中文摘要：

森林系统占全球陆地总面积的31%,是全球生物地球化学循环最活跃的地区之一。认识森林系统汞的生物地球化学过程对确立大气-森林系统汞的相关归趋,及进一步定量分析全球汞的生物地球化学循环过程至关重要。然而,当前森林系统在全球大气汞的循环中的角色认识还不清楚,即无法确定森林系统是大气汞的汇还是源。本文基于森林系统汞的质量平衡、土壤汞的累积过程及汞的同位素地球化学的研究,阐述了当前关于汞在全球森林生态系统多介质间汞的相互耦合作用过程及其迁移转化规律的认识。在此基础上,针对当前森林系统汞的生物地球化学过程研究的关键科学问题,提出了未来该领域的研究重点和方向。

英文摘要：

Global forest ecosystems account for 31% of global land areas,and the cycling of materials in the forest has been considered the most complicated among all terrestrial ecosystems also from the perspective of mercury（ Hg）. Elucidation of the Hg biogeochemical processes in the forest ecosystem yields insights on howatmospheric mercury is evaded and sequestered in terrestrial landscapes and the fundamental understanding of Hg biogeochemical processes in such an environmentally complex system also bridges the knowledge gap in quantifying global mercury budgets driven by global biogeochemical processes. However,there is a large knowledge gap in the role of forest ecosystem whether as a sink or source in global atmospheric Hg cycling. The reviewrepresents the current newunderstanding of the interacting processes of multiple Hg exchange,transformation and Hg isotope fractionation in this environmentally important compartment on the basis of studies during last two decades about Hg mass balance in global forest ecosystems,the processes of Hg accumulation in forest soil and the Hg isotope fractionation during Hg biogeochemical processes in such ecosystems. Finally,forthcoming research emphasis and directions of the field are proposed at the end of the reviewgiven the existing knowledge gap in this area.