Processes Affecting Oxygen Isotope Ratios of Atmospheric and Ecosystem Sulfate in Two Contrasting Forest Catchments in Central Europe
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- 作者：Martin Nová ; k ; Myron J. Mitchell ; Iva Ja
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- 刊名：Environmental Science & Technology
- 出版年：2007
- 出版时间：February 1, 2007
- 年：2007
- 卷：41
- 期：3
- 页码：703 - 709
- 全文大小：220K
- 年卷期：v.41,no.3(February 1, 2007)
- ISSN：1520-5851
文摘
Sulfate aerosols are harmful as respirable particles. Theyalso play a role as cloud condensation nuclei and haveradiative effects on global climate. A combination of 
18O-SO4 data with catchment sulfur mass balances wasused to constrain processes affecting S cycling in theatmosphere and spruce forests of the Czech Republic.Extremely high S fluxes via spruce throughfall and runoffwere measured at Jezeri (49 and 80 kg S ha-1 yr-1,respectively). The second catchment, Na Lizu, was 10times less polluted. In both catchments, 18O-SO4 decreasedin the following order: open-area precipitation >throughfall > runoff. The 18O-SO4 values of throughfallexhibited a seasonal pattern at both sites, with maxima insummer and minima in winter. This seasonal patternparalleled 18O-H2O values, which were offset by -18”.Sulfate in throughfall was predominantly formed byheterogeneous (aqueous) oxidation of SO2. Wet-depositedsulfate in an open area did not show systematic 18O-SO4 trends, suggesting formation by homogeneous (gaseous)oxidation and/or transport from large distances. Thepercentage of incoming S that is organically cycled insoil was similar under the high and the low pollution. High-temperature 18O-rich sulfate was not detected, whichcontrasts with North American industrial sites.
18O-SO4 data with catchment sulfur mass balances wasused to constrain processes affecting S cycling in theatmosphere and spruce forests of the Czech Republic.Extremely high S fluxes via spruce throughfall and runoffwere measured at Jezeri (49 and 80 kg S ha-1 yr-1,respectively). The second catchment, Na Lizu, was 10times less polluted. In both catchments, 18O-SO4 decreasedin the following order: open-area precipitation >throughfall > runoff. The 18O-SO4 values of throughfallexhibited a seasonal pattern at both sites, with maxima insummer and minima in winter. This seasonal patternparalleled 18O-H2O values, which were offset by -18”.Sulfate in throughfall was predominantly formed byheterogeneous (aqueous) oxidation of SO2. Wet-depositedsulfate in an open area did not show systematic 18O-SO4 trends, suggesting formation by homogeneous (gaseous)oxidation and/or transport from large distances. Thepercentage of incoming S that is organically cycled insoil was similar under the high and the low pollution. High-temperature 18O-rich sulfate was not detected, whichcontrasts with North American industrial sites.