Hartman Jelena S, Weisberg Peter J, Pillai Rekha, Ericksen Jody A, Kuiken Todd, Lindberg Steve E, Zhang Hong, Rytuba James J, Gustin Mae S
Department of Natural Resources and Environmental Science, University of Nevada-Reno, 1664 N Virginia Street, MS 370, Reno, Nevada 89557, USA.
Environ Sci Technol. 2009 Jul 1;43(13):4989-94. doi: 10.1021/es900075q.
Ecosystems that have low mercury (Hg) concentrations (i.e., not enriched or impacted by geologic or anthropogenic processes) cover most of the terrestrial surface area of the earth yet their role as a net source or sink for atmospheric Hg is uncertain. Here we use empirical data to develop a rule-based model implemented within a geographic information system framework to estimate the spatial and temporal patterns of Hg flux for semiarid deserts, grasslands, and deciduous forests representing 45% of the continental United States. This exercise provides an indication of whether these ecosystems are a net source or sink for atmospheric Hg as well as a basis for recommendation of data to collect in future field sampling campaigns. Results indicated that soil alone was a small net source of atmospheric Hg and that emitted Hg could be accounted for based on Hg input by wet deposition. When foliar assimilation and wet deposition are added to the area estimate of soil Hg flux these biomes are a sink for atmospheric Hg.
汞（Hg）浓度较低（即未受地质或人为过程富集或影响）的生态系统覆盖了地球大部分陆地表面，但它们作为大气汞的净源或汇的作用尚不确定。在此，我们利用经验数据，在地理信息系统框架内开发了一个基于规则的模型，以估算代表美国大陆45%面积的半干旱沙漠、草原和落叶林的汞通量的时空模式。这项工作表明了这些生态系统是大气汞的净源还是净汇，同时也为未来野外采样活动中建议收集的数据提供了依据。结果表明，仅土壤就是大气汞的一个小净源，并且排放的汞可以根据湿沉降输入的汞来解释。当将叶面吸收和湿沉降添加到土壤汞通量的面积估算中时，这些生物群落就是大气汞的汇。
