-64,共12页
Geographical Research
基金
国家自然科学基金项目(41030751
41273102
41273103)
江苏省普通高校研究生科研创新计划(CXZZ13_0395)
江苏高校优势学科建设工程资助项目
