日出
环境科学
水槽(地理)
草原
Mercury(编程语言)
大气科学
日落
植被(病理学)
早晨
日循环
高原(数学)
生态学
地质学
植物
地理
生物
医学
物理
数学分析
病理
程序设计语言
地图学
计算机科学
数学
天文
作者
Shiwei Sun,Ming Ma,Xiaobo He,Daniel Obrist,Qianggong Zhang,Xiufeng Yin,Tao Sun,Jie Huang,Junming Guo,Shichang Kang,Dahe Qin
标识
DOI:10.1021/acs.est.9b06636
摘要
Measurements of land-air mercury (Hg) exchanges over vegetated surfaces are needed to further constrain Hg fluxes over vegetated terrestrial surfaces. Yet, knowledge of land-air Hg dynamics in alpine grasslands remains poor. Hg fluxes over an alpine meadow were measured throughout a full vegetation period in the central Tibetan Plateau (TP). This TP grassland served as a small source of atmospheric total gaseous Hg (TGM) during vegetation period (0.92 μg m–2). Hg fluxes decreased logarithmically during plant growing season, resulting from the influence of vegetation by light shading and plant Hg uptake, although the latter might be minor due to low biomass at this site. Temporal patterns of TGM indicated the importance of land-air dynamics in regulating TGM levels. During the plant emergence, diel pattern of TGM covaried with Hg emission fluxes resulting in lower concentrations at night and higher concentrations in afternoon. During all other vegetation stages, TGM showed minima before dawn and "morning peak" shortly after sunrise, in conjunction with corresponding Hg fluxes showing sink before dawn and source after sunrise. Moreover, TGM concentrations showed a decreasing trend with plant growing, further indicating the role of vegetation in driving seasonal TGM variations by regulating land-air Hg dynamics.
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