低气压对高海拔湖泊甲烷气泡排放的驱动力及机理

项目名称： 低气压对高海拔湖泊甲烷气泡排放的驱动力及机理

项目编号： No.31200371

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 生态学

项目作者： 朱单

作者单位： 中国科学院成都生物研究所

项目金额： 29万元

中文摘要： 甲烷是大气中重要的温室气体。湖泊是甲烷排放的"热点"，其排放的甲烷绝大部分通过气泡途径进入大气。低海拔地区大气压力在时间尺度上小幅下降即能极大提高湖泊甲烷气泡排放速率。高海拔地区通常是湖泊分布的集中区域，但目前大气压力在海拔梯度上的大幅下降对高海拔湖泊甲烷气泡排放的影响尚不明确，这在很大程度上增加了全球甲烷源强的不确定性。 本项目选取位于中、高两个海拔梯度的湖泊各一个作为研究对象。采用人为模拟的方法对取自同一湖泊的沉积物分别施加两个海拔梯度所对应气压值的控制试验，以对沉积物甲烷排放的相关过程进行动态监测与分析。同时，在野外监测湖泊原位状态下的甲烷排放过程。通过综合分析上述实验的结果，探讨大气压力在海拔梯度上的变化对湖泊甲烷气泡排放途径的影响，从而进一步揭示大气压力控制甲烷气泡排放的关键过程及其机理，最终为解析高海拔湖泊的甲烷动态和准确估算全球湖泊的甲烷源强提供基础数据和理论依据。

中文关键词： 甲烷排放；喜马拉雅南坡；大气压力；高海拔；

英文摘要： Due to its critical control on methane ebullition from lakes, the atmospheric pressure is thought to be the "trigger" of methane flux. However, our kownledge about the relationship between methane ebullition and atmospheric presure is limited in low altitute regions, and in temporal variation. The potential effect of low atmospheric pressure in high altitute environment on the methane ebullition from countless lakes in alpine regions worldwide, are urgently needed to be monitored. In the present program, two lakes, one in middle altitute (2150 m a.s.l.)and one in high altitute (3450 m a.s.l.), will be choosen to be studied. Sediment cores selected from each lake will be taken back to lab and placed into PVC tubes，with manipulated capsules of air pressure fixed to two air pressure gradient corresponding to the two altitutes, respectively. Under those condition, methane production, methane bubbles formation, transport in sediment and their emission to atmosphere will be studied, while in situ methane daynamics in lakes will be studied as well. Based on the results of those experiment, we aim to analysis the effect of low atmospheric pressure in high altitute environment on methane ebullition from lakes in alpine region, and confirm the key proccess that atmospheric pressure controlled. This program would be halpfu

英文关键词： Atmospheric pressure；High altitude；Methane emission；The South Slope of the Himalayas；