祁连山青海云杉林内穿透雨中微量元素变化特征

大气沉降是微量元素进入陆地生态系统的主要途径，但森林生态系统穿透雨中微量元素的研究还很缺乏。以甘肃祁连山国家级自然保护区的天涝池流域为研究区，以2018年夏季13次降雨事件样品中微量元素为研究对象，分析了祁连山典型森林生态系统穿透雨中Cu和Cd的变化特征及其影响因素。结果表明，青海云杉林内穿透雨量（1.0~24.8 mm）大于林外降雨量（0.1~23.2 mm），林冠对降雨呈现负截留现象，雨水的pH整体呈中性或弱酸性。青海云杉林内穿透雨中Cu（5.97~12.05 μg·L^-1）和Cd（0.12~0.78 μg·L^-1）的浓度均高于林外降雨（Cu:3.28~11.37 μg·L^-1，Cd:0.05~1.03 μg·L^-1），且雨水中Cu浓度要远高于Cd浓度。雨水中Cu和Cd的浓度与降雨量呈负相关关系，说明Cu和Cd受降雨量影响显著，但还与其他因素有关，如风速、降雨强度等。本研究能够为该流域森林生态系统服务功能评估提供重要的借鉴。

Distribution Characteristics of Trace Elements in Throughfall of Picea crassifolia Forest in the Qilian Mountains

The atmospheric precipitation is the main way for trace elements entering the land ecosystem.Few studies have been reported on throughfall trace elements in the forest ecosystem.In this study,Tianlaochi Catchment of Gansu Qilian Mountains National Nature Reserve was set as the study area,the trace elements in rainfall samples collected from 13 rainfall events in the summer of 2018 were used as research objects to examine the variation characteristics and affecting factors of two trace elements,Cu and Cd in the throughfalls occurring in typical forest ecosystem in the Qilian Mountains.The results showed that the amount of throughfall (1.0-24.8 mm) within the Picea crassifolia forest was higher than the amount (0.1-23.2 mm) of rainfall outside the forest.The canopy had negative interception effect on the rainfall.The pH of rainfall was neutral or weak acid.The concentrations of Cu and Cd in the throughfall (Cu:5.97-12.05 μg·L^-1,Cd:0.12-0.78 μg·L^-1 ) of P.crassifolia forest were higher than those (Cu:3.28-11.37 μg·L^-1,Cd:0.05-1.03 μg·L^-1) of the rainfall outside the forest,and the concentrations of Cu in the throughfall and rainwater were much higher than Cd.The concentrations of Cu and Cd in rainwater had negative correlation with rainfall,indicating that Cu and Cd were significantly affected by rainfall,but also related to other factors,such as wind speed,rainfall intensity,etc.