项目名称: 有机质分解对泥炭中大气金属沉降记录的影响及历史累积通量修正
项目编号: No.41301215
项目类型: 青年科学基金项目
立项/批准年度: 2014
项目学科: 天文学、地球科学
项目作者: 鲍锟山
作者单位: 中国科学院南京地理与湖泊研究所
项目金额: 26万元
中文摘要: 有机质分解是泥炭自身发育的重要过程之一,对泥炭中化学元素分布和累积有重要影响。目前利用泥炭重建大气金属沉降历史的研究很少考虑到有机质分解及质量损失对元素记录的影响,这关系到计算大气金属沉降通量和评估环境污染强度的准确性。本项目拟通过大兴安岭摩天岭雨养泥炭基本理化指标和化学元素的综合分析,结合Pb-210和Cs-137年代框架,探讨泥炭沉积特征及其所记录的近百年来元素分布与累积变化规律;采用主成分分析(PCA)等统计方法探讨有机质分解与质量损失对各元素记录的影响,揭示泥炭分解过程中元素发生迁移等变化的原因;运用质量损失补偿因子(MLCF)修正痕量元素的累积速率,准确重建区域近现代大气金属沉降历史,揭示社会发展过程中人类活动干扰对自然环境的影响。本研究将增进对泥炭档案中元素地球化学行为的理解,为污染物历史沉降通量的科学估算提供新的思路,研究结果将为我国东北地区生态安全和可持续发展提供科技支持。
中文关键词: 泥炭;百年尺度;210Pb和137Cs年代学;重金属;稳定Pb同位素
英文摘要: As one of the key processes in peat development, the decomposition of organic matter greatly affects the distribution and accumulation of elements in peat. Peat deposits are frequently used as environmental archives of historical atmospheric deposition of trace elements and pollutants; however, this approach assumes that the elements are not affected by organic matter decay, which results in uncertainty in estimating the atmospheric deposition rate and assessing the environmental pollution. This program will mainly analyze the sedimentation information in Motianling ombrotrophic peat bog in Great Hinggan Mountain which is a valuable outdoor laboratory for studies of atmospheric environmental changes. Firstly, the peat cores will be dated by Pb-210 and Cs-137 techniques for an age model. Secondly, we will measure the major and trace elements by ICP-AES and HG-AFS, respectively, and determine the peat humification degree and mass loss based on alkali extraction method and C/N ratios. Then, the relationship between peat decomposition and the fate of those chemical elements will be statistically evaluated by principal component analysis (PCA). At last, mass loss compensation factor (MLCF) will be proposed to normalize mass accumulation rates to the same degree of humification and to correct the atmospheric depositi
英文关键词: Peat;Centennial scale;210Pb and 137Cs chronology;Heavy metal pollution;Stable Pb isotopes