摘要
本文以中国五大淡水湖泊之一的巢湖作为研究对象,在对18cm的沉积钻孔中TOC、TN、δ13C、和δ13N测定的基础上,通过对巢湖现代沉积物中结合态脂肪酸的组成及其单体碳同位素特征的讨论,探讨了近70年来巢湖的富营养化过程。研究结果表明,巢湖沉积物中总有机质基本参数变化可以划分成二个主要阶段,其中7cm至表层段,δ13N、TOC和TN显著增大,可能与该时期湖泊富营养化持续加剧有关。利用结合态脂肪酸单体分子C16∶0、C18∶2W6和单体分子组合TARFA、C18∶1w7/C18∶1w9、(i-C15∶0+a-C15∶0)/nC15∶0比值的特征变化,表明12cm以来结合态脂肪酸以内源的藻类和细菌输入为主,并且从下向上对沉积物中的结合态脂肪酸贡献不断增加,反映出湖泊富营养化过程。结合态脂肪酸以单体C16∶0为主峰,沉积剖面中结合态脂肪酸中单体C16∶0的δ13C值在12cm开始迅速的增加,可以作为指示巢湖富营养化发生的重要指标。
This study investigated one of the five great China＇s freshwater lakes-Chaohu Lake. Overall characteristics of organic matter, including δ13C, δ13N, TN and TOC, from a 18 cm surface sediment core were analyzed. The concentrations and stable carbon isotopic composition of the bound fatty acids were also analyzed. Based on the above analyses, this paper discussed the eutrophication process in the Chaohu Lake in recent 70 years. The results indicate that the paleoenvironment evolution recorded in the modern sediments of Chaohu Lake can be divided into two main stages, and the values of δ13N , TOC and TN increased at the 0~7 cm interval, and it is related with the eutrophication process in the Chaohu Lake. Variations in C16∶0, C18∶2W6, C18∶1w7/C18∶1w9, （i-C15-0＋a-C15∶0）/nC15∶0 and TARFA indicate that the sedimentary organic matter was derived mainly from aquatic planktons and bacteria, and the abundance of aquatic algae led to the enhancement of lake eutrophication. The δ13C values of bound nC16∶0 fatty acids in Chaohu Lake sediments are better to record the enhancement of lake eutrophication in recent few decades. Consequently, the δ13C values of bound nC16∶0 fatty acids may be an important indicator to reflect lake eutrophication process.
出处
《地球与环境》
CAS
CSCD
北大核心
2010年第4期393-401,共9页
Earth and Environment
基金
中科院重要方向项目(kzcx2-yw-102)
国家重点基础研究发展规划项目(2008CB418200)
国家自然科学基金项目(40525011
U0833603
40873080)
中国环科院(2007KYYW01)的联合资助
