岩溶泉口沉积物有机碳的来源及环境指示意义  

Sources of Organic Carbon from Sediment of a Karst Spring and Its Environmental Significance

作　　者：郭芳[1,2] 王文科[1] 姜光辉[2] 黄思宇[2] GUO Fang WANG Wenke JIANG Guanghui HUANG Siyu(School of Environmental Science and Engineering, Chang＇an University, Xi＇an 710054, China Key Laboratory of Karst Dynamics, Institute of Karst Geology, Guilin 541004, China)

机构地区：[1]长安大学环境科学与工程学院,西安710054 [2]中国地质科学院岩溶地质研究所国土资源部岩溶动力学重点实验室,广西桂林541004

出　　处：《地球与环境》2016年第5期485-491,共7页Earth and Environment

基　　金：广西自然科学基金项目(2013GXNSFDA019024);中国地质科学院基本科研业务费项目(YYWF201504);国家自然科学基金项目(41172231;41472239)

摘　　要：灵水湖为岩溶大泉出口形成的水体,具有优良的水质和几乎恒定的水温,但近年来水生生态系统却发生退化,湖底水草几近绝迹。为了寻找退化原因,利用沉积物的有机碳及其同位素、总氮、烧失量、C/N比值环境代用指标,以及^(210)Pb测年来重建过去环境。结果显示,灵水湖沉积物具有稳定的沉积速率(1.769 cm/a),1957~2013年,δ^(13)C_(org)在-29.6‰^-20.3‰之间波动,与TOC有很好的负相关关系,C/N显示有机碳主要来源于内源的湖泊生物;1960至1990年期间,降雨量、气温和湖水最高水位与δ^(13)C_(org)均有一定的对应关系,是此阶段影响有机碳碳同位素的主要因素;而1990至2013年,尽管有机碳主要来源不变,但与降雨量、气温和湖水水位等无明显对应关系,说明影响此阶段有机碳碳同位素的还有人类活动等其它原因。总结该区水生环境演化模型,认为区域尺度的人类活动是导致局部尺度(泉口)环境变化的主要原因。Lingshui Lake in Southwest China is formed by concentracted discharge of nine karst springs. It has good water quality but the aquatic ecosystem is degrading. The environment proxy indexes including organic carbon and its isotope,total nitrogen,loss on ignition,C/N,and-（210）Pb dating were used to analyze the information of environment change of the lake and its drainage area. Results show that δ^13Corghad ranged from-29. 6‰ to-20. 3‰ during 1957 and 2013,having good negative relationship with TOC. C/N indicates that organic carbon mainly originates from autochthonous organism in the lake. According to variation sequence of δ^13Corg in the sediment core,the evolution of environment in the lake can be divided into six stages. Rainfall,air temperature and the highest water level had a certain corresponding relation with δ^13Corg during 1960 and 1990,and they are also the main factors affected the isotope.However,they had no corresponding relation with the isotope of organic carbon during 1990 and 2013,although the source of organic carbon was not changed,suggesting that there are other factors such as human activities influencing the isotope. A conceptual model for aquatic environmental evolution is summarized,considering that human actives in regional scale is the main cause for environment change in the karst lake.

关 键 词：灵水 岩溶湖 有机碳同位素 环境演变 人类活动 

分 类 号：X524[环境科学与工程—环境工程]