| 喀斯特坡地土壤硫同位素变化指示的土壤硫循环 |
| 摘要点击 5285 全文点击 3150 投稿时间：2009-04-07 修订日期：2009-05-25 |
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| 中文关键词 喀斯特 黄色石灰土 黄壤 硫同位素 硫循环 |
| 英文关键词 yellow limestone soils yellow soils sulfur isotopes sulfur cycling |
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| 中文摘要 |
| 用土壤硫形态连续提取方法分离测定了喀斯特坡地土壤总硫、有机硫、SO2-4和FeS2的硫同位素组成及其含量．总体来看，土壤剖面表层各形态硫δ34S值FeS2最低，介于-6.86‰～-4.22‰，其次为SO2-4(-2.64‰～-1.34‰)，第三为总硫(-3.25‰～-1.03‰)，最高为有机硫(-1.63‰～0.50‰)，随土壤剖面加深各形态硫δ |
| 英文摘要 |
| Sequential extraction methods for soil sulfur were used to determine δ34S ratios and sulfur contents of total sulfur,organic sulfur,SO2-4 and FeS2 in slope soils of karst areas. In general,FeS2 has the lowest δ34S ratios,ranging from -6.86‰ to -4.22‰,followed in ascending order by SO 2-4(-2.64‰--1.34‰),total sulfur (-3.25‰--1.03‰) and organic sulfur (-1.63‰-0.50‰) in surface soils of profiles,and δ34S ratios in different sulfur forms all show increasing trend with profiles deepening. Covariations of δ34S ratios of SO2-4 and FeS2 with increasing depth are related to SO2-4 dissimilatory reduction,while the increase in parallel of δ34S ratios of total sulfur and organic sulfur could be resulted from organic sulfur cycling. δ34S ratios have been extensively used to indicate sulfur sources,moreover,SO2-4 dissimilatory reduction and organic sulfur mineralization result in significant sulfur isotopic fractionation,and sulfides oxidation and SO2-4 assimilation have no isotopic fractionation occurred,the vertical variations of δ34S ratios in different sulfur forms can therefore be good records for depth-dependant sulfur cycling processes. Furthermore,by comparing depth distributions of sulfur contents and δ34S ratios in different sulfur forms,it is easily to discuss the migration of SO2-4 and organic sulfur fractions in soil profiles. |
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