农业活动对表层岩溶泉溶解无机碳及稳定碳同位素的影响  

Influence of Agricultural Activities on Dissolved Inorganic Carbon and Stable Isotopic of Epikarst Springs

作　　者：张笑微[1] 周小萍[1] 徐尚全[1] 王鹏[1] 

机构地区：[1]西南大学地理科学学院,三峡库区生态环境教育部重点实验室,重庆北碚400715

出　　处：《水土保持学报》2013年第2期218-221,227,共5页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41072192,41103068);重庆市科委院士专项(CSTS,2010BC7004);中国地质调查局项目(1212011087119);重庆市国土房管局科技项目;西南大学博士基金项目(SWU111009)

摘　　要：以农业活动强度不同的3个表层岩溶泉为研究对象,通过分析不同泉点溶解无机碳(DIC)及稳定碳同位素(δ13 CDIC)的变化,探讨农业活动对岩溶作用的影响。结果表明,无农业活动影响下的柏树湾泉DIC浓度最高(332.45mg/L),少量农业活动影响下的兰花沟泉DIC浓度次之(235.13mg/L),农业活动影响强烈的后沟泉DIC浓度最低(203.52mg/L);随农业活动强度增加,δ13 CDIC值呈现与之相反的趋势:柏树湾泉(-9.84‰)<兰花沟泉(-8.06‰)<后沟泉(-5.72‰)。进一步分析3个泉点DIC浓度与δ13 CDIC的关系,发现DIC浓度与δ13 CDIC的相关性也与农业活动干扰强度有关,即在无农业活动影响条件下(柏树湾泉),DIC浓度与δ13 CDIC呈较好的正相关,随着农业活动干扰的增强(兰花沟泉),DIC浓度与δ13 CDIC的相关性逐渐减弱,在农业活动干扰强烈时(后沟泉),二者基本无任何相关关系。综上,农业活动不利于岩溶碳汇,在遭受全球变暖威胁的当代,为利于岩溶作用的碳汇效应,岩溶区应退耕还林,以利于保持良好的生态环境。In this study, groundwater samples were collected from three epikarst springs, with same climatic and geological condition, but different agricultural activities. Impact of agriculture activities on karst process was explored by DIC and 8laCDIc values. The results showed that： Baishuwan spring which was not affected by agricultural activities had the highest DIC concentration（332.45 mg/L）. The DIC concentration（235.13 mg/L） of Lanhuagou spring was slightly lower, which was affected by agriculture activities. And Hougou spring had the lowest DIC concentration（203.52 mg/L）, owing to the most intense agriculture activities. Meanwhile, the 8la CDIC value had an opposite trend with the intensity of agricultural activities： Baishuwan （9.84‰） 〈Lanhuagou（-8. 06‰）〈Hougou（--5.72%o）. Further more, the relationship between DIC and δ13CDIC values of the three springs showed that agricultural activities could also affect the correlation between DIC and δ13 CDIC, which was better under non-anthropogenic condition（Baishuwan）, and became faintness with the increase of agricultural activities intensity（Lanhuagou）, while no barely correlation was found at Hougou spring with the most intense agriculture activities. In summary, agricultural activities were not conducive to karst carbon sink. Suffering the threat of global warming, to increase the carbon sink, karst area should be returned farmland to forest, in order to maintain a good ecological environment.

关 键 词：农业活动 岩溶作用 DIC浓度 δ13CDIC 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]