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| 喀斯特坡地石灰土硫形态分布及其同位素组成特征 | |
| 引用本文： | 张伟,刘丛强,刘涛泽,李晓东,张丽丽.喀斯特坡地石灰土硫形态分布及其同位素组成特征[J].地球化学,2010,39(3):251-257. |
| 作者姓名： | 张伟 刘丛强 刘涛泽 李晓东 张丽丽 |
| 作者单位： | 1. 天津师范大学天津市水环境与水资源重点实验室,天津,300387 2. 中国科学院地球化学研究所环境地球化学国家重点实验室,贵州,贵阳,550002 3. 贵州师范大学化学与材料科学学院,贵州,贵阳,550001 |
| 基金项目： | 中国科学院西部行动计划项目，国家重点基础研究发展计划项目，天津市科技发展计划项目 |
| 摘 要： | 土壤中S形态及各形态硫化物的稳定S同位素组成的分布特征对于土壤S循环研究具有重要意义。利用S形态连续提取方法测定了喀斯特坡地石灰土总S、SO4^2- -S、S^0-S、FeS—S、FeS2-S和有机S含量及其δ^34S值。有机S是石灰土主要的S形态，占总S的76．5％～93．6％。总S和有机S含量随土壤深度加深而降低，这与有机S矿化有关，对应有机S的δ^34S值逐渐增大。总体来看，FeS2是石灰土主要的无机S形态，其次为SO4^2-、FeS和S^0。石灰土表层以下深度FeS2-S增加与SO4^2-异化还原反应速率增大有关，对应SO4^2-和FeS2的δ^34S值平行增大。深层土壤FeS2-S降低则主要与SO4^2-异化还原反应速率减小及无机S厌氧氧化有关。土壤各形态S含量及其δ^34S值的分布特征，可以记录与深度相关的S形态转化过程。值得注意的是，受石灰土类型、植被状况及地形特征等因素的影响，喀斯特坡地石灰土中SO4^2-、FeS2和有机S组分容易迁移，这也是石灰土中各形态S分布变异的主要原因。 |
| 关 键 词： | 喀斯特 坡地 石灰土 S形态 S同位素 |
Sulfur species and isotopic compositions in limestone soils on slopes of karst regions |
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| ZHANG Wei,LIU Cong-qiang,LIU Tao-ze,LI Xiao-dong,ZHANG Li-li.Sulfur species and isotopic compositions in limestone soils on slopes of karst regions[J].Geochimica,2010,39(3):251-257. | |
| Authors: | ZHANG Wei LIU Cong-qiang LIU Tao-ze LI Xiao-dong ZHANG Li-li |
| Institution: | Sulfur species and isotopic compositions in limestone soils on slopes of karst regions ZHANG Wei1,LIU Cong-qiang2*,LIU Tao-ze2,LI Xiao-dong2 and ZHANG Li-li3 1. Key Laboratory for Water Environment and Resources,Tianjin Normal University,Tianjin 300387,China,2. State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,3. School of Chemistry and Material Sciences,Guizhou Normal University,Guiyang 550001 |
| Abstract: | The distribution of sulfur species and coreesponding δ^34S values have important significances for study on sulfur cycling in soils. Sequential extraction methods for sulfur species were used to determine sulfur contents and δ^34S values of total sulfur, SO4^2--S, S^0-S, FeS-S, FeS2-S and organic sulfur in soils on slopes of karst regions. Organic sulfur was the dominant sulfur species in limestone soils, constituting 76.5% to 93.6% of the total sulfur. The decreases of total sulfur and organic sulfur contents with increasing depths are related to organic sulfur mineralization, which corresponded to the increase in δ^34S values of organic sulfur. FeS2 is generally the dominant inorganic sulfur fomls in limestone soils, followed by SO4^2-, FeS and S^0. The increases of FeS2-S contents with depths below the surface soils are related to increasing rate of dissimilatory sulfate reduction. Correspondingly, the δ^34S values of SO4^2- and FeS2 increase in parallel. The decrease in FeS2-S in deep soil layers might due to the decreasing rate of dissimilatory sulfate reduction, and anaerobic oxidation of inorganic sulfur. The distributions of sulfur contents and δ^34S values in different sulfur fomls can be used to record depth-dependant sulfur transformations. Nevertheless, the migrations of SO4^2- , FeS2 and organic sulfur fractions in limestone soils on slopes of karst areas, mainly affected by limestone soil types, vegetable status, topographical features etc., are easily occurred, which in turn are apparently causative of the variations in distributions of different sulfur species in limestone soils. |
| Keywords: | karst areas slopes limestone soils sulfur forms sulfur isotopes |
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