کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4440916 | 1311083 | 2010 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Seasonal variability in gaseous mercury fluxes measured in a high-elevation meadow Seasonal variability in gaseous mercury fluxes measured in a high-elevation meadow](/preview/png/4440916.png)
Seasonal patterns of atmospheric mercury (Hg) fluxes measured over vegetated terrestrial systems can provide insight into the underlying process controlling emission and deposition of Hg to vegetated surfaces. Gaseous elemental Hg fluxes were measured for week-long periods in each season (spring, summer, fall, and winter) over an uncontaminated high-elevation wetland meadow in Shenandoah National Park, Virginia using micrometeorological methods. Mean net deposition was observed in the spring (−4.8 ng m−2 h−1), emission in the summer (2.5 ng m−2 h−1), near zero flux in the fall (0.3 ng m−2 h−1), and emission in the winter (4.1 ng m−2 h−1). Nighttime deposition (when stomata are closed) and the poor correlation between Hg fluxes and canopy conductance during periods of active vegetation growth suggest that stomatal processes are not the dominant mechanism for ecosystem-level GEM exchange at this site. The strong springtime deposition relative to summer implies that young vegetation is better at scavenging Hg, with the highest deposition occurring at night possibly via a cuticular pathway. These results suggest that spring is a period of GEM deposition while other seasons exhibit net emission, emphasizing the importance of capturing GEM flux seasonality when determining total Hg budgets.
Journal: Atmospheric Environment - Volume 44, Issue 18, June 2010, Pages 2176–2185