中亚热带典型林分汞的输入/输出平衡

马明1 赖大坤2 孙涛1 杨光1 王定勇1,3

(1.西南大学资源环境学院三峡库区生态环境教育部重点实验室, 重庆 400715)
(2.重庆市江津区四面山森林资源管理局, 重庆 402296)
(3.西南大学重庆市农业资源与环境研究重点实验室, 重庆 400716)

【摘要】针对四面山常绿阔叶林中汞的输入/输出量进行了为期1年的监测, 结果显示:四面山大气降雨中总汞 (THg) 和总甲基汞 (TMe Hg) 的浓度分别为 (11.23±2.6) ng/L和 (0.35±0.24) ng/L, 该地区大气降水受到了人为汞污染的影响;大气降水在经过森林林冠层的过程中, 淋溶了沉降在林冠层的大气干沉降, 进而导致林内降雨中的THg浓度升高, 但是林内降雨中的TMe Hg浓度基本保持不变;森林地表径流水中THg的浓度 (4.5±2.0) ng/L相较大气降水明显降低, 说明该森林生态系统对大气降水中的汞具有很强的拦截固定作用.枯枝落叶是该森林生态系统主要的汞输入途径, 其主要通过叶片对大气环境中汞的吸收, 而随着枯枝落叶在地表的积累并分解, 这部分汞被富含高浓度溶解性有机物的表层土壤固定在土壤层中.林地地表/大气界面释汞是该森林生态系统汞流失的主要途径, 地表释汞通量暖季比较大而冷季较小, 其主要受光照、温度、地表汞浓度、土壤含水量等影响.该森林生态系统, 总的汞输入量大于总输出量, 在汞的地球化学循环中起到汇的作用.

【关键词】 汞; 甲基汞; 森林生态系统; 四面山; 输入/输出;

【DOI】

【基金资助】 国家“973”项目 (2013CB430003) 国家自然科学基金资助项目 (41573105, 41173116) 重庆市自然科学基金资助项目 (cstc2016jcyj A1643)

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This Article

ISSN:1000-6923

CN:11-2201/X

Vol 37, No. 12, Pages 4744-4750

December 2017

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摘要

  • 1 试验区概况
  • 2 材料与方法
  • 3 结果与分析
  • 4 结论
  • 参考文献